Emulsion type annulus protection fluid and preparation method thereof

Abstract

The invention relates to the technical field of oilfield chemistry, in particular to an emulsion type annulus protection fluid and a preparation method thereof.The emulsion type annulus protection fluid is prepared from, by mass, 1%-2% of a carbon dioxide corrosion inhibitor, 1%-2% of a sulfur removal agent, 1%-2% of a bactericide, 1%-5% of a surfactant, 40%-60% of organic oil, 0.1%-2% of an emulsion polymer stabilizer and 5%-50% of water; the emulsion type annulus protection liquid is prepared according to the following method: adding a required amount of a carbon dioxide-resistant corrosion inhibitor, a sulfur removal agent, a bactericide, a surfactant, an emulsion polymer stabilizer and water into a required amount of organic oil, and mixing and stirring to obtain the emulsion type annulus protection liquid. The preparation process is simple, the anti-corrosion effect is good, a good protection effect on a shaft pipe column of a well containing carbon dioxide and hydrogen sulfide is achieved, meanwhile, organic oil is used as a continuous phase, a water-in-oil stable emulsion is formed, the characteristics of an oil-based product can be reserved, and the cost can be greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemistry and relates to an emulsion type annular space protection fluid and a preparation method thereof. Background Art

[0002] With the deepening of oil and gas field development, the research and development and application of carbon dioxide flooding enhanced oil recovery (EOR) technology have been vigorously carried out at home and abroad in recent years. This technology can not only meet the needs of oil field development, but also solve the problem of carbon dioxide storage, protect the atmospheric environment, and control the greenhouse effect. Oil fields often use carbon dioxide to improve oil and gas recovery. This technology can significantly improve crude oil recovery, especially for low-permeability and ultra-low-permeability reservoirs containing high-viscosity crude oil. However, in the process of carbon dioxide flooding oil production, on the one hand, according to production experience, the wellbore will inevitably have the problem of carbon dioxide gas entering the annulus; on the other hand, during the completion operation, there will be retained liquid medium in the annulus, so the wellbore material will suffer from the damage caused by carbon dioxide corrosion. If there is sulfur corrosive medium in the annulus, it may further induce environmental cracking of the pipe.

[0003] In order to solve the above problems, carbon dioxide corrosion-resistant alloy steel is generally used, but due to its high cost, it is not suitable for large-scale promotion. At the same time, water-based annular space protection fluid is used, but its long-term performance is low and needs to be replaced regularly. There are also scaling problems. There have been cases of corrosion fracture in China when water-based annular space protection fluid was used.

[0004] A Chinese patent document with publication number CN104498010A discloses an oil casing annulus protection fluid for oil production, comprising the following raw materials: base oil, bactericide, corrosion inhibitor, scale inhibitor, surfactant, preservative and pH regulator; the percentage of the total weight of each component is 0.5-3% of bactericide, 1-5% of anti-carbon dioxide corrosion inhibitor, 0.2-1% of scale inhibitor, 0.1-0.5% of surfactant, 2-5% of preservative and 2-10% of pH regulator, and the balance is base oil.

[0005] However, since the oil-based annular space protection fluid used in the prior art is expensive, it is necessary to develop a new annular space protection fluid to solve the above problems. Summary of the invention

[0006] The present invention provides an emulsion type annulus protection fluid and a preparation method thereof, which overcome the above-mentioned deficiencies of the prior art and can effectively solve the problems that the existing water-based annulus protection fluid has low corrosion resistance to carbon steel pipes and is not suitable for highly carbonic acid gas environments, and that the performance of the oil-based annulus protection fluid can meet the corrosion resistance requirements but is relatively expensive.

[0007] One of the technical solutions of the present invention is achieved through the following measures: an emulsion-type annular space protection fluid, comprising, by mass percentage: 1% to 2% anti-carbon dioxide corrosion inhibitor, 1% to 2% desulfurizer, 1% to 2% bactericide, 1% to 5% surfactant, 40% to 60% organic oil, 0.1% to 2% emulsion polymer stabilizer, 5% to 50% water. The emulsion-type annular space protection fluid is prepared according to the following method: add the required amount of anti-carbon dioxide corrosion inhibitor, desulfurizer, bactericide, surfactant, emulsion polymer stabilizer and water to the required amount of organic oil, mix and stir to obtain the emulsion-type annular space protection fluid.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above-mentioned anti-carbon dioxide corrosion inhibitor is prepared according to the following method: S01, uniformly mixing a required amount of macromolecular petroleum acid and polyamine and reacting them to obtain an intermediate 1; S02, mixing the intermediate 1 and a required amount of guanidine hydrochloride uniformly and reacting them to obtain the intermediate 2; S03, adding a solvent and a chain transfer agent to a required amount of monomer, and then adding a required amount of initiator to react to obtain an intermediate three; S04, mixing the intermediate 2, the intermediate 3 and a required amount of polyetheramine uniformly and reacting them to obtain a first polymer; S05, reacting a required amount of the intermediate 1 obtained in step S01 with a polycarboxylic acid to obtain a first reaction product; S06, mixing the chlorine-containing compound with the first reaction product and performing a cross-linking reaction to obtain a second polymer; S07, mixing the obtained first polymer, the second polymer and the modified imidazoline and compounding them to obtain a carbon dioxide corrosion inhibitor, wherein the required amount of the intermediate 1 obtained in step S01, guanidine hydrochloride and a primary amine are mixed and reacted to obtain a modified imidazoline.

