GB1566639A - Additive for compositions used in oil recovery - Google Patents

Description

(54) ADDITIVE FOR COMPOSITIONS USED IN OIL RECOVERY (71) We, MERCK & CO. INC., a Corporation duly organized and existing under the laws of the State of New Jersey, United States of America, of Rahway, New Jersey, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- Recovery of oil by flooding with a displacement fluid is a well known technique for revitalizing developed oil fields. Previously, as primary recovery techniques exhausted a field, newer fields exploitable by primary recovery were preferentially developed. Lately as exploration to develop newer fields has become more risky and costly, and as the price of crude petroleum becomes more attractive, enhanced oil recovery techniques are becoming ever more widely practised in the petroleum industry. It is estimated that 25 to 60 thousand million barrels of oil are recoverable from fields in the U.S.A. alone with these methods.

Secondary oil recovery techniques are well known and are a common practice.

Following secondary recovery, tertiary recovery may be carried out by adding to waters and brines such chemicals as surfactants, e.g., hydrocarbon sulfates and sulfonates, co-surfactants such as alkanols and alkanol ethers, thickeners and viscosity modifiers (mobility control agents), corrosion inhibitors and emulsifiers, to form a microemulsion with displaced oil. This in turn is brought to the surface with additional volumes of displacement and driving fluids. This tertiary recovery technique is described in detail in U.S.P.

3,885,626.

In the usual secondary or tertiary recovery process, displacement and driving fluids are injected into a subterranean formation through a plurality of injection wells which surround one or more producing wells. The displacement and driving fluids are forced through the injection well bores into the formation.

There these fluids act to remove the oil and push it toward the producing well where it is recovered by conventional methods. Most commonly, water or brine comprises the injection fluid in secondary oil recovery.

The almost universal practice is to include viscosity-modifying agents in the injection fluid to increase its viscosity.

Suitable agents for modifying viscosity are well known water-soluble polymers and include the natural and synthetic gums, e.g., guar gums and xanthan gums, as well as cellulosic derivatives such as carboxylalkyl cellulose and hydroxyalkyl cellulose. Also included as suitable viscosity-modifying agents are the modified starches and starch derivatives and polymers of the polyacrylamide type. Such viscosityincreasing agents and techniques for their use are amply disclosed in the literature, for example, U.S.P. 2,731,414, which discloses the use of carboxymethyl cellulose, locust bean gum, gum Karaya, and Irish moss for increasing the viscosity of the injection fluid. U.S.P. 2,771,138 discloses the use of a combination of sugar and a metal salt.

U.S.P. 3,053,765 teaches the incorporation of a polysaccharide to thicken the injection fluid, while U.S.P. 3,305,016 teaches the use of a heteropolysaccharide made by a bacterium of the genus Xanthomonas.

In addition to such naturally occurring compounds, synthetic polymers are used as in U.S.P. 2,842,492, which teaches the use of copolymers of methacrylic acid and methyl methacrylate as thickening agents. U.S.P.

3,020,953, U.S.P. 2,827,964 and U.S.P.

3,039,529 teach the use of water-soluble polyacrylamides. U.S.P. 3,116,791 teaches the use of water-soluble polyalkylene oxides; Canadian Patent 864,433 proposes the use of N-sulfohydrocarbon-substituted acrylamides, while cross-linked polyacrylamide is used in certain types of well treatment in U.S.P. 3,210,310.

The technique of "selective plugging" of more permeable sections of the formation in order to increase flow in a less permeable section, through the use of various synthetic water-soluble polymers is disclosed in U.S.P. 2,864,448.

One widely used synthetic polymer is partially hydrolysed polyacrylamide, for example, see U.S.P. 3,418,239.

Synthetic polymers such as acrylamide polymers are used in oil recovery together with ammonium hydroxide (U.S.P.

