Oil-based annular space protection fluid and preparation method thereof

Abstract

The present invention relates to the technical field of preparation of oilfield chemical additives, and is an oil-based annular space protection fluid and a preparation method thereof. The raw materials of the former include, by mass percentage, 1% to 2% of an anti-carbon dioxide corrosion inhibitor, 1% to 2% of a polycyclic azide structure desulfurizer, 1% to 2% of an oil-soluble polymerized guanidine bactericide, 1% to 10% of a surfactant, and the rest is organic oil. The latter is prepared according to the following method: adding the required amount of an anti-carbon dioxide corrosion inhibitor, a polycyclic azide structure desulfurizer, an oil-soluble polymerized guanidine bactericide, and a surfactant to the organic oil, mixing and stirring to obtain an oil-based annular space protection fluid. The preparation process of the present invention is simple, and the obtained oil-based annular space protection fluid has the dual effects of corrosion inhibition and sterilization, good thermal stability, strong high temperature resistance, and is suitable for highly acidic gas environments. It also has low corrosion performance on carbon steel pipes and good anti-corrosion effect. At the same time, the organic oil used does not contain aromatic hydrocarbons, and has the advantages of being non-toxic, low-cost, and renewable.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield chemical auxiliary agent preparation, in particular to an oil-based annular space protection fluid and a preparation method thereof. Background Art

[0002] Annular fluids, a crucial technology for protecting oil and casing in highly sour gas wells, have been widely used both domestically and internationally in recent years. Commonly used annular fluids can be categorized as water-based and emulsion-based, depending on the properties of their continuous phase. Oil-based fluids, however, are less commonly used in the field due to their high cost. Water-based fluids are commonly used after well completion due to their low cost and minimal reservoir damage. However, their corrosion protection is suboptimal when applied to ordinary carbon steel pipes in highly sour environments, making them unsuitable for long-term corrosion protection in the annular spaces of highly sour oil and gas wells.

[0003] At present, there are many studies on water-based annular space protection fluids in China. The Chinese patent document with authorization publication number CN102719233B discloses an annular space protection fluid for oil and gas wells. This protection fluid can provide continuous protection and extend the service life of the wellbore annular space string by more than 50%. However, the corrosion rate of N80 steel sheets is as high as 0.070 mm / a, and the impact of highly acidic gas environments on the corrosion performance of the annular space protection fluid is not considered; the Chinese patent document with authorization publication number CN102816560B discloses a high-temperature annular space protection fluid and a preparation method thereof. The protection fluid is made of the following raw materials in the following weight ratios: 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 regulator, and the remainder is distilled water. The preparation method comprises the following sequential steps: 1) adding a certain amount of distilled water to a reactor; 2) adding a fungicide to the distilled water and stirring uniformly; 3) adding a scavenger to the solution from step 2) and stirring to completely dissolve the scavenger; 4) sequentially adding an organic salt, a pH adjuster, and a gas well corrosion inhibitor to the solution from step 3) and stirring uniformly to obtain the product. This protective fluid has a temperature resistance of up to 160°C, but its corrosion rate is 0.040 mm / a, making it unsuitable for long-term corrosion protection of ordinary carbon steel pipes. Furthermore, the corrosion performance of the annular protective fluid in a highly acidic gas environment is not considered.

[0004] Emulsion annulus protection fluid can achieve layered protection and has strong anti-corrosion targeting. The Chinese patent document with authorization announcement number CN103275685B discloses an annulus protection fluid for annular mechanical sealing of oil and gas wells and its construction process. Its composition includes: 10-14% low interfacial tension surfactant emulsifier + 0.1-0.5% non-ionic surfactant foaming agent + 0.1-0.3% plant gum foam stabilizer + 25-28% oil phase + 0.5-1% water-based quaternary ammonium salt corrosion inhibitor + 8-10% inert gas + water. The solution forms a foam emulsion under stirring and automatically forms a foam after entering the annulus. It is divided into three layers: gas, oil and water. The upper gas is compressible, the middle oil layer effectively protects the casing annulus, and the lower water base separates the oil base to prevent aging of the packer rubber sleeve. However, after the gas, oil and water are separated, the galvanic corrosion at the oil-water interface is serious, resulting in unsatisfactory anti-corrosion effect; Chinese patent document with publication number CN104498010A discloses an oil casing annulus protection fluid for oil production and its preparation method, which comprises: base oil + 0.5-3% bactericide + 1-5% corrosion inhibitor + 0.2-1% scale inhibitor + 0.1-0.5% surfactant + 2-5% preservative + 2-10% pH regulator. The base fluid is base oil, the bactericide is a halogenated hydantoin bactericide, and the corrosion inhibitor is a compound product of organic phosphate and polyacrylate. In an environment with no high H2S and CO2 content, the corrosion rate is as high as 0.076mm / a, and the bactericidal effect is ≤6 pieces / mL. The influence of the highly acidic gas environment on the corrosion performance of the annular space protection fluid is not considered, and it is not suitable for long-term corrosion protection of the annular space of the oil casing in a highly acidic environment.