[0009] In the above step S01, the molar ratio of macromolecular petroleum acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 9h to 11h, wherein the polyamine is polyethylene polyamine, and the macromolecular petroleum acid is a by-product in the petroleum refining process; in step S02, the molar ratio of intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 140°C to 150°C, and the reaction time is 2.5h to 3.5h; in step S03, the monomers are acrylic acid and maleic anhydride. , methacrylic acid, the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, xylene, trimethylbenzene, dimethyl sulfoxide, and dimethylformamide, the chain transfer agent is n-dodecyl mercaptan, the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature is 60°C to 120°C, and the reaction time is 3.5h to 4.5h. In step S04, the polyetheramine is one of D350 and D600, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

[0010] In the above step S05, the polycarboxylic acid is one of adipic acid and oxalic acid, the molar ratio of the polycarboxylic acid to the intermediate one is 1:1 to 2, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h. In step S06, the chlorine-containing compound is 1,4-dichlorobenzyl, the molar ratio of the chlorine-containing compound to the first reaction product is 1:1 to 2, the reaction temperature is 70°C to 100°C, and the reaction time is 3.5h to 4.5h. In step S07, the molar ratio of the intermediate one, guanidine hydrochloride and the primary amine is 1:1:1, the reaction temperature is 145°C to 155°C, and the reaction time is 3.5h to 4.5h, wherein the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0011] The above desulfurizer is prepared according to the following method: S11, mixing a required amount of alcohol amine and aldehyde and reacting them to obtain a desulfurizing agent intermediate; S12, vacuum dehydrating and purifying the desulfurizing agent intermediate, and then sequentially adding required amounts of polycarboxylic acid, high carbonic acid, catalyst, and xylene to react to obtain a desulfurizing agent.

[0012] In the above step S11, the alcohol amine is monoethanolamine, the aldehyde is formaldehyde, wherein the molar ratio of the alcohol amine to the aldehyde is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 60°C to 80°C, and the reaction time is 2h to 4h; or / and, in step S12, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic acid, the high carbonic acid is one or more of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid, and the catalyst is one of dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and aminosulfonic acid, wherein the molar ratio of the polycarboxylic acid to the desulfurizer intermediate is 1:1 to 2, the molar ratio of the high carbonic acid to the desulfurizer intermediate is 1:1 to 2, the mass of the catalyst added is 0.5% to 2.5% of the mass of the desulfurizer intermediate, the reaction temperature is 120°C to 150°C, and the reaction time is 2h to 10h.

[0013] The above-mentioned fungicide is an oil-soluble polymerized guanidine, which is prepared according to the following method: S21, mixing a required amount of petroleum acid and polyethylene polyamine and reacting them to obtain an intermediate 1; S22, mixing the intermediate 1 and a required amount of guanidine hydrochloride uniformly and reacting them to obtain the intermediate 2; S23, uniformly mixing the reaction monomer, the solvent and the chain transfer agent, and then adding a required amount of initiator to react to obtain a reaction product; S24, adding intermediate 2 and a required amount of p-toluenesulfonic acid to the reaction product and reacting to obtain an oil-soluble polymerized guanidine.

[0014] In the above step S21, the molar ratio of petroleum acid to polyethylene polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 10h to 12h; or / and, in step S22, the molar ratio of intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 150°C to 180°C, and the reaction time is 2h to 4h; or / and, in step S23, the reaction monomer is one or more of acrylic acid, methyl acrylate, ethyl acrylate, and maleic anhydride, the solvent is xylene, the chain transfer agent is n-dodecyl mercaptan, and the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide.

[0015] The above-mentioned surfactant is one or more of a sorbitan fatty acid ester surfactant, a Tween emulsifier, EO-50, PO-50, a monostearate emulsifier, and a distearate emulsifier; or / and the organic oil is one of a vegetable oil, a bio-oil, and a biodiesel; or / and the emulsion polymer stabilizer is one of a polyacrylic acid, a polymethyl acrylate, a polyethyl acrylate, an acrylic acid-methyl acrylate copolymer, and an ethylene-vinyl acetate.

[0016] The above surfactants are Tween 80 and Tween 60.

[0017] The second technical solution of the present invention is achieved through the following measures: a method for preparing an emulsion type annular space protection fluid is carried out according to the following method: adding the required amount of anti-carbon dioxide corrosion inhibitor, desulfurizer, bactericide, surfactant, emulsion polymer stabilizer and water to the required amount of organic oil, mixing and stirring to obtain an emulsion type annular space protection fluid.

[0018] The invention has a simple preparation process and good anti-corrosion effect, and has a good protective effect on wellbore tubulars of wells containing carbon dioxide and hydrogen sulfide. At the same time, organic oil is used as a continuous phase to form an oil-in-water stable emulsion, which can not only retain the characteristics of oil-based products, but also greatly reduce costs. DETAILED DESCRIPTION

[0019] The present invention is not limited by the following embodiments, and specific implementation methods can be determined according to the technical scheme of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all known and commonly used chemical reagents and chemicals in the prior art.

