GB2061315A - Micellar Compositions and Their Use in Breaking Petroleum Emulsions - Google Patents

Abstract

A micellar composition comprises: (a) 5% to 75% by weight of a thin film spreading agent; (b) 2% to 30% by weight of a hydrotropic agent; (c) 2% to 30% by weight of an amphiphatic agent; and (d) 15% to 90% by weight of water. It is useful for breaking or preventing the formation of petroleum or bitumen emulsions, and thus is of value in the recovery of petroleum.

Description

SPECIFICATION Micellar Compositions and their Use in Breaking Petroleum Emulsions The invention relates to a new and improved micellar solution of a thin film spreading agent and which is particularly useful for breaking or preventing petroleum emulsions. More specifically, the invention relates to a composition in which water replaces all or a substantial part of the organic solvents formerly required for preparation of liquid solutions of this interfacially active compound.

One of the principal uses of the present composition is in the breaking of petroleum emulsion to permit the separation thereof into two bulk phases. Much of the crude petroleum oil produced throughout the world is accompanied by some water or brine which originates in or adjacent to the geological formation from which the oil is produced. The amount of aqueous phase accompanying the oil may vary from a trace to a very large percentage of the total fluid produced. Due to the natural occurrence in most petroleum of oil-soluble or dispersible emulsifying agents, much of the aqueous phase produced with oil is emulsified therein, forming stable water-in-oil emulsions.

The literature contains numerous references to such emulsion, the problems resulting from their occurrence, and the methods employed to break them and separate salable petroleum. See, for example, "The Technology of Resolving Petroleum Emulsions" by L. T. Monson and R. W. Stenzel, p.

535 et seq in Colloid Chemistry Vol VI, Ed. by Jerome Alexander, Rheinhold Publishing Corp., New York (1946) and "Interfacial Films Affecting the Stability of Petroleum Emulsions" by Chas. M. Blair, Jr. in Chemistry and Industry (London), p. 538 et seq (1960).

Early demulsifiers used to resolve petroleum emulsions were water-soluble soaps, Twitchell reagents, and sulfonated glycerides. These products were readily compounded with water to form easily pumpable liquids and were conveniently applied by pumping into flow lines at the well head or by washing down the casing annulus with water to commingle with well fluids prior to their flow to the surface. These products, however, were effective only at relatively high concentrations and their use added substantially to the cost of production.

Some time ago, it was discovered that certain lightly sulfonated oils, acetylated caster oils and various polyesters, all of which were insoluble in water but soluble in alcohols and aromatic hydrocarbons, were much more effective in breaking emulsions. Accordingly, essentially all commercial demulsifier development has led to production of agents which are insoluble in both water and petroleum oils and have other properties to be described below which cause them to spread at oilwater interfaces to form very thin, mobile films which displace any emulsifying agent present in the oil to allow coalescence of dispersed water droplets. Generally, such interfacially active compounds are hereafter referred to as Thin Film Spreading Agents, or "TFSA".In the past, these have had to be compounded with and dissolved in alcohols or highly aromatic hydrocarbon solvents in order to produce readily applied liquid compositions. A wide variety of such compositions are required to treat the many different emulsions encountered throughout the world.

While present TFSA compositions are highly effective, being, perhaps, up to fifty to a hundred times more effective per unit volume than the original water-soluble demulsifiers, they suffer serious practical deficiencies because of their solubility characteristics. For example, alcohols and the aromatic hydrocarbons, which are required for preparation of liquid, pumpable compositions are quite expensive, today approaching in cost that of the active demulsifier ingredient itself. Further, such solvents are flammable and thus create safety problems and entail more expense in shipping, storing and use. The low flash point flammability can be improved by using high boiling aromatic solvents, but these are increasingly rare, expensive and dangerous from the standpoint of carcinogenicity and dermatological effects.

Still further, present demulsifiers cannot generally be used in a subterranean oil or gas well, injection well, or the like, since they cannot be washed down with either water (or brine) or a portion of the produced oil, and, being viscous liquids which are required in very small amounts, they cannot be reliably and continuously delivered several thousand feet down at the fluid level in a typical well without use of elaborate and expensive delivery means.

Other applications of TFSA compositions would be facilitated if they were readily soluble or dispersible in water. For example much heavy, viscous oil is produced in the United States by steam injection procedures. Typically, wet steam is injected into the oil producing strata for several weeks in order to heat the oil, lower its viscosity and increase reservoir energy. Steam injection is then stopped and oil is flowed or pumped from the bore hole which was used for steam injection. Much of the water resulting from condensation of the steam is also produced with the oil in emulsified form.Since emulsions are more viscous than the external phase at the same temperature, and thus create increased resistance to flow, productivity of the steamed wells can be improved by injecting a watersoluble demulsifier into the wet steam during the steam injection period to prevent emulsion formation.

See, for example, U.S Patent 3,396,792, dated April 1, 1966, to F. D. Muggee. At present, the requirement of water solubility seriously limits the choice of demulsifiers for use in steam or water injection to the relatively inefficient composition.

As disclosed in our Applications Nos. 8,018,204, 8,018,205 and 8,018,206 TFSA's are useful in processes for enhanced recovery of petroleum. Used in such processes involving displacement of residual oil by aqueous solutions, polymer solutions and other aqueous systems, these agents act to increase the amount of oil recovered. Such action possibly arises from their ability to further water wetting of reservoir rock, lessen the viscosity of the oil-water interfacial layer and promote coalescence of dispersed droplets of either water or oil in the other phase.

By use of the present aqueous micellar-solutions, the introduction of TFSA into aqueous displacement or flooding fluids is greatly facilitated. In addition, the present micellar solutions, per se, or in combination with other components, can be used as the flooding agent or as a pretreating bank or slug ahead of other aqueous fluids.

Other applications for the present TFSA micellar solutions include their use as flocculation aids for finely ground hematite and magnetite ores during the desliming step of ore beneficiation, as additives for improving the oil removal and detergent action of cleaning compositions and detergents designed for use on polar materials, for the improvement of solvent extraction processes such as those used in extraction of antibiotic products from aqueous fermentation broths with organic solvents, for the improvement of efficiency and phase separation in the purification and concentration of metals by solvent extraction with organic solutions of metal complex-forming agents, and as assistants to improve the wetting and dying of natural and synthetic fibers and for other processes normally involving the interface between surfaces of differing polarity or wetting characteristics.

A primary object of the present invention is to provide aqueous, liquid compositions of these TFSA's having new and useful characteristics which allow production of: petroleum emulsion breakers and emulsion preventing compositions free or relatively free of highly flammable and environmentally objectionable aromatic hydrocarbons; compositions having a comparatively low cost, compositions which are soluble or dispersible in water and which, therefore, can often be applied by more effective methods than can existing products; compositions which can be used in enhanced recovery operations such as steam flooding and aqueous medium flooding where present products cannot be readily applied; and compositions which can be compounded with water-soluble reagents of other types, such as corrosion inhibitors, wetting agents, scale inhibitors, biocides, acids, etc., to provide multipurpose compounds for use in solving many oil well completion, production, transportation and refining problems.

In accordance with the present invention, these aims are accomplished by means of amphipathic agents which are capable of forming micellar solutions and which by this mechanism or other undefined actions, combined with those of a second essential component which will be referred to as a hydrotropic agent, are able to form homogeneous aqueous solutions containing a relatively wide range of concentrations of TFSA.

The TFSA compositions of the present invention can be broadly categorized by the following general characteristics: 1. Solubility in water and isooctane at about 250C is less than about 1% by volume; 2. Solubility parameter at about 250C is in the range of from between about 6.8 to about 8.5, with a majority in the range of from between- 7.0 and about 7.9; and 3. Spread at the interface between white, refined mineral oil and distilled water to form films having calculated thickness no greater than about 20 Angstroms at a spreading pressure of about 1 6 dynes per cm.

TFSA compositions having these properties are generally organic polymers or semi-polymers having molecular weights ranging from about 2,000 to about 100,000 and having structures containing a multiplicity of distributed hydrophilic and hydrophobic moieties arranged in linear or planar arrays which make them surface active and lead to their adsorption at oil-water interfaces to form very thin films.

Unlike most commonly encountered surface-active compounds, the present TFSA appears to be incapable of forming a micelle in either oil or water. The distributed and alternating occurrence of polar and nonpolar or hydrophilic and hydrophobic groups in the molecule apparently prevents the kind of organization required for micelle formation and thus impairs dispersion or solution in either water or low polarity organic solvents.

The TFSA's useful in the present invention have the previously recited properties: 1. The solubility in water and in isooctane at about 250C is less than about 1% by volume Solubility tests may be run by placing a 1 ml sample (or the weight of solid product calculated to have a volume of 1 ml) in a graduated cylinder of the type which may be closed with a ground glass stopper. Thereafter place 99 ml of water in the cylinder, close, place in a 250C water bath until thermal equilibrium is reached, and remove from the bath and shake vigorously for one minute. Return the sample to the bath for five minutes and then repeat the shaking procedure. Finally, return the sample to the bath and allow it to stand quietly for one hour. The cylinder contents should be carefully examined and any cloudiness or opacity of the liquid phase or the appearance of any sediment or undissolved material in the cylinder noted, thus indicating that the sample satisfied the requirement for insolubility in water.

Isooctane solubility is determined similarly by substituting this hydrocarbon for the water used above.

2. The Solubility Paramter (S.P.) at about 250C is from between about 6.9 and about 8.5, inclusive Methods of determination of solubility parameter are disclosed in Joel H. Hildebrand, "The Solubility of Nonelectrolytes", Third Edition, pgs. 425 et seq. However, a simplified procedure, sufficiently accurate for qualification of a useful TFSA composition may be utilized. Components of a give solubility parameter are generally insoluble in hydrocarbon (non-hydrogen-bonding) solvents having a lower solubility parameter than themselves. Therefore, the present composition should be insoluble in a hydrocarbon solvent of a solubility parameter of about 6.8.Since the solubility parameter of mixtures of solvents is an additive function of volume percentage of components in the mixture test solutions of the desired solubility parameters may be easily prepared by blending, for example, benzene (S.P. 9.1 5) and isooctane (S.P. 6.85) or perfluoro-n-heptane (S.P. 5.7).

A mixture of about 72 parts of benzene with about 28 parts of isooctane will provide a solvent having a solubility parameter of about 8.5 at room temperature (about 250C). Perfluoro-n-heptane has a solubility parameter of about 5.7 at 250C, so a mixture of 68 parts of this solvent with 32 parts of benzene provides a solvent with a solubility parameter of about 6.8, or isooctane of a solubility parameter 6.85 may be used.

When 5 ml of the TFSA are mixed with 95 ml of an 8.5 solubility parameter solvent at room temperature, a clear solution should result. When 5 ml of TFSA is mixed with a 6.85 solubility parameter solvent, a cloudy mixture or one showing phase separation should result. Solvent mixtures have a solubility parameter between about 7.0 and about 7.9 may be prepared as described above and utilized in a similar test procedure.

In interpreting the solubility parameter and other tests, it should be recognized that the TFSA consists not of a single material or compound but a cogeneric mixture of products containing a range of products of molecular weights distributed around the average molecular weight and even containing small amounts of the starting compounds employed in the synthesis. As a result, in running solubility and solubility parameter tests, very slight appearances of cloudiness or lack of absolute clarity should not be interpreted as a pass or a failure to pass the criteria. The intent of the test is to ensure that the bulk of the cogeneric mixture, i.e., 75% or more, meets the requirement.When the result is in doubt, the solubility tests may be run in centrifuge tubes allowing subsequent rapid phase separation by centrifuging, after which the separated non-solvent phase can be removed, any solvent contained in it can be evaporated, and the actual weight or volume of separated phase can be determined.

3. The TFSA should spread at the interface between distilled water and refined mineral oil to form films with thickness no greater than about 20 Angstroms (0.0020 micrometer) at a film pressure of about 16 dynes per cm (0.016 Newton per meter) Suitable methods of determining film pressure are disclosed in N. K. Adam, "Physics and Chemistry of Surfaces", Third Edition, Oxford University Press, London, 1941, pgs. 20 et seq, and C. M.

Blair, Jr., "Interfacial Films Affecting the Stability of Petroleum Emulsions", Chemistry and lndustry (London), 1 960, pgs. 538 et seq. Film thickness is calculated on the assumption that all of the TFSA remains on the area of interface between oil and water on which the product or its solution in a volatile solvent has been placed. Since spreading pressure is numerically equal to the change in interfacial tension resulting from spreading of a film, it is conveniently determined by making interfacial tension measurements before and after adding a known amount of TFSA to an interface of known area.

