Water-based annulus protection fluid and preparation method thereof

Abstract

The present application relates to the technical field of oilfield chemical technology, and is a water-based annulus protection fluid and a preparation method thereof.The former raw materials, calculated according to mass percentage, comprise 0.1% to 2% acid gas corrosion inhibitor, 0.1% to 2% polycyclic azide structure sulfur removal agent, 0.1% to 2% polymeric guanidine bactericide, 0.1% to 5% oxygen scavenger, and 0.1% to 2% pH regulator, with the rest being water.The required amount of acid gas corrosion inhibitor, polycyclic azide structure sulfur removal agent, polymeric guanidine bactericide, oxygen scavenger and pH regulator are added to water, and after mixing and stirring, the water-based annulus protection fluid is obtained.The present application has good corrosion inhibition effect under simulated working conditions, with a corrosion inhibition rate of less than 0.05 mm / a, which is much lower than the corresponding industry standard.The scale inhibition rate and bactericidal rate meet the industry standard, and the present application has good protection function for the inner wall of the casing and the outer wall of the oil and gas pipeline in the annular space under acidic environment, which not only prolongs the service life, but also guarantees the safety production of oilfields.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field chemistry, and is a water-based annulus protection fluid and a preparation method thereof. BACKGROUND

[0002] The annulus protection fluid is a liquid filled in the annular space between the oil and gas pipe and the casing pipe, and is mainly used for protecting the casing pipe, the oil pipe and the downhole operation tool in the oil and casing annulus, reducing the reservoir pressure borne by the casing head or the packer, reducing the pressure difference between the oil pipe or the gas pipe and the annulus, inhibiting the corrosion, scaling and bacterial reproduction of the oil pipe or the gas pipe and the casing pipe, and prolonging the service life of the injection-production well.

[0003] In the production process, the annulus medium usually has high salinity and high concentration of scale-forming ions, causing serious scaling of the oil and casing pipe, pipeline plugging and under-deposit corrosion. At the same time, the oil and casing annulus often has CL - , CO2 and H2S and other corrosion factors due to sealing problems, causing corrosion of the oil and casing pipe. In addition, the annular space also has certain microorganisms, such as sulfate-reducing bacteria and iron bacteria, causing deterioration of the static water quality of the oil and casing annulus, microbial corrosion and plugging of the oil and casing pipe. Therefore, the annulus protection fluid needs to have the main functions of corrosion inhibition, scale inhibition and sterilization, and under necessary conditions, additives such as density adjusting agents and pH adjusting agents are added to meet the production requirements.

[0004] A kind of annulus protection fluid is disclosed in Chinese patent document with authorized publication number CN106520101B, raw materials include 5%-15% halide, 10%-20% organic acid salt, 2%-4% imidazoline corrosion inhibitor, 1%-4% oxime oxygen scavenger, 0.5%-2% zwitterionic bactericide, 1.5%-3% polymer scale inhibitor and the balance of water. Halide is introduced in the system, which has potential pitting risk to the oil pipe and the casing pipe, and the application process is quite different from the actual working condition.

[0005] Chinese patent document with authorized publication number CN102816560B discloses a high-temperature annulus protection fluid and a preparation method thereof, the protection fluid is made of raw materials in the following weight ratio: organic salt 0.14-83.70%, bactericide 0.1-0.5%, oxygen scavenger 0.1-0.5%, gas well corrosion inhibitor 1.5-2.0%, pH value adjusting agent 0.7-1.3%, and the rest is distilled water. The system has density adjusting function, but the corrosion rate of the system on N80 steel sheet is high, and the influence of acid gas on the corrosion performance of the annulus protection fluid is not considered.

[0006] The Chinese patent document with the authorization publication number CN105220157B discloses a protection liquid and a preparation method of the protection liquid, the protection liquid comprising components and weight ratios of 98.5-99.2 parts of seawater, 0.6-1 part of modified sodium metaborate; the modified sodium metaborate comprises sodium metaborate and sodium bicarbonate, the annulus protection liquid has good compatibility with seawater, but its corrosion and scale inhibition performance needs to be further investigated and improved.