[0020] The present invention will be further described below in conjunction with embodiments: Example 1: The emulsion type annulus protection fluid, in terms of mass percentage, includes: 1% to 2% anti-carbon dioxide corrosion inhibitor, 1% to 2% desulfurizer, 1% to 2% bactericide, 1% to 5% surfactant, 40% to 60% organic oil, 0.1% to 2% emulsion polymer stabilizer, and 5% to 50% water. The emulsion type annulus protection fluid is prepared according to the following method: add the required amount of anti-carbon dioxide corrosion inhibitor, desulfurizer, bactericide, surfactant, emulsion polymer stabilizer and water to the required amount of organic oil, mix and stir to obtain the emulsion type annulus protection fluid.

[0021] The emulsion type annulus protection fluid of the present invention has a good protection effect on the wellbore tubulars of wells containing carbon dioxide and hydrogen sulfide, and uses organic oil as a continuous phase to form an oil-in-water stable emulsion, which is relatively low in cost compared to pure oil-based annulus protection fluids.

[0022] Example 2: As an optimization of the above example, the anti-carbon dioxide corrosion inhibitor was prepared according to the following method: S01, uniformly mixing a required amount of macromolecular petroleum acid and polyamine and reacting them to obtain an intermediate 1; S02, mixing the intermediate 1 and a required amount of guanidine hydrochloride uniformly and reacting them to obtain the intermediate 2; S03, adding a solvent and a chain transfer agent to a required amount of monomer, and then adding a required amount of initiator to react to obtain an intermediate three; S04, mixing the intermediate 2, the intermediate 3 and a required amount of polyetheramine uniformly and reacting them to obtain a first polymer; S05, reacting a required amount of the intermediate 1 obtained in step S01 with a polycarboxylic acid to obtain a first reaction product; S06, mixing the chlorine-containing compound with the first reaction product and performing a cross-linking reaction to obtain a second polymer; S07, mixing the obtained first polymer, the second polymer and the modified imidazoline and compounding them to obtain a carbon dioxide corrosion inhibitor, wherein the required amount of the intermediate 1 obtained in step S01, guanidine hydrochloride and a primary amine are mixed and reacted to obtain a modified imidazoline.

[0023] Example 3: As an optimization of the above example, in step S01, the molar ratio of macromolecular petroleum acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 9h to 11h, wherein the polyamine is polyethylene polyamine, and the macromolecular petroleum acid is a by-product in the petroleum refining process; in step S02, the molar ratio of intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 140°C to 150°C, and the reaction time is 2.5h to 3.5h; in step S03, the monomer It is one or more of acrylic acid, maleic anhydride, and methacrylic acid, the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, xylene, trimethylbenzene, dimethyl sulfoxide, and dimethylformamide, the chain transfer agent is n-dodecyl mercaptan, the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature is 60°C to 120°C, and the reaction time is 3.5h to 4.5h. In step S04, the polyetheramine is one of D350 and D600, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

[0024] Example 4: As an optimization of the above example, in step S05, the polycarboxylic acid is one of adipic acid and oxalic acid, the molar ratio of the polycarboxylic acid to the intermediate one is 1:1 to 2, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h. In step S06, the chlorine-containing compound is 1,4-dichlorobenzyl, the molar ratio of the chlorine-containing compound to the first reaction product is 1:1 to 2, the reaction temperature is 70°C to 100°C, and the reaction time is 3.5h to 4.5h. In step S07, the molar ratio of the intermediate one, guanidine hydrochloride and the primary amine is 1:1:1, the reaction temperature is 145°C to 155°C, and the reaction time is 3.5h to 4.5h, wherein the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0025] In the present invention, when preparing the carbon dioxide corrosion inhibitor, the chemical reaction mechanism of obtaining the intermediate 1 is as follows: The value range of k is 2 to 10.

[0026] The chemical reaction mechanism to obtain intermediate 2 is as follows: The value range of k is 2 to 10.

[0027] The chemical reaction mechanism to obtain intermediate 3 is as follows: The chemical reaction mechanism for obtaining the first polymer is as follows: The values ​​of a, b, c and k are all in the range of 2 to 10.

[0028] The chemical reaction mechanism to obtain the first reaction product is as follows: The value range of k is 2 to 10.

[0029] The chemical reaction mechanism to obtain the second polymer is as follows: The value ranges of k and d are both 2 to 10.

[0030] The chemical reaction mechanism for obtaining modified imidazoline is as follows: The value ranges of k and d are both 2 to 10.

[0031] Example 5: As an optimization of the above example, the desulfurizer was prepared according to the following method: S11, mixing a required amount of alcohol amine and aldehyde and reacting them to obtain a desulfurizing agent intermediate; S12, vacuum dehydrating and purifying the desulfurizing agent intermediate, and then sequentially adding required amounts of polycarboxylic acid, high carbonic acid, catalyst, and xylene to react to obtain a desulfurizing agent.

[0032] Example 6: As an optimization of the above example, in step S11, the alcoholamine is monoethanolamine, and the aldehyde is formaldehyde, wherein the molar ratio of the alcoholamine to the aldehyde is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 60°C to 80°C, and the reaction time is 2h to 4h.

