Environment-friendly petroleum drilling fluid as well as preparation method and application thereof

Abstract

The invention discloses an environment-friendly petroleum drilling fluid as well as a preparation method and application thereof, and belongs to the technical field of petroleum drilling fluids. The environment-friendly petroleum drilling fluid is prepared from 100 parts by weight of water, 10 to 15 parts by weight of bentonite, 0.5 to 1.5 parts by weight of organic silicon microspheres, 1 to 3 parts by weight of a compound filtrate reducer, 2 to 3 parts by weight of a blocking agent, 5 to 8 parts by weight of a vegetable oil lubricant and 1.5 to 2.5 parts by weight of organic amine salt. Comprising the steps of basic mud preparation, additive mixing, primary mixing, secondary mixing and performance testing, according to the environment-friendly petroleum drilling fluid and the preparation method and application thereof, the friction force between a drill bit and a rock stratum is reduced by means of the excellent lubricating performance of organic silicon microspheres, abrasion of the drill bit is reduced, the service life is prolonged, meanwhile, a composite filtrate reducer is adopted, and the cost is reduced. The compound filtrate reducer contains cotton and hemp cellulose, so that the viscosity and the consistency of the drilling fluid can be increased, and the suspension capacity and the load bearing capacity of the drilling fluid are improved.

Description

Technical Field

[0001] The invention specifically relates to an environmentally friendly petroleum drilling fluid and a preparation method and application thereof, belonging to the technical field of petroleum drilling fluid. Background Art

[0002] Oil drilling fluid is a general term for various circulating fluids that meet the needs of drilling work with its multiple functions during the oil drilling process. It is also called drilling flushing fluid. According to its composition, it can be divided into clean water, mud, clay-free flushing fluid, emulsion, foam and compressed air. Clean water is the earliest drilling fluid used. It does not need to be treated and is easy to use. It is suitable for intact rock formations and areas with sufficient water resources. Mud is a widely used drilling fluid, mainly suitable for loose, fractured, easily collapsed and shattered rock formations with unstable pore walls such as those that swell and peel when exposed to water. The preparation method of drilling fluid has different selections and adjustments according to specific drilling needs and formation characteristics. During the preparation process, the proportion of materials and the order of addition are usually strictly controlled to ensure that the performance of the mud meets the requirements. At the same time, the mud must be fully stirred and performance tested to ensure its effectiveness in actual applications. The high-temperature stability and environmental performance of existing drilling fluids are average. In view of this, this application is proposed. Summary of the invention

[0003] The purpose of the present invention is to provide an environmentally friendly petroleum drilling fluid and its preparation method and application in view of the deficiencies of the prior art, so as to improve the stability of the petroleum drilling fluid, reduce the mud loss, improve the environmental performance and reduce the production cost.

[0004] An environmentally friendly petroleum drilling fluid comprises 100 parts by weight of water, 10-15 parts by weight of bentonite, 0.5-1.5 parts by weight of organosilicon microspheres, 1-3 parts by weight of a composite fluid loss reducer, 2-3 parts by weight of a plugging agent, 5-8 parts by weight of a vegetable oil lubricant and 1.5-2.5 parts by weight of an organic amine salt.

[0005] The present invention adds organic silicon microspheres to the traditional drilling fluid. By adding the organic silicon microspheres, the superior lubricating performance of the organic silicon microspheres is utilized to reduce the friction between the drill bit and the rock formation, reduce the wear of the drill bit, extend the service life, and reduce the resistance during the drilling process. The content of the organic silicon microspheres in the drilling fluid can also be adjusted to effectively control the viscosity of the drilling fluid, making it easier to pump and circulate, while reducing the energy consumption during the drilling process, improving the stability of the drilling fluid, adjusting the viscosity and enhancing the lubricity, thereby effectively preventing well wall collapse and formation pollution, optimizing the drilling process, and improving the drilling efficiency.

[0006] On the other hand, a composite fluid loss reducer is used, which includes cotton and linen cellulose. As a natural polymer compound, cotton and linen cellulose has excellent properties such as high strength, high modulus, acid and alkali resistance, and biodegradability. It can increase the viscosity and consistency of the drilling fluid, thereby improving its suspension capacity and load-bearing capacity, which helps to prevent the deposition of solid particles. At the same time, it can form a protective film on the well wall to prevent erosion and side leakage of the well wall, prevent well wall collapse, effectively reduce the sedimentation rate of solid phase particles due to gravity, effectively block the pores of the well wall, and reduce the filtration loss of mud, which helps to reduce the pollution of the formation, improve the mud performance and the utilization rate of the drilling fluid;

[0007] At the same time, the present invention also uses a plant-based lubricant, which has higher biodegradability than traditional mineral oil lubricants, can reduce adverse effects on the environment, can reduce the amount of crude oil added in inclined wells or horizontal wells, thereby reducing biological toxicity and is highly environmentally friendly.

