NO161979B - MICELLULAR THIN FILM MIXTURES MIXTURES AND USE OF IT TO DEGREE PETROLEUM OR BITUMEN EMULSIONS. - Google Patents

Description

The present invention relates to new and improved micellar solutions of a thin film dispersant comprising nolye<p>oxide condensates of resinous polyalkylene oxide adducts and polyether polyols, as well as the use of these to break or prevent the formation of petroleum emulsions.

More particularly, the invention relates to a mixture in which water replaces all or a significant part of the organic solvents that were previously necessary for the production

ling of liquid solutions of this surface-active compound.

One of the main uses for the present mixture is npd breaking of petroleum emulsions, which enables the separation of these into two main phases. Much of the crude petroleum oil produced in the world is accompanied by some water or brine originating from or adjacent to the geological formations from which the oil is produced. The amount of aqueous phase accompanying the oil can vary from traces to a very large percentage of the total liquid flow. As a result of it

■. natural presence of oil-soluble or dispersible emulsifiers in petroleum, then much of the aqueous phase formed in the oil will be emulsified in it, forming stable water-in-oil emulsions.

The literature contains numerous references to such emulsions, the problems caused by them, as well as methods used to break down the emulsions and separate a salable petroleum. See, for example, "The Technology of Resolving Petroleum Emulsions" by L.T. Monson and R.W. Stenzel, pp. 535 etc. in Colloid Chemistry Vol VI, Ed. by Jerorae 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), pp. 538 etc. (1960).

Previously known demulsifiers used to break petroleum emulsions were water-soluble soaps, "Twitchell reagents" and sulfonated glycerides. These products could be easily mixed with water to provide easily pumpable fluids which were conveniently used by pumping into the flow lines at the wellhead or washed down the well casing with water to mix with the well fluids prior to their upflow to the surface. However, these products are only effective in relatively high concentrations and their use contributes significantly to production costs.

Some time ago it was found that certain lightly sulfonated oils, acetylated castor oils and various polyesters, all of which are insoluble in water but soluble in alcohols and aromatic hydrocarbons, were more effective in breaking emulsions. Consequently, essentially the commercial development of demulsifiers has led to the production of agents which are insoluble in both water and petroleum oils and which have other properties which will be described below which cause them to spread at oil-water interfaces to give very thin, moving films that replace any emulsifier present in the oil and enable coalescence of dispersed water droplets. In general, such surfactants will be referred to hereinafter as "thin film dispersants" or "TFSA".

Previously, these compounds had to be composed with and dissolved

in alcohols or highly aromatic hydrocarbon solvents to give readily usable liquid mixtures. A wide spectrum of such mixtures is necessary to treat the many different emulsions that can be encountered around the world.

Although the current TFSA mixtures are very effective and are possibly up to 50-100 times more effective per volume unit than the original water-soluble demulsifiers (so

they are subject to certain practical disadvantages due to their solubility properties. For example, alcohols and aromatic hydrocarbons, which are necessary for the production of a liquid, pumpable mixture, are quite expensive and whose price is close to that of the active demulsifier itself. Furthermore, such solvents are flammable and thus create safety problems and cause greater costs for transport, storage and use. The low flash point can

is improved by the use of high-boiling aromatic solvents, but these are increasingly rare, expensive, and not harmless due to their carcinogenic and dermatological effects.

Furthermore, the existing demulsifiers generally cannot be used in an underground oil or gas well, injection well or the like as they cannot be washed down with either water (or brine) or part of the produced oil, and as they are viscous liquids which only are required in very small quantities, they cannot be safely continuously emitted several thousand meters underground at the liquid level in a typical well without the use of complicated and expensive equipment.

Other applications of TFSA compositions would be facilitated if they were readily soluble or dispersible in water. For example, large quantities of heavy, viscous oil are produced in the USA. using steam injection methods. Typically, wet-steam is injected into the oil-producing strata for several weeks to heat the oil, lower its viscosity and reduce the energy of the reservoir. The steam injection is then stopped and the oil flows or is pumped out from the borehole that was used for the steam injection. Much of the water that forms as a result of condensation of the steam is also carried with the oil in emulsified form. Since emulsions are more viscous than the external phase at the same temperature, the flow resistance will increase and the productivity of "steamed" wells can be improved by injecting a water-soluble demulsifying agent into the steam during the steam injection period to prevent emulsion formation, as stated in US patent No. 3,396.7 92.

The requirement for water solubility will significantly limit the choice of demulsifiers for use by steam or water injection to relatively ineffective mixtures.

As shown in the Norwegian patent applications No. 80.1661, 80.1662, 80.1663 and 80.1664, TFSA are useful when used in the extraction of petroleum. Used in such processes which involve the displacement of residual oil by means of aqueous solutions, polymer solutions or other aqueous systems, these compounds will act to increase the amount of recovered oil. Such an effect is possibly due to their ability to promote further water wetting of the reservoir rock, lower the viscosity of the oil-water interface layer and promote coalescence of dispersed droplets of either water or oil in the second phase.

By using the present aqueous micellar solutions, the introduction of TFSA into aqueous displacement or flow fluids can be facilitated to a significant extent. In addition, present micellar solutions as such or in combination with other components will only be used as a flocculating agent or as a pre-treatment agent that is introduced before other aqueous fluids.

Other uses for the present TFSA micellar solutions include their use as flocculation aids for finely ground hematite and magnetite ores during the de-sliming step or ore processing, as additives to improve oil removal and to promote detergency in cleaning compositions and in detergents for use on polar materials, to improve solvent extraction processes such as those used in the extraction of antibiotics where an aqueous fermentation liquid is extracted with organic solvents, to improve efficiency and phase separation in the purification and concentration of metals by solvent extraction with organic solutions of metal complexing agents, as well as to improve wetting and dyeing of natural and synthetic fibers and for other processes that normally involve interfaces between surfaces of different polarity or wetting properties.

An aim of the present invention is to provide aqueous, liquid mixtures of these TFSAs with new and useful properties which enable the production of: petroleum emulsion breakers and emulsion preventing mixtures which are free or relatively free of highly flammable and environmentally harmful aromatic hydrocarbons, mixtures which are relatively cheap, mixtures that are soluble or dispersible in water and which can therefore often be used using more efficient methods than are possible for existing products, mixtures that can be used in enhanced recovery operations such as steam flotation and flotation with an aqueous medium in which the currently existing products cannot be easily used, as well as compositions that can be mixed with water-soluble agents of other types, such as corrosion inhibitors, wetting agents, scaling inhibitors, biocides, acid, etc. to provide multi-purpose compounds for use in solving many oil well closures , prod tion, transport and refining problems.