[0033] Example 7: As an optimization of the above example, in step S12, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic acid, the percarbonic acid is one or more of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid, and the catalyst is one of dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and aminosulfonic acid, wherein the molar ratio of the polycarboxylic acid to the desulfurizer intermediate is 1:1 to 2, the molar ratio of the percarbonic acid to the desulfurizer intermediate is 1:1 to 2, the mass of the catalyst added is 0.5% to 2.5% of the mass of the desulfurizer intermediate, the reaction temperature is 120°C to 150°C, and the reaction time is 2h to 10h.

[0034] Example 8: As an optimization of the above example, the fungicide is an oil-soluble polymerized guanidine, which is prepared according to the following method: S21, mixing a required amount of petroleum acid and polyethylene polyamine and reacting them to obtain an intermediate 1; S22, mixing the intermediate 1 and a required amount of guanidine hydrochloride uniformly and reacting them to obtain the intermediate 2; S23, uniformly mixing the reaction monomer, the solvent and the chain transfer agent, and then adding a required amount of initiator to react to obtain a reaction product; S24, adding intermediate 2 and a required amount of p-toluenesulfonic acid to the reaction product and reacting to obtain an oil-soluble polymerized guanidine.

[0035] Example 9: As an optimization of the above example, in step S21, the molar ratio of petroleum acid to polyethylene polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 10h to 12h; in step S22, the molar ratio of intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 150°C to 180°C, and the reaction time is 2h to 4h.

[0036] Example 10: As an optimization of the above example, in step S23, the reaction monomer is one or more of acrylic acid, methyl acrylate, ethyl acrylate, and maleic anhydride, the solvent is xylene, the chain transfer agent is n-dodecyl mercaptan, and the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide.

[0037] Embodiment 11: As an optimization of the above embodiment, the surfactant is one or more of a sorbitan fatty acid ester surfactant, a Tween emulsifier, EO-50, PO-50, a monostearate emulsifier, and a distearate emulsifier.

[0038] Example 12: As an optimization of the above example, the surfactant is Tween 80 or Tween 60.

[0039] Example 13: As an optimization of the above example, the organic oil is one of vegetable oil, bio-oil, and biomass diesel.

[0040] Example 14: As an optimization of the above example, the emulsion polymer stabilizer is one of polyacrylic acid, polymethyl acrylate, polyethyl acrylate, acrylic acid-methyl acrylate copolymer, and ethylene-vinyl acetate.

[0041] Example 15: The preparation method of the emulsion type annulus protection fluid is carried out according to the following method: add the required amount of anti-carbon dioxide corrosion inhibitor, desulfurizer, bactericide, surfactant, emulsion polymer stabilizer and water to the required amount of organic oil, mix and stir to obtain the emulsion type annulus protection fluid.

[0042] Example 16: In the emulsion type annular space protection fluid, The anti-carbon dioxide corrosion inhibitor is prepared according to the following method: In the first step, 350 kg (1 kmol) of macromolecular petroleum acid (molecular weight 350) and 439 kg (1 kmol) of polyethylene polyamine (molecular weight 439) were added to the reactor, mixed evenly, and then slowly heated to 280°C, and refluxed for 10 hours to obtain intermediate 1; In the second step, the intermediate 1 is mixed evenly with 95.5 kg (1 kmol) of guanidine hydrochloride, and the temperature is controlled at 150°C for 3 hours to obtain the intermediate 2; Step 3: Take 200 kg of solvent (ethanol), add 100 kg of monomer (acrylic acid), 2 kg of chain transfer agent (n-dodecyl mercaptan), control the temperature at 80°C, add 0.4 kg of initiator (azobisisobutyronitrile) (add in 4 times, 0.1 kg / h), react for 4 hours, and remove the solvent by vacuum dehydration to obtain intermediate 3; Step 4: 884.5 kg of intermediate 2 and 302 kg of intermediate 3 were mixed evenly, 50 kg of polyetheramine (D350) was added, and the temperature was controlled at 150° C. to react for 4 hours to obtain the first polymer (comb-shaped imidazoline); Step 5: Take 789 kg of intermediate 1 and 73 kg of adipic acid (0.5 kmol), control the temperature at 150°C for 4 hours, then add 87.5 kg (0.5 kmol) of 1,4-dichlorobenzyl chloride, and react at 80°C for 4 hours to obtain a second polymer (linear structure imidazoline); Step 6: Take 789 kg of intermediate 1, 95.5 kg of guanidine hydrochloride, and 214.5 kg of hexadecyl primary amine, and react at 150° C. for 4 hours to prepare modified imidazoline; Step 7: Mix the first polymer, the second polymer, and the modified imidazoline in a mass ratio of 9:0.5:0.5, and stir evenly to obtain a carbon dioxide corrosion inhibitor; The desulfurizer is prepared according to the following method: 1830 kg of ethanolamine was added to the kettle, stirring was started and the temperature was controlled at 60°C, 2500 kg (mass percentage was 36%) of formaldehyde aqueous solution was slowly added dropwise, after the addition was completed, the reaction was continued at 60°C for 3 hours to obtain a desulfurizer intermediate (i.e., a triazine desulfurizer), the desulfurizer intermediate was vacuum dehydrated for 2 hours, 181 kg of adipic acid, 11.5 kg of aminosulfonic acid, 4510 kg of octadecanoic acid were added, 2710 kg of xylene was added, the temperature was controlled at 140°C for 6 hours to obtain a cross-linked and oil-soluble desulfurizer; The fungicide was prepared according to the following method: Add 200 kg of macromolecular petroleum acid and 200 kg of polyethylene polyamine to the reactor, stir evenly, slowly heat to 280°C, reflux for 10 hours to prepare intermediate 1, then add 7 kg of guanidine hydrochloride, control the temperature at 150°C for 3 hours to prepare intermediate 2, take 50 kg of xylene, add 5 kg of methyl acrylate and 0.1 kg of dodecanethiol, control the temperature at 80°C, add 0.1 g of azobisisobutyronitrile (AIBN) for 4 hours to obtain a reaction product, then add intermediate 2 and 2 kg of p-toluenesulfonic acid to the reaction product, control the temperature at 150°C for 4 hours to obtain a fungicide (i.e., oil-soluble polymerized guanidine); Take 1000 kg of biomass diesel, add 40 kg of the above-obtained anti-carbon dioxide corrosion inhibitor, 40 kg of desulfurizer, 40 kg of fungicide, 100 kg of span80, 10 kg of Tween 80, 20 kg of polyacrylic acid, and 1000 kg of tap water, mix and stir for 3 hours to obtain an emulsion type annulus protection liquid.