[0007] The above existing annulus protection liquids are all water-based systems, which cannot meet the corrosion and scale inhibition requirements of oil well annuli with high salinity and strong acidity in actual applications. Although the oil-based system has the advantage of good corrosion inhibition effect compared with the water-based system, the system composition is relatively complex, which can easily cause environmental pollution, is prone to sedimentation and plugging in high salinity water environment, and is expensive, so the on-site application is less. Therefore, the water-based system annulus protection liquid is still the first choice for post-completion annulus protection liquid due to simple construction and low cost. Therefore, developing a water-based annulus protection liquid suitable for the coexistence of CO2, O2 and H2S and containing complex bacteria has become a new demand for the development of annulus protection liquid. SUMMARY

[0008] The present application provides a water-based annulus protection liquid and a preparation method thereof, which overcomes the shortcomings of the prior art, and effectively solves the problem of corrosion and plugging of pipelines caused by corrosion and scale of casings and oil and gas pipelines and bacterial reproduction after scale formation.

[0009] One of the technical solutions of the present application is realized by the following measures: a water-based annulus protection liquid, the raw materials are calculated according to mass percentage, including 0.1% to 2% of an acid gas corrosion inhibitor, 0.1% to 2% of a multi-ring azide structure sulfur removal agent, 0.1% to 2% of a polymeric guanidine bactericide, 0.1% to 5% of an oxygen scavenger, 0.1% to 2% of a pH regulator, and the rest is water, the water-based annulus protection liquid is prepared by the following method: adding the required amount of acid gas corrosion inhibitor, multi-ring azide structure sulfur removal agent, polymeric guanidine bactericide, oxygen scavenger and pH regulator into water, and mixing and stirring to obtain the water-based annulus protection liquid.

[0010] The following is a further optimization or / and improvement of one of the above technical solutions:

[0011] The above acid gas corrosion inhibitor is prepared by the following method:

[0012] S01, the required amount of dicarboxylic acid is mixed with polyamine to obtain intermediate one;

[0013] S02, intermediate one is mixed with the required amount of dicarboxylic acid to obtain intermediate two;

[0014] S03, intermediate two is mixed with the required amount of halogenated alkane to obtain the first polymer;

[0015] S04, reacting the intermediate one obtained in step S01 with a chlorine-containing compound to obtain intermediate three;

[0016] S05, mixing intermediate three with guanidine hydrochloride and primary amine in a required amount and then reacting to obtain a second polymer;

[0017] S06, mixing the obtained first polymer and second polymer uniformly and then compounding to obtain an acid gas corrosion inhibitor.

[0018] 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 to 300°C, and the reaction time is 9 to 11 hours, wherein the polyamine is polyethylene polyamine, and in step S02, the molar ratio of intermediate one to dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145 to 155°C, and the reaction time is 2.5 to 3.5 hours.

[0019] In the above step S03, the halogenated alkane is one of bromododecane, bromohexadecane, chlorododecane, and chlorohexadecane, and in step S04, the molar ratio of intermediate one to chlorine-containing compound is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 70 to 100°C, the reaction time is 2.5 to 3.5 hours, and the chlorine-containing compound is 1,4-p-dichlorobenzene.

[0020] 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 to 155°C, the reaction time is 3.5 to 4.5 hours, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine, and octadecyl primary amine.

[0021] The above polycyclic azide structure desulfurizing agent is prepared according to the following method:

[0022] S11, mixing a required amount of alcohol amine with aldehyde and then reacting to obtain a desulfurizing agent intermediate;

[0023] S12, vacuum dehydrating and purifying the desulfurizing agent intermediate, and then adding a required amount of polycarboxylic acid, a catalyst, and dimethylbenzene in sequence and reacting to obtain a polycyclic azide structure desulfurizing agent.

[0024] In the above step S11, the alcohol amine is monoethanolamine, and the aldehyde is formaldehyde, wherein the molar ratio of alcohol amine to aldehyde is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 60 to 80°C, and the reaction time is 2 to 4 hours.

[0025] In the step S12, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic acid, and the catalyst is one of dodecyl benzene sulfonic acid, p-toluene sulfonic acid, and sulfamic acid, wherein the molar ratio of the polycarboxylic acid to the desulfurization agent intermediate is 1:1 to 2, the added amount of the catalyst is 0.5% to 2.5% of the mass of the desulfurization agent intermediate, the reaction temperature is 120°C to 150°C, and the reaction time is 2h to 10h.

[0026] The polymeric guanidine bactericide is a water-soluble polymeric guanidine, which is prepared by the following method:

[0027] In the step S21, the petroleum acid and the polyethylene polyamine are mixed in a molar ratio of 0.9 to 1.1:0.9 to 1.1, and reacted at a temperature of 250°C to 300°C for 10h to 12h to obtain the intermediate one.

[0028] In the step S22, the intermediate one and the guanidine hydrochloride are mixed in a molar ratio of 0.9 to 1.1:0.9 to 1.1, and reacted at a temperature of 120°C to 180°C for 2h to 4h to obtain the intermediate two.