[0008] A method for preparing an environmentally friendly petroleum drilling fluid, which is used to prepare the drilling fluid, comprises the following steps:

[0009] S1. Preparation of base mud: Mix bentonite with water, disperse by ultrasonic and stir to mix evenly, and let stand naturally for 24 hours to obtain bentonite base mud;

[0010] S2, mixing additives, mixing the organosilicon microspheres, the composite fluid loss agent and the plugging agent as the combined additive A added in the first mixing, and mixing the vegetable oil lubricant and the organic ammonium salt as the combined additive B added in the second mixing;

[0011] S3, once mixing, adding the combined additive A to the bentonite-based slurry, stirring at a stirring speed of 1000-2000 r / min for 20-30 min to form a semi-finished drilling fluid;

[0012] S4, secondary mixing, adding the combined additive B to the semi-finished drilling fluid, stirring at a stirring speed of 4000-6000 r / min for 45-60 min to obtain a finished drilling fluid;

[0013] S5. Performance test: the performance of the finished drilling fluid is tested. The test items include the apparent viscosity and API filtration loss after standing at room temperature for 16 hours, the apparent viscosity and API filtration loss after hot rolling at 170℃ for 16 hours, and the high temperature and high pressure filtration loss.

[0014] Furthermore, the organosilicon microspheres are made of the following raw materials in parts by weight: 0.4-0.8 parts of organosilicon resin, 1 part of emulsifier, 4-6 parts of organic solvent and 8-12 parts of water.

[0015] Furthermore, the preparation method of the organosilicon microspheres is as follows: an emulsifier is added to an organic solvent to prepare a mixed solution, and then an organosilicon resin is added to water to prepare an organosilicon resin solution, and then the organosilicon resin solution is added to the mixed solution, and ultrasonically dispersed at 80kHz-120kHz for 5-8min to obtain a uniformly mixed milky white mixed solution;

[0016] Add an alkaline solution to the milky white mixed liquid at 200-300 rpm to obtain a mixed liquid with a pH value of 9-11, continue stirring at 200-300 rpm for 6-10 minutes to obtain a uniform mixed liquid, seal the reaction container of the uniform mixed liquid at 500-600 rpm, and heat it in a water bath at 60°C-70°C for 18-20 hours to obtain a crude product of hollow silicone microspheres, then wash it once by centrifugation with an organic solvent, finally wash it once with distilled water, and freeze-dry it at -40°C--60°C for 18h-22h to obtain a finished product of hollow silicone microspheres, wherein the silicone resin is any one of methylphenyl silicone resin, acryl silicone resin, vinyl silicone resin or methylphenylvinyl silicone resin.

[0017] Furthermore, the composite fluid loss reducer is prepared by compounding cotton and linen cellulose, modified humic acid, quaternized chitosan, a silane coupling agent and a surfactant. The preparation method of the modified humic acid is as follows: adding humic acid and an aqueous solution of potassium persulfate into a reactor, then controlling the internal temperature of the reactor to rise to 80-90°C, and starting to stir the solution in the reactor at the same time, and slowly dropping a mixed monomer aqueous solution of sodium p-styrene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid while stirring, and after the addition is completed, keeping the temperature for reaction for 2.5-4 hours, thereby preparing the modified humic acid, and the mass ratio of the humic acid, sodium p-styrene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid is 2:0.5:1.

[0018] Furthermore, the preparation method of the cotton and linen cellulose is as follows: using cotton and linen as raw materials, adding cotton and linen to a NaOH solution, the ratio of the two being 1:20-25, stirring at a temperature of 80-90°C for 2-2.5h, and then filtering, and washing the solid residue after filtration with distilled water until the solution filtered out of the residue reaches neutrality, and then drying the residue to obtain cotton and linen cellulose.

[0019] Furthermore, the plugging agent is any one or more of rosin emulsion, sodium cyclohexaneate and sodium fatty acid.