[0005] Therefore, it is necessary to develop an oil-based annular space protection fluid with reasonable cost and environmental acceptance for high acid environment to be applied in current oil and gas wells. Summary of the Invention

[0006] The present invention provides an oil-based annular space protection fluid and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of the existing oilfield chemical auxiliary annular space protection fluid, such as strong corrosion performance to carbon steel pipes, unsuitability for highly acidic gas environments, and easy occurrence of galvanic corrosion after oil-water stratification.

[0007] One of the technical solutions of the present invention is achieved through the following measures: an oil-based annular space protection fluid, the raw materials of which include, by mass percentage, 1% to 2% of an anti-carbon dioxide corrosion inhibitor, 1% to 2% of a polycyclic azide structure desulfurizer, 1% to 2% of an oil-soluble polymeric guanidine fungicide, 1% to 10% of a surfactant, and the rest is organic oil. The oil-based annular space protection fluid is prepared according to the following method: the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymeric guanidine fungicide, and surfactant are added to the organic oil, and after mixing and stirring, the oil-based annular space protection fluid is obtained.

[0008] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0009] The above-mentioned anti-carbon dioxide corrosion inhibitor is prepared according to the following method:

[0010] S01, uniformly mixing a required amount of macromolecular petroleum acid and polyamine and reacting them to obtain intermediate 1;

[0011] S02, mixing the intermediate 1 with a required amount of guanidine hydrochloride and reacting the mixture to obtain the intermediate 2;

[0012] 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 intermediate three;

[0013] S04, uniformly mixing the intermediate 2, the intermediate 3 and a required amount of polyetheramine and reacting them to obtain a first polymer;

[0014] S05, reacting a required amount of the intermediate 1 obtained in step S01 with a polycarboxylic acid to obtain a first reaction product;

[0015] S06, mixing the chlorine-containing compound with the first reaction product and performing a cross-linking reaction to obtain a second polymer;

[0016] 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.

[0017] 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. 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.

[0018] In the above step S05, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic 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.

[0019] The polycyclic azide structure desulfurizer is prepared according to the following method:

[0020] S11, mixing a required amount of an alcohol amine and an aldehyde and reacting them to obtain a desulfurizing agent intermediate;

[0021] 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 polycyclic azide structure desulfurizing agent.

[0022] In the above step S11, the alcoholamine is ethanolamine, the aldehyde is formaldehyde, the molar ratio of alcoholamine to 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.

[0023] In the above 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 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.

[0024] The above oil-soluble polymeric guanidine fungicide is prepared according to the following method:

[0025] S21, mixing a required amount of petroleum acid and polyethylene polyamine and reacting them to obtain intermediate 1;

[0026] S22, mixing the intermediate 1 and a required amount of guanidine hydrochloride and reacting them to obtain the intermediate 2;

[0027] S23, uniformly mixing the reaction monomer, solvent and chain transfer agent, adding a required amount of initiator and reacting to obtain a reaction product, and then adding intermediate 2 and a required amount of catalyst to the reaction product and reacting to obtain an oil-soluble polymeric guanidine fungicide.

[0028] 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.

[0029] In the above step S22, 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 120° C. to 180° C., and the reaction time is 2 h to 4 h.

[0030] In the above step S23, the reaction monomer is one or more of methyl acrylate and ethyl acrylate, 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 during the reaction after the initiator is added is 60°C to 120°C, the reaction time is 3.5h to 4.5h, the catalyst is one of aminosulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid, the reaction temperature during the reaction after the catalyst is added is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

[0031] The organic oil is one of vegetable oil, bio-oil and biomass diesel.

[0032] The surfactant is one of sorbitan monooleate and polyoxyethylene fatty amine.