Alternatively, one may utilize an interfacial film balance of the Langmuir type such as that described by J. H. Brooks and B. A. Pethica, Transactions of the Faraday Society (1964), p.20 et seq,.

or other methods which have been qualified for such interfacial spreading pressure determinations.

In determining the interfacial spreading pressure of the TFSA products, I prefer to use as the oil phase a fairly available and reproducible oil such as a clear, refined mineral oil. Such oils are derived from petroleum and have been treated with sulfuric acid and other agents to remove nonhydrocarbon and aromatic constituents. Typical of such oils is "Nujol", distributed by Plough, Inc. This oil ranges in denstiy from about 0.85 to 0.89 and usually has a solubility parameter between about 6.9 and about 7.5. Numerous similar oils of greater or smaller density and viscosity are commonly available from chemical supply houses and pharmacies.

Other essentially aliphatic or naphthenic hydrocarbons of low volatility are equally usable and will yield similar values of spreading pressure. Suitable hydrocarbon oils appear in commercial trade as refined "white oils", "textile lubricants", "paraffin oil", and the like. Frequently, they may contain very small quantities of alpha-tocopherol (Vitamin E) or similar antioxidants which are oil-soluble and do not interfere with the spreading measurements.

While the existence of micelles and of oily or aqueous micellar solutions have been known for some time (see, e.g., "Surface Activity", Moilliet, Collie and Black, D. Van Nostrand 8 Co., New York (1961)) and are probably involved in many operations involving detergency where either oily (nonpolar) or earthy (highly polar) soil particles are to be removed, their utility in cooperation with hydrotropic agents for the present purposes is an unexpected and unpredicable discovery.

In U.S. Patent No. 2,356,205, issued August 22, 1944, to Chas. M. Blair, Jr. s Sears Lehman, Jr., a wide variety of micellar solutions designed to dissolve petroleum oils, bitumen, wax, and other relatively nonpolar compounds are described for purposes of cleaning oil formation faces and for effecting enhanced recovery of petroleum by solution thereof. At this early date, however, the use of micellar principles was not contemplated for the preparation of solutions of the relatively high molecular weight demulsifiers.

However, some of the principles disclosed in the above patent, omitting the main objective therein of dissolving relatively large amounts of hydrocarbons, chlorinated hydrocarbons, and the like, are applicable to preparation of the present compositions.

The four necessary components of the micellar solutions of TFSA are: 1. A micelle-forming amphipathic agent Such may be anionic, cationic, or nonionic and, if anionic or cationic, may be either in salt form or as the free acid or free base or mixtures thereof.

2. A hydrotropic agent This is a small to medium molecular weight semi-polar compound containing oxygen, nitrogen or sulfur and capable of forming hydrogen bonds. It is believed that such agents cooperate in some manner with the amphipathic agent to form clear or opalescent, stable compositions.

3. Water 4. TFSA Having the properties recited above.

In addition to these components, the micellar solutions may contain, but are not required to contain, salts, hydrocarbons, or small amounts of other inorganic or organic material. Such constituents may be impurities, solvents, or by-products of syntheses used in forming the hydrotropic agent, or may be additions found useful in forming the composition of this invention. As an example of the latter, small amounts of inorganic salts such as NaCI, Na2SO4, KNO3,CaCl2,a and the like, are sometimes helpful in promoting homogeneity with a minimum of amphipathic and hydrotropic agents.

They may also yield compositions of lower freezing point, a property useful when the composition is employed in cold climates. Similarly, ethylene glycol, methanol, ethanol, acetic acid, or similar organic compounds may be incorporated into the compositions to improve physical properties such as freezing point, viscosity, and density, or to improve stability.

As stated above, the micelle-forming amphipathic agents which may be used in preparing the aqueous solutions herein contemplated may be either cation active, anion-active, or of the nonelectrolytic type. Amphipathic agents generally have present at least one radical containing about 10 or more carbon atoms and not more than about 64 carbon atoms per molecule. This is true of the amphipathic agents employed in the present invention as a component of the vehicle or solvent or dispersant employed in the present compositions. The hydrophobic portions of these agents may be aliphatic, alicyclic, alkylalicyclic, aromatic, arylalkyl, or alkylaromatic. The preferred type of agents are those in which the molecule contains a long, uninterrupted carbon chain containing from 10 to 22 carbon atoms in length.Examples of suitable anion-active amphipathic agents include the common soaps, as well as materials such as sodium cetyl sulfate, ammonium lauryl sulfonate, ammonium di isopropyl naphthalene sulfonate, sodium oleyl glyceryl sulfate, mahogany and green sulfonates from petroleum or petroleum fractions or extracts, sodium stearamido-ethyl sulfonate, dodecylbenzene sulfonate, dioctyl sodium sulfosuccinate, sodium naphthenate, and the like. Other suitable sulfonates are disclosed and taught in U.S. Patent No. 2,278,171, issued February 17, 1942, to De Groote and Keiser.

Suitable cation-active compounds include cetyl pyridinium chloride, stearamidoethyl pyridinium chloride, trimethyl-heptadecyl ammonium chloride, dimethyl-pentadecyl sulfonium bromide, octadecylamine acetate, and 2-heptadecyl-3-diethylene diaminoimidazoline diacetate.

Suitable nonelectrolytic amphipathic agents include the oleic acid ester of nonaethylene glycol, the steric acid ester of polyglycerol, oxyethylated alkylphenols, and long chain alcohol ethers of polyethylene glycols.

It is of course; well known that amphipathic compounds are readily and commercially available, or can be readily prepared to exhibit the characteristics of more than one of the above mentioned types. Such compounds are disclosed in U.S. Patent No. 2,262,743 dated November 11, 1941, to De Groote, Keiser and Blair. For convenience, in such instances where a surface-active material may show the characteristics of more than one of the above described types, it is understood that it may be classified under either or both types.

The mutual solvent or hydrotropic agents of the solution utilized in the present invention are characterizable as compound of a hydrophobic hydrocarbon residue of comparatively low molecular weight combined with a hydrophilic group of low molecular weight and are free from surface-active properties. The hydrophobic residue may contain from 2 to 12 carbon atoms and may be alkyl, alicyclic, aromatic, or alkyl substituted alicyclic or aromatic, or may be the hydrocarbon portion of a heterocyclic or hydrocarbon substituted heterocyclic group. The hydrocarbon residue may have branched or normal chain structure, but no branch may have a length of more than 7 carbon atoms from the point of attachment to the hydrophilic residue, counting a benzene or cyclohexyl group as being equivalent in length to an aliphatic chain of three carbon atoms.Where the hydrocarbon residue consists of not more than 4 carbon atoms, structures of the normal primary alkyl type are preferred.

Where the residue is made up of more than four carbon atoms, then structures of secondary and tertiary types are also good where the second and third branches may be methyl or ethyl groups.

This hydrophobic hydrocarbon residue is combined either directly or indirectly with a hydrophilic group of one of the following groups: (a) A hydroxyl group which may be alcoholic, phenolic, or carboxylic; (b) An aldehyde group; (c) A carboxy amide group; (d) An amine salt group; (e) An amine group; and (f) An alkali phenolate group.

By "indirectedly combined with one of these groups" is meant that the hydrocarbon residue is combined as by etherification, esterification, or amidification, or the like, with another organic residue which contains not more than four carbon atoms and also one or more of the hydrophilic groups named above, provided that after said combination, at least one of the hydrophile groups remains free.

Specific examples illustrating this class of compounds are: Ethyl alcohol, n-amyl alcohol, alphaterpineol, p-cresol, cyclohexanol, n-butyraldehyde, benzaldehye, n-butyric acid, glycol monobutyrate, propyl lactate, mono n-butyl amine hydrochloride, n-propionamid, ethylene glycol mono nbutyl amine hydrochloride, n-propionamid, ethylene glycol mono n-butyl ether, pyridine, methylated pyridine, piperidine, or methylated piperidines.

The solubilizer (mutual solvent or hydrotropic compound above described) is essentially a semipolar liquid in the sense that any liquid whose polar character is no greater than that of ethyl alcohol and which shows at least some tendency to dissolve in water, or have water dissolved in it, is properly designated as semi-polar.

The solubilizer or semi-polar liquid indicated may be illustrated by the formula X-Z, in which X is a radical having 2 to 12 carbon atoms, and which may be alkyl, alicyclic, aromatic, alkylalicyclic, alkylaryl, arylalkyl, or alicyclicalkyl in nature, and may, furthermore, include heterocyclic compounds and substituted heterocyclic compounds. There is the added limitation that the longest carbon atom chain must be less than eight carbon atoms, and that, in such characterization, cyclic carbon atoms must be counted as one-half. Z represents:

where U and V are hydrogen or a hydrocarbon substituent and Me is an alklalie metal;

if X is a cyclic tertiary amine nucleus;

if X is a cyclic secondary amine nucleus.

The semi-polar liquid also may be indicated by the following formula: #X#Y#R#(Z)# Here X and Z have their previous significance, R is -CH2-, #2H4-, -C#H #= -C3H 6-or-C2H4-0- C2H4- and n is either one or two as the choice of R demands. Y is one of the following:

In general, these hydrotropic agents are liquids having dielectric constant values between about 6 and about 26, and have at least one polar group containing one or more atoms of oxygen, and/or nitrogen. It is significant, perhaps, that all of the solubilizers are of types known to be able to form hydrogen bonds.

The- choice of solubilizer or common solvent and its proportion in the mixture depends somewhat upon the amphiphatic agent used, the amount and kind of TFSA used, and the proportion of water used, and is best determined by preparing experimental mixtures on a small scale.

In some cases, it is desirable to include in the solution small amounts of acid, alkali, or inorganic salts, as it has been found that the presence of these electrolytes often gives solutions having greater stability and a wider range of miscibility with water and organic material. Excess acid, when used, will usually be in solutions containing a cation-active or nonelectrolytic wetting agent, but not exclusively so. Excess alkali, when used, will usually be in a solution containing anion-active wetting agents, but, again, not exclusively.

The TFSA utilized in this invention is generally an organic polymer or semi-polymer with an average molecular weight above about 800 and below about 30,000 and has a structure which will allow orientation on polar surfaces with much or most of the elements of the molecule in a thin plane. To be effectively adsorbed at oil-water or oil-rock interfaces and subsequently to be desorbed at water-rock interfaces, the TFSA must generally contain constituents which give it a highly distributed -hydrophile and hydrophobe character, and without such concentrations of either hydrophilic or hydrophobic groups as to produce water solubility or oil solubility, in the ordinary macroscopic sense. The TFSA also appears to differ from formerly used surfactants in that the effects on oil-water interfacial tensions as a function of concentration are limited.While spreading efficiently at such interfaces to form thin films with spreading pressures up to about 35 to 40 dynes per cm, addition or larger amounts of TFSA have relatively little effect on interfacial tension. Also, the present TFSA constituent of the micelle solution in contrast to formerly used surfactants, has relatively little or no tendency to stabilize either oil-in-water or water-in-oil emulsions when present in normal use amounts.

Usually the TFSA constituents applicable to the practice of the invention are organic molecules containing carbon, hydrogen and oxygen, although in some instances they may also contain sulfur, nitrogen, silicon, chlorine, phosphorous or other elements. Small amounts of inorganic material such as alkalies, acids or salts may appear in the compositions as neutralizing agents, catalyst residues or otherwise. The critical requirements for the TFSA compositions are not so much compositional as structural and physical.They must be made up of hydrophilic (polar) moieties usually ones capable of forming hydrogen bonds, such as hydroxyl, carbonyl, ester, ether sulfonium, amino, ammonium, phospho or similar hydrogen bonding groups, connected by or to hydrophobic groups, such as alkylene, alkyl, cycloalkyl, aryl, arylene, aralkyl, polyalkylene, polyalkylyne, combinations of such groups and such groups containing relatively non-polar substituents, such as hydrocarbon, chlorine, fluorine and the like.

Sometimes the hydrophobic moieties are larger and contain more atoms than the polar groups in the molecule, having a minimum of two carbon atoms in each group and up to as many as 36 carbon atoms, although the actual ratio of sizes depends greatly on the structure of the hydrophilic moiety.

Most commonly, the hydrophobic groups will contain 14 to 22 carbon atoms and will have linear or sheet-like conformations allowing for relatively flat orientation on surface.

Polar moieties other than hydrogen bonding ones are not exluded from these compositions and, indeed, may be deliberately included in some structures to improve adsorption and interfacial spreading tendencies. For example, quaternary ammonium groups, while incapable of forming hydrogen bonds, can improve spreading and interfacial adsorption in some applications by way of their highly ionized form which imparts cationic character to the molecules in which they occur and, via coulombic repulsion effects, can improve spreading in a film.

