Water-based annulus protection fluid and preparation method thereof

Abstract

The invention relates to the technical field of oilfield chemistry, in particular to a water-based annulus protection fluid and a preparation method thereof.The water-based annulus protection fluid is prepared from, by mass, 0.1%-2% of an acid-gas-resistant corrosion inhibitor, 0.1%-2% of a polycyclic azide structure sulfur removal agent, 0.1%-2% of a polymerized guanidine bactericide, 0.1%-5% of a deoxidant, 0.1%-2% of a pH regulator and the balance water; the method comprises the following steps: adding a required amount of an acid-gas-resistant corrosion inhibitor, a polycyclic azide structure sulfur removal agent, a polymeric guanidine bactericide, a deoxidant and a pH regulator into water, and mixing and stirring to obtain the water-based annulus protection liquid. The corrosion inhibitor has a good corrosion inhibition effect under the simulated working condition, the corrosion inhibition rate is lower than 0.05 mm / a and far lower than the corresponding industrial standard, the scale inhibition rate and the sterilization rate meet the industrial standard, the corrosion inhibitor has a good protection function on the inner wall of a sleeve and the outer wall of an oil and gas pipeline in an annular space under the acid environment, the service life is prolonged, and safe production of an oil field is guaranteed.

Description

Technical Field

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

[0002] Annulus protection fluid is a liquid filled in the annular space between the oil and gas pipes and the casing. It is mainly used to protect the casing, tubing and downhole operating tools in the oil and casing annulus, reduce the reservoir pressure borne by the casing head or packer, reduce the pressure difference between the tubing or gas pipe and the annulus, inhibit the corrosion, scaling and bacterial growth of the tubing or gas pipe and casing, and extend the life of the injection and production wells.

[0003] During the production process, the annular medium usually has a high mineralization and high concentration of scaling ions, which causes serious scaling of the oil and casing, pipeline blockage and under-scale corrosion. At the same time, the oil-casing annular space often has CL in the annular medium due to sealing problems. - , CO2 and H2S and other corrosive factors cause corrosion of oil and casing lines. In addition, there are certain microorganisms in the annular space, such as sulfate-reducing bacteria, iron bacteria and other corrosive bacteria, which can cause deterioration of the stagnant water quality of the oil and casing annulus, microbial corrosion and blockage of the oil and casing. Therefore, the annular space protection fluid must have the main functions of corrosion inhibition, scale inhibition and sterilization. Under necessary conditions, additives such as density regulators and pH regulators will also be added to meet production needs.

[0004] The Chinese patent document with the authorization announcement number CN106520101B discloses an annular space protection liquid, the raw materials of which include 5%-15% of halides, 10%-20% of organic acid salts, 2%-4% of imidazoline corrosion inhibitors, 1%-4% of oxime deoxidizers, 0.5%-2% of zwitterionic bactericides, 1.5%-3% of polymer scale inhibitors and the balance of water. The introduction of halide ions into the system has a potential pitting risk for oil pipes and casings, and the application process is quite different from the actual working conditions.

[0005] The Chinese patent document with the authorization announcement number CN102816560B discloses a high-temperature annular space protection fluid and a preparation method thereof, wherein the protection fluid is made of the following raw materials in weight ratio: 0.14-83.70% organic salt, 0.1-0.5% bactericide, 0.1-0.5% deoxidizer, 1.5-2.0% gas well corrosion inhibitor, 0.7-1.3% pH value regulator, and the rest is distilled water. The system has a density adjustment function, but the system has a high corrosion rate for N80 steel sheets, and does not consider the effect of acidic gas on the corrosion performance of the annular space protection fluid.

[0006] A Chinese patent document with authorization announcement number CN105220157B discloses a protective liquid and a method for preparing the protective liquid. The protective liquid includes the following components and weight ratio: 98.5-99.2 parts of seawater and 0.6-1 parts of modified sodium metaborate; the modified sodium metaborate includes sodium metaborate and sodium bicarbonate. The annular space protective liquid has good compatibility with seawater, but its anti-corrosion and anti-scaling properties need to be further investigated and improved.