According to the present invention, these purposes are achieved by means of amphipathic agents which are capable of forming micelle solutions and which by this mechanism or another

. not well-defined effect, combined with those of the other essential component which will be referred to as a hydrotropic agent, is able to form homogeneous aqueous solutions containing TFSA in a relatively wide concentration range. The TFSA mixtures according to the present invention can be briefly described using the following general properties: 1. Solubility in water and isooctane at approx. 25° C is less than approx. 1 percent by volume; 2. Solubility parameter at 25° C lies in the range from approx. 6.8 to approx. 8.5 with the main component in the range between 7 and 7.9, and 3. Spreads at the interface between a clear refined mineral oil and distilled water to give a film of a calculated thickness not exceeding approx. 20 Angstroms at a dispersion pressure of approx. 16 dyne/cm.

TFSA mixtures with these properties are generally organic polymers or semi-polymers with molecular weights from approx. 2,000 to approx. 100,000 and have a structure containing a number of distributed hydrophilic and hydrophobic groups arranged in linear or planar rows, which makes them surface-active and causes them to be absorbed at oil-water interfaces under

formation of very thin films.

In contrast to most known surface-active compounds, the present TFSA does not seem to be able to form a micelle in either oil or water. The distributed and alternating presence of polar and non-polar or hydrophilic or hydrophobic groups in the molecule apparently prevents the degree of organization necessary for micelle formation and thus reduces dispersion or dissolution either in water or low polar organic solvents.

TFSAs useful in the present invention have the previously stated properties: 1. Solubility in water and in isooctane at approx. 25° C is less than approx. 1 percent by volume.

Solubility determinations can be carried out by introducing 1 ml of sample (or weight of the solid product calculated to have a volume of 1 ml) into a measuring cylinder of the type that can be closed with a towed glass stopper. Then 99 ml of water is introduced into the cylinder and this is introduced into a water bath at 25° C until temperature equilibrium is reached, after which the measuring cylinder is removed from the bath and shaken vigorously for 1 min. The cylinder is then returned to the bath for 5 min. after which the shaking procedure is repeated, finally the cylinder is returned to the bath and allowed to stand quietly for 1 h. The contents of the cylinder are then carefully examined for any milky consistency or opacity of the liquid phase or the presence of any sediment or undissolved material in the cylinder, which indicates that the sample satisfies the requirements for insolubility in water.

Insolubility in isooctane is similarly determined by using this hydrocarbon rather than water. 2. Solubility parameter (S.P.) at approx. 25° C is in the range 6.9 - 8.5.

Methods for determining the solubility parameter are shown in Joel H. Hildebrand, "The Solubility of Nonelectrolytes", third edition, page 425 etc. However, a simplified method can be used which is sufficiently accurate for the identification of a useful TFSA mixture. Components with a given solubility parameter are generally insoluble in hydrocarbon (non-hydrogen-binding) solvents that have a lower solubility parameter than the actual TFSA mixture. Therefore, the present mixture will be insoluble in a hydrocarbon solvent with a solubility parameter of approx. 6.8. As the solubility parameter for mixtures of solvents is an additive function of the volume percentage of the components in the mixture, sample solutions with the desired solubility parameter can be easily prepared by, for example, mixing benzene (S.P. 9.15) and isooctane (S.P. 6.85) or perfluoro- n-heptane (S.P. 5.7).

A mixture of approx. 7 2 divides benzene by approx. 28 parts of isooctane will provide a solvent with a solubility parameter of approx. 8.5 at room temperature (approx. 25° C). Perfluoro-n-heptane has a solubility parameter of approx. 5.7 at approx. 25° C so that a mixture of 68 parts of this solvent with 32 parts of benzene gives a solvent with a solubility parameter of approx. 6.8 or isooctane with a solubility parameter of 6.85 can be used.

When 5 ml of TFSA is mixed at room temperature with 95 ml of a solvent with a solubility parameter of 8.5 a clear solution should be obtained. When 5 ml of TFSA is mixed with a solvent with a solubility parameter of 6.85, a cloudy mixture or a mixture showing phase separation should be obtained. Solvent mixtures with a solubility parameter between 7.0 and 7.9 can be prepared as described above using

of a corresponding test procedure.

When interpreting the solubility parameter and other determinations, it should be noted that TFSA does not consist of a single material or a single compound but a cogeneric mixture of products containing a number of products whose molecular weights are distributed around the average molecular weight and which also contain smaller amounts of the starting compounds which was used in the production. As a result, when determining solubility and solubility parameters, a faint presence of milkiness or a lack of absolute clarity should not be interpreted as "standing" or "crossed" with regard to satisfying the aforementioned criteria. The purpose of the test is to determine whether the main proportion of the cogeneric mixture, i.e. 75% or more, meets the requirements. When the result is doubtful, the solubility tests should be carried out in centrifuge tubes to enable a subsequent rapid phase separation by centrifugation, after which the separated non-solvent phase can be removed and any solvent contained therein can be evaporated and the relevant weight or volume of the separated phase

can be determined.

3. TFSA should spread at the interface between distilled water and refined mineral oil to give films with a thickness not exceeding approx. 20 Angstroms (200 nm) at a film pressure of approx. 16 dynes/cm (0.016 Newton/m).

Suitable methods for determining film pressure are shown in N.K. Adam "Physics and Chemistry of Surfaces", Third Edition, Oxford University Press, London, 1941, page 20 etc. and CM. Blair, Jr., "Interfacial Films Affecting The Stability of Petroleum Emulsions", Chemistry and Industry (London), 1960, page 538 etc. The film thickness is calculated on the assumption that all TFSA remains in the interfacial area between oil and water on which the product or a solution thereof in a volatile solvent is applied. As the spreading pressure is numerically equal to the change in the interfacial tension as a result of the film's spreading, interfacial tension measurements can be conveniently performed before and after the addition of a known amount of TFSA to an interface with a known area.

Alternatively, one can use a boundary film scale of the Langmuir type, such as that described by J.H. Brooks and B.A. Pethica, Transactions of the Faraday Society (1964), page 20 etc. or other methods suitable for the determination of the interfacial spreading pressure.

When determining the interfacial diffusion pressure for TFSA products, it is preferred to use a relatively easily available and reproducible oil, such as a clear refined mineral oil, as the oil phase. Such oils are derived from petroleum and are treated with sulfuric acid and other agents to remove non-hydrocarbon and aromatic constituents. Typical of such oils is "Nujol" (Plough, Inc.).

This oil has a density in the range 0.85 - 0.89 and usually a solubility parameter in the range 6.9 - 7.5. A number of similar oils of greater or lesser density and viscosity are usually available from chemical suppliers and pharmacies.

Other essentially aliphatic or naphthenic hydrocarbons with low volatility are equally suitable and will give similar values for the dispersion pressure. Suitable hydrocarbon oils are commercially available as "white oils", "textile lubricants", "paraffin oil" and the like. These can often contain very small amounts of alpha-tocopherol (vitamin E) or similar oil-soluble antioxidants, but these will not affect the scattering measurements.