Generally, the TFSA constituents will contain at least two each of the required hydrophilic (polar) and hydrophobic moieties, per molecule and commonly will contain many more of each. The effective products, however; must have the three properties described above.

While, as pointed out above, the effective TFSA may be derived from a wide variety of chemical reactants and may contain numerous different groups or moieties, I have found that particularly effective products are those which are described in our applications 8018204,8018205 and 8018206.

Suitable TFSA's include compounds of the formula

wherein: A is an alkylene oxide group, -C1H210-; O O is oxygen; is a positive integer no greater than about 10: is a positive integer no greater than about 100; k is a positive integer no greater than about 100; N is nitrogen; R' is one of hydrogen, a monovalent hydrocarbon group containing less than about C", or [ A,H ] ; L is a positive integer no greater than about 100; R is a hydrocarbon moiety of a polyol, a primary or secondary amine, a primary or secondary polyamine, a primary or secondary amino alcohol, or hydrogen; and m+n is no greater than about 4 when R is other than hydrogen and one of m and n is zero and the other is unity when R is hydrogen, said polyether polyol at about 250C: (a) being less than about 1% by volume soluble in water and in isooctane; (b) having a solubility parameter in the range of between about 6.9 and about 8.5; and (c) spreading at the interface between distilled water and refined mineral oil to form a film having a thickness no greater than about 20 Angstroms at a film pressure of about 16 dynes per cm.

Alternatively, these TFSA constituents may be described as polyether polyols derivable by the reaction of an alkylene oxide containing less than about 10 carbon atoms with a member of the group consisting of polyols, amines, polyamines and amino alcohol containing from between about 2 to about 10 active hydrogen groups capable of reaction with alkylene oxides.

Compositions incorporated within the scope of the formula set forth above contain an average of about 13 or more hydroxyl groups per molecule and are generally composed of a cogeneric mixture of products obtained by condensing alkylene oxides with smaller molecules containing two or more reactive hydrogens as part of hydroxyl or amino groups.

Representative of these compositions is polypropylene glycol having an average molecular weight of about 1,200, to which about 20% by weight of ethylene oxide has been added. Such a polyether glycol is theoritically obtainable by condensing about 20 moles of propylene oxide with about one mole of water, followed by addition of about six moles of ethylene oxide. Alternatively, one may condense about 20 moles of propylene oxide with a previously prepared polyethylene glycol of about 240 average molecular weight.

Alkylene oxides suitable for use in preparing the TFSA constituents used in the present solutions include ethylene oxide, propylene oxide, butylene oxide, 2-3-epoxy-2-methyl butane, trimethylene oxide, tetrahydrofuran, glycidol, and similar oxides containing less than about 10 carbon atoms.

Because of their reactivity and relatively low cost, the preferred alkylene oxides for preparing effective TFSA constituents are the 1,2-alkylene oxides (oxiranes) exemplified by ethylene oxide, propylene oxide and butylene oxide. In the preparation of many TFSA constituents more than one alkylene oxide may be employed either as mixtures of oxides or sequentially to form block additions of individual alkylene oxide groups.

Other suitable dihydric alcohols may be obtained by condensing alkylene oxides or mixtures of oxides or in successive steps (blocks) with difunctional (with respect to oxide addition) compounds, such as ethylene glycol, methyl amine, propylene glycol, hexamethylene glycol, ethyl ethanolamine, analine, resorcinol, hydroquinone and the like.

Trihydric ether alcohols may be prepared by condensation of ethylene, propylene or butylene oxides with, for example, glycerol ammonia, triethanolamine, diethanolamine, ethyl ethylene diamine or similar smaller molecules containing three hydrogens capable of reacting with alkylene oxides.

Similarly, polyether alcohols with a multiplicity of hydroxyl groups may be obtained by condensing alkylene oxides with multireactive starting compounds, such as pentaerythritol, glycerol, N-monobutyl ethylene diamine, trishydroxymethylaminomethane, ethylene diamine, diethylenetriamine, diglycerol, hexamethylene diamine, decylamine and cyclohexylamine. DeGroote, in U.S. Patent No. 2,679,511, describes a number of amino derived polyols which he subsequently esterifies. Product 1 5-200, manufactured and sold by the Dow Chemical Company and derived by oxyalkylation of glycerol with a mixture of ethylene and propylene oxides, is an example of a commercially available polyol of the kind contemplated herein.

Generally, these compositions will have average molecular weights of 15,000 or less and will be derived from reactive hydrogen compounds having 1 8 or fewer carbon atoms and 10 or fewer reactive hydrogens.

Other general descriptions of suitable compounds coming within the scope of the structure detailed above, along with methods for carrying out the actual manufacturing steps, are disclosed in "High Polymers, Vol. XIII, Polyethers," edited by N. Gaylord, John Wiley a Sons, New York, 1963.

Effective TFSA with improved performance may be prepared by acylation of the polyether polyols described above with a mono- or polybasic carboxylic acid, acid anhydride, isocyanate, diisocyanate or other polyisocyanate. An especially useful TFSA may be made by reacting an approximately difunctinal polyether polyol with a difunctional carboxylic acid, acid anhydride or isocyanate to form a polymeric ester or urethane. However, polymerisation is not always required, and where effected is usually not carried to the point of including a very large number-of monomer units in the molecule.Frequently, effective reagents are obtained where residual, unreacted hydroxyl or carboxyl groups remain in the product or, where a polyisocyanate is used, one or more residual isocyanate groups or amino or substituted urea groups which result from reaction of residual end groups with water, followed by decarboxylation, may remain.

Examples of acylating agents suitable for preparing useful esters include acetic acid, acetic anhydride, butyric acid, benzoic acid, abietic acid, adipic acid, diglycollic acid, phthallic anhydride, fumaric acid, hydroxyacetic acid, itaconic acid, succinic acid, dimerised fatty acids and the like. We have found the most generally useful acylating agents to be the di and mono-basic acids and anhydrides containing less than 13 carbon atoms.

Examples of isocyanates useful for the acylation of a polyether polyol to produce an effective TFSA include methylisocyanate, phenyl isocyanate, cyclohexylmethylene isocyanate, and the like.

Especially useful reactants are polyisocyanates containing two or more isocyanate groups and including phenylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, 1 ,5-Naphthalene diisocyanate and polymethylenepolyphenyl isocyanates.

Following acylation reactions of polyether polyols with polyisocyanates, where a stoichiometric excess of the latter reactant is employed, remaining isocyanate groups may be left as such or may, by appropriate addition of water or monohydric alcohol, be converted to carbamic acid groups, which immediately undergo decarboxylation to yield residual amino groups, or carbamate groups.

Examples of acylated polyether polyols and their manufacturing procedures are well known to the art, as disclosed in U.S. Patent No. 2,454,808, issued November 30, 1948, to Kirkpatrick, U.S. Patent No. 2,562,878, issued August 7, 1951, to Blair, U.S. Patent No. 2,679,511, issued May 25, 1954, to DeGroote, U.S. Patent No. 2,602,061, issued July 1, 1952, also to DeGroote, "Chemical Process Industries", by R. N. Shreve, McGraw Hill Publishing Co., 1967, page 654 et seq., and "High Polymers", Vol Xlil, edited by N. G. Gaylord, John Wiley s Sons, 1963, page 317 et seq., the disclosure of each of which is hereby incorporated by reference.

Another suitable type of compound for use as the TFSA is a polyalkylene oxide adduct of a fusible, water-insoluble organic aromatic hydrocarbon solvent-soluble synthetic resin, wherein said resin has from between about 4 to about 15 phenolic groups and is an alkyl or cycloaliphatic substituted phenol-aldehyde condensate of an ortho- or para-substituted phenol and an aldehyde, said condensate resin being thereafter further condensed with an alkylene oxide containing less than | t abouve five carbon atoms in an amount equal to at least one mole of alkylene oxide per phenolic moeity of said resin. These adducts must conform to the physical property parameters set forth above.

These compositions are broadly described in U.S. Patent 2,499,365, entitled "Chemical Manufacture", dated March 7, 1950, to DeGroote et al. These compositions also include materials wherein less than one or two alkylene oxide units may be reacted with each reactive structural group of the starting resin.

The most common resin is an alkyl or cycloaliphatic substituted phenol-aldehyde resin prepared by condensing an ortho or para-substituted phenol with an aldehyde, most commonly with formaldehyde or a formaldehyde progenitor such as paraformaldehyde or trioxane, under mildly alkaline or acidic conditions to form a fusible and xylene-soluble polymer of low or moderate molecular weight and which typically will contain from between about 4 to about 12 phenolic groups. This resin is then condensed, usually with an alkaline catalyst, with an alkylene oxide or a mixture of alkylene oxides containing 4 or fewer carbon atoms and exemplified by ethylene oxide, propylene oxide, butylene oxide, glyceryl chlorohydrin, epichlorohydrin and glycidol.

To be suitable for use in the present process, addition and condensation of oxide must not be carried to the point of producing water- soluble products. Where ethylene oxide alone is condensed with the resin, the amount added preferably will be between one and five moles per phenolic moeity in the resin. The actual amount will vary with the si#e of the alkyl or cycloalkylene group attached to the phenol ring as well as, apparently, with the composition and properties of the oil, aqueous phase and rock formation encountered in the method.

Where propylene or butylene oxides or mixtures of one or both of these with ethylene oxide are condensed with the phenolic resin intermediate, generally a greater amount of such oxides may be reacted without leading to extremely polar, water-insoluble products. In contrast, the amount of epichlorohydrin or glycerol chlorohydrin which can be condensed without producing agents not meeting the solubility and interfacial spreading criteria defined above is usually somewhat lower.

On a solvent-free weight basis, the amount of alkylene oxide or mixture of oxides condensed with the resin will fall within the range of about one part oxides to about 1 0 parts of resin and up to from between about 1-to-5 and about 3-to-1. The final product should contain at least about one mole of alkylene oxides per phenolic moeity of the resin.

The compositions suitable for practicing the present invention are prepared by reacting formaldehyde or a substance which breaks down to formaldehyde under the reaction conditions, e.g., paraformaldehyde and trioxane, and a difunctional, with respect to reaction with formaldehyde, alkyl phenol, often a crude mixture of alkyl phenols for economic reasons, by heating the reactants between about 1000 and about 1 250C in the presence of a small amount of an acid catalyst such as sulfamic acid or muriatic acid or, alternatively, in the presence of an alkaline catalyst such as sodium hydroxide or sodium methylate and, preferably, under substantially anhydrous conditions, excepting the water produced during the reaction. The aqueous distillate which begins to form is collected and removed from the reaction mixture. After several hours of heating at temperatures slightly above the boiling point of water, the mass becomes viscous and is permitted to cool to about 1 00#-1 050C. At this point, an aromatic hydrocarbon fraction such as xylene may be added, and heating is resumed. Further aqueous distillate begins to form, and heating is continued for an additional number of hours until at 5 10 15 20 25 30 least about one mole of aqueous distillate per mole of the formaldehyde has been distilled off. Xylene or other hydrocarbon which may be distilled with the water is returned to the reaction mass. The temperature at the end of the reaction reaches about 1 800--2 500C. The product is permitted to cool to yield the phenol-formaldehyde condensation product in the aromatic solvent.

The molecular weight of these intermediate condensation products cannot be ascertained with certainty, but it is estimated that the resins employed herein should contain from between about 4 to about 1 5, preferably from about 4 to about 6, phenolic nuclei per resin molecule. The solubility of the condensation product in hydrocarbon solvent would indicate that the resin is a linear or sheet-like polymer, thus distinguishing it from the more common phenol-formaldehyde resins of the insoluble cross-linked type.

Having prepared the intermediate phenol-formaldehyde products, the next step is the oxyalkylation of the condensation products with alkylene oxide. This is achieved by mixing the intermediate phenol-formaldehyde condensation product as is or contained in the aromatic solvent with a small amount of a suitable catalyst, usually potassium hydroxide or sodium methylate, in an autoclave. The condensation product is heated above 1000C, and ethylene oxide, propylene oxide, butylene oxide or mixtures of two or all three of these oxides, either as a mixture or by sequential addition of first either one or another of the oxides is charged into the autoclave until the pressure is in the vicinity of 75-100 psi.