[0033] The second technical solution of the present invention is achieved through the following measures: a method for preparing an oil-based annular space protection fluid is carried out according to the following method: adding the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymeric guanidine fungicide, and surfactant to organic oil, mixing and stirring to obtain an oil-based annular space protection fluid.

[0034] The preparation process of the present invention is simple, and the obtained oil-based annular space protection fluid has the dual functions of corrosion inhibition and sterilization, good thermal stability, strong high temperature resistance, and is suitable for highly acidic gas environments. It also has low corrosion performance on carbon steel pipes and good anti-corrosion effect. At the same time, the organic oil used does not contain aromatic hydrocarbons, and has the advantages of being non-toxic, low-cost and renewable. DETAILED DESCRIPTION

[0035] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions. 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.

[0036] The present invention will be further described below in conjunction with the embodiments:

[0037] Example 1: The oil-based annular space protection fluid, the raw materials of which are calculated by mass percentage, include 1% to 2% anti-carbon dioxide corrosion inhibitor, 1% to 2% polycyclic azide structure desulfurizer, 1% to 2% oil-soluble polymeric guanidine fungicide, 1% to 10% surfactant, and the rest is organic oil. The oil-based annular space protection fluid is prepared according to the following method: the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymeric guanidine fungicide and surfactant are added to the organic oil, and the mixture is mixed and stirred to obtain the oil-based annular space protection fluid.

[0038] Example 2: As an optimization of the above example, an anti-carbon dioxide corrosion inhibitor was prepared according to the following method:

[0039] S01, uniformly mixing a required amount of macromolecular petroleum acid and polyamine and reacting them to obtain intermediate 1;

[0040] S02, mixing the intermediate 1 with a required amount of guanidine hydrochloride and reacting the mixture to obtain the intermediate 2;

[0041] 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 intermediate three;

[0042] S04, uniformly mixing the intermediate 2, the intermediate 3 and a required amount of polyetheramine and reacting them to obtain a first polymer;

[0043] S05, reacting a required amount of the intermediate 1 obtained in step S01 with a polycarboxylic acid to obtain a first reaction product;

[0044] S06, mixing the chlorine-containing compound with the first reaction product and performing a cross-linking reaction to obtain a second polymer;

[0045] 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.

[0046] 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.

[0047] Example 4: As an optimization of the above example, in step S05, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic 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.

[0048] In the present invention, when preparing the carbon dioxide corrosion inhibitor, the chemical reaction mechanism for obtaining the intermediate 1 is as follows:

[0049]

[0050] The value of k ranges from 2 to 10.

[0051] The chemical reaction mechanism to obtain intermediate 2 is as follows:

[0052]

[0053] The value of k ranges from 2 to 10.

[0054] The chemical reaction mechanism to obtain intermediate 3 is as follows:

[0055]

[0056] The chemical reaction mechanism to obtain the first polymer is as follows:

[0057]

[0058] The values ​​of a, b, c, and k all range from 2 to 10.

[0059] The chemical reaction mechanism to obtain the first reaction product is as follows:

[0060]

[0061] The value of k ranges from 2 to 10.

[0062] The chemical reaction mechanism to obtain the second polymer is as follows:

[0063]

[0064] The value ranges of k and d are both 2 to 10.

[0065] The chemical reaction mechanism for obtaining modified imidazoline is as follows:

[0066]

[0067] The value ranges of k and d are both 2 to 10.

[0068] Example 5: As an optimization of the above example, a polycyclic azide structure desulfurizer was prepared according to the following method:

[0069] S11, mixing a required amount of an alcohol amine and an aldehyde and reacting them to obtain a desulfurizing agent intermediate;

[0070] 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 polycyclic azide structure desulfurizing agent.

[0071] Example 6: As an optimization of the above example, in step S11, the alcoholamine is ethanolamine, and the aldehyde is formaldehyde, wherein the molar ratio of alcoholamine to 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.

[0072] 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 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 mass of the added 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.

[0073] Example 8: As an optimization of the above example, an oil-soluble polymeric guanidine fungicide was prepared according to the following method:

[0074] S21, mixing a required amount of petroleum acid and polyethylene polyamine and reacting them to obtain intermediate 1;

[0075] S22, mixing the intermediate 1 and a required amount of guanidine hydrochloride and reacting them to obtain the intermediate 2;

[0076] S23, uniformly mixing the reaction monomer, solvent and chain transfer agent, adding a required amount of initiator and reacting to obtain a reaction product, and then adding intermediate 2 and a required amount of catalyst to the reaction product and reacting to obtain an oil-soluble polymeric guanidine fungicide.