Although the existence of micelles, as well as oil or aqueous micelle solutions, has been known for some time, (see for example "Surface Activity", Moilliet, Collie and Black, D. Van Nostrand & Co., New York (1961)) and probably forms part of many operations involving detergents in which either oily

(non-polar) or soil particles (very polar) are to be removed, then their use in collaboration with hydrotropic agents for the present purpose is an unexpected and unforeseeable discovery.

In US patent no. 2,356,205, a number of different micellar solutions are indicated designed to dissolve petroleum oils, bitumen, waxes and other relatively non-polar compounds with the intention of clearing oil formations in order to achieve an improved recovery of petroleum by dissolving it. At this early date, however, application of the micelle principles was not contemplated for the preparation of solutions of relatively high molecular weight demulsifiers.

However, some of the principles set forth in said patent, apart from the main purpose therein of dissolving relatively large amounts of hydrocarbons, chlorinated hydrocarbons and the like, are applicable to the preparation of the present compositions.

The necessary four ingredients for the micelle solutions of TFSA are: 1. A micelle-forming amphipathic agent. Such an agent can be anionic, cationic or non-ionic and if it is anionic or cationic it can either be present in salt form or as the free acid or free base or mixtures thereof. 2. Hydrotropic agent. This is a polar compound of low to medium molecular weight containing oxygen, nitrogen or sulfur and capable of forming hydrogen bonds. It is believed that such agents cooperate in some way with the amphipathic agent to give a clear or opalescent, stable mixture.

3. Water

4. TFSA with the above characteristics.

In addition to these components, the micelle solutions may possibly contain salts, hydrocarbons or smaller amounts of other inorganic or organic material. Such components can be impurities, solvents, or by-products from the production of the hydrotropic agent,

or there may be additives which have been found useful in the preparation of the mixtures according to the invention. As exem-

Finally, small amounts of inorganic salts such as NaCl, Na 2 SO 4 , KN0 3 , CaCl 2 and the like can sometimes be useful to promote homogeneity with a minimal amount of amphipathic and hydrotropic agents. They can also provide mixtures with a reduced freezing point, a property that is useful when the mixture is to be used in cold climates. In the same way, ethylene glycol, methanol, ethanol, acetic acid and similar organic compounds can

or be incorporated into the mixtures to improve physical properties such as freezing point, viscosity and density or to improve stability.

As stated above, the micelle-forming amphipathic agents used in the preparation of the present aqueous solutions can either be cationically active, anionically active or of the non-electrolytic type. Amphipathic agents generally have at least one group containing 10 or more carbon atoms and no more than approx. 6 4 carbon atoms per molecule. This is the case for the amphipathic agents used according to the invention as a component of the carrier or the solvent or dispersant used in the present mixtures. The hydrophobic parts of these agents can be aliphatic, alicyclic, alkylalicyclic, aromatic, arylalkyl or alkylaromatic. The preferred type of mid-

Clays are those where the molecule contains a long, uninterrupted carbon chain containing 10-22 carbon atoms in length. Examples of suitable anion-active amphipathic agents include the usual soaps as well as materials such as sodium cetyl sulfate, ammonium lauryl sulfate, ammonium diisopropyl naphthalene sulfonate, sodium oleyl glyceryl sulfate, brown and green sulfonates from petroleum or petroleum fractions or extracts, sodium stearamidoethyl sulfonate, dodecylbenzene sulfonate, dioctyl sodium sulfosuccinate, sodium naphthenate and the like. Second

suitable sulfonates are those shown in US Patent No. 2,278. 171.

Suitable cationic active compounds include cetylpyridine chloride, stearamidoethylpyridine chloride, trimethylheptadecylammonium chloride, dimethylpentadecylsulfonbromide, octadecylamine acetate and 2-heptadecyl-3-diethyleneamino imidazole diacetate.

Suitable non-electrolytic amphipathic agents include oleic esters of nonaethylene glycol, the stearic 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 they can be readily prepared to exhibit the properties of one or more of the above-mentioned types. Such compounds are shown in US Patent No. 2,262,743. In cases where a surface-active material exhibits the properties of one or more of the above-mentioned types, it will be understood that it can be classified under either each or both of the types.

The solvent or the hydrotropic agents in the solution used according to the present invention can be described as compounds of a hydrophobic hydrocarbon residue with a relatively low molecular weight combined with a hydrophilic group with a low molecular weight and which is free of surface-active properties. The hydrophobic residue may contain 2-12 carbon atoms and may be an alkyl group, 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 can be branched or unbranched, but no branch can have a length of more than approx. 7 carbon atoms from the attachment point for the hydrophilic residue, benzene or a cyclohexyl group being considered to have an equivalent length to an aliphatic chain of 3 carbon atoms.

When the hydrocarbon residue consists of no more than 4 carbon atoms, the structure for a normal, primary alkyl group is preferred. When the residue consists of more than 4 carbon atoms, structures of the secondary or tertiary type can also be good if the second and third branches are methyl or ethyl groups.

The hydrophobic hydrocarbon residue is combined either directly or indirectly with a hydrophilic group of one of the following types: (a) A hydroxyl group which may be alcoholic, phenolic or carboxylic; (b) An aldehyde group; (c) A carboxyamide group; (d) An amine salt group;

(e) An amine group; and

(f) An alkali phenolate group.

By "indirectly combined with one of these groups" is meant that the hydrocarbon residue is associated by etherification, esterification, amide formation or the like with other organic residues that do not contain more than four carbon atoms and also one or more of the above-mentioned hydrophilic groups, provided that after each combination, at least one of the hydrophilic groups remains free.

Special examples showing this class of compounds are: Ethyl alcohol, n-amyl alcohol, alphaterpineol, p-cresol, cyclohexanol, n-butyraldehyde, benzaldehyde, n-butyric acid, glycol monobutyrate, propyl lactate, mono-n-butylamine hydrochloride, n-propionamide , ethylene glycol mono-n-butylamine hydrochloride, n-propionamide, ethylene glycol mono-n-butyl ether, pyridine, methylated pyridine, piperidine or methylated piperidines.

The cosolvent (hydrotropic compounds described above) is essentially a semipolar liquid in the sense that any liquid whose polar properties are not greater than that of ethyl alcohol and which exhibits at least a tendency to and dissolve in water or dissolve water is designated as

semipolar.

The co-solvent or the semi-polar liquid as indicated above can be described by the formula X - Z, in which X is a group with 2-13 carbon atoms and which can be an alkyl, phenyl, phenylalkyl, cycloalkyl or cycloalkenylalkyl group. It is a limitation that the longest carbon chain must be less than 8 carbon atoms and with such a characterization cyclic carbon atoms must be counted as half.

Z means

where U and V are hydrogen or a hydrocarbon group means if X is a cyclic tertiary amlno group, is

if X is a cyclic secondary amlnogroup.

The semipolar liquid can also be indicated by the following formula:

R 1 -NH-(CH 2 ) n -NH-(CH 2 ) n -NH-R 2

where n=1-5 and R 1 is alkyl or imidazolinyl.