3,367,418) and with polyvalent cations (U.S.P. 2,842,338); cationic polymers may be used because of their advantages as outlined in U.S.P. 3,744,566. Generally, any polymeric material is satisfactory so long as it adequately adjusts the viscosity, remains in solution in the driving and displacement fluids, and resists elevated temperatures and mechanical shear forces.

Various bacteria cause serious problems in water flooding operations for oil recovery.

They include sulfate-reducers, iron bacteria, and capsule-or-slime-formers.

Algae and particular fungi are also implicated in various surface components of the total recovery systems. Oil sands may become impervious to the injection fluids because of insoluble metal sulfides formed from metal ions and microbial reduction of sulfate, or in the presence of gelatinous slimes produced by microbial oxidation of iron to ferric hydroxide and other conversions. Unfortunately, the injection fluid itself may serve as the inoculum and nutrients for these bacteria. This serious problem has hampered the full potential of the application of secondary and tertiary recovery. When such bacteria proliferate in oil fields, the sulfuric and sulfurous acids produced also have an extremely deleterious effect on metallic equipment subject to the corrosive attack of such acids.

The use of antibacterials to inhibit the growth of such bacteria has thus far not been entirely satisfactory because of poor efficiencies, narrow antimicrobial spectra, unsatisfactory partitioning between oil and water phases and chemical or thermal instability.

The inclusion of any of the novel compounds set forth in the specification of our copending application No. 1014/76 (1,484,445) especially 1 - [1,5 - di - (3,3 - dimethylnorborn - 2 - yl) - 3 - pentyl] - 1,5,9 - triazanonane or its salts, is effective in inhibiting the growth of sulfate-reducing bacterial and other types, as well as providing protection to surfaces subject to corro- sion, e.g., metallic surfaces exposed to brine. Other suitable compounds are 1 - [1,5 -di -(3,3 -dimethylnorborn - 2 - yl) - 3 - pentyll - 1,3 - diamino - 2 hydroxypropane and 1 - [1,3 - di - (3,3 dimethylnorborn - 2 - yl) - 2 - propyl] - 1,5,9 - triazanonane and salts thereof.

The present invention provides a premix for incorporation into displacing and driving fluids used for injection into oil-bearing strata during oil production subsequent to primary recovery which comprises at least 0.0005% by weight of a dibicycloheptyl or dibicycloheptenylalkylene polyamine, at least 0.05% by weight of a solvent-soluble surfactant, and a hydrocarbon or oxygenated hydrocarbon solvent that is liquid at ambient temperature and contains 3 or more carbon atoms to the molecule.

The surfactant in this composition may be a crude oil sulfonate, a polyethoxylated phenol or a polyether derived from a C2 to C4 epoxy compound and a hydroxylated non-heterocyclic aromatic hydrocarbon having from 6 to 14 carbon atoms in the molecule and at least one hydroxy substituent. In another embodiment of the invention a premix for addition to water or brine for injection into petroleum-bearing strata for enhanced oil recovery comprises from 0.00050/, to 10 /O by weight of the polyamine 1 - [1,5 - di - 3,3 - dimethyl norborn - 2 - yl) - 3 - pentyl] - 1,5,9 - triazanonane or a salt thereof, and a carrier.

The solutions or dispersions of the antimicrobial may be added to flooding, displacing or driving fluids by continuous metering to the flow or in portions. The composition of the present invention may be diluted with brine to form a solution having ionic constituents similar or identical to those in the water in the oil field where the recovery procedure is to be carried out.

In a preferred method of operation, a flooding composition is prepared with oil field brine obtained from the producing strata or from strata adjacent to the producing strata, whereby undesired changes in the strata by reason of introduction of the pusher fluid are minimized, and the antimicrobial premix is admixed with this fluid. The prior art describes in detail the preparation of displacement and driving fluids in which the antimicrobial premix of the present invention is incorporated. The concentrations are calculated and adjusted so that the antimicrobial is present in the finished flooding composition at a concentration of 0.1 to 400 ppm, (0.00001 to 0.04% by weight).