[0029] In the 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, dimethylbenzene, trimethylbenzene, dimethyl sulfoxide, and dimethyl formamide, the chain transfer agent is n-dodecanethiol, 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.

[0030] In the step S24, the catalyst is one of sulfamic acid, p-toluene sulfonic acid, and dodecyl benzene sulfonic 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 by adding the aqueous sodium hydroxide solution.

[0031] In the step S21, the petroleum acid and the polyethylene polyamine are mixed in a molar ratio of 0.9 to 1.1:0.9 to 1.1, and reacted at a temperature of 250°C to 300°C for 10h to 12h to obtain the intermediate one.

[0032] In the step S22, the intermediate one and the guanidine hydrochloride are mixed in a molar ratio of 0.9 to 1.1:0.9 to 1.1, and reacted at a temperature of 120°C to 180°C for 2h to 4h to obtain the intermediate two.

[0033] In the 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, dimethylbenzene, trimethylbenzene, dimethyl sulfoxide, and dimethyl formamide, the chain transfer agent is n-dodecanethiol, 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.

[0034] In the step S24, the catalyst is one of sulfamic acid, p-toluene sulfonic acid, and dodecyl benzene sulfonic 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 by adding the aqueous sodium hydroxide solution.

[0035] The oxygen scavenger is one or more of ascorbic acid alkali metal salt and dimethyl ketoxime.

[0036] The pH regulator is C2 to C 10 alkyl alcohol amine, wherein the C2 to C 10 alkyl alcohol amine is one or more of methyldiethanolamine, triethanolamine, and isopropanolamine.

[0037] The second technical solution of the present application is realized by the following measures: a preparation method of a water-based annulus protection fluid, which is performed according to the following steps: adding required amounts of an acid gas corrosion inhibitor, a polycyclic azide structure sulfur removal agent, a polymeric guanidine bactericide, an oxygen removal agent, and a pH regulator into water, and obtaining the water-based annulus protection fluid after mixing and stirring.

[0038] The present application has good corrosion inhibition effect under simulated working conditions, the corrosion inhibition rate is lower than 0.05 mm / a, which is far lower than the corresponding industry standard, the scale inhibition rate and the bactericidal rate meet the industry standard, the water-based annulus protection fluid has good protection function for the inner wall of the casing and the outer wall of the oil and gas pipeline in the annular space under the acidic environment, which not only prolongs the service life, but also guarantees the safety production of the oil field. DETAILED DESCRIPTION

[0039] The present application is not limited by the following examples, and the specific implementation can be determined according to the technical solutions of the present application and the actual situation. The various chemical reagents and chemical supplies mentioned in the present application are well-known and commonly used chemical reagents and chemical supplies in the prior art unless otherwise specified; the percentages in the present application are mass percentages unless otherwise specified; the solution in the present application is a water solution with water as the solvent unless otherwise specified, for example, a hydrochloric acid solution is a hydrochloric acid water solution; the normal temperature and room temperature in the present application generally refer to a temperature of 15℃ to 25℃, which is generally defined as 25℃.

[0040] The present application will be further described below in combination with examples:

[0041] Example 1: The water-based annulus protection fluid, the raw materials are calculated according to the mass percentage, including 0.1% to 2% of an acid gas corrosion inhibitor, 0.1% to 2% of a polycyclic azide structure sulfur removal agent, 0.1% to 2% of a polymeric guanidine bactericide, 0.1% to 5% of an oxygen removal agent, and 0.1% to 2% of a pH regulator, and the rest is water. The water-based annulus protection fluid is prepared according to the following method: adding required amounts of an acid gas corrosion inhibitor, a polycyclic azide structure sulfur removal agent, a polymeric guanidine bactericide, an oxygen removal agent, and a pH regulator into water, and obtaining the water-based annulus protection fluid after mixing and stirring.

[0042] The water-based annulus protection fluid provided by the application is prepared by mixing the acid-resistant gas corrosion inhibitor, the polyazido structure sulfur removal agent and the polymeric guanidine bactericide, and has good chemical stability, can effectively slow down the corrosion rate of the casing and the oil and gas pipeline, solves the problems of fouling, bacterial reproduction, under-deposit corrosion and plugging caused thereby, and can reduce the pressure difference between the oil and gas pipeline and the annulus, and is suitable for annulus protection of oil and gas wells, and is especially suitable for high-acid and high-sulfur oil and gas wells.