[0043] Example 17: In the emulsion type annular space protection fluid, The difference between the preparation method of the anti-carbon dioxide corrosion inhibitor and Example 16 is that in the third step, the added monomer is methacrylic acid; The desulfurizer is prepared according to the following method: 1830 kg of ethanolamine was added to the kettle, stirring was started and the temperature was controlled at 60°C, 2500 kg (mass percentage was 36%) of formaldehyde aqueous solution was slowly added dropwise, and after the addition was completed, the reaction was continued at 60°C for 3 hours to obtain a desulfurizer intermediate (i.e., a triazine desulfurizer), the desulfurizer intermediate was vacuum dehydrated for 2 hours, 181 kg of glutaric acid, 11.5 kg of p-toluenesulfonic acid, 4510 kg of hexadecanoic acid were added, and 2710 kg of xylene was added, and the temperature was controlled at 140°C for 6 hours to obtain a cross-linked and oil-soluble desulfurizer; The fungicide was prepared according to the following method: Add 200 kg of macromolecular petroleum acid and 200 kg of polyethylene polyamine to the reactor, stir evenly, slowly heat to 280°C, reflux for 10 hours to prepare intermediate 1, then add 7 kg of guanidine hydrochloride, control the temperature at 150°C for 3 hours to prepare intermediate 2, take 50 kg of xylene, add 6 kg of ethyl acrylate and 0.1 kg of dodecanethiol, control the temperature at 80°C, add 0.1 g of dibenzoyl peroxide (BPO) and react for 4 hours to obtain a reaction product, then add intermediate 2 and 2 kg of p-toluenesulfonic acid to the reaction product, control the temperature at 150°C for 4 hours to obtain a fungicide (i.e., oil-soluble polymerized guanidine); Take 1000 kg of biomass diesel, add 40 kg of the above-obtained anti-carbon dioxide corrosion inhibitor, 40 kg of desulfurizer, 40 kg of fungicide, 100 kg of span85, 10 kg of Tween 60, 20 kg of acrylic acid-methyl acrylate copolymer, and 1000 kg of tap water, mix and stir for 3 hours to obtain an emulsion type annular space protection liquid.

[0044] Example 18: In the emulsion type annular space protection fluid, The difference between the preparation method of the anti-carbon dioxide corrosion inhibitor and Example 16 is that in the sixth step, 214.5 kg of hexadecyl primary amine is replaced by 185.3 kg of dodecyl primary amine; The desulfurizer is prepared according to the following method: 1830 kg of ethanolamine was added to the kettle, stirring was started and the temperature was controlled at 60°C, 2500 kg (mass percentage was 36%) of formaldehyde aqueous solution was slowly added dropwise, and after the addition was completed, the reaction was continued at 60°C for 3 hours to obtain a desulfurizer intermediate (i.e., a triazine desulfurizer), the desulfurizer intermediate was vacuum dehydrated for 2 hours, 181 kg of glutaric acid, 11.5 kg of p-toluenesulfonic acid, 4510 kg of hexadecanoic acid were added, and 2710 kg of xylene was added, and the temperature was controlled at 140°C for 6 hours to obtain a cross-linked and oil-soluble desulfurizer; The fungicide was prepared according to the following method: Add 200 kg of macromolecular petroleum acid (weight average molecular weight 350 g / mol) and 251 kg of polyethylene polyamine into the reactor, stir evenly, slowly heat to 280°C, reflux for 10 hours to prepare intermediate 1, then add 7 kg of guanidine hydrochloride, control the temperature at 150°C for 3 hours to prepare intermediate 2, take 50 kg of xylene, add 6 kg of ethyl acrylate and 0.1 kg of dodecanethiol, control the temperature at 80°C, add 0.1 g of dibenzoyl peroxide (BPO) and react for 4 hours to obtain a reaction product, then add intermediate 2 and 2 kg of p-toluenesulfonic acid to the reaction product, control the temperature at 150°C for 4 hours to obtain a fungicide (i.e., oil-soluble polymerized guanidine); Take 1000 kg of biomass diesel, add 40 kg of the above-obtained anti-carbon dioxide corrosion inhibitor, 40 kg of desulfurizer, 40 kg of fungicide, 100 kg of span85, 10 kg of Tween 60, 20 kg of ethylene vinyl acetate, and 1000 kg of tap water, mix and stir for 3 hours to obtain an emulsion type annular space protection liquid.