[0007] The above-mentioned currently disclosed annulus protection fluids are all water-based systems. In actual applications, they cannot meet the corrosion and scale inhibition requirements of the annulus of oil wells with high mineralization and strong acidity. Although the oil-based system has the advantage of good corrosion inhibition effect compared with the water-based system, the system components are more complex and easily cause environmental pollution. When encountering a highly mineralized water environment, it is very easy to deposit and clog. In addition, it is expensive and has few field applications. Therefore, the water-based system annulus protection fluid is still the first choice for the annulus protection liquid after completion because of its simple construction and low cost. Therefore, the development of a water-based annulus protection fluid suitable for the coexistence of CO2, O2 and H2S and containing complex bacteria has become a new demand for the development of annulus protection fluids. Summary of the invention

[0008] The present invention provides a water-based annulus protection fluid and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of corrosion and scaling of casing and oil and gas pipelines and scaling caused by bacterial growth in the existing water-based annulus protection fluid, which can lead to corrosion and pipeline blockage.

[0009] One of the technical solutions of the present invention is achieved through the following measures: a water-based annular space protection fluid, wherein the raw materials, calculated by mass percentage, include 0.1% to 2% of an acidic gas corrosion inhibitor, 0.1% to 2% of a polycyclic azide structure desulfurizer, 0.1% to 2% of a polymerized guanidine fungicide, 0.1% to 5% of a deoxidizer, 0.1% to 2% of a pH regulator, and the rest is water. The water-based annular space protection fluid is prepared according to the following method: adding the required amount of an acidic gas corrosion inhibitor, a polycyclic azide structure desulfurizer, a polymerized guanidine fungicide, a deoxidizer and a pH regulator to water, mixing and stirring to obtain a water-based annular space protection fluid.

[0010] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above-mentioned acid gas corrosion inhibitor is prepared according to the following method: S01, mixing a required amount of dicarboxylic acid and polyamine and reacting them to obtain an intermediate 1; S02, mixing the intermediate 1 with a required amount of dicarboxylic acid and reacting them to obtain the intermediate 2; S03, mixing the intermediate 2 with a required amount of halogenated alkane and reacting them to obtain a first polymer; S04, reacting a required amount of the intermediate 1 obtained in step S01 with a chlorine-containing compound to obtain an intermediate 3; S05, mixing the intermediate three with a required amount of guanidine hydrochloride and a primary amine and reacting them to obtain a second polymer; S06, mixing the obtained first polymer and the second polymer evenly and compounding them to obtain an anti-acid gas corrosion inhibitor.

[0011] In the above step S01, the molar ratio of dicarboxylic 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. In step S02, the molar ratio of intermediate 1 to dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145°C to 155°C, and the reaction time is 2.5h to 3.5h.

[0012] In the above step S03, the halogenated alkane is one of brominated dodecane, brominated hexadecane, chlorododecane, and chlorohexadecane; in step S04, the molar ratio of the intermediate 1 to the chlorine-containing compound is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 70° C. to 100° C., the reaction time is 2.5 h to 3.5 h, and the chlorine-containing compound is 1,4-dichlorobenzyl.

[0013] In the above step S05, the molar ratio of intermediate three to guanidine hydrochloride and primary amine is 0.9 to 1.1:1.5 to 2:1.5 to 2, the reaction temperature is 145°C to 155°C, the reaction time is 3.5h to 4.5h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0014] The above-mentioned polycyclic azide structure 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, catalyst, and xylene to react to obtain a polycyclic azide structure desulfurizing agent.

[0015] In the above step S11, the alcoholamine is monoethanolamine, 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 2 h to 4 h.

[0016] In the above step S12, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic 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 added mass of the catalyst 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.