The reaction mixture is gradually heated until an exothermic reaction begins. The external heating is then removed, and alkylene oxide or oxide mixture is added at such a rate that the temperature is maintained between about 1300--1 600C in a pressure range of 30-1 00 psi. After all of the alkylene oxide has been added, the temperature is maintained for an additional 10 to 20 minutes to assure substantially complete reaction of the alkylene oxide.The resulting product is the alkylene oxide adduct of an alkyl phenol-formaldehyde condensation product, in which the weight ratio of the oxide to the condensation product (on a solvent-free basis) is between about 1 -to-1 0 and about 10-to-1, preferably between about 1-to-5 and about 3-to-1, and containing at least about one mole of alkylene oxide per phenolic moiety of the resin.

Another suitable type of compound for use as the TFSA is a polyepoxide condensate of at least one of (1) a polyalkylene oxide adduct formed by condensation of an alkylene oxide containing less than 5 carbon atoms with a fusible water insoluble organic aromatic hydrocarbon solvent-soluble resin that is a condensate of an aldehyde with a phenol that is ortho- or para-substituted by alkyl or cycloaliphatic and that contains 4 to 15 phenolic groups, the amount of alkylene oxide being at least one mole per phenolic moiety, and (2) a polyether polyol of the formula:

35 40 45 50 55 wherein:: A is an alkylene oxide group, -C1H210-; O is oxygen; is a positive integer of from 2 to 10; is a positive integer no greater than about 100; k k is a positive integer no greater than about 100; N is nitrogen; R' is one of hydrogen, a monovalent hydrocarbon group containing less than about C", or [ A,H ] ; L is a positive integer no greater than about 100, and R is a hydrocarbon moiety of a polyol, a primary or secondary amine, a primary or secondary polyamine, a primary or secondary amino alcohol, or is hydrogen. When R is hydrogen one of m and n is zero.

m+n is no greater than 10 and preferably no greater than about 4 when R is other than hydrogen and when R is hydrogen one of m and n is zero and the other is preferably unity.

Suitable polyalkylene oxide adducts for use as component (1) are described in U.S. Patent No.

2,499,365. These compositions also include materials wherein less than one or two alkylene oxide units may be reacted with each reactive structural group of the starting resin.

The most common resin is an alkyl or cycloaliphatic substituted phenol-aldehyde resin prepared by condensing an ortho- or para-mono or poly substituted phenol with an aldehyde, most commonly with formaldehyde or a formaldehyde progenitor such as paraformaldehyde or trioxane, under mildly alkaline or acidic conditions to form a fusible and xylene-soluble polymer of low or moderate molecular weight and which typically will contain from between about 4 to about 12 phenolic groups. This resin is then condensed, usually with an alkaline catalyst, with an alkylene oxide or a mixture of alkylene oxides.

Alkylene oxides suitable for use in preparing the compositions used in the present process include 5 10 15 20 25 30 35 40 45 50 55 ethylene oxide, propylene oxide, butylene oxide, 2-3-epoxy-2-methyl butane, trimethylene oxide, tetrahydrofuran, glycidol, and similar oxides containing less than about 10 carbon atoms. Because of their reactivity and relatively low cost, the preferred alkylene oxides for preparing effective TFSA's are the 1,2-alkylene oxides (oxiranes) exemplified by ethylene oxide, propylene oxide and butylene oxide.

In the preparation of many TFSA's more than one alkylene oxide may be employed either as mixtures of oxides or sequentially to form block additions of individual alkylene oxide groups.

To be suitable for use in the present process, addition and condensation of oxide must not be carried to the point of producing water-soluble products. Where ethylene oxide alone is condensed with the resin, the amount added preferably will be between one and five moles per phenolic moiety in the resin. The actual amount will vary with the size of the alkyl or cylcoalkylene group attached to the phenol ring as well as, apparently, with the composition and properties of the oil, aqueous phase and rock formation encountered in the method.

Where propylene or butylene oxides or mixtures of one or both of these with ethylene oxide are condensed with the phenolic resin intermediate, generally a greater amount of such oxides may be reacted without leading to extremely polar, water-soluble products. In contrast, the amount of epichlorohydrin or glycerol chlorohydrin which can be condensed without producing agents not meeting the solubility and interfacial spreading criteria defined above is usually somewhat lower.

On a solvent-free weight basis, the ratio of alkylene oxide or mixture of oxides to the resin will.

generally fall within the range of about 1:10 to 10:1, generally from 1 :5 to 3:1. The final product should contain at least about one mole of alkylene oxides per phenolic moiety of the resin and may contain between 1 and 5 moles alkylene oxide.

Suitable materials for use as component (1) may be prepared by reacting formaldehyde or a substance which breaks down to formaldehyde under the reaction conditions, e.g. para-formaldehyde and trioxane, and a difunctional, with respect to reaction with formaldehyde, alkyl phenol, often a crude mixture of alkyl phenols for economic reasons, by heating the reactants between about 1000 and about 1 250C in the presence of a small amount of an acid catalyst such as sulfamic acid or muriatic acid or, alternatively in the presence of an alkaline catalyst such as sodium hydroxide or sodium methylate and, preferably, under substantially anhydrous conditions, excepting the water produced during the reaction. The aqueous distillate which begins to form is collected and removed from the reaction mixture.After several hours of heating at temperatures slightly above the boiling point of water, the mass becomes viscous and is permitted to cool to about 1 000#1 050C. At this point, an aromatic hydrocarbon fraction such as xylene may be added, and heating is resumed. Further aqueous distillate begins to form, and heating is continued for an additional number of hours until at least about one mole of aqueous distillate per mole of the formaldehyde has been distilled off. Xylene or other hydrocarbon which may be distilled with the water is returned to the reaction mass. The temperature at the end of the reaction reaches about 1 800--2500C. The product is permitted to cool to yield the phenol-formaldehyde condensation product in the aromatic solvent.

The molecular weight of these intermediate condensation products cannot be ascertained with certainty, but it is estimated that the resins employed herein should contain from between about 4 to about 1 5, preferably from about 4 to about 6, phenolic nuclei per resin molecule. The solubility of the condensation product in hydrocarbon solvent would indicate that the resin is a linear or sheet-like polymer, thus distinguishing it from the more common phenol-formaldehyde resins of the insoluble cross-linked type.

Having prepared the intermediate phenol-formaldehyde products the next step is the oxyalkylation of the condensation products with alkylene oxide. This is achieved by mixing the intermediate phenol-formaldehyde condensation product as is or contained in the aromatic solvent with a small amount of a suitable catalyst, usually potassium hydroxide or sodium methylate, in an autoclave. The condensation product is heated above 1000C, and ethylene oxide, propylene oxide, butylene oxide or mixtures of two or all three of these oxides, either as a mixture or by sequential addition of first either one or another of the oxides is charged into the autoclave until the pressure is in the vicinity of 75-100 psi.

The reaction mixture is gradually heated until an exothermic reaction begins. The external heating is then removed, and alkylene oxide or oxide mixture is added at such a rate that the temperature is maintained between about 1 300--1 600C in a pressure range of 30-100 psi. After all of the alkylene oxide has been added, the temperature is maintained for an additional 10 to 20 minutes to assure substantially complete reaction of the alkylene oxide. The resulting product is the alkylene oxide adduct of an alkyl phenol-formaldehyde condensation product, in which the weight ratio of the oxide to the condensation product (on a solvent-free basis) is between about 1 -to-1 0 and about 10-to-1, preferably between about 1 -to-5 and about 3-to-1, and containing at least about one mole of alkylene oxide per phenolic moiety of the resin.

Suitable polyether polyols for use as component (2) generally contain an average of about 13 or more hydroxyl groups per molecule and are generally composed of a cogeneric mixture of products obtained by condensing alkylene oxides with smaller molecules containing two or more reactive hydrogens as part of hydroxyl or amino groups.

Representative of these compositions is polypropylene glycol, having an average molecular weight of about 1,200, to which about 20% by weight of ethylene oxide has been added. Such a polyether glycol is theoretically obtainable by condensing about 20 moles of propylene oxide with about one mole of water, followed by addition of about six moles of ethylene oxide. Alternatively, one may condense about 20 moles of propylene oxide with a previously prepared polyethylene glycol of about 240 average molecular weight.

Other suitable dihydric alcohols may be obtained by condensing alkylene oxides or mixtures of oxides or in successive steps (blocks) with difunctional (with respect to oxide addition) compounds, such as ethylene glycol, methyl amine, propylene glycol, hexamethylene glycol, ethyl ethanolamine, analine, resorcinol, hydroquinone and the like.

Trihydric ether alcohols may be prepared by condensation of ethylene, propylene or butylene oxides with, for example, glycerine ammonia, triethanolamine, diethanolamine, ethyl ethylene diamine or similar smaller molecules containing three hydrogens capable of reacting with alkylene oxides.

Similarly, polyether alcohols with a multiplicity of hydroxyl groups may be obtained by condensing alkylene oxides with multireactive starting compounds, such as pentaerythritol, glycerol, Nmonobutylethylene diamine, trishydroxymethylaminomethane, ethylene diamine, diethylenetriamine, diglycerol, hexamethylene diamine, decylamine and cylcohexylamine. DeGroote, in U.S. Patent No.

2,679,511, describes a number of amino derived polyols which he subsequently esterifies. Product 15-200, manufactured and sold by the Dow Chemical Company and derived by oxyalkylation of glycerol with a mixture of ethylene and propylene oxides, is an example of a commercially available polyol of the kind contemplated herein.

Generally, these compositions will have average molecular weights of 15,000 or less and will be derived from reactive hydrogen compounds having 18 or fewer carbon atoms and 10 or fewer reactive hydrogens.

Other general descriptions of suitable polyether polyols coming within the scope of the structure detailed above, along with methods for carrying out the actual manufacturing steps, are disclosed in "High Polymers, Vol. XIII, Polyethers," edited by N. G. Gaylord, John Wiley s Sons, New York, 1963.

Suitable polyepoxide for condensation with components 1 or 2 discussed above include, particularly, the diglycidyl ether of dihydroxyphenyl- methylmethane and the lower polymers thereof, which may be formed as cogeneric mixtures and which have the general formula:

where n is zero of a positive integer of less than about 6.

Other poiyepoxides containing two or more oxirane or epoxy groups, such as diisobutenyl dioxide, polyepoxypolyglycerols, epoxidized linseed oil, epoxidized polybutadiene or the like, may also be employed.

As to the limits of the various constituents of the micellar solutions containing TFSA, the following will serve as a guide, the percentages being by weight: Percent TFSA Constituents about 5 to about 75 Hydrotropic Agent about 2 to about 30 Amphipathic Agent about 2 to about 30 Water about 15 to about 90 Although the exact function of the electrolytes previously referred to is not completely understood, the effect, in part, may be due to the ability to bind water, i.e., to become hydrated. This suggests that certain other materials which are highly hydrophile in character and clearly differentiated from the classes of non-polar solvents and semi-polar solubilizers may be the functional equivalent of an electrolyte. Substances of this class which ordinarily do not dissociate include glycerol, ethylene glycol, diglycerol, sugar, glucose, sorbitol, mannitol, and the like.

Also, as stated above, these solutions may contain other organic constituents such as hydrocarbons. These frequently are used as thinning agents, azetropic distillation aids or reflux temperature controllers in the manufacture of the TFSA constituents and may be left therein when the present micellar solutions are prepared. To the extent that such compounds are present they appear to compete somewhat with the TFSA constituent for micelle space, thus limiting, to some extent, the maximum amount of TFSA constituent which can be brought into homogeneous solution.

Selection of an effective TFSA composition for a given petroleum emulsion and determination of the amount required is usually made by so-called "bottle tests", conducted, in a typical situation, as follows: A sample of fresh emulsion is obtained and 100 ml portions are poured into each of several 180 ml screw top prescription or similar graduated bottles. Dilute solutions (1% to 2%) of various TFSA constituents are prepared in isopropyl alcohol. By means of a graduated pipette, a small volume of a TFSA solution is added to a bottle. A similar volume of each composition is added to other bottles containing emulsion. The bottles are then closed and transferred to a water bath held at the same temperature as that employed in the field treating plant. After reaching this temperature, the bottles are shaken briskly for several minutes.

After the shaking period, the bottles are placed upright in the water bath and allowed to stand quietly. Periodically, the volume of the separated water layer is recorded along with observations on the sharpness of the oil-water interface, appearance of the oil and clarity of the water phase.

After the standing period, which may range from 30 minutes to several hours, depending upon the temperature, the viscosity of the emulsion and the amount of TFSA compositions used, small samples of the oil are removed by pipette or syringe and centrifuged to determine the amount of free and emulsified water left in the oil. The pipette or syringe used to remove the test samples should be fitted through a stopper or other device which acts as a position guide to insure that all bottles are sampled at the same fluid level.