In general, all of these hydrotropic agents are liquids with a dielectric value of 6-26, and have at least one polar group containing one or more oxygen atoms and/or nitrogen atoms.

It is possibly significant that all these co-solvent

agents are of types known to form hydrogen bonds.

The choice of solubilizer or co-dissolver

agent and its proportion in the mixture is to some extent dependent on the amphipathic agent used, the amount and type of TFSA used and the proportion of water used and is best determined by preparing test mixtures on a small scale.

In certain cases, it may be desirable to incorporate small amounts of acid, alkali or inorganic salts into the solution and it has been found that the presence of these electrolytes often gives solutions with greater stability and a wider range of miscibility with water and organic materials. The excess of acid, if used, will usually be

in solutions containing a cationically active or non-electrolytic wetting agent. When an excess of alkali is used, the

this usually be in a solution containing an anion-

active moisturizer.

The polyether polyol or TFSA used according to the invention

The solvent is generally an organic polymer or semi-polymer with an average molecular weight above approx. 800 and under approx. 30,000 and has a structure that will enable an orientation on polar surfaces with most or all of the molecule's elements in a thin plane. In order to be effectively adsorbed at oil-water or oil-rock interfaces and then desorbed at water-rock interfaces, TFSA must generally contain components that give it widely distributed hydrophilic and hydrophobic properties and without such a concentration of either hydrophilic or hydro-

phobic groups to give water solubility or oil solu-

hot in the usual macroscopic sense. TFSA seems too

to differ from previously used surfactants in that the effects on the oil-water interfacial tensions as a function of concentration are limited.

During spreading on such interfaces to give thin fil-

more with a spreading pressure of up to 35-40 dyne/cm will

higher amounts of TFSA have relatively little effect on

the interfacial tension. TFSA constitutes a component of the micellar solution in contrast to previously used surfactants and has little or no tendency to stabilize either oil-in-water or water-in-oil emulsions when present in normally used amounts.

Generally, the TFSA components that are usable in the practice of the present invention are made up of organic molecules containing carbon, hydrogen and oxygen, although in certain cases they may also contain sulphur, nitrogen, silicon, chlorine, phosphorus and other elements. Small amounts of inorganic materials such as alkalis, acids or salts may be present in the mixture as neutralizing agents, catalyst residues or otherwise. The critical requirements for the TFSA mixture are not so much the composition as such but more of a structural or physical nature. They must consist of hydrophilic (polar) groups, usually one capable of forming hydrogen bonds, such as hydroxyl, carbonyl, ester, ether, sulfone, amino, ammonium, phosphorus or similar hydrogen-bonding groups attached with or to hydrophobic groups such as alkylene-, alkyl-, cycloalkyl-, aryl-, arylene-, aralkyl-, polyalkylene-, polyalkylene-, combinations of such groups and such groups containing relatively non-polar substituents such as hydrocarbon, chlorine, fluorine and the like. Sometimes the hydrophobic groups are larger and contain more atoms than the polar groups in the molecule and have at least two carbon atoms in each group and up to as many as 36 carbon atoms, although the actual ratio between the sizes is largely dependent on the structure of the hydrophilic unit. Typically, the hydrophobic groups will contain 14-22 carbon atoms and will have linear or sheet-like conformations that allow a relatively flat orientation on surfaces.

Polar units other than the hydrogen bond positions are not excluded from these mixtures and may in fact be intentionally included in certain structures to improve adsorption and the tendency for interfacial diffusion. For example, quaternary ammonium groups, which are unable to form hydrogen bonds, can improve dispersion and interfacial adsorption in certain applications as a result of their highly ionized form, which imparts cationic character to molecules in which they are present and, via Coulombic repulsion effects, improve dispersion in a film.

In general, the TFSA components will contain at least two of each of the required hydrophilic (polar) and hydrophobic units per molecule and usually they will contain many more of each of these. However, the effective products must exhibit the three characteristics described above.

As indicated above, an effective TFSA may be derived from a wide number of different chemical reactants and may contain many different groups or units, however, it has been found that the mixing parameters should satisfy the requirements set forth in the characterizing portion of claim 1.

The polyalkylene oxide adducts are described in US patent no. 2,499,365. These mixtures also include materials in which less than one or two alkylene oxide units may be reacted with each of the reactive structural groups in the starting resin.

The most common resin is an alkyl or cycloaliphatic substituted phenolaldehyde resin prepared by condensing an ortho- or para-substituted phenol with an aldehyde, usually formaldehyde or a precursor of formaldehyde such as paraformaldehyde or trioxane under slightly alkaline or acidic conditions to give a fusible and xylene-soluble polymer with low to medium high molecular weight and which will typically contain 4-12 phenolic groups. This resin is then condensed, usually in the presence of an alkaline catalyst with an alkylene oxide or mixtures of alkylene oxides.

Alkylene oxides suitable for use in the preparation of the mixtures used in the present method include ethylene oxide, propylene oxide, butylene oxide, 2,3-epoxy-2-methylbutane, trimethylene oxide, tetrahydrofuran, glycidol and similar oxides containing less than approx. 10 carbon atoms. Due to their reactivity and low price, the preferred alkylene oxides for the production of effective TFSAs are the following 1,2-alkylene oxides exemplified by ethylene oxide, propylene oxide and butylene oxide. In the preparation of many TFSAs, more than 1 alkylene oxide can be used either as a mixture of oxides or in sequence to provide block addition of the individual alkylene oxide groups.

To be suitable for use in the present method, the addition and condensation of oxides must not lead to the formation of water-soluble products. When ethylene oxide alone is condensed with the resin, the added amount will preferably be between 1 and 5 mol per phenol unit in the resin. The amount in question will vary with the size of the alkyl or cycloalkyl group attached to the phenol ring, as well as the composition and properties of the oil, the aqueous phase and rock formation treated according to the present method.

When propylene or butylene oxide or mixtures of one or more of these with ethylene oxide are condensed with the phenolic resin intermediate, generally larger amounts of such oxides can be converted without this leading to extremely polar, water-insoluble products. In contrast, the amount of epichlorohydrin and glycerol chlorohydride that can be condensed without forming agents that do not satisfy the solubility product and interfacial spreading criteria as defined above may be somewhat lower.

On a solvent-free weight basis, the amount of alkylene oxide or mixtures of oxides condensed with the resin will be in the range of one part oxide to 10 parts resin and up from 1-5 to 3-1. The finished product should contain at least one mole of alkylene oxide per phenol group in the resin.

Mixtures that fall within the range of the previously stated formula for the polyether polyol contain on average approx. 1.5 or more hydroxyl groups per molecule and is 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 a hydroxyl or amino group.