[0043] In the embodiment, the acid-resistant gas corrosion inhibitor is prepared by the following steps:

[0044] S01, reacting the required amount of dicarboxylic acid with a polyamine to obtain intermediate one;

[0045] S02, reacting intermediate one with the required amount of dicarboxylic acid to obtain intermediate two;

[0046] S03, reacting intermediate two with the required amount of halogenated alkane to obtain the first polymer;

[0047] S04, reacting the required amount of intermediate one obtained in step S01 with a chlorine-containing compound to obtain intermediate three;

[0048] S05, reacting intermediate three with the required amount of guanidine hydrochloride and primary amine to obtain the second polymer;

[0049] S06, uniformly mixing the obtained first polymer and second polymer to obtain the acid-resistant gas corrosion inhibitor.

[0050] In the application, the petroleum acid is a macromolecular petroleum acid, and the molecular weight of the macromolecular petroleum acid is 3000-10000.

[0051] In the embodiment, in step S01, the molar ratio of dicarboxylic acid to polyamine is 0.9-1.1:0.9-1.1, the reaction temperature is 250-300 DEG C, and the reaction time is 9-11 h, wherein the polyamine is polyethylene polyamine, in step S02, the molar ratio of intermediate one to dicarboxylic acid is 0.9-1.1:0.9-1.1, the reaction temperature is 145-155 DEG C, and the reaction time is 2.5-3.5 h.

[0052] In the embodiment, in step S03, the halogenated alkane is one of bromododecane, bromohexadecane, chlorododecane and chlorohexadecane, in step S04, the molar ratio of intermediate one to chlorine-containing compound is 0.9-1.1:0.9-1.1, the reaction temperature is 70-100 DEG C, the reaction time is 2.5-3.5 h, and the chlorine-containing compound is 1,4-p-dichlorobenzene.

[0053] In step S05, the molar ratio of intermediate III 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 DEG C to 155 DEG C, the reaction time is 3.5 h to 4.5 h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0054] The chemical reaction mechanism for obtaining the intermediate I in the preparation of the acid gas corrosion inhibitor is as follows:

[0055]

[0056] The value range of k is 2 to 10.

[0057] The chemical reaction mechanism for obtaining the intermediate II is as follows:

[0058]

[0059] The value range of k and a is 2 to 10.

[0060] The chemical reaction mechanism for obtaining the first polymer (taking the reaction of intermediate II and bromoalkane as an example) is as follows:

[0061]

[0062] The value range of k and a is 2 to 10.

[0063] The chemical reaction mechanism for obtaining the intermediate III is as follows:

[0064]

[0065] The value range of b and k is 2 to 10.

[0066] The chemical reaction mechanism for obtaining the second polymer is as follows:

[0067]

[0068] The value range of b and k is 2 to 10.

[0069] In the preparation of the polycyclic azide structure sulfur removal agent, the following steps are taken:

[0070] S11, the required amount of alcohol amine is mixed with aldehyde to obtain a sulfur removal agent intermediate;

[0071] S12, the sulfur removal agent intermediate is vacuum dehydrated and purified, and then the required amount of polycyclic azide structure sulfur removal agent is obtained by adding polycyclic azide structure sulfur removal agent.

[0072] Embodiment 7: As an optimization of the above-mentioned embodiments, 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℃ to 80℃, and the reaction time is 2h to 4h.

[0073] Embodiment 8: As an optimization of the above-mentioned embodiments, 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 sulfamic acid, wherein the molar ratio of the polycarboxylic acid to the sulfur removal agent intermediate is 1:1 to 2, the added mass of the catalyst is 0.5% to 2.5% of the mass of the sulfur removal agent intermediate, the reaction temperature is 120℃ to 150℃, and the reaction time is 2h to 10h.

[0074] Embodiment 9: As an optimization of the above-mentioned embodiments, the polymeric guanidine bactericide is a water-soluble polymeric guanidine, which is prepared by the following method:

[0075] S21, the required amount of petroleum acid is mixed with polyethylene polyamine and reacted to obtain intermediate one;

[0076] S22, intermediate one is uniformly mixed with the required amount of guanidine hydrochloride and reacted to obtain intermediate two;

[0077] S23, the reaction monomer, solvent, and chain transfer agent are uniformly mixed, and then the required amount of initiator is added for reaction to obtain intermediate three;

[0078] S24, intermediate three and intermediate two are uniformly mixed, and the required amount of catalyst is added for reaction, and after the reaction is completed, sodium hydroxide aqueous solution is added to adjust the pH value to obtain water-soluble polymeric guanidine.