[0045] Example 19: In the emulsion type annular space protection fluid, The difference between the preparation method of the carbon dioxide corrosion inhibitor and that of Example 16 is that 73 kg of adipic acid is replaced by 87 kg of suberic acid; The desulfurizer is prepared according to the following method: 1830 kg of ethanolamine was added to the kettle, stirring was started and the temperature was controlled at 60°C, 2500 kg (mass percentage was 36%) of formaldehyde aqueous solution was slowly added dropwise, after the addition was completed, the reaction was continued at 60°C for 3 hours to obtain a desulfurizer intermediate (i.e., a triazine desulfurizer), the desulfurizer intermediate was vacuum dehydrated for 2 hours, 181 kg of adipic acid, 11.5 kg of aminosulfonic acid, 4510 kg of octadecanoic acid were added, 2710 kg of xylene was added, the temperature was controlled at 140°C for 6 hours to obtain a cross-linked and oil-soluble desulfurizer; The fungicide was prepared according to the following method: Add 200 kg of macromolecular petroleum acid (weight average molecular weight 350 g / mol) and 251 kg of polyethylene polyamine into the reactor, stir evenly, slowly heat to 280°C, reflux for 10 hours to prepare intermediate 1, then add 7 kg of guanidine hydrochloride, control the temperature at 150°C for 3 hours to prepare intermediate 2, take 50 kg of xylene, add 5 kg of methyl acrylate and 0.1 kg of dodecanethiol, control the temperature at 80°C, add 0.1 g of azobisisobutyronitrile (AIBN) for 4 hours to obtain a reaction product, then add intermediate 2 and 2 kg of p-toluenesulfonic acid to the reaction product, control the temperature at 150°C for 4 hours to obtain a fungicide (i.e., oil-soluble polymerized guanidine); Take 1000 kg of biomass diesel, add 40 kg of the above-obtained anti-carbon dioxide corrosion inhibitor, 40 kg of desulfurizer, 40 kg of fungicide, 100 kg of span85, 10 kg of Tween 60, 20 kg of ethylene vinyl acetate, and 1000 kg of tap water, mix and stir for 3 hours to obtain an emulsion type annular space protection liquid.

[0046] Example 20: In the emulsion type annular space protection fluid, The difference between the preparation method of the anti-carbon dioxide corrosion inhibitor and Example 16 is that in the third step, the initiator is dibenzoyl peroxide; The desulfurizer is prepared according to the following method: 1830 kg of ethanolamine was added to the kettle, stirring was started and the temperature was controlled at 60°C, 2500 kg (mass percentage was 36%) of formaldehyde aqueous solution was slowly added dropwise, and after the addition was completed, the reaction was continued at 60°C for 3 hours to obtain a desulfurizer intermediate (i.e., a triazine desulfurizer), the desulfurizer intermediate was vacuum dehydrated for 2 hours, 181 kg of glutaric acid, 11.5 kg of p-toluenesulfonic acid, 4510 kg of hexadecanoic acid were added, and 2710 kg of xylene was added, and the temperature was controlled at 140°C for 6 hours to obtain a cross-linked and oil-soluble desulfurizer; The fungicide was prepared according to the following method: Add 200 kg of macromolecular petroleum acid (weight average molecular weight 350 g / mol) and 251 kg of polyethylene polyamine into the reactor, stir evenly, slowly heat to 280°C, reflux for 10 hours to prepare intermediate 1, then add 7 kg of guanidine hydrochloride, control the temperature at 150°C for 3 hours to prepare intermediate 2, take 50 kg of xylene, add 5 kg of methyl acrylate and 0.1 kg of dodecanethiol, control the temperature at 80°C, add 0.1 g of azobisisobutyronitrile (AIBN) for 4 hours to obtain a reaction product, then add intermediate 2 and 2 kg of p-toluenesulfonic acid to the reaction product, control the temperature at 150°C for 4 hours to obtain a fungicide (i.e., oil-soluble polymerized guanidine); Take 1000 kg of biomass diesel, add 40 kg of the above-obtained anti-carbon dioxide corrosion inhibitor, 40 kg of desulfurizer, 40 kg of fungicide, 100 kg of span85, 10 kg of Tween 60, 20 kg of ethylene vinyl acetate, and 1000 kg of tap water, mix and stir for 3 hours to obtain an emulsion type annular space protection liquid.