In recovery operations, the concentration of the viscosity-modifying agent in the injected fluid is adjusted to produce the desired viscosity. In general, with highmolecular-weight viscosity-modifying agents, it is desirable to use from 0.01 to 0.5 percent by weight or more of such agents in the fluid. In practice, the fluid may have a viscosity of from slightly over that of pure water (1.0 centipoise at 200C.) to about 1,000 centipoises and preferably from 1.1 to 100 centipoises. The exact viscosity employed for maximum efficiency in recovery of oil will vary depending upon such factors as the porosity and permeability of the oil-bearing formation, the viscosity of the oil in the formation and the particular type of oil-bearing strata involved. In many cases, good results are obtained when the fluid is adjusted to a viscosity ranging from about the viscosity of the oil in place in the producing strata to about one-half the viscosity of such oil or even above the oil viscosity.

The antimicrobial can be in the form of an acid-addition salt, e.g., the hydrochloride, to increase its solubility in an aqueous injection fluid. If used as the base compound, the antimicrobial is usually not completely soluble, but so long as it is uniformly admixed or emulsified with the injection fluid its activity is not seriously affected. Suitable solvents for use in the compositions of the present invention include aliphatic and aromatic hydrocarbons that are fluid at ambient temperature, e.g. petroleum fractions such as kerosene; xylene; toluene; and mineral spirits. Gasoline and similar hydrocrabons are suitable solvents, but their low flash point presents hazards that, while not precluding their use, certainly renders such use less desirable. Suitable surfactants that are solvent-soluble (e.g., hydrophobic) are well known in this art. Preferred examples include polyethoxylated C4 to C18 alkyl phenols, polypropoxylated C4 to C18 alkyl phenols, C8 to C30 alkyl and aralkyl sulfates and sulfonates. The polyamine solvent surfactant mixture comprises at least 0.0005 by weight polyamine, 0.05% by weight surfactant and the balance solvent.

In preferred embodiments, there are included 1 to 10% by weight polyamine, 1 to 20% by weight surfactant and the balance solvent. A preferred formulation is: % By Weight 8% polyamine 3% polyethoxylated nonylphenol 89% kerosene Upon metering such a premix into an aqueous injection fluid, a dispersion forms which is persistent and tends not to precipitate.

While not necessary to operation, the premix described above can include water so that a stable emulsion is produced.

Although the means or sequence of addition used to incorporate the antimicrobial in the injection fluid to form a flooding composition is not critical to performance, it is preferred that sufficient mechanical, e.g. an impeller or air, agitation be used to ensure a uniformed admixture. One satisfactory technique is to meter or bleed the premix into the injection fluid immediately prior to its introduction into the well. Another satisfactory technique is to prepare a premix of fluid, viscositymodifying agent, and antimicrobial and add this premix to the water or brine stream just prior to injection. Such a premix includes from 0.0005% to 10% by weight of antimicrobial, the remainder being viscosity-modifying agent, and optionally water or brine.

To summarize, the use in oil recovery of compositions of the invention comprises injecting a flooding composition, such as an injection, displacement or driving fluid, to which the said antimicrobials have been added, into an injection well penetrating a subterranean oil-bearing formation and forcing the flooding medium through the formation toward at least one output well in the formation.

Acid-addition salts of the polyamines are prepared and isolated, if desired, by precipitation, evaporation of solutions or other usual techniques.

Suitable anions for the salts include anions derived from inorganic acids as well as those of organic acids, for example, halide, e.g. chloride, bromide or iodide, sulfate bisulfate, nitrate, phosphate, acetate, propionate, maleate, succinate, laurate, oleate, palmitate, stearate, ascorbate, gluconate, citrate, carbonate, bicarbonate, benzoate, salicylate, pamoate, phthalate, furoate, picolinate, dodecylbenzenesulfonate, laurylethersulfate or nicotinate.

Generally, any anion derived from an acid is suitable and satisfactory when the polyamine salt anion X-, e.g., chloride, is to be replaced with other anions by well known anion-exchange techniques.