[0077] 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.

[0078] Example 10: 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.

[0079] Example 11: As an optimization of the above example, in step S23, the reaction monomer is one or more of methyl acrylate and ethyl acrylate, 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 during the reaction after the initiator is added is 60°C to 120°C, and the reaction time is 3.5h to 4.5h, the catalyst is one of aminosulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid, the reaction temperature during the reaction after the catalyst is added is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

[0080] Example 12: As an optimization of the above example, the organic oil is one of vegetable oil, bio-oil, and biodiesel.

[0081] Example 13: As an optimization of the above example, the surfactant is one of sorbitan monooleate and polyoxyethylene fatty amine.

[0082] Example 14: The preparation method of the oil-based annular space protection fluid is carried out according to the following method: adding the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymeric guanidine fungicide, and surfactant to organic oil, mixing and stirring to obtain the oil-based annular space protection fluid.

[0083] Example 15: Preparation of the oil-based annular space protection fluid

[0084] (1) Preparation of anti-carbon dioxide corrosion inhibitor:

[0085] 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 a reactor, mixed evenly, and then slowly heated to 280°C and refluxed for 10 hours to obtain intermediate 1;

[0086] In the second step, intermediate 1 was mixed evenly with 95.5 kg (1 kmol) of guanidine hydrochloride, and the mixture was reacted at 150°C for 3 hours to obtain intermediate 2.

[0087] In the third step, 200 kg of solvent (ethanol) was added with 100 kg of monomer (acrylic acid) and 2 kg of chain transfer agent (n-dodecyl mercaptan). 0.4 kg of initiator (azobisisobutyronitrile) was added at 80°C (4 additions at 0.1 kg / h). After reacting for 4 hours, the solvent was removed by vacuum dehydration to obtain intermediate 3.

[0088] 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);

[0089] Step 5: 789 kg of intermediate 1 and 73 kg of adipic acid (0.5 kmol) were reacted at 150°C for 4 hours to obtain a first reaction product. 87.5 kg (0.5 kmol) of 1,4-dichlorobenzyl was then added to the first reaction product (0.5 kmol) and the mixture was reacted at 80°C for 4 hours to obtain a second polymer (linear imidazoline).

[0090] Step 6: Take 789 kg of intermediate 1, 95.5 kg of guanidine hydrochloride, and 214.5 kg of hexadecyl primary amine, control the temperature at 150° C. and react for 4 hours to prepare modified imidazoline;

[0091] In the seventh step, the first polymer, the second polymer, and the modified imidazoline are mixed in a mass ratio of 9:0.5:0.5, and stirred evenly to obtain a carbon dioxide corrosion inhibitor.

[0092] (2) Preparation of polycyclic azide structure desulfurizer:

[0093] Add all 1830 kg of alcoholamine (ethanolamine) into the kettle, start stirring and control the temperature at 60°C, slowly add 2500 kg (volume concentration of 36%) formaldehyde aqueous solution dropwise, and continue the reaction at 60°C for 3 hours to obtain a desulfurizer intermediate (also known as a triazine desulfurizer);

[0094] The desulfurizer intermediate was vacuum dehydrated for 2 hours, and 181 kg of polycarboxylic acid (adipic acid), 11.5 kg of catalyst (sulfamic acid), 4510 kg of high carbonic acid (octadecanoic acid), and 2710 kg of xylene were added. The temperature was controlled at 140 ° C and the reaction was carried out for 6 hours to obtain a polycyclic azide structure desulfurizer (also known as a cross-linked and oil-soluble desulfurizer).

[0095] (3) Preparation of oil-soluble polymeric guanidine fungicide:

[0096] 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 obtain intermediate 1;

[0097] Add 7 kg of guanidine hydrochloride to intermediate 1, control the temperature at 150 ° C and react for 3 hours to obtain intermediate 2;

[0098] Take 50 kg of solvent (xylene), add 5 kg of reaction monomer (methyl acrylate) and 0.1 kg of chain transfer agent (n-dodecyl mercaptan), control the temperature at 80 ° C, add 0.1 g of initiator (azobisisobutyronitrile) and react for 4 hours, then add all the intermediates II and 2 kg of catalyst (p-toluenesulfonic acid), control the temperature at 150 ° C and react for 4 hours to obtain an oil-soluble polymeric guanidine fungicide (also known as oil-soluble polymeric guanidine).