The combined information on residual water and emulsion, speed of the water separation and interface appearance provides, the basis for selection of the generally most effective TFSA constituent.

Where none of the results are satisfactory, the tests should be repeated using higher concentrations of TFSA constituents and, conversely, where all results are good and similar, the tests should be repeated at lower concentrations until good discrimination is possible.

In practicing the process for resolving petroleum emulsions of the water-in-oil type with the present micellar solution, such solution is brought into contact with or caused to act upon the emulsion to be treated, in any of the various methods or apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulate a volume of emulsified oil in a tank and conduct a batch treatment type of demulsification procedure to recover the clean oil. In this procedure, the emulsion is admixed with the micellar TFSA solution, for example, by agitating the tank of emulsion and slowly dripping the micellarTFSA solution into the emulsion. In some cases, mixing is achieved by heating the emulsion while dripping in the micellar TFSA solution, depending upon the convection currents in the emulsion to produce satisfactory admixture. In a third modification of this type of treatment, a circulating pump withdraws emulsion from, e.g., the bottom of the tank and reintroduces it into the top of the tank, the micellar TFSA solution being added, for example, at the suction side of said circulating pump.

In a second type of treating procedure, the micellar TFSA solution is introduced into the well fluids at the wellhead, or at some point between the wellhead and the final oil storage tank, by means of an adjustable proportioning mechanism or proportioning pump. Ordinarily, the flow of fluids through the subsequent lines and fittings suffices to produce the desired degree of mixing of micellar TFSA solution and emulsion, although, in some instances, additional mixing devices may be introduced into the flow system. In this general procedure, the system may include various mechanical devices for withdrawing free water, separating entrained water, or accomplishing quiescent settling of the chemically treated emulsion. Heating devices may likewise be incorporated in any of the treating procedures described herein.

A third type of application (down-the-hole) of ImicellarTFSA solution to emulsion is to introduce the micellar solution either periodically or continuously in diluted form into the well and to allow it to come to the surface with the well fluids, and then to flow the chemical-containing emulsion through any desirable surface equipment, such as employed in the other treating procedures. This particular type of application is #especially useful when the micellar solution is used in connection with acidification of calcareous oil-bearing strata, especially if dissolved in the acid employed for acidification.

In all cases, it will be apparent from the foregoing description, the broad process consists simply in introducing a relatively small proportion of micellar TFSA solution into a relatively large proportion of emulsion, admixing the chemical and emulsion either through natural flow, or through special apparatus, with or without the application of heat, and allowing the mixture to stand quiescent until the undesirable water content of the emulsion separates and settles from the mass.

Besides their utility for breaking petroleum emulsions, the present micellar TFSA solutions, as mentioned earlier, may be used to prevent emulsion formation in steam flooding, in secondary waterflooding, in acidizing of oil-producing formations, and the like.

Petroleum oils, even after demulsification, may contain substantial amounts of inorganic salts, either in solid form or as small remaining brine droplets. For this reason, most petroleum oils are desalted prior to refining. The desalting step is effected by adding and mixing with the oil a few volume percentages of fresh water to contact the brine and salt. In the absence of demulsifier, such added water would also become emulsified without effecting its washing action. The present micellar solutions may be added to the fresh water to prevent its emulsification and to aid in phase separation and removal of salt by the desalting process. Alternatively, if desired, they may be added to the oil phase as are present aromatic solvent compositions.

Most petroleum oil, along with its accompanying brines and gases, is corrosive to steel and other metallic structures with which it comes in contact. Well tubing, casing, flow lines, separators and lease tanks are often seriously attacked by well fluids, especially where acidic gases such as H2S or CO2 are produced with the liquids, but also in systems free of such gases.

It has been known for some time, and as exemplified in U.S. Patent 2,466,517, issued April 5, 1949, to Chas. M. Blair and Wm. F. Gross, that such corrosive attack of crude oil fluids can be mitigated or prevented by addition to the fluids of small amounts of organic inhibitors. Effective inhibitors compositions for this use are usually semi-polar, surface active compounds containing a nonpolar hydrocarbon moiety attached to one or more polar groups containing nitrogen, oxygen or sulfur or combinations of such elements. Generally these inhibitors or their salts are soluble in oil and/or water (brine) and frequently appear to be able to form micelles in one or both of these phases.Typical inhibitors include amines such as octyl amine, dodecyl amine, dioctodecyl amine, butyl naphthyl amine, dicyclohexyl amine, benzyl dimethyldodecyl ammonium chloride, hexadecylaminopropyl amine, decyloxypropyl amine, mixed amines prepared by hydrogenation of nitrile derivatives of tall oil fatty acids, soya acid esters of monoethanol amine, 2-undecyl, 1-amino ethyl imidazoline and a wide variety of cationic nitrogen compounds of semi-polar character. Also effective in some applications are nonyl succinic acid, dioctylnaphthalene sulfonic acid, trimeric and dimeric fatty acids, propargyl alcohol, mercaptobenzothiozole, 2, 4, 6-trimethyl-1, 3, 5-trithiaane, hexadecyldimethyl benzimidazolium bromide, 2-thio-butyl-N-tetrodecylpyridinium chloride, tetrahydronaphthylthiomorpholine, and the like.

In contrast to the TFSA, corrosion inhibitors appear to function by forming on the metal surface strongly adherent, thick, closely packed films which prevent or lessen contact of corrosive fluids and gases with the metal and interfere with ionic and electron transfer reactions involved in the corrosion process.

Corrosion inhibitors are quite commonly introduced down the casing annulus of oil wells where they commingle with the well fluids before their travel up the well tubing and thus can effectively prevent corrosion of well equipment. Where corrosive attack occurs at the surface, the inhibitor may be introduced at or near the well head, allowing it to adsorb on the flow lines and surface equipment to insure protection.

Addition of inhibitor at either downhole or surface locations may be combined conveniently with demulsifier addition since the latter is also frequently introduced in one of these locations.

Inhibitors such as those mentioned above, may generally be incorporated into the TFSA micellar solutions, replacing a portion of or in addition to the TFSA constituent. Also, since many of these inhibitors are themselves micelle-forming amphipathic agents, they may be included in the micellar solution as such, replacing other amphipathic agents which might be otherwise utilized. Combining the micellar solution with corrosion inhibitor permits more economic chemical treatment by reducing inventory to one compound, requiring only one chemical injection system rather than two and lessening the labor and supervision required.

Still another important effect of using the micellar solution of TFSA and corrosion inhibitor results from the prevention of emulsification by the inhibitor. Frequently, it has been found that inhibitor in the amount required for effective protection causes the formation of very refractive emulsions of water and hydrocarbon, especially in systems containing light, normally nonemulsifying hydrocarbons such as distillate, casing head gasoline kerosene, diesel fuel and various refinery fractions. Inhibitors are commonly used in refinery systems where emulsification is highly objectionable and where the compositions could be designed to include an effective emulsion preventative micellar solution of TFSA.

Inhibitor use may range from a few to several hundred parts per million based on the oil to be treated, depending upon the severity of corrosion. For a given oil field or group of wells, tests will normally be run to determine the requirement for micellar solution of TFSA and for inhibitor and a composition incorporating these components in approximately the desired ratio will be prepared. In some instances, the requirement for micellar solution of TFSA in the best concentration may result in use of corrosion inhibitor, employed as micelle-former, in some excess over that required for inhibition.

This will not affect the utility of the micellar solution and will provide a comfortable excess of inhibition which can be helpful during the periods when higher corrosivity may be encountered.

Examples of micellar solutions employing TFSA with inhibitor in water dispersible, micellar solutions are given below.

Selection of the proper corrosion inhibitor for a given system or oil is usually made by conducting laboratory tests under conditions simulating those encountered in the well or flowline. Such tests are exemplified by that described in Item No. 1 K1 55, "Proposed Standardized Laboratory Procedure for Screening Corrosion Inhibitor for Oil and Gas Wells", published by the National Association of Corrosion Engineers, Houston, Texas.

Examples of Thin Film Spreading Agents Example 1 To an autoclave equipped with a means of mechanical stirring, heating, and cooling, 4.7 parts of dipropylene glycol and 0.25 parts potassium hydroxide were added. The contents of the autoclave were heated to 1 250C. At this temperature, 1,2-propylene oxide was slowly introduced from a transfer bomb which contained 200 parts of 1,2-propylene oxide. Cooling was applied during the addition to maintain the temperature below 1 300C with a pressure of 60-75 psi. Approximately two hours were required to introduce the 1,2-propylene oxide. The reaction mass was maintained at 1 300C for four hours to ensure that the unreacted 1,2-propylene oxide was at a minimum.Five parts of ethylene oxide were then added from a transfer bomb at such a rate that the temperature was maintained between 1 500--1600C with a pressure of 60-75 psi. After all of the ethylene oxide had been added, the temperature was held at 1 500C for an additional hour to complete the reaction. The molecular weight of the final product was approximately 4,000.

This product is insoluble in water and diisobutylene, has a Solubility Parameter of 7.2 and spreads at the distilled water-mineral oil interface to yield a spreading pressure of 21 dynes per cm at a calculated thickness of 10 Angstroms.

Example 2 In an apparatus similar to that of Example 1, 9.2 parts of glycerol were reacted with 275 parts of a mixture of 225 propylene oxide and 50 parts of ethylene oxide, using the same procedure as that employed in Example II of co-pending application 8018205 the disclosure of which is hereby incorporated by reference The final product was a clear, almost colorless viscous oil having a molecular weight of about 3,000. This product was not soluble to the extent of 1% in water or diisobutylene. It has a solubility parameter of 7.5 and spread at the distilled water-mineral oil interface to yield a pressure of 20 dynes per cm with a calculated film thickness of 12 Angstroms.

Example 3 Using the apparatus and procedure of Example l,4,000 Ibs. of polypropylene glycol of average molecular weight 1,200 was condensed with 700 Ibs. of ethylene oxide. Forty pounds of potassium hydroide was dissolved in the polypropylene glycol prior to oxide addition, which was carried out within the temperature range of about 1400--1600C under a maximum pressure of about 75 psi.

This product, on cooling to room temperature, was found to be insoluble to the extent of 1% in water and isooctane, to have a solubility parameter of 8.0 and to spread at a white oil-distilled water interface at 250C to form a film exerting a spreading pressure of 16 dynes per cm with a calculated film thickness of 20 Angstroms.

Example 4 To a 200 gal. vessel equipped like the larger one of Example I, was placed 175 Ibs. of diethylene triamine. The temperature was raised to 11 00C and propylene oxide was slowly admitted at a rate sufficient to raise the temperature by way of the heat of reaction to about 1400 C. Cooling was then applied to maintain this temperature until 700 Ibs. of propylene oxide had been added. At this point the contents of the vessel were cooled to 700C and pumped into a 2,000 gal. stainless steel vessel similar to that of Example I.

Nine pounds of flake caustic potash was stirred into the vessel contents. Pure nitrogen was blown through the liquid contents to remove water and the temperature was raised to 1 1 OOC. The vessel was then closed, the nitrogen valve was closed and propylene oxide was again pumped into the reaction mass at a rate sufficient to bring the temperature to about 1 400#1 600 C. Such addition was continued until the rate of oxide addition fell to two Ibs. per minute. The vessel was then opend briefly and an additional 25 Ibs. of flake caustic potash was introduced followed by 30 minutes of nitrogen sparging.

Propylene oxide was again pumped into the reaction mass until the total of all propylene oxide additions came to 8,000 Ibs. At this point the propylene oxide addition was stopped and ethylene oxide was introduced at a rate sufficient to maintain a liquid temperature of about 1400--1500C or until a total of 900 Ibs. had been added.

The cooling system was then activated to reduce the temperature to about 400C at which point the product was pumped to store.

This product met the three criteria for a suitable TFSA recited above.

Example 5 Two Hundred pounds of triethanolamine were substituted for the diethylene triamine of Example 4. The synthesis procedure was followed except that the 9 Ibs. of flake caustic potash was stirred into the triethanolamine prior to the addition of propylene oxide.

The final product met the required criteria for the TFSA.

Example 6 3,000 Ibs. of the product of Example 2 were placed in a 1,000 gal. stainless steel reaction vessel equipped with a gas-fired heater, an overhead outlet pipe connected through a condenser to a steam eductor and having an efficient, heavy duty stirrer. 220 Ibs of adipic acid were added after which the vessel was closed, the stirrer was started and heating was initiated. The temperature was gradually increased to 1400C and held at this point for 3 hours during which about 28 Ibs. of water were distilled over from the reaction vessel and condensed. The steam ejector system was then activated and adjusted to maintain a vacuum of about 26 inches of mercury while heating was continued at 1 400C for another 1 qg hours. About 4 Ibs. of additional water condensate were collected.The final product was a pale, viscous oil having an acid number of 14 and was found to meet the three spreading and solubility criteria as set forth above.