A typical illustrative enhanced oil recovery formulation comprises: % By Weight 0.0005-10% polyamine 3-20%, surfactant 560% water containing electrolyte 1W60% hydrocarbon cosurfactant, e.g. isopropyl, amyl or hexyl alcohol, cyclohexanone or acetone, to provide a system with 5x 10-5 ohm-' cm-l conductivity.

Electrolyte preferably comprises 5d0 wt.% based on water of NaCI, Na2SO4, KC1, K2SO4, KOH or CaCI2- Substituted bicycloheptanes obtained as described hereinafter may be in exo and endo isomer configurations and generally are mixtures of both. Many factors enter into the actual ratio of isomers formed and these include temperature, solvents, steric effects, equilibration conditions and nature of substituents. However, it appears that the utility of this invention is served without the necessity for strictly controlling the isomer composition. The content of a product mixture may be determined by vapor or liquid phase chromatography, NMR spectral analysis, fractional distillation and other methods. It is also possible to isolate pure isomers by selection of these and other known separation techniques.

The following data illustrates the preparation of the antimicrobials used in this invention.

The word 'Celite' is a trade mark.

(a) Preparation of 3 - (3,3 - dimethyl norborn - 2 - yl)propionic Acid To refluxing acetic anhydride (1050 g., 10 moles), there is added dropwise over six hours a solution of camphene (136 g., 1 mole) and di-tert-butyl peroxide (0.1 mole, 14.6 g). After complete addition, the mixture is heated at reflux for five hours.

The cooling reaction mixture is concentrated under reduced pressure to leave a yellow-orange residual oil; 750 ml. of 2.5 N NaOH is added to the residue which is then heated on the steam bath for one hour.

The cooled solution is extracted once with ether, made acidic with concentrated HCI, and extracted thoroughly with ether. The dried (Na2SO4) ethereal extracts are concentrated under reduced pressure and the residue distilled under vacuum to give a colorless product, b.p. 141 0C.-1440C./0.5 mm.

(b) Preparation of 1,5 - Di - (3,3 dimethylnorborn - 2- yl) - 3 pentanone 3 - (3,3 - Dimethylnorborn - 2yl)propionic acid (392 g., 2.0 moles) and iron (hydrogen-reduced, 61.5 g., 1.1 moles) are heated for 1.5 hours at 1950C. under a nitrogen atmosphere. After that time the temperature is increased to 2900 C. and maintained at that temperature for three hours. The cooled reaction mass is extracted well with ether and filtered through 'Celite', and the ethereal extracts concentrated under vacuum. The residual oil is distilled under vacuum to leave the product as a liquid, b.p. 172"C.-- 173"C./0.05--0.1 mm.

(c) Preparation of 1 - [1,5 - Di - (3,3 - dimethylnorborn - 2- yl) - 3 pentyl] - 1,5,9 - triazanonane Trihydrochloride 1,5 - Di - (3,3 - dimethylnorborn - 2 - yl) - 3 - pentanone (6.04 g., 0.02 mole) and 3,3' - iminobispropylamine (13.1 g., 0.10 mole) in 150 ml. toluene is heated at reflux overnight with a Dean-Stark water separator. The cooled solution is concentrated under reduced pressure. The residue is dissolved in ethanol and hydrogenated with PtO2 at room temperature and 40 psi hydrogen pressure.

The platinum catalyst is filtered off and the ethanol removed under vacuum. The residual oil is dissolved in ether and the ethereal solution washed several times with water to remove the excess of 3,3'iminobispropylamine. The ethereal extracts are dried over anhydrous sodium sulfate and concentrated under vacuum to leave the polyamine as a colorless oil (8.3 g., 100% yield).

The oil is dissolved in ether and hydrogen chloride gas is bubbled into the solution until no further precipitation occurs. The ether is evaporated under reduced pressure to leave the product as a solid which is digested with hot isopropyl alcohol. The solids are collected by filtration and dried under vacuum at 700 C. to give a colorless product 10.8 g., (97%), m.p. 2600C.-2620C.