[0099] (4) Preparation of the oil-based annular space protection fluid:

[0100] Take 1000 kg of biomass diesel, add 20 kg of the obtained anti-carbon dioxide corrosion inhibitor, 20 kg of polycyclic azide structure desulfurizer, 20 kg of oil-soluble polymerized guanidine fungicide, and 20 kg of anhydrous sorbitan monooleate (also known as span80), mix and stir evenly to obtain an oil-based annular space protection fluid.

[0101] Example 16:

[0102] The difference between the preparation process of Example 16 and Example 15 is that:

[0103] When preparing the carbon dioxide corrosion inhibitor, in the fourth step, 50 kg of polyetheramine (D350) was replaced with 50 kg of polyetheramine (D600);

[0104] When preparing the polycyclic azide structure desulfurizer, the polycarboxylic acid is glutaric acid, the high carbonic acid is hexadecanoic acid, and the catalyst is p-toluenesulfonic acid;

[0105] When preparing an oil-soluble polymeric guanidine fungicide, the reaction monomer is 6 kg of ethyl acrylate and the initiator is dibenzoyl peroxide;

[0106] The rest of the process is the same.

[0107] Example 17:

[0108] The difference between the preparation process of Example 17 and Example 15 is that:

[0109] When preparing the polycyclic azide structure desulfurizer, the polycarboxylic acid is glutaric acid, the high carbonic acid is hexadecanoic acid, and the catalyst is p-toluenesulfonic acid;

[0110] When preparing an oil-soluble polymeric guanidine fungicide, the reaction monomer is 6 kg of ethyl acrylate and the initiator is dibenzoyl peroxide;

[0111] The rest of the process is the same.

[0112] Example 18:

[0113] The difference between the preparation process of Example 18 and that of Example 15 is that:

[0114] When preparing the carbon dioxide corrosion inhibitor, the added monomer is methacrylic acid;

[0115] The rest of the process is the same.

[0116] Example 19:

[0117] The difference between the preparation process of Example 19 and Example 15 is that:

[0118] When preparing the polycyclic azide structure desulfurizer, the polycarboxylic acid is glutaric acid, the high carbonic acid is hexadecanoic acid, and the catalyst is p-toluenesulfonic acid;

[0119] The rest of the process is the same.

[0120] The performance of the oil-based annular space protection fluid obtained in Examples 15 to 19 was tested and evaluated. The specific evaluation method is as follows:

[0121] Corrosion tests were conducted using a 1.5L stainless steel corrosion evaluation autoclave. Appropriate amounts of the oil-based annular space protection fluid samples obtained in Examples 15 to 19 were injected into the autoclave. The autoclave was sealed and nitrogen was introduced for 5 hours at a total pressure of 7.0 MPa. The system temperature was raised to 150°C, and H2S and CO2 gases were introduced at H2S partial pressures of 1.0 MPa and CO2 partial pressures of 1.0 MPa, respectively. Corrosion tests were conducted on A3 and N80 steel sheets for 72 hours. The experimental results are shown in Table 1.

[0122] Table 1

[0123] .

[0124] As shown in Table 1, the oil-based annular space protection fluid of the present invention exhibits excellent thermal stability and high temperature resistance. At a total pressure of 7.0 MPa, an H2S partial pressure of 1.0 MPa, a CO2 partial pressure of 1 MPa, and a reaction temperature of 150°C for 72 hours, the corrosion rate for A3 steel is ≤0.0013 mm / a, and the corrosion rate for N80 steel is ≤0.0047 mm / a. The fluid also exhibits excellent bactericidal efficacy, with a sterilization rate of ≤3 particles / mL, meeting the corrosion protection requirements for the annular space of ordinary carbon steel pipes in highly acidic environments.

[0125] In summary, the preparation process of the present invention is simple, and the obtained oil-based annular space protection fluid has the dual functions of corrosion inhibition and sterilization, good thermal stability, strong high temperature resistance, and is suitable for highly acidic gas environments. It also has low corrosion performance on carbon steel pipes and good anti-corrosion effect. At the same time, the organic oil used does not contain aromatic hydrocarbons, and has the advantages of being non-toxic, low-cost and renewable.

[0126] 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 removed according to actual needs to meet the requirements of different situations.

