Oil-based annulus protection fluid and preparation method thereof

Abstract

The invention relates to the technical field of preparation of oilfield chemical assistants, in particular to an oil-based annulus protection fluid and a preparation method thereof.The oil-based annulus protection fluid is prepared from, by mass, 1%-2% of an anti-carbon dioxide corrosion inhibitor, 1%-2% of a polycyclic azide structure sulfur removal agent, 1%-2% of an oil-soluble polymeric guanidine bactericide, 1%-10% of a surfactant and the balance organic oil; the oil-based annulus protection liquid is prepared according to the following method: adding a required amount of the carbon dioxide-resistant corrosion inhibitor, the polycyclic azide structure sulfur removal agent, the oil-soluble polymeric guanidine bactericide and the surfactant into the organic oil, and mixing and stirring to obtain the oil-based annulus protection liquid. The preparation process is simple, and the obtained oil-based annulus protection fluid has double effects of corrosion inhibition and sterilization, is good in thermal stability, strong in high-temperature resistance, suitable for a high-acidity gas environment, low in corrosion resistance to carbon steel pipes and good in anti-corrosion effect, does not contain aromatic hydrocarbon in the used organic oil, and has the advantages of being non-toxic, low in 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] As an important technology for protecting oil and casing in highly acidic gas wells, annulus protection fluid has been widely used at home and abroad in recent years. Commonly used annulus protection fluids can be divided into water-based annulus protection fluids and emulsion annulus protection fluids according to the properties of their continuous phases, while oil-based annulus protection fluids are rarely used on site due to their high prices. Water-based annulus protection fluids are more commonly used after well completion because of their low cost and little damage to the reservoir. However, when used for ordinary carbon steel pipes in highly acidic environments, their anti-corrosion effect is not ideal and is not suitable for long-term corrosion protection of the annular space of highly acidic 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 announcement number CN102719233B discloses an annular space protection fluid for oil and gas wells. The protection fluid can provide continuous protection and extend the service life of the wellbore annular space pipe by more than 50%. However, the corrosion rate of N80 steel sheet is as high as 0.070mm / a, and the influence of high acid gas environment on the corrosion performance of the annular space protection fluid is not considered; the Chinese patent document with authorization announcement 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 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 preparation method comprises the following steps in sequence: 1) adding a certain amount of distilled water to a reactor; 2) adding a bactericide to the distilled water and stirring evenly; 3) adding a deoxidizer to the solution of step 2) and stirring to dissolve the deoxidizer completely; 4) adding an organic salt, a pH regulator, and a gas well corrosion inhibitor to the solution of step 3) in sequence and stirring evenly to obtain the product. The temperature resistance of the protective liquid reaches 160°C, but the corrosion rate is 0.040mm / a, which is not conducive to the long-term corrosion protection of ordinary carbon steel pipes, and the effect of a highly acidic gas environment on the corrosion performance of the annular protective liquid 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 enters the annulus 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 of 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 non-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 high acid gas environment on the corrosion performance of annular space protection fluid is not considered, and it is not suitable for long-term corrosion protection of oil casing annular space in high acid environment.

[0005] Therefore, it is necessary to develop an oil-based annulus protection fluid for highly acidic environments with reasonable cost and acceptable environment for application 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 above-mentioned deficiencies of the prior art and can effectively solve the problems of the existing oilfield chemical additive annular space protection fluid having strong corrosion performance to carbon steel pipes, being unsuitable for highly acidic gas environments, and being prone to 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, in terms of mass percentage, include 1% to 2% anti-carbon dioxide corrosion inhibitor, 1% to 2% polycyclic azide structure desulfurizer, 1% to 2% oil-soluble polymerized 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: add the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymerized guanidine fungicide, and surfactant to the organic oil, mix and stir to obtain the oil-based annular space protection fluid.

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

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

[0010] In the above step S05, the polycarboxylic acid is one of adipic acid, 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.

[0011] 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, high carbonic acid, catalyst, and xylene to react to obtain a polycyclic azide structure desulfurizing agent.

[0012] In the above step S11, the alcoholamine is ethanolamine, 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 2 h to 4 h.

[0013] 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 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.

[0014] The above oil-soluble polymeric guanidine fungicide 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, adding a required amount of initiator and reacting to obtain a reaction product, and then adding the intermediate 2 and a required amount of catalyst to the reaction product and reacting to obtain an oil-soluble polymerized guanidine fungicide.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] The above-mentioned organic oil is one of vegetable oil, bio-oil and biomass diesel.

[0019] The surfactant is one of sorbitan monooleate and polyoxyethylene fatty amine.