In an analogous manner, but substituting an equimolar quantity of 1,3 - diamino - 2 hydroxypropane for the 3,3'- iminobispropylamine, there is prepared 1 - [1,5 di - (3,3 - dimethylnorborn - 2 - yl) - 3 pentyl] - 1,3 - diamino - 2 hydroxypropane.

WHAT WE CLAIM IS: 1. A premix for addition to water or brine for injection into petroleum-bearing strata for enhanced oil recovery comprising from 0.0005% to 10% by weight of the polyamine I - [1,5 - dit- (3,3 - dimethylnorborn - 2 yl) - 3 - pentyl] - 1,5,9 - triazanonane or a salt thereof, and a carrier.

2. A premix according to Claim 1 in which the carrier is a hydrocarbon solvent.

3. A premix according to Claim 1 or 2 in which the carrier includes at least 0.05% by weight of a surfactant for dispersing the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   % By Weight 0.0005-10% polyamine 3-20%, surfactant 560% water containing electrolyte 1W60% hydrocarbon cosurfactant, e.g. isopropyl, amyl or hexyl alcohol, cyclohexanone or acetone, to provide a system with 5x 10-5 ohm-' cm-l conductivity.

   Electrolyte preferably comprises 5d0 wt.% based on water of NaCI, Na2SO4, KC1, K2SO4, KOH or CaCI2- Substituted bicycloheptanes obtained as described hereinafter may be in exo and endo isomer configurations and generally are mixtures of both. Many factors enter into the actual ratio of isomers formed and these include temperature, solvents, steric effects, equilibration conditions and nature of substituents. However, it appears that the utility of this invention is served without the necessity for strictly controlling the isomer composition. The content of a product mixture may be determined by vapor or liquid phase chromatography, NMR spectral analysis, fractional distillation and other methods. It is also possible to isolate pure isomers by selection of these and other known separation techniques.

   The following data illustrates the preparation of the antimicrobials used in this invention.

   The word 'Celite' is a trade mark.

   (a) Preparation of 3 - (3,3 - dimethyl norborn - 2 - yl)propionic Acid To refluxing acetic anhydride (1050 g., 10 moles), there is added dropwise over six hours a solution of camphene (136 g., 1 mole) and di-tert-butyl peroxide (0.1 mole, 14.6 g). After complete addition, the mixture is heated at reflux for five hours.

   The cooling reaction mixture is concentrated under reduced pressure to leave a yellow-orange residual oil; 750 ml. of 2.5 N NaOH is added to the residue which is then heated on the steam bath for one hour.

   The cooled solution is extracted once with ether, made acidic with concentrated HCI, and extracted thoroughly with ether. The dried (Na2SO4) ethereal extracts are concentrated under reduced pressure and the residue distilled under vacuum to give a colorless product, b.p. 141 0C.-1440C./0.5 mm.

   (b) Preparation of 1,5 - Di - (3,3 dimethylnorborn - 2- yl) - 3 pentanone

   3 - (3,3 - Dimethylnorborn - 2yl)propionic acid (392 g., 2.0 moles) and iron (hydrogen-reduced, 61.5 g., 1.1 moles) are heated for 1.5 hours at 1950C. under a nitrogen atmosphere. After that time the temperature is increased to 2900 C. and maintained at that temperature for three hours. The cooled reaction mass is extracted well with ether and filtered through 'Celite', and the ethereal extracts concentrated under vacuum. The residual oil is distilled under vacuum to leave the product as a liquid, b.p. 172"C.-- 173"C./0.05--0.1 mm.