Propylene glycol is representative of these mixtures

an average molecular weight of approx. 1,200 to which is added approx. 20% by weight ethylene oxide. Such a polyether glycol is theoretically obtainable by condensation of approx. 20 mol of propylene oxide with 1 mol of water, followed by the addition of approx. 6 moles of ethylene oxide. Alternatively, you can condense approx. 20 mol of propylene oxide with a previously prepared polyethylene glycol with an average molecular weight of approx. 240.

Other suitable dihydric alcohols can be obtained by condensing alkylene oxides or mixtures of oxides in successive steps (blocks) with the functional (in relation to oxide addition) compounds such as ethylene glycol, methylamine, propylene glycol, hexamethylene glycol, ethyl ethanolamine, analin, resorcinol, hydroquinone and such.

Trihydric ether alcohols can be produced by condensation of ethylene, propylene or butylene oxides with, for example, glycerol, ammonia, triethanolamine, diethanolamine, ethylethylenediamine and correspondingly smaller molecules containing three hydrogen atoms which are capable of reacting with the alkylene oxides. Similarly, polyether alcohols with several hydroxyl groups can be obtained by condensation of alkylene oxides with multireactive starting compounds such as pentaerythritol, glycerol, N-mono-butylethylenediamine, trishydroxymethylaminomethane, ethylenediamine, diethylenetriamine, diglycerol, hexamethylenediamine, decylamine or cyclohexylamine. US patent no. 2,679,511 describes a number of polyols derived from amino compounds which are then esterified. "Product 15-200" manufactured and sold by the Dow Chemical Company is produced by oxyalkylation of glycerol with a mixture of ethylene and propylene oxides and is an example of a commercially available polyol of the type contemplated for use in carrying out the present invention.

In general, these compounds will have an average molecular weight of 15,000 or less and are derived from compounds containing reactive hydrocarbon atoms and having 18 or fewer carbon atoms and 10 or fewer reactive hydrogen atoms.

Other general descriptions of suitable compounds falling within the scope of the above-described structure, as well as procedures for carrying out the various preparation steps are shown in "High Polymers, Vol. XIII, Polyethers," edited by N.G. Gaylord, John Wiley & Sons, New York, 1963.

Suitable polyepoxides for condensation with the compounds listed above include, in particular, diglycidyl ethers of dihydroxyphenylmethylmethane and lower polymers thereof, which can be formed as a cogeneric mixture and which have the general formula:

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

Other polyepoxides containing two or more epoxy groups

per such as diisobutenyl dioxide, polyepoxypolyglycerols, epoxidized linseed oils, epoxidized polybutadiene or similar

nende can also be used.

Compounds suitable for the formation of the present invention are produced by reacting formaldehyde or a compound that breaks down to formaldehyde under the reaction conditions, for example paraformaldehyde and trioxane and ct difunctionally,

with regard to turnover with formaldehyde, alkylphenol as of

economic considerations can be a crude mixture of alkylphenols,

and where the reactants are heated to 100° - 125°C in the presence of a small amount of acidic catalyst, such as sulfamic acid or hydrochloric acid, or optionally in the presence of an alkaline catalyst

sator such as sodium hydroxide or sodium methylate and preferably under essentially anhydrous conditions, except

seen from the water formed during the reaction. The aqueous distillate that forms is collected and removed from the reaction mixture. After several hours of heating to temperatures slightly

above the boiling point of water, the mass becomes viscous and is allowed to cool to ]00 - 105°C. At this point, an aromatic hydro-

carbon fraction such as xylene is added and heating is resumed. Further aqueous distillates will begin to form and heating is continued for a further number of hours until approx. 1 mole of aqueous distillate per moles of formaldehyde have

'distilled by. Xylene or another hydrocarbon that can be distilled with water can be returned to the reaction mass. The temperature at the end of the reaction reaches 180 - 250°C. The product is allowed to cool to give a phenol formaldehyde condensation product in an aromatic solvent.

The molecular weight of these between condensation products can

cannot easily be determined with certainty, but it is assumed that in the resins used, these will contain 4-15, preferably 4-6 phenolic groups per resin molecule1. The solubility of the condensation product in a hydrocarbon solvent will indicate that the resin is a linear or sheet-like polymer, which distinguishes it from the more common phenol formaldehyde resins of the insoluble cross-linked type.

After the phenol formaldehyde intermediate has been produced, the next step is oxyalkylation of the condensation products with alkylene oxide. This is accomplished by mixing the phenol-formaldehyde condensation intermediate, as is or dissolved in an aromatic solvent, with a small amount of a suitable catalyst, usually potassium hydroxide or sodium methylene in an autoclave. The condensation product heated to over 100°C and ethylene oxide, propylene oxide or mixtures of two or three of these oxides, either as a mixture or a successive addition of one of the oxides is introduced into the autoclave until a pressure in the range of 5-7 kp/ cm 2.

The reaction mixture is gradually heated to an exotherm

reaction begins. The external heat supply is removed and alkyl oxide or oxide mixture is added in such a quantity that the temperature is maintained at 130 - 160°C at a pressure in the range 2-7 kp/cm. After all the alkylene oxide has been added

holds, the temperature for a further 10 - 20 min. to ensure essentially complete conversion of the alkylene oxide.

The product obtained is the alkylene oxide adduct of an alkylphenol-formaldehyde condensation product in which the weight ratio of oxide to condensation product (calculated on a solvent-free basis) is in the range 1:10 to 10:1, preferably

show in the range 1:5 to 3:1 and contains at least 1 mol of alkylene oxide per phenol group in the resin.

With regard to the limits of the various constituents i

the micellar solutions containing TFSA can therefore

serve as a guide, the information is in % by weight:

Although the exact function of electrolytes previously discussed is not fully understood, the effect can in any case be partially attributed to their ability to bind water, i.e. get hydrated. This indicates that certain other materials of a very hydrophilic nature and which clearly differ from the class of non-polar solvents and semi-polar co-solvents can be functional equivalents of an electrolyte. Components in this class that do not usually dissociate include glycerol, ethylene glycol, diglycerol, sugar, glucose, sorbitol, mannitol and the like.

As indicated above, these solutions may contain other organic constituents such as hydrocarbons. These are often used as diluents, azeotropic distillation aids or for control of reflux temperatures in the production of the TFSA component and may be back in this when the present micellar solutions are produced. To the extent that such compounds are present, they seem to compete to a certain extent with the TFSA component for micelle space and thus to a certain extent limit the maximum amount

TFSA component that can be brought into a homogeneous solution.

Selection of an effective TFSA mixture for a given petroleum emulsion and determination of the amount that is necessary is carried out by so-called "bottle tests" which are typically carried out in the following way:

A fresh emulsion is obtained and 100 ml portions are poured into each

of several 180 ml screw-cap precipitation or equivalent graduated bottles. Dilute solutions (1% to 2%) of various TFSA ingredients are prepared in isopropyl alcohol.