Example 7 Using the apparatus of Examples 2 and 6 with the condenser arranged for reflux, 2750 Ibs. of the product of Example 2 and 2,250 Ibs. of commercial mixed xylene were placed in the reactor. The mixture was stirred to effect solution of polyether glycol in the xylene while the temperature was brought to about 800 C. An inlet feed line to the reactor was then opened and a 10% solution in xylene of toluene diisocyanate was pumped slowly through the line to the reactor at a rate to deliver 1,100 Ibs. of solution during a 26 hour period. The temperature was maintained at 800C during this addition.

The value was then closed and the temperature brought to 1 400C where it was held until a sample of reaction product taken from the vessel was found to have a viscosity within the range of 2,500 to 3,500 centipoises at a temperature of 1000C. At this point, heating was discontinued and cooling water was circulated through the internal coils of the reactor to bring about rapid cooling of the product The final product met the three required tests for a TFSA compound, as set forth above, being soluble to an extent of less than 1% in water and isooctane, having a solubility parameter of 8.4 and spreading at the interface between distilled water and refined mineral oil to give a spreading pressure of 20 dynes per cm when the amount on the surface has a thickness of 17 Angstroms.

Example 8 1 50 Ibs. of maleic anhydride was substituted for the 220 Ibs. of adipic acid in Example 3 while maintaining the same operating procedure. Only about 7 Ibs. of aqueous distillate were obtained in this case. The product was a viscous, slightly yellow oil.

Example 9 To an autoclave equipped with a means of mechanical stirring, heating and cooling, 4.7 parts of dipropylene glycol and 0.25 parts potassium hydroxide were added. The contents of the autoclave were heated to 1 250C. At this temperature, 1,2-propylene oxide was slowly introduced from a transfer bomb which contained 200 parts of 1,2-propylene oxide. Cooling was applied during the addition to maintain the temperature below 1 300C with a pressure of 60~75 psi. Approximately two hours were required to introduce the 1,2-propylene oxide. The reaction mass was maintained at 1 300C for four hours to ensure that the unreacted 1,2-propylene oxide was at a minimum.Five parts of ethylene oxide were then added from a transfer bomb at such a rate that the temperature was maintained between 1 1 500#1 600C with a pressure of 60-75 psi. After all of the ethylene oxide had been added, the temperature was held at 1 500C for an additional hour to complete the reaction. The molecular weight of the final product was approximately 4,000.

Polyepoxide condensate preparation of each of the polyalkylene oxide adducts and the polyether polyols are well known to the art and are disclosed in U.S. Patent No. 2,771,435, issued November 20 1956, to DeGroote, wt al, and U.S. Patent No. 3,383,325, issued May 14, 1968, to Seale, et al.

The invention is further illustrated in the following additional examples: Example 10 P-nonyl phenol is employed as the alkyl phenol to produce a polyalkylene oxide, employing a small amount of dinonyl phenol sulfonic acid as catalyst. After completion of the resin-forming reaction the acid is neutralized with aqueous KOH and an excess of about 0.2% KOH is further added. Water is removed by warming under a vacuum for one hour after which the vessel is closed and a mixture of equal weights of propylene and ethylene oxide is then added in an amount equal to three times the weight of nonyl phenol-formaldehyde resin (solvent-free basis) such additions being carried out under about 40 psi pressure over a three-hour period.

Example 11 In order to prepare another resinous, polyalkylene oxide adduct, into a 4,000 gal. stainless steel reactor, equipped with steam heating and cooling coils, stirrer, reflux and take-off condensors, steam vacuum jet and inlet feed lines, were placed: High boiling aromatic solvent 5,200 Ibs.

Paraformaldehyde 120 Ibs.

Para-tertiary amyl phenol 4,600 Ibs.

After warming to 550C while stirring, 68 Ibs. of 50% aqueous caustic soda solution were introduced. A mildly exothermic reaction ensued. The condensor was opened to a decanter, the steam jet was activated and a vacuum of 26 inches of mercury was held on the vessel for a period of 26 hours during which the temperature was gradually raised to 1 650C. At this point resin formation is essentially complete.

1 50 Ibs. of additional 50% caustic soda were then introduced and a full vacuum applied while continuing heating for one hour. The vessel was then closed, cooled to 1 350C. and then was introduced: Ethylene Oxide, 3,050 Ibs. at a rate which maintained a temperature of about 1 250#1 300 C.

Aromatic Solvent, 3,000 bis. were then added, the batch was cooled and filled into drums.

Example 12 One hundred parts of the polyglycol prepared in Example 9, 16 parts of the diglycidyl ether of dihydroxyphenyidimethyimethane and 50 parts of toluene were placed in a three-necked flask equipped with a means of mechanical stirring and heating. The mixture was heated to 1 000C and held at that temperature for one hour. The heat was again increased until the mixture refluxed at 1 350C. At this stage of the reaction, the viscosity of the reaction mass increased slowly. When the mixture had become very viscous, a second addition of 75 parts of high boiling aromatic solvent was made. The temperature was maintained at 1 700C for 13 hours. The mixture was heated to 2200C and held for 30 minutes. During heating to 2200C all of the toluene was removed.

The final product was subjected to vacuum distillation to remove the high boiling aromatic solvent. The remaining product was a very viscous, semi-solid, waxy, reddish material, insoluble in water and diisobutylene, having a solubiiity-parameter of 7:1 and spreading rapidly from a dilute benzene solution at the distilled water-Nuyol interface to produce a pressure of 20 dynes per cm when present on the surface at a calculated thickness of 19 Angstroms.

Example 13 To equipment similar to that used in Example 12, 100 parts of a polyglycol prepared from 9.2 parts glycerol and 275 parts of a mixture of 225 parts propylene oxide and 50 parts ethylene oxide, 20 parts of the diglycidyl ether of dihydroxyphenyldimethylmethane and 50 parts xylene were added. The mixture was heated to 1 000C and held at that temperature for one hour. The heat was again increased until the mixture refluxed at 1400 C. After refluxing at 1 400C for one hour, 100 parts of the oxyalkylated resin prepared in Example 10 and 100 parts of xylene were added. The reaction was completed using the same procedure as in Example 12. The behaviour of this reaction mixture was identical to that in Example 12 in every respect, except that the rates of thickening differed.Upon cooling, the xylene which had been removed together with 300 parts of additional xylene were added.

The final product was an effective reagent meeting the three basic criteria set forth above.

Example 14 The alkyl phenol resin derivative used in Example 13 was replaced by one made with equal amounts of p-tert-amyl and p-n-decyl phenol in place of nonyl phenol and by using a commercial polyepoxide sold by Shell Chemical Company under the designation, Epon 828, and described as a lower polymer of the diglycidyl ether of dihydroxyphenyldimethyimethane.

This product was an effective TFSA compound meeting the required solubility and spreading criteria described above.

Example 15 In a reactor fitted with a reflux condenser, were placed 1,000 Ibs. of the polyether polyol product as described in Example 13, 240 Ibs. of commercial diglycidyl ether of diphenyldimethylmethane and 500 Ibs. of crude xylene. The temperature was brought to 1 000C and held, while stirring, for one hour.

The temperature was then raised to about 1 500C, where it was maintained for an hour. 3,000 Ibs. of the oxyalkylated p-nonyl phenol resin of Example 10 were then added along with an additional 1,000' Ibs. of xylene. The temperature was then slowly raised to 1 75 OC, while stirring. Samples of the reaction mixture were periodically removed and the viscosity determined at 1000C. When the viscosity reached 1,000 centipoises (usually after 3 to 5 hours) heating was stopped and 2,000 Ibs. of a highly aromatic, heavy petroleum solvent were run into the mixture.

The product was a dark, viscous oil, insoluble in water and diisobutylene and spreading on the distilled water-refined mineral oil interface with a pressure of 20 dynes per cm at a calculated film thickness, omitting the hydrocarbon solvents contained in the product, of 8 Angstroms.

Example 16 In a 4,000 gal. stainless steel reactor similar to that of Example Ill and equipped with steam heating and cooling coils, stirrer, reflux and take-off condensers, nitrogen sparging line, and inlet feed lines, was placed 4,300 Ibs. of the polyether polyol of Example 13 and 560 Ibs. of commercial xylene.

The reactor was closed and heating was initiated to bring the temperature to 1 700F while passing a slow stream of dry nitrogen through the mixture. After 15 minutes at 1700 F, the temperature was raised to 2200F while continuing to sparge with nitrogen for an additional 30 minutes.At this point the nitrogen was turned off and a commercial polyepoxide, designated Epon 828, and manufactured by Shell Chemical Company, was introduced through an inlet line at a slow rate while maintaining a temperature of 1 700#1 800 F. A total of 560 Ibs. of Epon 828 was introduced over a 30-minutes period, after which the temperature was lowered to 1 650F and held at this point until the viscosity of the mixture had reached 550 cps, at which time 3,200 Ibs. of heavy aromatic solvent and 20 Ibs glacial acetic acid were added to the mixture. Stirring was then continued for 30 minutes, after which 1,210 Ibs. of resinous polyalkylene oxide adduct of Example II was pumped into the reaction vessel.

After addition of the resinous polyalkylene oxide adduct was completed, the temperature was raised to 2 7 5 0--2 8 5 0 F. While continuing the stirring, the viscosity of the mixture was checked at 10minute intervals until a viscosity of about 800 cps was reached, at which point the heating was discontinued and the reaction was terminated by the addition of 1 00 Ibs. of dodecylbenzene sulphonic acid dissolved in heavy aromatic solvent.

Example 17 Reference is made to U.S. Patent No. 2,499,365, to M. De Groote, issued March 7, 1 950, which described generally the manufacture of demulsifiers by the oxyalkylation of fusible, organic solventsoluble, alkylphenol resins. The procedure of Example 74a of this patent was followed to prepare a fusible, xylene soluble p-dodecylphenol resin in xylene solution. The acid catalyst was neutralized, water was removed by azetropic distillation some xylene and 0.5% by weight of sodium methylate catalyst was added. Using the procedure of Example 1 b of the cited patent, 25% by weight of ethylene oxide, based on the final batch weight, was added and reacted with the resin.

The product met the three requirements relating to solubility solubility parameter and ability to spread at interfaces. It was also found to be an effective additive for improving oil recovery by waterflooding.

Example 18 Into a 2,000 gal. stainless steel reactor equipped with jacket and coils for steam heating and cooling, a decanter-condensor and appropriate inlet and outlet fittings was placed 2,400 Ibs. of commercial grade p-nonyl phenol,1,200 Ibs. of high boiling aromatic hydrocarbon solvent and 420 Ibs.

of flake paraformaldehyde. After stirring for about 30 minutes, 9 Ibs. of dipropylnaphthalene sulfonic acid was added to the vessel contents and the reactor was closed.

The contents were warmed to about 400C at which point an exothermic reaction started. The temperature was allowed to rise at 1 200C, using cooling when necessary to maintain this maximum.

The pressure rose to 60 psi and the vessel was vented when needed to maintain the pressure at or below this point. After heating and stirring under these conditions for about one hour, the temperature was lowered to 950C and the vessel was opened to the reflux decanter system. The temperature was then increased and water was collected in the decanter which was adjusted to reflux aromatic solvent back to the reactor and discard the water. The temperature was gradually raised to about 2300C and held until no more water was evolved, at which point the finished resin was cooled to 1 300C and an additional 1,200 Ibs. of aromatic solvent was added.

After completion of the resin synthesis the decanter-condensor system was closed and 40 Ibs. of a 50% solution of potassium hydroxide was added slowly to the reactor contents while stirring. A nitrogen stream was then introduced through a bottom discharging tube and allowed to flow through the contents for one hour while the temperature was brought to 11 00C. The nitrogen was then shut off and introduction of a propylene oxide was started. The temperature was allowed to rise to 1 500C and was maintained between 1400 and 1 600C until 2,000 Ibs. of the oxide had been added and reacted.

The propylene oxide line was then closed and ethylene oxide was slowly introduced and allowed to react until a total of 800 Ibs. had been added.

This product was then cooled and pumped to storage. Aromatic solvent was vacuum distilled from a sample of this batch. It was found to have a solubility parameter of 8.0 and was insoluble to the extent of 1% in water and isooctane. It was found to spread reapidly at a white oil distilled water interface with a spreading pressure of 20 dynes per cm at a calculated thickness of 13 Angstroms and a spreading pressure of 29 dynes per cm at a calculated thickness of 20 Angstroms.