[0020] Furthermore, the preparation method of the plant-based lubricant is as follows: tung oil, dimethylphenylphosphine and acetone are preliminarily mixed, mercapto silicone oil is added, and then the mixture is fully mixed, nitrogen is introduced for protection, the mixture is heated to 40-42° C. and stirred again, and irradiated for 2-2.5 hours, and then vacuum dried to recover acetone to obtain an organosilicon oligomer;

[0021] Mix the organosilicon oligomer, diethanolamine and tetrahydrofuran, pass nitrogen protection, heat to 55-58°C, stir and add sodium hydride several times at regular intervals, recover tetrahydrofuran by rotary evaporation after the reaction is completed, wash the substrate with water, remove the aqueous phase and vacuum dry to obtain an aminolysis precursor, mix the aminolysis precursor, trimethylene chlorohydrin and ethanol, first heat to 70-72°C, stir and pressurize to 2.5-3.5 bar, heat to 90-100°C and reflux for 1.5-2h, then remove ethanol by rotary evaporation to obtain a plant-based lubricant.

[0022] Furthermore, the organic amine salt is any one or more of piperazine acetate, N-ethylpiperazine acetate, N-methylpiperazine acetate, 2-methylpiperazine acetate, piperazine citrate, N-ethylpiperazine citrate, N-methylpiperazine citrate and 2-methylpiperazine citrate.

[0023] The invention discloses an environmentally friendly petroleum drilling fluid and a preparation method thereof and their application in the field of petroleum drilling.

[0024] Beneficial effects:

[0025] 1. On the one hand, the present invention adds silicone microspheres to the traditional drilling fluid. By adding silicone microspheres, the superior lubrication performance of silicone microspheres is utilized to reduce the friction between the drill bit and the rock formation, reduce the wear of the drill bit, extend the service life, and reduce the resistance during the drilling process. The content of silicone microspheres in the drilling fluid can also be adjusted to effectively control the viscosity of the drilling fluid, making it easier to pump and circulate, while reducing energy consumption during the drilling process, improving the stability of the drilling fluid, adjusting the viscosity and enhancing the lubricity, thereby effectively preventing well wall collapse and formation pollution, optimizing the drilling process, and improving drilling efficiency.

[0026] 2. The composite fluid loss reducer including cotton and linen cellulose is used in the present invention, which can increase the viscosity and consistency of the drilling fluid, thereby improving its suspension capacity and load bearing capacity, helping to prevent the deposition of solid particles, and at the same time forming a protective film on the well wall to prevent the erosion and side leakage of the well wall, prevent the well wall from collapsing, effectively reduce the sedimentation speed of solid phase particles due to gravity, effectively block the well wall pores, and reduce the filtration loss of mud, which helps to reduce the pollution of the formation, improve the mud performance and the utilization rate of the drilling fluid;

[0027] 3. The drilling fluid of the present invention is added with a plant-based lubricant, which has higher biodegradability than traditional mineral oil lubricants, can reduce adverse effects on the environment, can reduce the amount of crude oil added in inclined wells or horizontal wells, thereby reducing biological toxicity and having strong environmental protection. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] An environmentally friendly petroleum drilling fluid comprises 100 parts by weight of water, 10-15 parts by weight of bentonite, 0.5-1.5 parts by weight of organosilicon microspheres, 1-3 parts by weight of a composite fluid loss reducer, 2-3 parts by weight of a plugging agent, 5-8 parts by weight of a vegetable oil lubricant and 1.5-2.5 parts by weight of an organic amine salt.

[0030] A method for preparing an environmentally friendly petroleum drilling fluid, which is used to prepare the drilling fluid, comprises the following steps:

[0031] S1. Preparation of base mud: Mix bentonite with water, disperse by ultrasonic and stir to mix evenly, and let stand naturally for 24 hours to obtain bentonite base mud;

[0032] S2, mixing additives, mixing the organosilicon microspheres, the composite fluid loss agent and the plugging agent as the combined additive A added in the first mixing, and mixing the vegetable oil lubricant and the organic ammonium salt as the combined additive B added in the second mixing;

[0033] S3, once mixing, adding the combined additive A to the bentonite-based slurry, stirring at a stirring speed of 1000-2000 r / min for 20-30 min to form a semi-finished drilling fluid;

[0034] S4, secondary mixing, adding the combined additive B to the semi-finished drilling fluid, stirring at a stirring speed of 4000-6000 r / min for 45-60 min to obtain a finished drilling fluid;

[0035] S5. Performance test: the performance of the finished drilling fluid is tested. The test items include the apparent viscosity and API filtration loss after standing at room temperature for 16 hours, the apparent viscosity and API filtration loss after hot rolling at 170℃ for 16 hours, and the high temperature and high pressure filtration loss.