[0047] The performance test and evaluation of the emulsion type annular space protection fluid obtained in Examples 16 to 20 of the present invention were carried out The specific evaluation method is: a 1.5L stainless steel corrosion evaluation kettle is used to conduct the corrosion test. Appropriate amounts of the emulsion annular space protection fluid samples obtained in Examples 16 to 20 of the present invention are respectively injected into the kettle, the autoclave is sealed, nitrogen is introduced for 5 hours, the total pressure is 7.0MPa, the system is heated to 80°C, H2S and CO2 gases are introduced, the H2S partial pressure is 1.0MPa, and the CO2 partial pressure is 1.0MPa. The corrosion test is conducted on the A3 steel sheet and the N80 steel sheet for 72 hours. The experimental results are shown in Table 1.

[0048] Table 1 .

[0049] As shown in Table 1, the emulsion type annular space protection fluid of the present invention has good thermal stability. After reacting for 72 hours under the environment of total pressure of 7.0MPa, H2S partial pressure of 1.0MPa, CO2 partial pressure of 1.0MPa, and 80°C, the corrosion rate of A3 steel sheet is ≤0.0011mm / a, and the corrosion rate of N80 steel sheet is ≤0.0037mm / a; it has good bactericidal effect, and the bactericidal effect is ≤3 / mL, which can meet the corrosion protection requirements of the annular space of ordinary carbon steel pipes in a high carbonic acid environment.

[0050] The beneficial effects of the present invention are as follows: The anti-carbon dioxide corrosion inhibitor used in the present invention has strong hydrophobicity and significantly improves the corrosion inhibition performance compared with common oleic acid imidazoline; The desulfurizer used in the present invention realizes polycyclic azide by condensing dibasic or tribasic carboxylic acid with triazine desulfurizer. The polycyclic azide desulfurizer has a distinct polycyclic coupling structure. The special coupling group can realize efficient chain decomposition when reacting with sulfur, and the desulfurization performance is higher than that of the traditional single-ring structure. The bactericide used in the present invention is prepared by imidazoline, and has the dual functions of corrosion inhibition and bactericidal. In addition, after further cross-linking, the bactericidal and corrosion inhibition capabilities can be further enhanced.

[0051] The present invention introduces the water of the emulsified part of the emulsion type annular space protection fluid into the system to form a stable oil-in-water emulsion, which can retain the characteristics of the oil-based product and greatly reduce the cost.

[0052] Therefore, the emulsion type annulus protection fluid provided by the present invention has good thermal stability and strong high temperature resistance. Under the environment of total pressure of 7.0MPa, H2S partial pressure of 1.0MPa and CO2 partial pressure of 1.0MPa, the corrosion rate of A3 steel sheet is ≤0.0011mm / a, and the corrosion rate of N80 steel sheet is ≤0.0037mm / a after reacting at 80°C for 72h. The bactericidal effect of saprophytes, iron bacteria and sulfate-reducing bacteria (SRB) is ≤3 / mL, which can effectively prevent the corrosion damage of the wellbore environment to the oil casing, provide continuous protection capability, greatly extend the service life of the wellbore annulus string, reduce the cost of oil and gas production, and meet the needs of annulus protection of highly carbonated oil and gas wells. At the same time, the oil phase adopts biomass oil, which is free of aromatics, has reduced harm to human body and environment, and biomass oil is renewable.

[0053] In summary, the emulsion-type annulus protection fluid of the present invention has a simple preparation process and good anti-corrosion effect, and has a good protective effect on the wellbore tubing of wells containing carbon dioxide and hydrogen sulfide. At the same time, organic oil is used as a continuous phase to form an oil-in-water stable emulsion, which can not only retain the characteristics of oil-based products, but also greatly reduce costs.

[0054] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. An emulsion type annular space protection fluid, characterized in that Calculated by mass percentage, it includes: 1% to 2% anti-carbon dioxide corrosion inhibitor, 1% to 2% desulfurizer, 1% to 2% bactericide, 1% to 5% surfactant, 40% to 60% organic oil, 0.1% to 2% emulsion polymer stabilizer, and 5% to 50% water. The emulsion type annulus protection fluid is prepared according to the following method: add the required amount of anti-carbon dioxide corrosion inhibitor, desulfurizer, bactericide, surfactant, emulsion polymer stabilizer and water to the required amount of organic oil, mix and stir to obtain the emulsion type annulus protection fluid.

2. The emulsion type annulus protection fluid according to claim 1, characterized in that The anti-carbon dioxide corrosion inhibitor is prepared according to the following method: S01, uniformly mixing a required amount of macromolecular petroleum acid and polyamine and reacting them to obtain an intermediate 1; S02, mixing the intermediate 1 and a required amount of guanidine hydrochloride uniformly and reacting them to obtain the intermediate 2; S03, adding a solvent and a chain transfer agent to a required amount of monomer, and then adding a required amount of initiator to react to obtain an intermediate three; S04, mixing the intermediate 2, the intermediate 3 and a required amount of polyetheramine uniformly and reacting them to obtain a first polymer; S05, reacting a required amount of the intermediate 1 obtained in step S01 with a polycarboxylic acid to obtain a first reaction product; S06, mixing the chlorine-containing compound with the first reaction product and performing a cross-linking reaction to obtain a second polymer; S07, mixing the obtained first polymer, the second polymer and the modified imidazoline and compounding them to obtain a carbon dioxide corrosion inhibitor, wherein the required amount of the intermediate 1 obtained in step S01, guanidine hydrochloride and a primary amine are mixed and reacted to obtain a modified imidazoline.