Using a measuring pipette, add a small volume of a TFSA solution to the bottle. An equivalent volume of each of the mixtures is added to the other bottles containing the emulsion. The bottles are then closed and transferred to a water

bath and kept at the same temperature as that used at the treatment plant in question. When this temperature is reached, shake the bottles vigorously for several minutes. After shaking, the bottles are placed upright in the water bath and allowed to stand still.

At suitable intervals, the volume of separated water is observed

layer together with the sharpness of the oil-water interface, the appearance of the oil and the clarity of the water phase.

After the grace period, which can vary from 30 min. to

several hours, depending on the temperature, the viscosity of the emulsion, and the amount of TFSA mixture used, small samples of the oil are removed using a pipette or injection syringe and after the sample they are centrifuged to determine the amount of free and emulsified water back in the oil.

The pipette or syringe used to remove the samples should be inserted via a cap or other device that acts as a position control to ensure that all bottles are sampled at the same liquid level.

The combined information regarding residual water and emulsion, water separation rate and appearance of the interface forms the basis for choosing the generally most effective TFSA component. If none of the results are satisfactory, the experiments should be carried out using higher concentrations of the TFSA components and, in the opposite case, if all the results are good and equal, the experiments should be carried out at lower concentrations until good differentiation is possible.

When dissolving petroleum emulsions of the water-in-oil type with the present micellar solution, the solution is brought into contact with the emulsion to be treated using one of the various methods or devices that are now generally used to break petroleum emulsions with a chemical agent , the method indicated above being used alone or in combination with other demulsification procedures, such as the electrical dehydration process.

One method is to accumulate a volume of emulsified oil

in a tank and perform a batch demulsification treatment to recover pure oil. In such a method, the emulsion is mixed with the micellar TFSA solution, for example by stirring the emulsion in the tank and slowly dripping the micellar TFSA solution into the emulsion. In certain cases, the mixture can be achieved by heating the emulsion while the micellar TFSA solution is added dropwise, as the convection currents in the emulsion can provide a satisfactory mixture. A third modification of this type of treatment is to extract the emulsion from the bottom of the tank by means of a circulation pump and reintroduce it to the top of the tank, while it

micellular TFSA solution, for example, is supplied at the suction side of the circulation pump.

In the second type of treatment, the micellar TFSA solution is introduced into the well fluids at the wellhead or at a location between the wellhead and the final oil storage tank, using an adjustable metering mechanism or a metering pump. Normally, the liquid flow through the subsequent pipelines and connections will be sufficient to provide the desired mixing of the micellar TFSA solution and emulsion, although in certain cases additional mixing may be introduced into the flow system. In this general method, the system can include various mechanical devices for discharging free water, separating entrained water or treating the chemically treated emulsion in stationary precipitation tanks. Heating devices can be used in connection with the treatment methods described above.

The third way of using the micellar TFSA solution when treating an emulsion is to introduce the micellar solution either intermittently or continuously in diluted form into the well and let it follow the well fluids to the surface and then let the chemical-containing emulsion flow through a any suitable surface equipment as used in other treatment methods. This particular method of application is useful when the micellar solution is used in connection with the acidification of cold oil-containing strata, especially if it is dissolved in the acid used in the acidification.

In all cases, it will appear from the given description

that the method generally comprises only introducing a relatively small proportion of a micellar TFSA solution in a relatively

large proportion of the emulsion, mix the added chemical and the emulsion either by natural flow or by means of special apparatus, with or without the application of heat and then allow the mixture to stand until the content of unwanted water in the emulsion is separated and settled.

In addition to their use to break petroleum emulsions, the present micellar TFSA solutions, as previously mentioned, can be used to prevent emulsion formation by steam flotation, by secondary water flotation, by acidification of oil-producing formations and the like.

Petroleum oils can also contain significant amounts of inorganic salts after demulsification, either in solid form or as small residual brine droplets. For this reason, most petroleum oils will be desalted before refining. The desalination step is carried out by adding and mixing the oil with a few percent by volume of fresh water to bring this into contact with the brine and the salt. In the absence of a demulsifier, such added water will also be emulsified without providing the desired washing effect. Existing micellar solutions can be added to the fresh water to prevent it from emulsifying and thus facilitate phase separation and removal of salt during the desalination process. If desired, the solution can be added to the oil phase in the same way as the currently used aromatic solvent mixtures. Most petroleum oils together with accompanying brines and gases have a corrosive effect on steel and other metal structures with which they come into contact. Well pipes, well casings, flow pipelines, separators and storage tanks are often severely attacked by well fluids, especially when acidic gases such as R^S and CO2 are present in the fluids, but also in systems that are free of these gases.

It is previously known, for example as stated in US patent no. 2.4 66,517, that such corrosive attacks of crude oil liquid can be avoided or prevented by adding small amounts of organic inhibitors to the liquids. Effective inhibitor mixtures for such an application are usually semi-polar surfactant compounds containing a non-polar hydrocarbon unit linked to one or more polar groups containing nitrogen, oxygen or sulfur or combinations of these elements. In general, these inhibitors or salts thereof will be soluble in oil and/or water (brine) and will often apparently be able to form micelles in one or both of these phases. Typical inhibitors include amines such as octylamine, dodecylamine, dioctodecylamine, butylnaphthylamine, dicyclohexylamine, benzyldimethyldodecylammonium chloride, hexadecylaminopropylamine, decyloxypropylamine, mixed amines prepared by hydrogenation of nitrile derivatives of tall oil fatty acids, soy acid esters of monoethanolamine, 2-undecyl-1-aminoethylimidazoline and a wide number of cationic nitrogen-containing compounds of a semipolar character.

Active in certain applications are nonylsuccinic acid, diocylnaphthalene sulfonic acid, trimeric and dimeric fatty acids, propargyl alcohol, mercaptobenzothiozole, 2, 4, 6-trimethyl-1, 3, 5-trithiaan, hexadecyldimethylbenzimidazole bromide, 2-thiobutyl-N-tetrodecylpyridine chloride, tetrahydronaphthylthiomorpholine, etc.

In contrast to TFSA, corrosion inhibitors seem to work by forming strongly adherent, thick, densely packed films on the metal surface that prevent or reduce the contact between the corrosive fluids and gases with the metal •and affect the ion and electron transfer reactions that are part of the corrosion process.

Corrosion inhibitors are often brought down into the well space in oil wells where they are mixed with the well fluids before being fed up through the well pipe and can thus effectively prevent corrosion of the well equipment. When corrosive attack occurs at the surface, the inhibitor can be introduced near or at the wellhead and allowed to adsorb into the pipelines and surface equipment to ensure protection.

Addition of inhibitor either down in the hole or at surface locations can be suitably combined with the addition of the demulsifier as the latter is also often added at one of these locations.

Inhibitors such as those mentioned above can generally be incorporated into TFSA micellar solutions and replace part of or in addition to the TFSA component. Furthermore, since many of these inhibitors are in themselves micelle-forming amphipathic agents, they can be included in the micellar solution as such and replace other amphipathic agents that could otherwise be used. Combining the micellar solution with a corrosion inhibitor enables a more economical chemical treatment and reduces the inventory of one compound and requires only one chemical injection system instead of two and thus facilitates the work and necessary monitoring.