[0017] The above-mentioned polymerized guanidine fungicide is a water-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 an intermediate three; S24, mixing the intermediate 3 and the intermediate 2 evenly, adding a required amount of catalyst to react, and after the reaction is completed, adding a sodium hydroxide aqueous solution to adjust the pH value to obtain a water-soluble polymerized guanidine.

[0018] 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 10 h to 12 h.

[0019] In the above 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 120° C. to 180° C., and the reaction time is 2 h to 4 h.

[0020] In the above step S23, the reaction monomer is one or more of acrylic acid, methacrylic acid, and maleic anhydride, 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.

[0021] In the above step S24, the catalyst is one of aminosulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid, the reaction temperature is 100° C. to 150° C., the reaction time is 3.5 h to 4.5 h, and the pH value is adjusted to 7 to 8 after adding sodium hydroxide aqueous solution.

[0022] The oxygen scavenger is one or more of an alkali metal salt of isoascorbic acid and dimethyl ketoxime.

[0023] The pH adjusting agent is C2 to C 10 Alkyl alcohol amines, wherein C2 to C 10 The alkyl alcohol amine is one or more of methyldiethanolamine, triethanolamine and isopropanolamine.

[0024] The second technical solution of the present invention is achieved through the following measures: a method for preparing a water-based annular space protection fluid, which is carried out according to the following steps: adding the required amount of anti-acid gas corrosion inhibitor, polycyclic azide structure desulfurizer, polymerized guanidine bactericide, deoxidizer and pH adjuster to water, mixing and stirring to obtain a water-based annular space protection fluid.

[0025] The present invention has good corrosion inhibition effect under simulated working conditions, with a corrosion inhibition rate lower than 0.05 mm / a, which is much lower than the corresponding industry standards. The scale inhibition rate and sterilization rate meet the industry standards. It has good protection function for the inner wall of the casing in the annular space and the outer wall of the oil and gas pipeline in the acidic environment, which not only prolongs the service life but also ensures the safe production of the oil field. DETAILED DESCRIPTION

[0026] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0027] The present invention will be further described below in conjunction with embodiments: Example 1: The water-based annular space protection fluid, the raw materials calculated by mass percentage, include 0.1% to 2% anti-acid gas corrosion inhibitor, 0.1% to 2% polycyclic azide structure desulfurizer, 0.1% to 2% polymeric guanidine fungicide, 0.1% to 5% deoxidizer, 0.1% to 2% pH adjuster, and the rest is water. The water-based annular space protection fluid is prepared according to the following method: add the required amount of anti-acid gas corrosion inhibitor, polycyclic azide structure desulfurizer, polymeric guanidine fungicide, deoxidizer and pH adjuster to water, mix and stir to obtain the water-based annular space protection fluid.

[0028] The acid gas corrosion inhibitor in the water-based annular space protection fluid of the present invention is a quaternary ammonium salt type imidazoline, the polycyclic azide structure desulfurizer contains a polycyclic azide structure, and the polymeric guanidine bactericide is a polymeric guanidine. The water-based annular space protection fluid obtained after mixing has good chemical stability, can effectively delay the corrosion rate of casing and oil and gas pipelines, solve the problems of scaling, bacterial reproduction and the under-scale corrosion and blockage caused thereby, can reduce the pressure difference between the oil and gas pipeline and the annulus, and is suitable for the annular space protection of oil and gas wells, and is particularly suitable for high-acid and high-sulfur oil and gas wells.