3. The emulsion type annulus protection fluid according to claim 2, characterized in that In step S01, the molar ratio of the macromolecular petroleum acid to the polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 9h to 11h, wherein the polyamine is polyethylene polyamine and the macromolecular petroleum acid is a by-product in the petroleum refining process; or / and, in step S02, the molar ratio of the intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 140°C to 150°C, and the reaction time is 2 .5h to 3.5h; or / and, in step S03, the monomer is one or more of acrylic acid, maleic anhydride, and methacrylic acid, the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, xylene, trimethylbenzene, dimethyl sulfoxide, and dimethylformamide, the chain transfer agent is n-dodecyl mercaptan, the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature is 60°C to 120°C, and the reaction time is 3.5h to 4.5h; or / and, in step S04, the polyetheramine is one of D350 and D600, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h; or / and, in step S05, the polycarboxylic acid is one of adipic acid and oxalic acid, the molar ratio of the polycarboxylic acid to the intermediate 1 is 1:1 to 2, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h; or / and, in step S06, the chlorine-containing compound is 1,4- benzyl dichloride, the molar ratio of the chlorine-containing compound to the first reaction product is 1:1 to 2, the reaction temperature is 70°C to 100°C, and the reaction time is 3.5h to 4.5h; or / and, in step S07, the molar ratio of the intermediate 1, guanidine hydrochloride and the primary amine is 1:1:1, the reaction temperature is 145°C to 155°C, and the reaction time is 3.5h to 4.5h, wherein the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

4. The emulsion type annulus protection fluid according to claim 1, 2 or 3, characterized in that The desulfurizer is prepared according to the following method: S11, mixing a required amount of alcohol amine and aldehyde and reacting them to obtain a desulfurizing agent intermediate; S12, vacuum dehydrating and purifying the desulfurizing agent intermediate, and then sequentially adding required amounts of polycarboxylic acid, high carbonic acid, catalyst, and xylene to react to obtain a desulfurizing agent.

5. The emulsion type annulus protection fluid according to claim 4, characterized in that In step S11, the alcohol amine is monoethanolamine, and the aldehyde is formaldehyde, wherein the molar ratio of the alcohol amine to the aldehyde is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 60°C to 80°C, and the reaction time is 2h to 4h; or / and, in step S12, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic acid, the percarbonic acid is one or more of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid, and the catalyst is one of dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and aminosulfonic acid, wherein the molar ratio of the polycarboxylic acid to the desulfurizer intermediate is 1:1 to 2, the molar ratio of the percarbonic acid to the desulfurizer intermediate is 1:1 to 2, the mass of the catalyst added is 0.5% to 2.5% of the mass of the desulfurizer intermediate, the reaction temperature is 120°C to 150°C, and the reaction time is 2h to 10h.

6. The emulsion type annulus protection fluid according to claim 5, characterized in that The bactericide is an oil-soluble polymerized guanidine, which is prepared according to the following method: S21, mixing a required amount of petroleum acid and polyethylene polyamine and reacting them to obtain an intermediate 1; S22, mixing the intermediate 1 and a required amount of guanidine hydrochloride uniformly and reacting them to obtain the intermediate 2; S23, uniformly mixing the reaction monomer, the solvent and the chain transfer agent, and then adding a required amount of initiator to react to obtain a reaction product; S24, adding intermediate 2 and a required amount of p-toluenesulfonic acid to the reaction product and reacting to obtain an oil-soluble polymerized guanidine.

7. The emulsion type annulus protection fluid according to claim 6, characterized in that In step S21, the molar ratio of petroleum acid to polyethylene polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 10h to 12h; or / and, in step S22, the molar ratio of intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 150°C to 180°C, and the reaction time is 2h to 4h; or / and, in step S23, the reaction monomer is one or more of acrylic acid, methyl acrylate, ethyl acrylate, and maleic anhydride, the solvent is xylene, the chain transfer agent is n-dodecyl mercaptan, and the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide.

8. The emulsion type annulus protection fluid according to claim 6 or 7, characterized in that The surfactant is one or more of a sorbitan fatty acid ester surfactant, a Tween emulsifier, EO-50, PO-50, a monostearate emulsifier, and a distearate emulsifier; or / and the organic oil is one of a vegetable oil, a bio-oil, and a biodiesel; or / and the emulsion polymer stabilizer is one of a polyacrylic acid, a polymethyl acrylate, a polyethyl acrylate, an acrylic acid-methyl acrylate copolymer, and an ethylene-vinyl acetate.

9. The emulsion type annulus protection fluid according to claim 8, characterized in that The surfactants are Tween 80 and Tween 60.

10. A method for preparing an emulsion type annulus protection fluid according to any one of claims 1 to 9, characterized in that The method is as follows: add the required amount of anti-carbon dioxide corrosion inhibitor, desulfurizer, bactericide, surfactant, emulsion polymer stabilizer and water to the required amount of organic oil, mix and stir to obtain an emulsion type annular space protection fluid.

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