   (c) Preparation of 1 - [1,5 - Di - (3,3 - dimethylnorborn - 2- yl) - 3 pentyl] - 1,5,9 - triazanonane Trihydrochloride 1,5 - Di - (3,3 - dimethylnorborn - 2 - yl) - 3 - pentanone (6.04 g., 0.02 mole) and 3,3' - iminobispropylamine (13.1 g., 0.10 mole) in 150 ml. toluene is heated at reflux overnight with a Dean-Stark water separator. The cooled solution is concentrated under reduced pressure. The residue is dissolved in ethanol and hydrogenated with PtO2 at room temperature and 40 psi hydrogen pressure.

   The platinum catalyst is filtered off and the ethanol removed under vacuum. The residual oil is dissolved in ether and the ethereal solution washed several times with water to remove the excess of 3,3'iminobispropylamine. The ethereal extracts are dried over anhydrous sodium sulfate and concentrated under vacuum to leave the polyamine as a colorless oil (8.3 g., 100% yield).

   The oil is dissolved in ether and hydrogen chloride gas is bubbled into the solution until no further precipitation occurs. The ether is evaporated under reduced pressure to leave the product as a solid which is digested with hot isopropyl alcohol. The solids are collected by filtration and dried under vacuum at 700 C. to give a colorless product 10.8 g., (97%), m.p. 2600C.-2620C.

   In an analogous manner, but substituting an equimolar quantity of 1,3 - diamino - 2 hydroxypropane for the 3,3'- iminobispropylamine, there is prepared 1 - [1,5 di - (3,3 - dimethylnorborn - 2 - yl) - 3 pentyl] - 1,3 - diamino - 2 hydroxypropane.

   WHAT WE CLAIM IS: 1. A premix for addition to water or brine for injection into petroleum-bearing strata for enhanced oil recovery comprising from 0.0005% to 10% by weight of the polyamine I - [1,5 - dit- (3,3 - dimethylnorborn - 2 yl) - 3 - pentyl] - 1,5,9 - triazanonane or a salt thereof, and a carrier.
2. 2. A premix according to Claim 1 in which the carrier is a hydrocarbon solvent.
3. 3. A premix according to Claim 1 or 2 in which the carrier includes at least 0.05% by weight of a surfactant for dispersing the

   polyamine in the displacing or driving fluids upon injection into oil-bearing strata.
4. 4. A premix for incorporation into displacing and driving fluids used for injection into oil-bearing strata during oil production subsequent to primary recovery which comprises at least 0.0005% by weight of a dibicycloheptyl or dibicycloheptenylalkylene polyamine, at least 0.050/, by weight of a solvent-soluble surfactant, and a hydrocarbon or oxygenated hydrocarbon solvent that is liquid at ambient temperature and contains 3 or more carbon atoms to the molecule.
5. 5. A premix according to Claim 1 in which the solvent is a petroleum distillate.
6. 6. A premix according to Claim 4 or 5 in which the polyamine is 1 - [1,5 - di - (3,3 dimethylnorborn - 2 - yl) - 3 - pentyl] - 1,5,9 - triazanonane.
7. 7. A premix according to Claim 4 or 5 in which the polyamine is 1 - [1,5 - di - (3,3 dimethylnorborn - 2 - yl) - 3 - pentyl] - 1,3 - diamino - 2- hydroxypropane and salts thereof.
8. 8. A premix according to Claim 4 or 5 in which the polyamine is 1 - [1,3 - di - (3,3 dimethylnorborn - 2 - yl) - 2 - propyl] - 1,5,9 - triazanonane and salts thereof.
9. 9. A premix according to any one of Claims 4 to 8 in which the surfactant is a polyether derived from a C2 to C4 epoxy compound and a hydroxylated nonheterocyclic aromatic hydrocarbon having from 6 to 14 carbon atoms in the molecule and at least one hydroxy substituent.
10. 10. A premix according to Claim 9 in which the surfactant is polyethoxylated phenol.
11. 11. A premix according to any one of Claims 4 to 8 in which the surfactant is a crude oil sulfonate.
12. 12. A premix according to Claim 4 comprising, by weight, 8% of the polyamine, 3% of polyethoxylated nonylphenol and 89% kerosene.