Claims

1. An oil-based annular space protection fluid, characterized in that The raw materials include, by mass percentage, 1% to 2% of an anti-carbon dioxide corrosion inhibitor, 1% to 2% of a desulfurizer, 1% to 2% of an oil-soluble polymerized guanidine fungicide, and 1% to 10% of a surfactant, with the remainder being organic oil. The oil-based annular space protection fluid is prepared according to the following method: adding a required amount of an anti-carbon dioxide corrosion inhibitor, a desulfurizer, an oil-soluble polymerized guanidine fungicide, and a surfactant to the organic oil, and mixing and stirring to obtain an oil-based annular space protection fluid. The carbon dioxide corrosion inhibitor is prepared according to the following method: S01, uniformly mixing a required amount of a macromolecular petroleum acid and a polyamine and reacting them to obtain an intermediate 1, wherein 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., the reaction time is 9 h to 11 h, the polyamine is polyethylene polyamine, and the macromolecular petroleum acid is a by-product of the petroleum refining process; S02, mixing the intermediate 1 and the required amount of guanidine hydrochloride uniformly and reacting to obtain the intermediate 2, wherein 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 2.5 h to 3.5 h; S03, after adding a solvent and a chain transfer agent to a required amount of monomer, a required amount of initiator is added for reaction to obtain intermediate three, wherein 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, and the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature is 60° C. to 120° C., and the reaction time is 3.5 h to 4.5 h; S04, uniformly mixing the intermediate 2, the intermediate 3 and a required amount of polyetheramine and reacting them to obtain a first polymer, wherein the polyetheramine is one of D350 and D600, the reaction temperature is 100° C. to 150° C., and the reaction time is 3.5 h to 4.5 h; S05, reacting a required amount of the intermediate 1 obtained in step S01 with a polycarboxylic acid to obtain a first reaction product, wherein the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic 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 3.5 h to 4.5 h; S06, mixing the chlorine-containing compound with the first reaction product and performing a cross-linking reaction to obtain a second polymer, wherein 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 3.5 hours to 4.5 hours; S07, mixing the obtained first polymer, the second polymer, and the modified imidazoline and compounding them to obtain an anti-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 the modified imidazoline, 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., 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; The desulfurizer was prepared according to the following method: S11, mixing a required amount of an alcoholamine and an aldehyde and reacting them to obtain a desulfurizer intermediate, wherein the alcoholamine is ethanolamine, the aldehyde is formaldehyde, 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; S12, vacuum dehydrating and purifying the desulfurizer intermediate, and then sequentially adding the required amounts of polycarboxylic acid, percarbonate, catalyst, and xylene for reaction to obtain a desulfurizer, wherein the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic acid, the percarbonate is one or more of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid, the catalyst is one of dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and aminosulfonic acid, 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 2 h to 10 h; The oil-soluble polymeric guanidine fungicide was 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, 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° C. to 300° C., and the reaction time is 10 to 12 hours; S22, uniformly mixing the intermediate 1 and a required amount of guanidine hydrochloride and reacting to obtain the intermediate 2, wherein 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 120° C. to 180° C., and the reaction time is 2 h to 4 h; S23, uniformly mixing the reaction monomer, solvent and chain transfer agent, adding the required amount of initiator and reacting to obtain a reaction product, and then adding intermediate 2 and the required amount of catalyst to the reaction product and reacting to obtain an oil-soluble polymerized guanidine fungicide, wherein the reaction monomer is one or more of methyl acrylate and ethyl acrylate, 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 during the reaction after the initiator is added is 60°C to 120°C, and the reaction time is 3.5h to 4.5h, the catalyst is one of aminosulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid, the reaction temperature during the reaction after the catalyst is added is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

2. The oil-based annular space protection fluid according to claim 1, characterized in that Organic oil is one of vegetable oil, bio-oil and biomass diesel.

3. The oil-based annular space protection fluid according to claim 1 or 2, characterized in that The surfactant is one of sorbitan monooleate and polyoxyethylene fatty amine.

4. A method for preparing an oil-based annular space protection fluid according to any one of claims 1 to 3, characterized in that The method is as follows: adding required amounts of anti-carbon dioxide corrosion inhibitor, desulfurizer, oil-soluble polymerized guanidine fungicide and surfactant into organic oil, mixing and stirring to obtain an oil-based annular space protection fluid.

Images