[0029] Example 2: As an optimization of the above example, an acid gas corrosion inhibitor was prepared according to the following method: S01, mixing a required amount of dicarboxylic acid and polyamine and reacting them to obtain an intermediate 1; S02, mixing the intermediate 1 with a required amount of dicarboxylic acid and reacting them to obtain the intermediate 2; S03, mixing the intermediate 2 with a required amount of halogenated alkane and reacting them to obtain a first polymer; S04, reacting a required amount of the intermediate 1 obtained in step S01 with a chlorine-containing compound to obtain an intermediate 3; S05, mixing the intermediate three with a required amount of guanidine hydrochloride and a primary amine and reacting them to obtain a second polymer; S06, mixing the obtained first polymer and the second polymer evenly and compounding them to obtain an anti-acid gas corrosion inhibitor.

[0030] In the present invention, the petroleum acid is a macromolecular petroleum acid, and the molecular weight of the macromolecular petroleum acid is 3000 to 10000.

[0031] Example 3: As an optimization of the above example, in step S01, the molar ratio of dicarboxylic 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 in step S02, the molar ratio of intermediate 1 to dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145°C to 155°C, and the reaction time is 2.5h to 3.5h.

[0032] Example 4: As an optimization of the above example, in step S03, the halogenated alkane is one of brominated dodecane, brominated hexadecane, chlorododecane, and chlorohexadecane; in step S04, the molar ratio of intermediate 1 to the chlorine-containing compound is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 70°C to 100°C, the reaction time is 2.5h to 3.5h, and the chlorine-containing compound is 1,4-dichlorobenzyl.

[0033] Example 5: As an optimization of the above example, in step S05, the molar ratio of intermediate three to guanidine hydrochloride and primary amine is 0.9 to 1.1:1.5 to 2:1.5 to 2, the reaction temperature is 145°C to 155°C, the reaction time is 3.5h to 4.5h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0034] When preparing the acid gas corrosion inhibitor in the present invention, the chemical reaction mechanism of obtaining the intermediate 1 is as follows: The value range of k is 2 to 10.

[0035] The chemical reaction mechanism to obtain intermediate 2 is as follows: The value range of k and a is 2 to 10.

[0036] The chemical reaction mechanism for obtaining the first polymer (taking the reaction of intermediate 2 with bromoalkane as an example) is as follows: The value range of k and a is 2 to 10.

[0037] The chemical reaction mechanism to obtain intermediate 3 is as follows: The value ranges of b and k are both 2 to 10.

[0038] The chemical reaction mechanism to obtain the second polymer is as follows: The value ranges of b and k are both 2 to 10.

[0039] Example 6: As an optimization of the above example, a polycyclic azide structure 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, catalyst, and xylene to react to obtain a polycyclic azide structure desulfurizing agent.

[0040] Example 7: 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.

[0041] Example 8: 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, 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 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.

[0042] Example 9: As an optimization of the above example, the polymeric guanidine fungicide is a water-soluble polymeric 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 an intermediate three; S24, mixing the intermediate 3 and the intermediate 2 evenly, adding a required amount of catalyst to react, and after the reaction is completed, adding a sodium hydroxide aqueous solution to adjust the pH value to obtain a water-soluble polymerized guanidine.

[0043] The macromolecular petroleum acid described in the present invention refers to a by-product in the process of petroleum refining.

[0044] Example 10: 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.

[0045] Example 11: As an optimization of the above example, 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 120°C to 180°C, and the reaction time is 2h to 4h.

[0046] Example 12: As an optimization of the above example, in S23, the reaction monomer is one or more of acrylic acid, methacrylic acid, and maleic anhydride, 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.

[0047] Example 13: As an optimization of the above example, in step S24, the catalyst is one of aminosulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid, the reaction temperature is 100°C to 150°C, the reaction time is 3.5h to 4.5h, and the pH value is adjusted to 7 to 8 after adding sodium hydroxide aqueous solution.

[0048] Example 14: As an optimization of the above example, the oxygen scavenger is one or more of alkali metal salt of isoascorbic acid and dimethyl ketoxime.

[0049] Example 15: As an optimization of the above example, the pH adjuster is C2 to C 10 Alkyl alcohol amines, wherein C2 to C 10 The alkyl alcohol amine is one or more of methyldiethanolamine, triethanolamine and isopropanolamine.