[0079] The macromolecular petroleum acid in the present application refers to a by-product in the petroleum refining process.

[0080] Embodiment 10: As an optimization of the above-mentioned embodiments, in step S21, the molar ratio of the petroleum acid to the polyethylene polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250℃ to 300℃, and the reaction time is 10h to 12h.

[0081] Embodiment 11: As an optimization of the above-mentioned embodiments, in step S22, the molar ratio of intermediate one to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 120℃ to 180℃, and the reaction time is 2h to 4h.

[0082] Example 12: As an optimization of the above-mentioned examples, in S23, the reaction monomer is one or more of acrylic acid, methacrylic acid, maleic anhydride, the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, xylene, mesitylene, dimethyl sulfoxide, dimethyl formamide, the chain transfer agent is n-dodecanethiol, the initiator is one of azobisisobutyronitrile, dibenzoyl peroxide, the reaction temperature is 60°C to 120°C, and the reaction time is 3.5h to 4.5h.

[0083] Example 13: As an optimization of the above-mentioned examples, in step S24, the catalyst is one of sulfamic acid, p-toluenesulfonic acid, 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 aqueous sodium hydroxide solution.

[0084] Example 14: As an optimization of the above-mentioned examples, the oxygen scavenger is one or more of isoascorbic acid alkali metal salt, dimethyl ketoxime.

[0085] Example 15: As an optimization of the above-mentioned examples, the pH adjuster is one or more of C2 to C 10 alkyl alcohol amine, wherein the C2 to C 10 alkyl alcohol amine is one or more of methyldiethanolamine, triethanolamine, isopropanolamine.

[0086] Example 16: The preparation method of the water-based annulus protection fluid is carried out according to the following steps: adding the required amount of acid gas corrosion inhibitor, polycyclic azide structure sulfur removal agent, polymeric guanidine bactericide, oxygen scavenger and pH adjuster into water, and mixing and stirring to obtain the water-based annulus protection fluid.

[0087] Example 17:

[0088] (1) Preparation of acid gas corrosion inhibitor:

[0089] Firstly, 146kg (1kmol) of adipic acid and 878kg (1kmol) of polyethylene polyamine (molecular weight 439) were added into a reaction kettle, and after being uniformly mixed, the temperature was slowly raised to 280°C, and refluxed for 10h to obtain intermediate one;

[0090] Secondly, intermediate one was uniformly mixed with 146kg (1kmol) of adipic acid, and reacted at 150°C for 3h to obtain intermediate two;

[0091] Thirdly, 249kg (1kmol) of bromododecane was added into intermediate two, and reacted at 80°C for 4h to obtain the first polymer;

[0092] Fourth step, take 1024 kg of intermediate one, add 1,4-p-dichlorobenzene 175 kg (1 kmol), 80 ℃ for 3 h, to prepare intermediate three;

[0093] The fifth step, in the above intermediate three, add 191 kg of guanidine hydrochloride (2 kmol), 429 kg of hexadecyl primary amine (2 kmol) control temperature 150 ℃ reaction 4 h, reaction to prepare the second polymer;

[0094] The sixth step, the first polymer and the second polymer are mixed according to the mass ratio of 1:1, and after stirring uniformly, the anti-acid gas corrosion inhibitor is obtained.

[0095] (2) Preparation of multi-ring azide structure sulfur removal agent:

[0096] Put 1830 kg of alcohol amine (ethanol amine) into the kettle, start stirring and control the temperature at 60 ℃, slowly add 2500 kg (volume concentration of 36%) of formaldehyde aqueous solution, after the addition is completed, continue to react at 60 ℃ for 3 h to obtain the sulfur removal agent intermediate (i.e. triazine type sulfur removal agent);

[0097] The sulfur removal agent intermediate is vacuum dehydrated for 2 h, 181 kg of polycarboxylic acid (glutaric acid), catalyst (aminosulfonic acid) 11.5 kg, and dimethylbenzene 2710 kg are added, the temperature is controlled at 140 ℃ for 6 h to obtain the multi-ring azide structure sulfur removal agent.