[0020] 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, which is carried out according to the following method: adding the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymerized guanidine bactericide, and surfactant to organic oil, mixing and stirring, to obtain an oil-based annular space protection fluid.

[0021] 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 high-acid 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 aromatics and has the advantages of being non-toxic, low-cost and renewable. DETAILED DESCRIPTION

[0022] The present invention is not limited by the following embodiments, and specific implementation methods can be determined according to the technical scheme of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all known and commonly used chemical reagents and chemicals in the prior art.

[0023] The present invention will be further described below in conjunction with embodiments: Example 1: The oil-based annular space protection fluid, the raw materials, 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: add the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymeric guanidine fungicide, and surfactant to the organic oil, mix and stir to obtain the oil-based annular space protection fluid.

[0024] Example 2: As an optimization of the above example, the anti-carbon dioxide corrosion inhibitor was prepared according to the following method: S01, uniformly mixing a required amount of macromolecular petroleum acid and polyamine and reacting them to obtain an intermediate 1; S02, mixing the intermediate 1 and a required amount of guanidine hydrochloride uniformly and reacting them to obtain the intermediate 2; S03, adding a solvent and a chain transfer agent to a required amount of monomer, and then adding a required amount of initiator to react to obtain an intermediate three; S04, mixing the intermediate 2, the intermediate 3 and a required amount of polyetheramine uniformly and reacting them to obtain a first polymer; S05, reacting a required amount of the intermediate 1 obtained in step S01 with a polycarboxylic acid to obtain a first reaction product; S06, mixing the chlorine-containing compound with the first reaction product and performing a cross-linking reaction to obtain a second polymer; S07, mixing the obtained first polymer, the second polymer and the modified imidazoline and compounding them to obtain a carbon dioxide corrosion inhibitor, wherein the required amount of the intermediate 1 obtained in step S01, guanidine hydrochloride and a primary amine are mixed and reacted to obtain a modified imidazoline.

[0025] 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.

[0026] 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.

[0027] In the present invention, when preparing the carbon dioxide corrosion inhibitor, the chemical reaction mechanism of obtaining the intermediate 1 is as follows: The value range of k is 2 to 10.

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

[0029] The chemical reaction mechanism to obtain intermediate 3 is as follows: The chemical reaction mechanism for obtaining the first polymer is as follows: The values ​​of a, b, c and k are all in the range of 2 to 10.

[0030] The chemical reaction mechanism to obtain the first reaction product is as follows: The value range of k is 2 to 10.

[0031] The chemical reaction mechanism to obtain the second polymer is as follows: The value ranges of k and d are both 2 to 10.

[0032] The chemical reaction mechanism for obtaining modified imidazoline is as follows: The value ranges of k and d are both 2 to 10.

[0033] Example 5: 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, high carbonic acid, catalyst, and xylene to react to obtain a polycyclic azide structure desulfurizing agent.

[0034] 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 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.

[0035] Example 7: As an optimization of the above example, in step S12, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic acid, the percarbonic acid is one or more of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid, and the catalyst is one of dodecylbenzenesulfonic acid, p-toluenesulfonic acid, and aminosulfonic acid, wherein the molar ratio of the polycarboxylic acid to the desulfurizer intermediate is 1:1 to 2, the 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.

[0036] Example 8: As an optimization of the above example, an 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; 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, adding a required amount of initiator and reacting to obtain a reaction product, and then adding the intermediate 2 and a required amount of catalyst to the reaction product and reacting to obtain an oil-soluble polymerized guanidine fungicide.

[0037] 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.

[0038] 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.

[0039] 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 after adding the initiator 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, and the reaction temperature after adding the catalyst is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

[0040] Example 12: As an optimization of the above example, the organic oil is one of vegetable oil, bio-oil, and biomass diesel.

[0041] Example 13: As an optimization of the above example, the surfactant is one of sorbitan monooleate and polyoxyethylene fatty amine.

[0042] Example 14: The preparation method of the oil-based annular space protection fluid is carried out according to the following method: add the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymerized guanidine bactericide, and surfactant to the organic oil, mix and stir to obtain the oil-based annular space protection fluid.