[0050] Example 16: The preparation method of the water-based annular space protection fluid is carried out according to the following steps: adding the required amount of anti-acid gas corrosion inhibitor, polycyclic azide structure desulfurizer, polymerized guanidine bactericide, deoxidizer and pH adjuster into water, mixing and stirring to obtain a water-based annular space protection fluid.

[0051] Embodiment 17: (1) Preparation of anti-acid gas corrosion inhibitor: In the first step, 146 kg (1 kmol) of adipic acid and 878 kg (1 kmol) of polyethylene polyamine (molecular weight 439) were added to the reactor, mixed evenly, and then the temperature was slowly raised to 280°C, and refluxed for 10 hours to obtain intermediate 1; In the second step, the intermediate 1 is mixed evenly with 146 kg (1 kmol) of adipic acid, and the temperature is controlled at 150° C. for 3 h to obtain the intermediate 2; Step 3: add 249 kg (1 kmol) of dodecane bromide to the intermediate 2, control the temperature at 80°C and react for 4 hours to obtain the first polymer; Step 4: Take 1024 kg of intermediate 1, add 175 kg (1 kmol) of 1,4-dichlorobenzyl chloride, and react at 80°C for 3 hours to prepare intermediate 3; Step 5: Add 191 kg guanidine hydrochloride (2 kmol) and 429 kg hexadecyl primary amine (2 kmol) to the intermediate 3, and control the temperature at 150°C to react for 4 hours to prepare a second polymer; In the sixth step, the first polymer and the second polymer are mixed at a mass ratio of 1:1, and stirred evenly to obtain an anti-acid gas corrosion inhibitor.

[0052] (2) Preparation of polycyclic azide structure desulfurizer: Add all 1830 kg of alcoholamine (ethanolamine) into the kettle, start stirring and control the temperature at 60°C, slowly drop 2500 kg (volume concentration is 36%) of formaldehyde aqueous solution, after the dropwise addition is completed, continue to react 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 polycarboxylic acid (glutaric acid), 11.5 kg of catalyst (aminosulfonic acid), and 2710 kg of xylene were added, and the temperature was controlled at 140°C for 6 hours to obtain a polycyclic azide structure desulfurizer.

[0053] (3) Preparation of polymeric guanidine fungicide: Add 200 kg of macromolecular petroleum acid and 200 kg of polyethylene polyamine into the reactor, stir evenly, slowly heat to 280°C, and reflux for 10 hours to prepare intermediate 1; Add 7 kg of guanidine hydrochloride to the intermediate 1, control the temperature at 150° C. to react for 3 h, and prepare the intermediate 2; 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, vacuum dehydrate to remove the solvent, and prepare intermediate three; Intermediate 3 was mixed with intermediate 2, 12 kg of catalyst (p-toluenesulfonic acid) was added, the temperature was controlled at 150° C. to react for 4 h, and then 600 kg of water and 30 kg of sodium hydroxide were added to obtain a polymerized guanidine fungicide.

[0054] (4) Preparation of the water-based annular space protection fluid: Add 1000 kg of clean water into the kettle, add 20 kg of the obtained anti-acid gas corrosion inhibitor, 20 kg of polycyclic azide structure desulfurizer, 20 kg of polymerized guanidine fungicide, 20 kg of dimethyl ketoxime, and 10 kg of methyldiethanolamine, stir evenly to obtain a water-based annular space protection liquid.

[0055] Embodiment 18: In Example 18, the preparation process of the acid gas corrosion inhibitor and the water-based annular space protection liquid is the same as that in Example 17, except that: When preparing the polycyclic azide structure desulfurizer, the catalyst is p-toluenesulfonic acid; When preparing the polymerized guanidine fungicide, the amount of guanidine hydrochloride is 14 kg.