[0036] The organic silicon microspheres are prepared from the following raw materials in parts by weight: 0.4-0.8 parts of organic silicon resin, 1 part of emulsifier, 4-6 parts of organic solvent and 8-12 parts of water.

[0037] The preparation method of the organosilicon microspheres is as follows: an emulsifier is added to an organic solvent to prepare a mixed solution, and then an organosilicon resin is added to water to prepare an organosilicon resin solution, and then the organosilicon resin solution is added to the mixed solution, and ultrasonically dispersed at 80kHz-120kHz for 5-8min to obtain a uniformly mixed milky white mixed solution;

[0038] Add an alkaline solution to the milky white mixed liquid at 200-300 rpm to obtain a mixed liquid with a pH value of 9-11, continue stirring at 200-300 rpm for 6-10 minutes to obtain a uniform mixed liquid, seal the reaction container of the uniform mixed liquid at 500-600 rpm, and heat it in a water bath at 60°C-70°C for 18-20 hours to obtain a crude product of hollow silicone microspheres, then wash it once by centrifugation with an organic solvent, finally wash it once with distilled water, and freeze-dry it at -40°C--60°C for 18h-22h to obtain a finished product of hollow silicone microspheres, wherein the silicone resin is any one of methylphenyl silicone resin, acryl silicone resin, vinyl silicone resin or methylphenylvinyl silicone resin.

[0039] The composite fluid loss reducer is prepared by compounding cotton and linen cellulose, modified humic acid, quaternized chitosan, silane coupling agent and surfactant. The preparation method of the modified humic acid is as follows: adding humic acid and potassium persulfate aqueous solution into a reactor, then controlling the internal temperature of the reactor to rise to 80-90°C, and starting to stir the solution in the reactor at the same time, and slowly dropping a mixed monomer aqueous solution of sodium p-styrene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid while stirring, and keeping the temperature for 2.5-4h after the dropping is completed, so as to prepare the modified humic acid, and the mass ratio of humic acid, sodium p-styrene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid is 2:0.5:1.

[0040] The preparation method of cotton and linen cellulose is as follows: using cotton and linen as raw materials, adding cotton and linen into NaOH solution, the ratio of the two is 1:20-25, stirring at a temperature of 80-90°C for 2-2.5h, and then filtering, and the solid residue after filtration is washed with distilled water until the solution filtered out of the residue reaches neutrality, and then the residue is dried to obtain cotton and linen cellulose.

[0041] The plugging agent is any one or more of rosin emulsion, sodium cyclohexaneate and sodium fatty acid.

[0042] The preparation method of the plant-based lubricant is as follows: tung oil, dimethylphenylphosphine and acetone are preliminarily mixed, mercapto silicone oil is added, and then the mixture is fully mixed, nitrogen is introduced for protection, the mixture is heated to 40-42° C., stirred again, and irradiated for 2-2.5 hours, and then vacuum dried to recover acetone to obtain an organosilicon oligomer;

[0043] Mix the organosilicon oligomer, diethanolamine and tetrahydrofuran, pass nitrogen protection, heat to 55-58°C, stir and add sodium hydride several times at regular intervals, recover tetrahydrofuran by rotary evaporation after the reaction is completed, wash the substrate with water, remove the aqueous phase and vacuum dry to obtain an aminolysis precursor, mix the aminolysis precursor, trimethylene chlorohydrin and ethanol, first heat to 70-72°C, stir and pressurize to 2.5-3.5 bar, heat to 90-100°C and reflux for 1.5-2h, then remove ethanol by rotary evaporation to obtain a plant-based lubricant.

[0044] The organic amine salt is any one or more of piperazine acetate, N-ethylpiperazine acetate, N-methylpiperazine acetate, 2-methylpiperazine acetate, piperazine citrate, N-ethylpiperazine citrate, N-methylpiperazine citrate and 2-methylpiperazine citrate.