A further important effect achieved by the use of the micellar solution of TFSA and the corrosion inhibitor is attributed to the prevention of emulsification of the inhibitor. It is often found that the inhibitor in an amount necessary to achieve an effective protection causes the formation of very stable emulsions of water and hydrocarbon, especially in systems containing light, normally non-emulsifying hydrocarbons such as distillates such as gasoline, kerosene, diesel oil and various other fractions . Inhibitors are commonly used in refining systems where emulsification is highly undesirable and where the mixtures could be reformulated to include an effective emulsion-• preventing micellar solution of TFSA.

Inhibitors can be used in an amount from a few to several hundred parts per million, calculated on the oil to be treated and depending on the extent of corrosion. For a given oil field or groups of wells, tests will normally be carried out to determine the requirement for the micellar dissolution of TFSA and for the inhibitor and a mixture will be prepared containing these components in approximately the desired conditions. In certain cases, the requirements for a micellar solution of TFSA in the best concentration will lead to the use of a corrosion inhibitor, used as a micelle former, in excess of what is necessary for inhibition. This will not affect the applicability of the micellar solution and will result in an inhibition "surplus" which may be useful during periods when high corrosivity can be expected. Examples of micellar solutions in which TFSA is used with inhibitors in water-dispersible micellar solutions will appear from the following.

Selection of the appropriate corrosion inhibitor for a given system or oil can be based on laboratory testing under conditions similar to those in the well or pipelines. Such tests are exemplified by that described in Item No. 1K155, "Proposed Standardized Laboratory Procedure for Screening Corrosion Inhibitors for Oil and Gas Wells", published by the National Association of Corrosion Engineers, Houston, Texas.

EXAMPLES OF THIN FILM SPREADING AGENTS

EXAMPLE IA

RESINOUS POLYALKYLENE OXIDE ADVANTAGE PRECURSORS

Reference is made to US patent no. 2,499,365 which generally describes the preparation of demulsifiers by oxyalkylation of fusible, organic solvent-soluble alkylphenol resins. The method according to example 74a in this patent was followed in the preparation of a fusible, xylene-soluble p-dodecylphenol resin in a xylene solution. The acid catalyst was neutralized and water removed by azeotropic distillation of some xylene and 0.5% by weight sodium methylate catalyst was added. Using example 1b in the aforementioned patent, 25% by weight of ethylene oxide was calculated

the finished batch weight, added and reacted with the resin.

EXAMPLE IB

MANUFACTURE OF END PRODUCT

Reference is made to US patent no. 3,383,325 which describes a demulsifier produced by condensing polyether polyols and oxyalkylated alkylphenol resins with diglycidyl ethers of bisphenol compounds.

100 parts of the product prepared according to example 1 in Norwegian application no..?9:???£ were reacted with 15 parts of diglycidyl ether of bisphenol A, followed by reaction with 80 parts of the product according to example IA above. These turnovers were carried out according to example D8 in the above-mentioned US patent.

Addition of the final 300 parts SO 2 was omitted. The product obtained satisfied the 3 criteria for the thin film dispersant.

EXAMPLE 2

The procedure of Example 44a of US Patent No. 2,499,365 was followed to provide an alkali-catalyzed, fusible, xylene-soluble p-tertiary amylphenol resin.

Using the method described in the example IA given above, 454 kg of this resin solution was reacted with 454 kg of a mixture of 68 kg of butylene oxide, 113 kg of propylene oxide and 272 kg of ethylene oxide. When the oxide addition was complete, the temperature was adjusted to 140°C and 32 kg of dimethyldiglycidylhydantoin dissolved in 113 kg of xylene was slowly introduced with rapid stirring. After the epoxy hydantoin addition was complete, stirring and heating to 140°C was continued until the batch viscosity at 100°C

was 1,500 - 2,000 centipoises.

EXAMPLE 3

The procedure of Example 1 was followed except that both condensation with the oxyalkylated phenolic resin and the final addition of SC 2 were omitted. The product obtained was an effective demulsifier satisfying the criteria described above. The product was also found to improve the percentage of oil recovery when used as an additive to water used in experimental secondary water flow tests.

EXAMPLE 4

The procedure of Example 1 was followed except that

12 parts of "resin XB2818" (Ciba-Geigy), an alkylated dihydantoin containing 3 epoxy groups, was used instead of 15 parts of diglycidyl ether used in example 1. The reaction was allowed to proceed until the product exhibited a viscosity of approx. 1,500 centipoises at 100° C. The final product satisfied the previously mentioned 3 criteria for TFSA.

EXAMPLE 5

Into a stainless steel autoclave with a capacity of 1,890 1 and equipped with a stirrer, steam jacket, cooling coils and suitable inlet and outlet pipes, 454 kg of commercially available polypropylene glycol with an average molecular weight of 4,000 was introduced. 7.3 kg of a 50% aqueous solution of potassium hydroxide was then added to the glycol.

Steam was introduced into the jacket and the contents stirred while the temperature was brought to approx. 125° C. A slow stream of nitrogen was blown through the contents of the vessel during the heating period to remove water. Nitrogen flushing was stopped when a sample of the glycol showed a water content below 0.1%.

Then a commercially available epoxidized soybean oil containing an average of 3 epoxy groups per glyceride molecule continuously slowly added while the temperature was raised to 145° C. The addition was stopped after 41 kg of epoxidized soybean oil had been introduced. Stirring and heating at 145°C were continued until the reaction mixture had a viscosity in the range of 1,200 - 1,400 centipoises measured at 100°C.

EXAMPLES OF MICELLULAR SOLUTIONS CONTAINING TFSA

EXAMPLE A

This product was an effective agent for breaking down emulsions formed in the Glendive field in Montana and is particularly useful as a synergistic component when mixed with other aqueous TFSA mixtures as described in Norwegian application no...8.°.'.2.9 .2.6 ....

EXAMPLE B

This is a solution with a very low pour point that is suitable for use as a demulsifier in oil fields where the ambient temperature is well below freezing.

EXAMPLE C

Of the test methods that have been found useful in the selection of suitable TFSA is one that includes the determination of oil displacement. the efficiency from treated oil-containing stone cores in the equipment described below. A round of glass or transparent polymethacrylate with an inner diameter of approx. 3.5 cm and a length of approx. 45 cm and provided with supply connections and suitable valves at each end. The tube is mounted vertically in a stand in an air bath equipped with a fan, heating elements and a thermostat that allows the selection and maintenance of temperatures in the range 25 - 13 0° C.