[0056] Embodiment 19: In Example 19, the preparation process of the acid gas corrosion inhibitor, the polycyclic azide structure desulfurizer, and the water-based annular space protection liquid is the same as that in Example 17, except that: When preparing the polymeric guanidine fungicide, the initiator is dibenzoyl peroxide.

[0057] Embodiment 20: In this Example 20, the preparation process of the polymeric guanidine fungicide is the same as that in Example 17, except that: When preparing the acid gas corrosion inhibitor, the halogenated alkane is 205 kg of chlorododecane; When preparing the polycyclic azide structure desulfurizer, the polycarboxylic acid is glutaric acid and the catalyst is p-toluenesulfonic acid; When preparing the water-based annular space protection fluid, the deoxidizer is alkali metal salt of isoascorbic acid and the pH regulator is triethanolamine.

[0058] Embodiment 21: The difference between this embodiment 21 and embodiment 17 is that: When preparing the acid gas corrosion inhibitor, the halogenated alkane is 261 kg of hexachlorodecane; When preparing the polycyclic azide structure desulfurizer, the polycarboxylic acid is glutaric acid and the catalyst is p-toluenesulfonic acid; When preparing the polymeric guanidine fungicide, the reaction monomer is methacrylic acid and the initiator is dibenzoyl peroxide; The catalyst is dodecylbenzenesulfonic acid; When preparing the water-based annular space protection fluid, the deoxidizer is alkali metal salt of isoascorbic acid and the pH regulator is triethanolamine.

[0059] Embodiment 22: The difference between this embodiment 22 and embodiment 17 is that: When preparing the acid gas corrosion inhibitor, 429 kg of hexadecyl primary amine was replaced with 370.6 kg of dodecyl primary amine; When preparing the water-based annular space protection fluid, the deoxidizer is alkali metal salt of isoascorbic acid and the pH regulator is triethanolamine.

[0060] The performance test and evaluation of the water-based annular space protection fluid obtained according to Examples 17 to 22 (1) Evaluation of bactericidal performance According to SY / T5890 "Evaluation Method for Performance of Bactericides", the extinction dilution method was used to determine the bactericidal effect of water-based annular space protection fluid on sulfate-reducing bacteria, iron bacteria and saprophytic bacteria. The dosing concentration of the water-based annular space protection fluid was 1%.

[0061] Comparative example: Use any water-based annular space protection fluid purchased on the market.

[0062] (Bacteria test bottle SRB (sulfate reducing bacteria) readings, IB (iron bacteria) readings, TGB (saprophytic bacteria) readings) The experimental results are shown in Table 1.

[0063] Table 1 .

[0064] It can be seen from Table 1 that the bactericidal effect of the water-based annular space protection fluid of the present invention on sulfate-reducing bacteria, iron bacteria and saprophytic bacteria is better than that of the water-based annular space protection fluid purchased on the market.

[0065] (2) Corrosion inhibition experiment Referring to the SYT5273 standard for the performance evaluation method of corrosion inhibitors for oilfield produced water reinjection water, six 1L stoppered bottles were taken, and oilfield water source well water and 1% water-based annular space protection fluids 1 to 6 (Examples 17 to 22) were added respectively, and the volume was adjusted to 1L. The prepared N80 hanging plate (with an outer size of 40mm×13mm×2mm, a round hole was drilled in the middle of one end 5mm away from the edge line, and the surface area was 12cm 2 ), CO2 and H2S were introduced to saturation to simulate the working conditions in acidic oil and gas wells. The samples were placed in a constant temperature oven at 90°C for 14 days, and the coupons were taken out. After cleaning the corrosion products on the surface of the coupons, they were dried with cold air and weighed. The corrosion rate of the steel coupons was calculated according to formula (1). The results are shown in Table 2.

[0066] Formula (1) Among them, γ c is the corrosion rate, in mm / a; is the initial mass of the coupon, in g; is the mass of the coupon at the end of the experiment, in g; S is the surface area of ​​the coupon, in cm 2 ; t is the reaction time, in h; g / cm 3 .