[0098] (3) Preparation of polyguanidine bactericide:

[0099] Add 200 kg of macromolecular petroleum acid and 200 kg of polyethylene polyamine to the reaction kettle, stir uniformly, slowly heat to 280 ℃, and reflux for 10 h to prepare intermediate one;

[0100] Add 7 kg of guanidine hydrochloride to the intermediate one, control the temperature at 150 ℃ for 3 h to prepare intermediate two;

[0101] Take 200 kg of solvent (ethanol), add 100 kg of monomer (acrylic acid), 2 kg of chain transfer agent (n-dodecanethiol), control the temperature at 80 ℃, add 0.4 kg of initiator (azobisisobutyronitrile) (add in 4 times, 0.1 kg / h), and react for 4 h. Vacuum dehydration to remove the solvent to prepare intermediate three;

[0102] Mix the intermediate three and the intermediate two, add 12 kg of catalyst (p-toluenesulfonic acid), control the temperature at 150 ℃ for 4 h, then add 600 kg of water and 30 kg of sodium hydroxide to obtain the polyguanidine bactericide.

[0103] (4) Preparation of the water-based annulus protection fluid:

[0104] In a kettle, add 1000 kg of clean water, add the obtained anti-acid gas corrosion inhibitor 20 kg, polycyclic azide structure sulfur removal agent 20 kg, polymeric guanidine bactericide 20 kg, dimethyl ketone oxime 20 kg, methyldiethanolamine 10 kg, stir uniformly to obtain a water-based annulus protection fluid.

[0105] Example 18:

[0106] In this example 18, the preparation process of the anti-acid gas corrosion inhibitor and the water-based annulus protection fluid is the same as in example 17, the difference is:

[0107] When preparing the polycyclic azide structure sulfur removal agent, the catalyst is p-toluenesulfonic acid;

[0108] When preparing the polymeric guanidine bactericide, guanidine hydrochloride is 14 kg.

[0109] Example 19:

[0110] In this example 19, the preparation process of the anti-acid gas corrosion inhibitor, polycyclic azide structure sulfur removal agent and water-based annulus protection fluid is the same as in example 17, the difference is:

[0111] When preparing the polymeric guanidine bactericide, the initiator is dibenzoyl peroxide.

[0112] Example 20:

[0113] In this example 20, the preparation process of the polymeric guanidine bactericide is the same as in example 17, the difference is:

[0114] When preparing the anti-acid gas corrosion inhibitor, the halogenated alkane is 205 kg of chlorinated dodecane;

[0115] When preparing the polycyclic azide structure sulfur removal agent, the polycarboxylic acid is glutaric acid, and the catalyst is p-toluenesulfonic acid;

[0116] When preparing the water-based annulus protection fluid, the oxygen scavenger is an alkali metal salt of erythorbic acid, and the pH adjuster is triethanolamine.

[0117] Example 21:

[0118] In this example 21, the difference from example 17 is:

[0119] When preparing the anti-acid gas corrosion inhibitor, the halogenated alkane is 261 kg of chlorinated hexadecane;

[0120] When preparing the polycyclic azide structure sulfur removal agent, the polycarboxylic acid is glutaric acid, and the catalyst is p-toluenesulfonic acid;

[0121] When preparing the polymeric guanidine bactericide, the reaction monomer is methyl methacrylate, and the initiator is dibenzoyl peroxide,

[0122] The catalyst is dodecyl benzene sulfonic acid;

[0123] When preparing the water-based annular protection fluid, the oxygen scavenger is alkali metal salt of erythorbic acid, and the pH regulator is triethanolamine.

[0124] Example 22:

[0125] In this example 22, the difference from example 17 is that:

[0126] When preparing the acid gas corrosion inhibitor, 429 kg of primary hexadecylamine is replaced by 370.6 kg of primary dodecylamine.

[0127] When preparing the water-based annular protection fluid, the oxygen scavenger is alkali metal salt of erythorbic acid, and the pH regulator is triethanolamine.

[0128] The water-based annular protection fluid obtained according to examples 17 to 22 is subjected to performance test evaluation

[0129] (1) Bactericidal performance evaluation

[0130] According to SY / T 5890 "Bactericide Performance Evaluation Method", the bactericidal effect of the water-based annular protection fluid on sulfate-reducing bacteria, iron bacteria and saprophytic bacteria is determined by the absolute trace dilution method, and the dosing concentration of the water-based annular protection fluid is 1%.

[0131] Comparative example: any one of the water-based annular protection fluids selected from the market is used.

[0132] The experimental results are shown in Table 1.

[0133] Table 1

[0134] .

[0135] As can be seen from Table 1, the bactericidal effect of the water-based annular protection fluid of the present application on sulfate-reducing bacteria, iron bacteria and saprophytic bacteria is better than that of the water-based annular protection fluid selected from the market.