Example 19 The procedure of Example 18 was followed except that 45 Ibs. of a 5% solution of sodium hydroxide in water was used in place of the dipropylnaphthalene sulfonic acid of Example 1 8. An alkaline catalyzed resin thus resulted after removal of the water. At this point 25 Ibs. of sodium methylate were added in place of the potassium hydroxide of Example 18, acting as additional catalyst for the subsequent addition of the propylene and ethylene oxides.

The product was more viscous than that of Example 18. A purified, solvent-free sample met the three criteria for TFSA recited above.

We now give some examples of some micellar solutions, and their properties and use, using some of these TFSA's. Other solutions can be formulated of other TFSA's using similar components.

Example A Wt.% Oleic Acid 7 Triethanolamine 7 Borax 3 Water 29 20% NaCI (in water) 5 Product of Example 17 35 isopropanol 14 Example B Wt.% Product of Example 17 30 Dodecyldimethylbenzyl ammonium chloride 8 Cyclohexanone 10 Water 52 In addition to being a demulsifier for water-in-oil petroleum emulsions, this product has strong biocidal activity as a result of the bio-toxicity of the amphipathic and hydrotropic agents employed (dodecyldimethylbenzyl ammonium chloride and cyclohexanone respectively).

Where the water separated from emulsions is to be disposed of by injection into a subsurface formation or where it is to be reinjected for flooding or pressure maintenance into the oil producing formation itself, it is especially important to prevent biological growths. Such growths create serious plugging problems on and within the subsurface formation and lead, as well, to sulfide production and corrosion problems in injection and production wells.

This formula, as a result of its inclusion of the surface-active quaternary ammonium salt, also assists in the clarification of the separated water, discharging the inherent negative surface charge on oil droplets and solids which may be dispersed therein during the demulsification and sedimentation steps, and thus further improving water quality prior to its reinjection or disposal.

Example C wt.% Product of Example 17 16 Cyclohexylamino-dodecylbenzene sulfonate 2 Sodium p-nonylphenoxy-pentaethoxy sulfate 8 High boiling aromatic hydrocarbon 6 Dipentene 10 Ethylene glycol monobutyl ether 10 Water 48 This composition is particularly useful for down-the-hole application where the oil is highly paraffinic and of high pour point. It contains demulsifier along with an effective wetting agent and solvents for prevention and/or removal or waxy or asphaltic deposits which may form in the tubing and flow line of the well.

Reference was made previously to the incorporation of water-insoluble treating agents such as biocides, scale inhibitors, etc., into the present compositions to form multifunctional compounds for use in oil field and refinery treating operations. It should be made clear, however, that other inherently water insoluble reagents or compounds as well may be incorporated into the present compositions by way of micellar solution also to provide very useful multifunctional compositions.

Example D wt.% Product of Example 18 32.2 Ammonium Tetradecyl Benzenesulphonate 8.8 n-Butanol 10.0 Sodium chloride 0.1 Water 48.9 Example E wt.% Product of Example 3 40 2-heptadecyl-3-triethylene triaminoimidazoline 6 Acetic Acid 1.5 Phenol 2.5 n-Butanol 10 Water 40 Besides having good demulsification action, this product has been found to be an. effective corrosion inhibitor for down-the-hole use, the imidazoline used as the amphipathic agent being a strongly adsorbed inhibitor for steel in anaerobic systems.

Example F Wt.% Product of Example 1 40 Sodium Mahogany Sulphonate (M.W. of about 470) 15 Methanol 5 Alpha Terpineol 10 Water 30 This product has substantial corrosion inhibiting action in aerated systems as well as being a useful demulsifier. This product was tested to determine its effective in enhancing the recovery of oil by water-flooding.

Among procedures which have been found useful in selecting effective micellar TFSA solutions for this use, one involves a determination of oil displacement efficiency from prepared oil-containing rock cores in equipment described below. A tube of glass or transparent polymethacrylate ester, having an inside diameter of about 3.5 cm (1 + in.) and a length of about 45 cm (18 in.), is fitted with inlet connections and appropriate valves at each end. The tube is mounted vertically on a rack in an air bath equipped with a fan, heater and thermostat which allows selection and maintenance of temperatures in the range of between about 250#1 300 C.

To select an effective micellar TFSA solution for use in a given oil formation, samples of the oil, of the producing rock formation and of the water to be used in the flooding operation were obtained. The formation rock is extracted with toluene to remove oil, is dried and is then ground in a ball mill to the point where a large percentage passes a 40 mesh sieve. The fraction between 60 and 100 mesh in size is retained. The tube described above is removed from the air bath, opened and, after insertion of a glass wool retainer at the lower end, is packed with the ground formation rock. The tube is tapped gently from time-to-time during filling to ensure close packing and is visually inspected to assure absence of voids.

The tube is then returned to the air bath, connected to the inlet tubing, the temperature is adjusted to the oil formation temperature and water respresentative of that produced from the formation is admitted slowly through the bottom line from a calibrated reservoir in an amount just sufficient to fill the packed rock plug in the tube. This volume is determined from the calibrations and is referred to as the "pore volume", being that volume of water just sufficient to fill the pores of interstices of the packed plug rock.

The upper line to the reservoir is then connected to a calibrated reservoir containing the oil representing that from the formation to be flooded. By proper manipulation of valves, the line is filled with oil which is then slowly pumped into the core from the reservoir after the lower valve is opened to allow displacement of the formation of water.

As breakthrough of oil at the bottom is noted, pumping is stopped and the volume of oil introduced into the sand is determined from the reservoir readings. This is referred to as the volume of oil in place. The tube of sand containing oil is then left in the air bath at the temperature of the formation for a period of three days to allow establishment of equilibrium between the ground formation rock and the oil with respect to adsorption of oil consituents on the rock and lowering of interfacial tension. The time allowed for equilibrium may be varied widely. At high temperatures, the time required to reach equilibrium is probably reduced. Usually, for comparative tests, three days are allowed to age the oil-rock plug. Results with this procedure closely simulate work with actual cores of oil-bearing rock.

The oil and water samples used for test purposes are preferably taken under an inert gas such as high purity nitrogen, and are maintained out of contact with air during all minipulations in order to prevent oxidation of the oil and concomitant introduction of spurious polar, surface-active constituents in the oil. At this point, the rock-oil system simulates the original oil formation before primary production oil has commenced and well before any secondary waterflood operation.

The upper inlet line to the tube is now connected to the sample of water used in the flooding of the oil formation and, by means of a syringe pump or similar very small volume positive displacement pump, the water is pumped into the sand body from the top to displace fluids out of the bottom tubing connection into a calibrated receiver. The pumping rate is adjusted to one simulating the rate of flood water advance in an actual operation which is usually in a range of 1 to 50 cm per day. Pumping is maintained at this rate until two pore volumes of water have been pumped through the sand.

The volumes of fluids collected in the receiver are measured and the relative amount of oil and water displaced from the rock sample are determined and recorded. Of special interest is the volume of oil displaced as a fraction of the original pore volume. This information may be viewed as an indication of the approximate percentage of oil originally in place which is produced by natural water drive following drilling of a well into the rock formation followed by the primary phase of field production carried to the approximate economic limit.

Following this step, one to three additional pore volumes of water containing the TFSA micellar solution to be tested are pumped slowly through the plug and the volumes of additional oil and water displaced are determined. Typically, where such an initial "slug" of micellar TFSA solution is introduced, it may be contained in a volume of fluid ranging from 1 % to 100% of the pore volume, but most frequenty it will be in a slug volume of 10% to 50% of pore volume.

After this final displacement step, the produced oil and water are again measured. By comparing the amount of oil produced by this additional injection of water containing, or preceded by a solution, of micellar TFSA solution with the amount produced when the same volume of water containing no TFSA solution is injected, one can evaluate the effectiveness of the particular micellar TFSA solution used for enhancing the recovery of additional oil over and above that obtained by ordinary waterflooding.

Generally, six or more sand columns of the kind described above are mounted in the heated air bath. Test of a given micellar TFSA solution is then run in triplicate, using identical conditions and concentrations, simultaneously with three blank tests run similarly but without addition of micellar TFSA solution to the water.

The composition of Examples D and F were tested by this procedure with the following conditions: Oil-Ranger Zone, Wilmington, Calif., field API Gravity approximately 13.5 Water-Mixed water used in flood operations Airbath Temperaturc 500F (Same as formation temperature) Oil was displaced by pumping two pore volumes of water into the sand. After measuring the volumes of oil and water produced through the bottom line, a further 0.2 pore volumes of water containing 3,500 ppm of the composition of Example B was injected followed by 2.8 volumes of water containing 200 ppm of the composition. Measurement of the volumes of oil and water produced were read after each 0.2 pore volumes of water was injected.

Results of this test at the points of 2,3 and 5 pore volumes of injected water are given in the table below wherein averages of three duplicate determinations are presented.

Oil Recovery as % of Oil in Place Composition of Ratio of Increment Example F of Oil Production Added to Water After Initial 2 Pore Volumes (P. V.) No Chemical after Initial P.V. Chemicall of Water Injected Addition 2 P. V. of Water No Chemical 2 36.5 36.5 3 40.0 44.5 2.3 5 43.1 54.8 2.8 Use of the composition of Example F in the amounts given above resulted in the production of 130% more oil from injection of one incremental pore volume of water than was produced by water injection along and gave 180pro more oil after three incremental pore volumes of treated water injection.

Oil Recovery as % of Oil in Place Composition of Ratio of Increment Example D of Oil Production Added to Water After Initial 2 Pore Volumes IP.V.J No Chemical after Initial P. V. Chemicall of Water Injected Addition 2 P.V. of Water No Chemical 2 36.5 36.5 3 40.0 47.5 3.1 5 43.1 60.0 3.6 Use of the composition of Example D in the amounts given above resulted in the production of 21 0% more oil from injection of one incremental pore volume of water than was produced by water injection alone and gave 260% more oil after three incremental pore volumes of treated water injection.

Example G Wt.% Product of Example 18 32 95% Ethanol 10 Dodecylbenzene sulfonic acid 11 Polyacrylamide (Dow NP 10) 1 Water 46 This acidic, homogeneous, aqueous, very viscous composition is especially useful as an emulsion preventer in hydrochloric acid solution used in treatment of calcareous oil-bearing strata. It is readily dispersible in 15% hydrochloric acid and mixtures thereof with hydrofluoric acid, prevents emulsification of the acid and also prevents emulsification of the spent acid solution which is ultimately regurgitated with the produced petroleum.It is also a particularly effective additive for aqueous flooding fluids injected for effecting secondary or tertiary recovery of petroleum; or, it may be used alone or diluted with one or two volumes of water to provide improved flow distribution in the flooded zone and to enhance oil recovery.

Example H Wt.% Product of Example 3 70 Oleyl amine 10 Acetic Acid 3 n-Propanol 2 Water 15 This is a clear, homogeneous but viscous solution. This product was found to be an effective demulsifier for emulsion produced in the Swan Hills, Alberta, field and was especially helpful in causing a clear water phase to separate from the oil phase in the field treating plant.

Example I Wt.% Product of Example 4 27.3 Dodecyldimethylbenzyl Ammonium Chloride 27.3 N-Butanol 9.1 Mixed cresylic acids 13.6 Water 22.7 This product in addition to having strong demulsification action on East Texas crude oil emulsions, is an effective bacteria acide with the quaternary ammonium salt and the cresylic acids which are sufficiently soluble in the aqueous phase separating from the emulsion to prevent bacterial growth therein and thus insure its ready injectability for disposal or enhanced recovery. In this composition the dodecyidimethylbenzyl ammonium chloride functions both as a micelle-forming amphiphatic agent and as a biocide.The utility of this product for the breaking and resolution of a petroleum emulsion was demonstrated by the following test: 100 ml of an emulsion from the Taching field, People's Republic of China, was placed into each of two 6 oz. graduated screw cap bottles. The emulsion contained 42% water as determined by azetropic distillation with xylene. The bottles were placed in a water bath and held at a temperature of 1300 F.

After 30 minutes in the bath, one bottle (No. 1) was opened and 0.8 ml of a 1% isopropanol solution of the composition of Example D was placed in the bottle by means of a calibrated 1.0 ml pipette. 0.8 ml of pure isopropanol was placed into the other bottle (No. 2) with a similar pipette. Both bottles were closed tightly, shaken in a mechanical shaking machine for five minutes at a rate of 134 four-inch oscillations per minute and then returned to the water bath.