[0043] Example 15: Preparation of the oil-based annular space protection fluid (1) Preparation of anti-carbon dioxide corrosion inhibitor: In the first step, 350 kg (1 kmol) of macromolecular petroleum acid (molecular weight 350) and 439 kg (1 kmol) of polyethylene polyamine (molecular weight 439) were added to the reactor, mixed evenly, and then slowly heated to 280°C, and refluxed for 10 hours to obtain intermediate 1; In the second step, the intermediate 1 is mixed evenly with 95.5 kg (1 kmol) of guanidine hydrochloride, and the temperature is controlled at 150°C for 3 hours to obtain the intermediate 2; Step 3: Take 200 kg of solvent (ethanol), add 100 kg of monomer (acrylic acid), 2 kg of chain transfer agent (n-dodecyl mercaptan), control the temperature at 80°C, add 0.4 kg of initiator (azobisisobutyronitrile) (add in 4 times, 0.1 kg / h), react for 4 hours, and remove the solvent by vacuum dehydration to obtain intermediate 3; Step 4: 884.5 kg of intermediate 2 and 302 kg of intermediate 3 were mixed evenly, 50 kg of polyetheramine (D350) was added, and the temperature was controlled at 150° C. to react for 4 hours to obtain the first polymer (comb-shaped imidazoline); Step 5: Take 789 kg of intermediate 1 and 73 kg of adipic acid (0.5 kmol), control the temperature at 150°C for 4 hours to obtain a first reaction product, then add 87.5 kg (0.5 kmol) of 1,4-dichlorobenzyl to the first reaction product (0.5 kmol), and react at 80°C for 4 hours to obtain a second polymer (linear structure imidazoline); Step 6: Take 789 kg of intermediate 1, 95.5 kg of guanidine hydrochloride, and 214.5 kg of hexadecyl primary amine, and react at 150 ° C for 4 hours to prepare modified imidazoline. 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.

[0044] (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 the reaction at 60°C for 3 hours to obtain a desulfurizer intermediate (also known as a triazine desulfurizer); The desulfurizer intermediate was vacuum dehydrated for 2 hours, and 181 kg of polycarboxylic acid (adipic acid), 11.5 kg of catalyst (aminosulfonic acid), 4510 kg of percarbonic acid (octadecanoic acid), and 2710 kg of xylene were added. The temperature was controlled at 140 ° C for 6 hours to obtain a polycyclic azide structure desulfurizer (also known as a cross-linked and oil-soluble desulfurizer).

[0045] (3) Preparation of oil-soluble 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 obtain intermediate 1; Add 7 kg of guanidine hydrochloride to the intermediate 1, control the temperature at 150°C and react for 3 hours to obtain the intermediate 2; Take 50 kg of solvent (xylene), add 5 kg of reaction monomer (methyl acrylate), 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 and 2 kg of catalyst (p-toluenesulfonic acid), control the temperature at 150 ° C and react for 4 hours to obtain an oil-soluble polymerized guanidine fungicide (also known as oil-soluble polymerized guanidine).

[0046] (4) Preparation of the oil-based annular space protection fluid: 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 dehydrated sorbitan monooleate (also known as span80), mix and stir evenly to obtain an oil-based annular space protection fluid.

[0047] Embodiment 16: The difference between the preparation process of Example 16 and Example 15 is that: When preparing the carbon dioxide corrosion inhibitor, in the fourth step, 50 kg of polyetheramine (D350) was replaced with 50 kg of polyetheramine (D600); 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; When preparing the oil-soluble polymerized guanidine fungicide, the reaction monomer is 6 kg of ethyl acrylate and the initiator is dibenzoyl peroxide; The rest of the process is the same.

[0048] Embodiment 17: The difference between the preparation process of Example 17 and that of Example 15 is that: 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; When preparing the oil-soluble polymerized guanidine fungicide, the reaction monomer is 6 kg of ethyl acrylate and the initiator is dibenzoyl peroxide; The rest of the process is the same.

[0049] Embodiment 18: The difference between the preparation process of Example 18 and that of Example 15 is that: When preparing the carbon dioxide corrosion inhibitor, the added monomer is methacrylic acid; The rest of the process is the same.

[0050] Embodiment 19: The difference between the preparation process of Example 19 and Example 15 is that: 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; The rest of the process is the same.

[0051] 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: A 1.5L stainless steel corrosion evaluation kettle was used for corrosion test. Appropriate amount of oil-based annular space protection fluid samples obtained in Examples 15 to 19 were injected into the kettle respectively, the autoclave was sealed, nitrogen was introduced for 5 hours, the total pressure was 7.0MPa, the system was heated to 150°C, H2S and CO2 gas were introduced, the H2S partial pressure was 1.0MPa, and the CO2 partial pressure was 1.0MPa. The corrosion test was carried out on A3 steel sheet and N80 steel sheet for 72 hours. The experimental results are shown in Table 1.

[0052] Table 1 .