[0136] (2) Inhibition experiment

[0137] Referring to the SYT5273 Oilfield Produced Water Reinjection Water Inhibitor Performance Evaluation Method Standard, six 1L bottles with stoppers are taken, and oilfield water source well water and 1% water-based annular protection fluid 1 to 6 (examples 17 to 22) are added respectively, and the volume is adjusted to 1L, and the prepared N80 hanging piece (the outer size is 40mmx13mmx2mm, a round hole is drilled in the middle position at a distance of 5mm from the edge line at one end, and the surface area is 12cm 2), CO2 and H2S were introduced into the water to saturation, and the working condition in the acid oil and gas well was simulated. The hanging piece was taken out from the constant temperature oven at 90℃ after 14 days, the corrosion product on the surface of the hanging piece was cleaned, and the hanging piece was dried by cold air and weighed. The corrosion rate of the steel piece was calculated according to formula (1), and the results are shown in Table 2.

[0138]

[0139] wherein, γ c is the corrosion rate, mm / a; ω0 is the initial mass of the hanging piece, g; ω1 is the mass of the hanging piece at the end of the experiment, g; S is the surface area of the hanging piece, cm 2 ; t is the reaction time, h; and ρ is g / cm 3 .

[0140] The blank example: CO2 and H2S were introduced into the water source well water to saturation, and no water-based annulus protection fluid was added, and the remaining steps were consistent with the above steps.

[0141] The comparative example: any one of the water-based annulus protection fluids selected from the market was used, and the results are shown in Table 2.

[0142] Table 2

[0143] .

[0144] As shown in Table 2, the water-based annulus protection fluid has good corrosion inhibition performance.

[0145] (3) Scale inhibition experiment

[0146] According to the standard of SY / T5673-93 "Performance evaluation method of scale inhibitor for oil field", the calcium carbonate scale inhibition rate is required to be greater than or equal to 90%, and the experimental results are shown in Table 3.

[0147] In 250mL of the water-based annulus protection fluid, 6mL of a calcium preparation solution (calcium ion content 4mg / L) and 6mL of a carbonate preparation solution (carbonate content 6.28mg / L) were added, and the mixture was placed in a water bath at 50℃ for 16h. The supernatant was taken and titrated with 0.005mol / L EDTA, and the amount of consumed EDTA was V1.

[0148] In 250mL of the water-based annulus protection fluid, 6mL of a calcium preparation solution (calcium ion content 4mg / L) and 6mL of a carbonate preparation solution (carbonate content 6.28mg / L) were added, and the mixture was placed in a water bath at 50℃ for 16h. The supernatant was taken and titrated with 0.005mol / L EDTA, and the amount of consumed EDTA was V1.

[0149] In 250 mL water-based annular protection fluid, 6 mL of calcium preparation solution (calcium ion content 4 mg / L) was added, and it was placed in a 50°C water bath for 16 h. The supernatant was used to calibrate 0.005 mol / L EDTA, and the amount of consumed EDTA was V0;

[0150] The scale inhibition rate = (V1-V2) / (V0-V2) * 100%

[0151] The comparative example: any water-based annular protection fluid selected from the market was used, and the results are shown in Table 3.

[0152] Table 3

[0153] .

[0154] As shown in Table 3, the water-based annular protection fluid of the present application has good corrosion inhibition effect under simulated conditions, the calcium carbonate scale inhibition rate is ≥ 90%, the scale inhibition rate meets the industry standard, and is better than the water-based annular protection fluid selected from the market. It has good protection function for the inner wall of the casing and the outer wall of the oil and gas pipeline in the annular space under acidic environment, prolongs the service life, and ensures the safety production of oil field.

[0155] In summary, the present application has good corrosion inhibition effect under simulated conditions, the corrosion inhibition rate is lower than 0.05 mm / a, which is much lower than the corresponding industry standard, the scale inhibition rate and the sterilization rate meet the industry standard, and it has good protection function for the inner wall of the casing and the outer wall of the oil and gas pipeline in the annular space under acidic environment, which not only prolongs the service life, but also ensures the safety production of oil field.

[0156] The above technical features constitute an embodiment of the present application, which has strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the needs of different situations.