After one hour of quiet standing at 1 300F the bottles were examined. In Bottle No. 1 a clear phase separation was apparent with a sharp interface at approximately the 40 ml graduation. Bottle No. 1 showed no free water or other phase separation.

The bottles were allowed to stand for another hour after which they were opened and 6 ml samples were pipetted from the 60 ml of each level and mixed with 6 ml portions of xylene in 12 ml API calibrated centrifuge tubes. The tubes were shaken for a few seconds to insure mixing of oil and xylene and then centrifuged for five minutes at 1 800 rpm. The sample from Bottle No. 1 contained 0.2% free water and 0.1% sedimented emulsion. The sample from Bottle No. 2 contained 52% of a sedimented emulsion layer and no free water.

Example J Wt.% Product of Example 3 . 30 Isopropanol 10 Ammonium nonylphenoxyethoxy sulfate 8 Polyox coagulant (polyethyleneoxide of Mol. Wt. about 5 million) 2 Water 50 This product was found to be an effective demulsifier for emulsions produced in the Salem, Illinois field and was further found to give a clear separated water phase, free of oil and other suspended matter, which could be reinjected for pressure maintenance with minimal contamination of filters and producing formation.

This product has a high viscosity and can be used as such or mixed with an approximate equal quantity of water as the drive fluid for secondary or tertiary oil recovery where mobility control, as well as improved water wetting and oil removal, is an important consideration.

Claims (47)

Claims

1. A micellar composition comprising (1) from 5 to 75% by weight of a thin film spreading agent which at 250C (a) is less than about 1% by volume soluble in water and in isooctane; (b) has a solubility parameter in the range of between about 6.9 and about 8.5; and (c) spreads at the interface between distilled water and refined mineral oil to form a film having a thickness no greater than about 20 Angstroms at a film pressure of about 16 dynes per cm; (2) from 2 to 30% by weight of a hydrotropic agent; (3) from 2 to 30% by weight of amphipathic agent having at least 1 radical per molecule having from 10 to 24 carbon atoms; and (4) from 15 to 90% by weight water.

2. A composition according to Claim 1 in which the TFSA is a polyether polyol obtained by reaction of an alkylene oxide containing less than 10 carbon atoms with a member of the group consisting of polyols, amines, polyamines and amino alcohols containing from 2 to 10 active hydrogen groups, and in which the hydrotropic agent is a semi polar hydrogen-bond forming compound containing at least 1 of oxygen, nitrogen and sulphur.

3. A composition according to Claim 1 in which the TFSA is a polyether polyol of the formula:

wherein: A is alkylene oxide group, -C1H210-; O is oxygen; is a positive integer of up to 10; j is a positive integer no greater than 100; k is a positive integer no greater than 100; N is nitrogen; R' is one of hydrogen, a monovalent hydrocarbon group containing less than C", or A,H; L is a positive integer no greater than 100; R is a hydrocarbon moiety of a polyol, a primary or secondary amine, a primary or secondary polyamine, a primary or secondary amino alcohol, or is hydrogen; and m+n is no greater than

4 when R is other than hydrogen and when R is hydrogen one of m and n is zero and the other is unity and in which the hydrotropic agent is a compound having the formula X-Z or the formula X-Y R(Z)n wherein Z is one of

X is an alkyl, alicyclic, aromatic, alkylalicyclic, alkylarlyl, arylalyl, alicyclicalkyl, heterocyclic or substituted heterocyclic radical having 2 to 13 carbon atoms; R is a member selected from -CH2-, -C2H4-,C3H5=,-C3H e' and-C2H4-0-C2H4-; n is either one or two dependent upon the selection of R; Y is a member selected from:

and U and V are individually hydrogen or hydrocarbon substituents 4.A composition according to Claim 2 or Claim 3 wherein the polyether polyol contains an average of 1 T or more hydroxyl groups per molecule and is the condensation reaction product of at least one alkylene oxide with a reactant having two or more reactive hydrogens of one or more hydroxyl or amino groups.

5. A composition according to any of Claims 2 to 4 wherein the polyether polyol is an ethylene oxide condensate of polypropylene glycol.

6. A composition according to any of Claims 2 to 5 wherein the polyether polyol is an ethylene oxide condensate of polypropylene glycol having an average molecular weight of at least 800.

7. A composition according to Claim 3 wherein R is the hydrocarbon residue of a dihydric alcohol.

8. A composition according to any of Claims 2 to 4 wherein the polyether polyol is a condensation product of a dihydric alcohol and at least one alkylene oxide.

9. A composition according to any of Claims 2 to 4 wherein the polyether polyol is a trihydric ether alcohol.

10. A composition according to any of Claims 2 tod 4 wherein the polyether polyol is a trihydric ether alcohol condensation product of at least one of ethylene, propylene and butylene oxide and a polyol, amine or amino alcohol containing three hydrogens for reaction with said oxide.

11. A composition according to any of Claims 2 to 4 wherein the polyether polyol is the oxyalkylation reaction product of glycerol and at least one of ethylene and propylene oxide.

12. A composition according to Claim 3 wherein the polyether polyol has, an average molecular weight of about 15,000 or less and R is a hydrocarbon moiety having present therein C18 or less and 10 or less reactive hydrogens.

13. A composition according to Claim 1 in which the TFSA is an acylated derivative of a polyether polyol as defined in any of Claims 2 to 12.

14. A method according to Claim 13 in which the agent is an acylated polyether polyol obtained by reaction of the polyether polyol and a mono- or polybasic carboxylic acid, acid anhydride, or an iso-, diiso, or polyisocyanate.

15. A method according to Claim 14 wherein the acylated polyether polyol is the reaction product of a difunctional polyether polyol and difunctional member of the glass consisting of carboxylic acids, acid anhydrides and isocyanates.

16. A method according to Claim 14 wherein the acylated polyether polyol is the reaction product of a polyether polyol and acylating agent selected from the class consisting of di- and monobasic acids and anhydrides having C13 or less.

17. A method according to Claim 14 wherein the acrylated polyether polyol is the reaction product of a polyether polyol and a polyisocyanate containing at least two isocyanate groups.

18. A composition according to Claim 1 in which the TFSA is a polyepoxide condensate of at least one of (1) a polyalkylene oxide adduct formed by condensation of an alkylene oxide containing less than 5 carbon atoms with a fusible water insoluble organic aromatic hydrocarbon solvent-soluble resin that is a condensate of an aldehyde with a phenol that is ortho- or para-substituted by alkyl or cycloaliphatic and that contains 4 to 15 phenolic groups, the amount of alkylene oxide being at least one mole per phenolic moiety and (2) a polyether polyol has the formula:

wherein:: A is an alkylene oxide group, -C1H210-; O is oxygen; is a positive integer of from 2 to 10; is a positive integer no greater than 100; k is a positive integer no greater than 100; N is nitrogen; R1 is one of hydrogen, a monovalent hydrocarbon group containing less than C", or [ A,H ] ; L is a positive integer no greater than 100; R is a hydrocarbon moiety of a polyol, a primary or secondary amine, a primary or secondary polyamine, a primary or secondary amino alcohol, or is hydrogen; and m+n is no greater than 4 when R is other than hydrogen and when R is hydrogen one of m and n is zero and the other is unity.

19. A composition according to Claim 18 wherein the polyepoxide is:

where n is zero or a positive integer of less than about 6.

20. A composition according to Claim 18 or 19, in which the polyepoxide condensate is with a polyoxylkylene adduct as defined in Claim 1 and wherein the weight ratio of alkylene oxide to resin is from 1:10to 10:1.

21. A composition according to Claim 20 in which the adduct contains 1 to 5 moles alkylene oxide per phenolic moiety in the resin.

22. A composition according to Claim 1 in which the TFSA is a polyalkylene oxide adduct formed by condensation of an alkylene oxide containing less than 5 carbon atoms with a fusible water insoluble organic aromatic hydrocarbon solvent-soluble resin that is a condensate of an aldehyde with a phenol that is substituted by alkyl or cycloaliphatic and that contains 4 to 15 phenolic groups, the amount of alkylene oxide being at least one mole per phenolic moiety, and at 250C: (a) is less than about 1% by volume soluble in water and in isooctane; (b) has a solubility parameter in the range of between about 6.9 and about 8.5; (c) spreads at the interface between distilled water and refined mineral oil to form a film having a a thickness no greater than about 20 Angstroms at a film pressure of about 16 dynes per cm, (2) from 2 to 30% by weight of a hydrotropic agent, (3) from 2 to 30% by weight of an amphiphathic agent having at least one radical per molecule of from 10 to 64 carbon atoms and (4) from 15 to 90% by weight water.

23. A composition according to Claim 22 in which the phenol is ortho or para substituted by alkyl or cycloaliphatic.

24. A composition according to Claim 22 or 23 in which the resin is an alkyl phenol formaldehyde condensate.

25. A composition according to any of Claims 22 to 24 in which the weight ratio of oxide to resin is from 1:5to3:1.

26. A composition according to any of Claims 22 to 25 in which the condensation of the resin with the oxide was conducted in a substantially solvent free environment.

27. A composition according to any of Claims 22 to 26 in which the alkylene oxide is ethylene oxide, propylene oxide or butylene oxide.

28. A composition according to any of Claims 22 to 27 in which the alkylene oxide is ethylene oxide and is present in an amount of 1 to 5 moles per phenolic moiety in the resin.

29. A composition according to any preceding claim in which the hydrotropic agent is an alcohol.

30. A composition according to any preceding claim in which the hydrotropic agent is a semipolar oxygen-containing compound capable of forming hydrogen bonds.

31. A composition according to any preceding claim in which the hydrotropic agent is not an alcohol of the formula XZ where X is alkyl or aromatic and Z is OH.

32. A composition according to any preceding claim in which the hydrotropic agent is not hexanol, cresol butanol or diisobutyl ketone.

33. A composition according to any of Claims 1 to 30, in which the hydrotropic agent is a hydroxy ester of a polyol, an aldehyde, an amide, a carboxy amide or a phenolate.

34. A composition according to any preceding claim in which the amphipathic agent contains a hydrophobic hydrocarbon residue which is an aliphatic, alkylalicyclic, aromatic, arylalkyl or alkylaromatic groups.

35. A composition according to any preceding claim in which the amphipathic agent contains an uninterrupted chain of between 10 and 22 carbon atoms.

36. A composition according to any preceding claim in which the amphipathic agent is an anionactive soap.

37. A composition according to any preceding claim in which the amphipathic agent is selected from sodium cetyl sulfate, ammonium lauryl sulfonate, ammonium diisopropyl napthalene sulfonate, sodium oleyl glyceryl sulfate, mahogany or green sulfonates of petroleum, petroleum fractions or petroleum extracts, sodium stearamidoethyl sulfonate, dodecylbenzene sulfonate, dioctyl sodium sulfosuccinate, sodium napthenate, cetyl pyridinium chloride, stearamidoethyl pyridium chloride, trimethyit heptadecyl ammonium chloride, dimethyl pentadecyl sulfonium bromide, octadecylamine acetate, 2heptadecyl-3-diethylene diamino-imidazoline diacetate, the oleic acid ester of nonaethylene glycol and the stearic acid ester of polyglycerol.

38. A composition according to any of Claims 1 to 36 in which the amphipathic agent comprises an oxyethylated alkylphenol.

39. A composition according to any of Claims 1 to 36 in which the amphipathic agent comprises an alcohol ether of a polyethylene glycol.

40. A composition according to any preceding claim in which the TFSA has a solubility-- parameter at 250C of between 7.1 and 7.9.

41. A composition according to Claim 1 substantially as herein described.

42. A method of breaking a petroleum or bitumen emulsion comprising subjecting the emulsion to the action of a micellar solution of a composition according to any preceding claim.

43. A method according to Claim 42 in which the emulsion is a water in oil emulsion.

44. A method of preventing the formation of an emulsion of an aqueous phase and a bitumen or petroleum phase comprising contacting the bitumen or petroleum phase before or during contact with the water, with a composition according to any of Claims 1 to 41.

45. A method according to Claim 28 conducted during the recovery of bitumen or heavy oil from tar sands and subterranean deposits by steaming, or flooding or a mixture thereof.

46. A method in which recovery of petroleum from a subterranean reservoir is assisted by contacting the petroleum in the reservoir with a composition according to any of Claims 1 to 41.

47. A method of recovering oil from an oil bearing formation into which extends a well bore, the method comprising generating steam at the surface, supplying the steam to the oil bearing formation through the well bore and supplying a composition according to any of Claims 1 to 41 to the oil bearing formation to inhibit the production of an oil in water emulsion as a result of the interaction of the steam with the oil and water in the formation.