[0067] Blank example: CO2 and H2S are introduced into the water of the oil field source well until it is saturated, and no water-based annular protection fluid is added. The remaining steps are the same as the above steps; Comparative Example: Any water-based annular space protection fluid purchased from the market was used. The results are shown in Table 2.

[0068] Table 2 .

[0069] It can be seen from Table 2 that the water-based annular space protection fluid of the present invention has good corrosion inhibition performance.

[0070] (3) Scale inhibition experiment According to the SY / T5673-93 "Performance Evaluation Method of Scale Inhibitors for Oilfields" standard, the scale inhibition rate of calcium carbonate is required to be ≥90%. The experimental results are shown in Table 3.

[0071] In 250mL of water-based annular space protection liquid, add 6mL of calcium preparative solution (calcium ion content 4mg / L) and 6mL of carbonate preparative solution (carbonate content 6.28mg / L), let it stand in a 50℃ water bath for 16h, take the supernatant and calibrate it with 0.005mol / L EDTA, and the amount of EDTA consumed is calculated as V1; Add 6 mL of calcium preparative solution (calcium ion content 4 mg / L) and 6 mL of carbonate preparative solution (carbonate content 6.28 mg / L) to 250 mL of distilled water, let stand in a 50°C water bath for 16 h, take the supernatant and standardize it with 0.005 mol / L EDTA, and the amount of EDTA consumed is calculated as V2; Add 6 mL of calcium preparative solution (calcium ion content 4 mg / L) to 250 mL of water-based annular protection solution, place in a 50°C water bath for 16 h, take the supernatant and calibrate it with 0.005 mol / L EDTA, and the amount of EDTA consumed is calculated as V0; Scale inhibition rate = (V1-V2) / (V0-V2) × 100% Comparative Example: Any water-based annular space protection fluid purchased from the market was used. The results are shown in Table 3.

[0072] Table 3 .

[0073] It can be seen from Table 3 that the water-based annulus protection fluid of the present invention has a good corrosion inhibition effect under simulated working conditions, and the scale inhibition rate of calcium carbonate is ≥90%. The scale inhibition rate meets the industry standard and is better than the water-based annulus protection fluid purchased on the market. It has a good protective function for the inner wall of the casing in the annular space and the outer wall of the oil and gas pipeline in the acidic environment, prolongs the service life, and ensures the safe production of the oil field.

[0074] In summary, the present invention has good corrosion inhibition effect under simulated working conditions, with a corrosion inhibition rate lower than 0.05 mm / a, which is far lower than the corresponding industry standards. The scale inhibition rate and sterilization rate meet the industry standards. It has good protection function for the inner wall of the casing in the annular space and the outer wall of the oil and gas pipeline in the acidic environment, which not only prolongs the service life, but also ensures the safe production of the oil field.

[0075] 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. A water-based annular space protection fluid, characterized in that The raw materials, calculated by mass percentage, include 0.1% to 2% of an acidic gas corrosion inhibitor, 0.1% to 2% of a polycyclic azide structure desulfurizer, 0.1% to 2% of a polymerized guanidine fungicide, 0.1% to 5% of a deoxidizer, 0.1% to 2% of a pH adjuster, and the rest is water. The water-based annular space protection fluid is prepared according to the following method: adding the required amount of an acidic gas corrosion inhibitor, a polycyclic azide structure desulfurizer, a polymerized guanidine fungicide, a deoxidizer and a pH adjuster to water, mixing and stirring to obtain a water-based annular space protection fluid.