In order to select the most effective TFSA for use in a given oil formation, samples of oil, the oil-producing rock formation and the water to be used in the flooding operation are obtained. The rock formation is extracted with toluene to remove oil, dried and then ground in a ball mill to a point where a greater percentage passes a 40 mesh sieve. The fraction between 60 mesh and 100 mesh is retained. The above-described tubes are removed from the air bath, opened and, after introducing a glass wool filter at the lower end, the tube is packed with the painted stone formation. The pipe is gently tapped from time to time during filling to ensure a tight packing and visually inspected to ensure the absence of voids.

The pipe is then returned to the air bath, connected to the supply pipe and the temperature is adjusted to the temperature of the oil formation and oil from such formation is slowly supplied through the bottom supply pipeline from a calibrated reservoir in an amount just sufficient to fill the packed rock plug in the pipe. This volume is determined from the calibrated reservoir and is referred to as "pore volume" and is the volume of oil that is just sufficient to fill the pores or cavities in the packed rock plug.

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

A breakthrough of oil at the bottom is noted and pumping is stopped and the volume of oil introduced into sand is determined from readings from the reservoirs. This is referred to as the volume of oil present. The pipe with the sand containing oil is then placed in the air bath at a temperature corresponding to that of the formation for a period of 3 days to allow equilibrium between the ground formation rock and the oil with regard to adsorption of the oil components on the rock and lowering of the interfacial tension. The time for reaching equilibrium can vary within wide limits. At higher temperatures, the time required to achieve equilibrium is probably less. Usually, for comparative tests, 3 days are used to age the oil-stone plug. Results of this procedure approximately simulate working with current cores of oil

bearing stone.

Oil and the water samples used for testing purposes are preferably taken under an inert gas such as pure nitrogen and are kept free from contact with air during all manipulation in the

aim to prevent oxidation of the oil and thus the introduction of foreign polar, surface-active components into the oil. On

at this point, rock-oil systems simulate the original oil formation before primary oil production has begun and the well before a possible secondary waterflow operation.

The other inlet pipe is now connected to the water sample to be used when flooding the oil formation and with the help of an injection syringe or other positive displacement pump with a small displacement, the water is pumped into the sand body from the top to displace liquid out at the bottom of the pipe which is connected to a calibrated receiver . The pump speed is adjusted so as to simulate the speed of the flood water during a current operation, which is usually in the range of 1-50 cm/day. Pumping is maintained at this rate up to two pore volumes

with water is pumped through the sand.

The volumes of the liquids collected in the receiver are measured and it

relative amount of oil and water displaced from the rock sample determined

. mes and recorded. Of particular interest is the volume of oil displaced in relation to the original pore volume. This information can be considered as an indication of the percentage

show the proportion of oil that was originally present and that has been produced by natural expulsion with water after drilling a well in a rock formation followed by the primary production

phase carried out to the approximate financial limit.

After this step, a further one to three pore volumes of water containing the TFSA micelle solution to be examined are slowly pumped through the plug and the further volumes for

required oil and water is determined. Typically, when such an initial "slug" of micellar TFSA solution is introduced, it can be contained in a liquid volume in the range of 1-100% of the pore volume,

but usually this volume will be made up of 10-50% of the pore

the volume.

After this final displacement step, produced oil and water are again determined. By comparing the amount of oil produced as a result of the further injection of water containing, or after a prior injection of a solution of micellar TFSA solution with an amount produced when the same volume of water is injected without TFSA solution present, then one can calculate the efficiency of the - special micellar TFSA solution used to improve the recovery of additional oil compared to that achieved by ordinary waterflooding.

In general, 6 or more sand columns of the described type will be installed in the heated air bath. Examination of a given micellar TFSA solution is carried out "in triplo" using identical conditions and concentrations simultaneously with three blank samples without addition of the micellar TFSA solution to the water.

The mixture according to Example B was examined by this method under the following conditions.

The oil was displaced by pumping two pore volumes of water into the sand. After measuring the volumes of oil and water produced via the bottom pipeline, a further 0.2 pore volumes of water containing 3,500 ppm of the mixture according to Example B were injected followed by 2.8 pore volumes of water containing 200 ppm of the mixture according to Example B. Measurement of the volumes of oil and formed water was read after every 0.2 pore volume of injected water.

The result of this test for the injection of 2,3 and 5 pore volumes of water, respectively, is given in the following table, in which average figures for 3 determinations are reproduced.

Use of the mixture according to example B in the above

for given quantities led to a production of 100% more oil from injection of an additional drilling volume of water than that provided by water injection alone and yielded 68% more oil after injection of an additional 3 pore volumes of treated water.

Claims (2)

1. Micellular thin film dispersant mixture, characterized in that it comprises: (1) 5-75 wt# of a polyepoxide concentrate of at least one of: (a) a polyalkylene oxide adduct of a fusible, water-insoluble synthetic resin which is soluble in an aromatic hydrocarbon solvent, which resin contains 4-15 phenol groups and is an alkyl-substituted phenol aldehyde concentrate of an ortho- or para-substituted phenol and an aldehyde, after which the condensate resin is further condensed with an alkylene oxide containing less than 5 carbon atoms in an amount equal to at least 1 mol of alkylene oxide per phenolic group in the resin, the weight ratio of oxide to condensation product in the solvent-free state being in the range of 1:10 to 10:1, and (b) a polyether polyol of the formula: wherein A is an alkylene oxide group of the formula -CjJH^iO-, 1 is a positive integer not greater than 10, J is a positive integer not greater than 100, k is a positive integer not greater than 100, R<1> is hydrogen, a monovalent alkyl group contained dende less than Cu or (AtH), L is a positive integer not greater than 100, R is a hydrocarbon residue of a polyol, a primary or secondary amine, a primary or secondary polyamine, a primary or secondary amino alcohol or hydrogen, m + n is not greater than 4 when R is different from hydrogen and one of m or n is zero and the other 1 when R is hydrogen, which condensate at 25°C: (a) is less than 1 volume soluble in water and in isooctane, (b) has a solubility parameter in the range 6.9-8.5, and (c) spreads on the interface between distilled water and refined mineral oil to give a film of a thickness not greater than 20 Angstroms at a film pressure of 16 dyne/cm, (2) 2-30 wt#> of a hydrotropic agent of one of the formulas in which X is an alkyl, optionally alkyl-substituted phenyl, phenylalkyl, cycloalkyl or cycloalkenylalkyl group with from 2 to 13 carbon atoms, and in which Z is: where U and V are hydrogen or hydrocarbon substituents, wherein n = 1-5, is hydrogen, alkyl or imidazolinyl, (3) 2-30 wt# of an amphipathic agent of formula where R 2 is alkyl of more than 10 carbon atoms, R3 is SO3X, where X is an alkali metal or optionally ammonium substituted with alkyl or cycloalkyl, or R3 is -0-((CH2)n~°)m~SO3X' where m and n are 1-10 and X as indicated above, (4) 15-90% by weight water. 2. Use of the agent according to claim I to break down petroleum or bitumen emulsions or prevent the formation of such emulsions.