Claims

1. A water-based annular protective fluid, characterized in that... The raw materials, calculated by mass percentage, include 0.1% to 2% acid gas corrosion inhibitor, 0.1% to 2% desulfurizer, 0.1% to 2% polymeric guanidine bactericide, 0.1% to 5% oxygen scavenger, and 0.1% to 2% pH adjuster, with the remainder being water. The water-based annular protective liquid is prepared by adding the required amounts of acid gas corrosion inhibitor, desulfurizer, polymeric guanidine bactericide, oxygen scavenger, and pH adjuster to water, mixing and stirring to obtain the water-based annular protective liquid. The acid gas corrosion inhibitor is prepared according to the following method: S01, after mixing the required amount of dicarboxylic acid and polyamine, an intermediate is obtained by reaction, wherein the molar ratio of dicarboxylic acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250℃ to 300℃, the reaction time is 9h to 11h, and the polyamine is polyethylene polyamine; S02, intermediate one is mixed with the required amount of dicarboxylic acid and reacted to obtain intermediate two, wherein the molar ratio of intermediate one to dicarboxylic acid is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 145℃ to 155℃, and the reaction time is 2.5h to 3.5h; S03, intermediate two is mixed with the required amount of haloalkanes and reacted to obtain the first polymer, wherein the haloalkanes are one of bromododecane, bromohexadecane, chlorododecane, and chlorohexadecane. S04, react the required amount of intermediate one obtained in step S01 with a chlorine-containing compound to obtain intermediate three, wherein 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 2.5 h to 3.5 h, and the chlorine-containing compound is 1,4-dichlorobenzyl. S05, intermediate three is mixed with the required amount of guanidine hydrochloride and primary amine and reacted to obtain a second polymer, wherein 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 3.5 h to 4.5 h, and the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine, and octadecyl primary amine; S06, after uniformly mixing the first polymer and the second polymer, a compound is prepared to obtain an acid gas corrosion inhibitor; The desulfurizing agent is prepared according to the following method: S11, the required amount of alcohol amine and aldehyde are mixed and reacted to obtain a desulfurizing agent intermediate, wherein the alcohol amine is monoethanolamine and the aldehyde is formaldehyde, wherein the molar ratio of alcohol amine to aldehyde is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 60℃ to 80℃, and the reaction time is 2h to 4h; S12, the desulfurizing agent intermediate is vacuum dehydrated and purified, and then the required amount of polycarboxylic acid, catalyst and xylene are added sequentially and reacted to obtain the desulfurizing agent. The polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid and malonic acid. The catalyst is one of dodecylbenzenesulfonic acid, p-toluenesulfonic acid and aminosulfonic acid. The molar ratio of polycarboxylic acid to desulfurizing agent intermediate is 1:1 to 2. The mass of catalyst added is 0.5% to 2.5% of the mass of desulfurizing agent intermediate. The reaction temperature is 120℃ to 150℃ and the reaction time is 2h to 10h. The polymeric guanidine bactericide is a water-soluble polymeric guanidine, which is prepared according to the following method: S21, the required amount of petroleum acid and polyethylene polyamine are mixed and reacted to obtain intermediate one, wherein 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℃ to 300℃, and the reaction time is 10h to 12h; S22, intermediate one is mixed with the required amount of guanidine hydrochloride and reacted to obtain intermediate two, wherein the molar ratio of intermediate one to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 120℃ to 180℃, and the reaction time is 2h to 4h. S23, the reactant monomer, solvent and chain transfer agent are mixed evenly, and then the required amount of initiator is added and reacted to obtain intermediate three. The reactant 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 benzoyl peroxide. The reaction temperature is 60℃ to 120℃ and the reaction time is 3.5h to 4.5h. S24, intermediate three and intermediate two are mixed evenly, and the required amount of catalyst is added to react. After the reaction is completed, sodium hydroxide aqueous solution is added to adjust the pH value to obtain water-soluble polymeric guanidine. The catalyst is one of aminosulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid. The reaction temperature is 100℃ to 150℃, 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.

2. The water-based annular protective fluid according to claim 1, characterized in that... The oxygen scavenger is one or more of the following: alkali metal salts of isoascorbic acid and dimethyl ketoxime.

3. The water-based annular protective liquid according to claim 1 or 2, characterized in that... pH adjuster is C2 to C 10 Alkyl alcoholamines, wherein C2 to C3 10 The alkyl alcoholamine is one or more of methyl diethanolamine, triethanolamine, and isopropanolamine.

4. A method for preparing a water-based annular protective liquid according to any one of claims 1 to 3, characterized in that... The following steps are followed: Add the required amounts of acid gas corrosion inhibitor, desulfurizer, polymeric guanidine bactericide, oxygen scavenger, and pH adjuster to water, mix and stir to obtain a water-based annular protective solution. The raw materials in the water-based annular protective solution, calculated by mass percentage, include 0.1% to 2% acid gas corrosion inhibitor, 0.1% to 2% desulfurizer, 0.1% to 2% polymeric guanidine bactericide, 0.1% to 5% oxygen scavenger, 0.1% to 2% pH adjuster, and the remainder is water.

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