2. The water-based annulus protection fluid according to claim 1, characterized in that The acid gas corrosion inhibitor was prepared according to the following method: S01, mixing a required amount of dicarboxylic acid and polyamine and reacting them to obtain an intermediate 1; S02, mixing the intermediate 1 with a required amount of dicarboxylic acid and reacting them to obtain the intermediate 2; S03, mixing the intermediate 2 with a required amount of halogenated alkane and reacting them to obtain a first polymer; S04, reacting a required amount of the intermediate 1 obtained in step S01 with a chlorine-containing compound to obtain an intermediate 3; S05, mixing the intermediate three with a required amount of guanidine hydrochloride and a primary amine and reacting them to obtain a second polymer; S06, mixing the obtained first polymer and the second polymer evenly and compounding them to obtain an anti-acid gas corrosion inhibitor.

3. The water-based annulus protection fluid according to claim 2, characterized in that In step S01, the molar ratio of dicarboxylic 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 9 h to 11 h, wherein the polyamine is polyethylene polyamine; or / and, in step S02, the molar ratio of intermediate 1 to dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145° C. to 155° C., and the reaction time is 2.5 h to 3.5 h; or / and, in step S03, the halogenated alkane is one of brominated dodecane, brominated hexadecane, chlorododecane, and chlorohexadecane; or / and, In step S04, the molar ratio of intermediate one to the chlorine-containing compound is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 70°C to 100°C, the reaction time is 2.5h to 3.5h, and the chlorine-containing compound is 1,4-dichlorobenzyl; or / and, in step S05, the molar ratio of intermediate three to guanidine hydrochloride and primary amine is 0.9 to 1.1:1.5 to 2:1.5 to 2, the reaction temperature is 145°C to 155°C, the reaction time is 3.5h to 4.5h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

4. The water-based annulus protection fluid according to claim 1, 2 or 3, characterized in that The polycyclic azide structure 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, catalyst, and xylene to react to obtain a polycyclic azide structure desulfurizing agent.

5. The water-based annulus protection fluid according to claim 4, characterized in that In 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, 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 added mass of the catalyst 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 water-based annulus protection fluid according to claim 5, characterized in that The polymeric guanidine fungicide is a water-soluble polymeric 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 an intermediate three; S24, mixing the intermediate 3 and the intermediate 2 evenly, adding a required amount of catalyst to react, and after the reaction is completed, adding a sodium hydroxide aqueous solution to adjust the pH value to obtain a water-soluble polymerized guanidine.

7. The water-based annulus protection fluid according to claim 5 or 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 120°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, methacrylic acid, and maleic anhydride, and the solvent is methanol, ethanol, n-butanol, propylene glycol, One of propylene glycol, 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 S24, the catalyst is one of aminosulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid, the reaction temperature is 100°C to 150°C, the reaction time is 3.5h to 4.5h, and the pH value is adjusted to 7 to 8 after adding sodium hydroxide aqueous solution.

8. The water-based annulus protection fluid according to claim 1 or 2 or 3 or 5 or 6, characterized in that The oxygen scavenger is one or more of an alkali metal salt of isoascorbic acid and dimethyl ketoxime.

9. The water-based annulus protection fluid according to claim 8, characterized in that pH adjuster is C2 to C 10 Alkyl alcohol amines, wherein C2 to C 10 The alkyl alcohol amine is one or more of methyldiethanolamine, triethanolamine and isopropanolamine.

10. A method for preparing a water-based annular space protection fluid according to any one of claims 2 to 9, characterized in that Proceed according to the following steps: add the required amount of anti-acid gas corrosion inhibitor, polycyclic azide structure desulfurizer, polymerized guanidine fungicide, deoxidizer and pH adjuster into water, mix and stir to obtain a water-based annular space protection fluid. In the water-based annular space protection fluid, the raw materials are calculated by mass percentage and include 0.1% to 2% anti-acid gas corrosion inhibitor, 0.1% to 2% polycyclic azide structure desulfurizer, 0.1% to 2% polymerized guanidine fungicide, 0.1% to 5% deoxidizer, 0.1% to 2% pH adjuster, and the rest is water.

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