[0053] As shown in Table 1, the oil-based annular space protection fluid of the present invention has good thermal stability and strong high temperature resistance. The corrosion rate of A3 steel sheet is ≤0.0013mm / a and the corrosion rate of N80 steel sheet is ≤0.0047mm / a when reacted at a total pressure of 7.0MPa, a H2S partial pressure of 1.0MPa, a CO2 partial pressure of 1MPa and 150°C for 72h; the sterilization effect is good, and the sterilization effect is ≤3 / mL, which can meet the requirements of corrosion protection of the annular space of ordinary carbon steel pipes in a highly acidic environment.

[0054] In summary, 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, suitable for high-acid gas environment, low corrosion performance to carbon steel pipes, and good anti-corrosion effect. At the same time, the organic oil used does not contain aromatics, and has the advantages of being non-toxic, low-cost and renewable.

[0055] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. An 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 polycyclic azide structure desulfurizer, 1% to 2% of an oil-soluble polymerized 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: adding the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymerized guanidine fungicide, and surfactant to the organic oil, mixing and stirring, and obtaining the oil-based annular space protection fluid.

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

3. The oil-based annulus protection fluid according to claim 2, characterized in that In step S01, the molar ratio of the macromolecular petroleum acid to the polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250° C. to 300° C., and the reaction time is 9 h to 11 h, wherein the polyamine is polyethylene polyamine and the macromolecular petroleum acid is a by-product in the petroleum refining process; or / and, in step S02, the molar ratio of the intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 140° C. to 150° C., and the reaction time is 2.5 h. h to 3.5h; or / and, in step S03, the monomer is one or more of acrylic acid, maleic anhydride, and methacrylic acid, the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, xylene, trimethylbenzene, dimethyl sulfoxide, and dimethylformamide, the chain transfer agent is n-dodecyl mercaptan, the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature is 60°C to 120°C, and the reaction time is 3.5h to 4.5h; or / and, step In step S04, the polyetheramine is one of D350 and D600, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h; or / and, in step S05, the polycarboxylic acid is one of adipic acid, 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 3.5h to 4.5h; or / and, in step S06, the chlorine-containing compound is 1,4 - benzyl dichloride, the molar ratio of the chlorine-containing compound to the first reaction product is 1:1 to 2, the reaction temperature is 70°C to 100°C, and the reaction time is 3.5h to 4.5h; or / and, in step S07, the molar ratio of the intermediate 1, guanidine hydrochloride and the primary amine is 1:1:1, the reaction temperature is 145°C to 155°C, and the reaction time is 3.5h to 4.5h, wherein the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

4. The oil-based annulus protection fluid according to any one of claims 1 to 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, high carbonic acid, catalyst, and xylene to react to obtain a polycyclic azide structure desulfurizing agent.

5. The oil-based annulus protection fluid according to claim 4, characterized in that In step S11, the alcoholamine is ethanolamine, 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; or / and, in step S12, the polycarboxylic acid is one of adipic acid, glutaric acid, oxalic acid, and malonic acid, the high carbonic acid is one or more of dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid, 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 oil-based annulus protection fluid according to claim 1, 2, 3 or 5, characterized in that The oil-soluble polymeric guanidine fungicide 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, adding a required amount of initiator and reacting to obtain a reaction product, and then adding the intermediate 2 and a required amount of catalyst to the reaction product and reacting to obtain an oil-soluble polymerized guanidine fungicide.

7. The oil-based annulus protection fluid according to claim 6, characterized in that In step S21, the molar ratio of petroleum acid to polyethylene polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 10h to 12h; or / and, in step S22, the molar ratio of intermediate 1 to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 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 methyl acrylate and ethyl acrylate, and the solvent is methanol, ethanol, or n-butanol. , propylene glycol, glycerol, ethylene glycol, xylene, trimethylbenzene, dimethyl sulfoxide, dimethylformamide, the chain transfer agent is n-dodecyl mercaptan, the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature after adding the initiator 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 after adding the catalyst is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

8. The oil-based annulus protection fluid according to claim 1, 2, 3, 5 or 7, characterized in that Organic oil is a type of vegetable oil, bio-oil, and biomass diesel.

9. The oil-based annulus protection fluid according to claim 8, characterized in that The surfactant is one of sorbitan monooleate and polyoxyethylene fatty amine.

10. A method for preparing an oil-based annular space protection fluid according to any one of claims 1 to 9, characterized in that The method is as follows: add the required amount of anti-carbon dioxide corrosion inhibitor, polycyclic azide structure desulfurizer, oil-soluble polymerized guanidine bactericide and surfactant into organic oil, mix and stir to obtain oil-based annular space protection fluid.

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