[0045] Example 1

[0046] A method for preparing an environmentally friendly petroleum drilling fluid, which is used to prepare the drilling fluid, comprises the following steps:

[0047] S1. Preparation of base mud: Mix bentonite with water, disperse by ultrasonic and stir to mix evenly, and let stand naturally for 24 hours to obtain bentonite base mud;

[0048] S2, mixing additives, mixing the organosilicon microspheres, the composite fluid loss agent and the plugging agent as the combined additive A added in the first mixing, and mixing the vegetable oil lubricant and the organic ammonium salt as the combined additive B added in the second mixing;

[0049] S3, once mixing, adding the combined additive A to the bentonite-based slurry, stirring at a stirring speed of 1000-2000 r / min for 20-30 min to form a semi-finished drilling fluid;

[0050] S4, secondary mixing, adding the combined additive B to the semi-finished drilling fluid, stirring at a stirring speed of 4000-6000 r / min for 45-60 min to obtain a finished drilling fluid;

[0051] S5. Performance test: the performance of the finished drilling fluid is tested. The test items include the apparent viscosity and API filtration loss after standing at room temperature for 16 hours, the apparent viscosity and API filtration loss after hot rolling at 170℃ for 16 hours, and the high temperature and high pressure filtration loss.

[0052] The composite fluid loss reducer is prepared by compounding cotton and linen cellulose, modified humic acid, quaternized chitosan, silane coupling agent and surfactant. The preparation method of cotton and linen cellulose is as follows: using cotton and linen as raw materials, adding cotton and linen into NaOH solution, the ratio of the two is 1:20, stirring at a temperature of 80-90°C for 2-2.5h, and then filtering, and the solid filter residue after filtration is washed with distilled water until the solution filtered out of the filter residue reaches neutrality, and then the filter residue is dried to obtain cotton and linen cellulose.

[0053] Example 2

[0054] A method for preparing an environmentally friendly petroleum drilling fluid, which is used to prepare the drilling fluid, comprises the following steps:

[0055] S1. Preparation of base mud: Mix bentonite with water, disperse by ultrasonic and stir to mix evenly, and let stand naturally for 24 hours to obtain bentonite base mud;

[0056] S2, mixing additives, mixing the organosilicon microspheres, the composite fluid loss agent and the plugging agent as the combined additive A added in the first mixing, and mixing the vegetable oil lubricant and the organic ammonium salt as the combined additive B added in the second mixing;

[0057] S3, once mixing, adding the combined additive A to the bentonite-based slurry, stirring at a stirring speed of 1000-2000 r / min for 20-30 min to form a semi-finished drilling fluid;

[0058] S4, secondary mixing, adding the combined additive B to the semi-finished drilling fluid, stirring at a stirring speed of 4000-6000 r / min for 45-60 min to obtain a finished drilling fluid;

[0059] S5. Performance test: the performance of the finished drilling fluid is tested. The test items include the apparent viscosity and API filtration loss after standing at room temperature for 16 hours, the apparent viscosity and API filtration loss after hot rolling at 170℃ for 16 hours, and the high temperature and high pressure filtration loss.

[0060] The composite fluid loss reducer is prepared by compounding cotton and linen cellulose, modified humic acid, quaternized chitosan, silane coupling agent and surfactant. The preparation method of cotton and linen cellulose is as follows: using cotton and linen as raw materials, adding cotton and linen into NaOH solution, the ratio of the two is 1:23, stirring at a temperature of 80-90°C for 2-2.5h, and then filtering, and the solid filter residue after filtration is washed with distilled water until the solution filtered out of the filter residue reaches neutrality, and then the filter residue is dried to obtain cotton and linen cellulose.

[0061] Example 3

[0062] A method for preparing an environmentally friendly petroleum drilling fluid, which is used to prepare the drilling fluid, comprises the following steps:

[0063] S1. Preparation of base mud: Mix bentonite with water, disperse by ultrasonic and stir to mix evenly, and let stand naturally for 24 hours to obtain bentonite base mud;

[0064] S2, mixing additives, mixing the organosilicon microspheres, the composite fluid loss agent and the plugging agent as the combined additive A added in the first mixing, and mixing the vegetable oil lubricant and the organic ammonium salt as the combined additive B added in the second mixing;

[0065] S3, once mixing, adding the combined additive A to the bentonite-based slurry, stirring at a stirring speed of 1000-2000 r / min for 20-30 min to form a semi-finished drilling fluid;

[0066] S4, secondary mixing, adding the combined additive B to the semi-finished drilling fluid, stirring at a stirring speed of 4000-6000 r / min for 45-60 min to obtain a finished drilling fluid;

[0067] S5. Performance test: the performance of the finished drilling fluid is tested. The test items include the apparent viscosity and API filtration loss after standing at room temperature for 16 hours, the apparent viscosity and API filtration loss after hot rolling at 170℃ for 16 hours, and the high temperature and high pressure filtration loss.

[0068] The composite fluid loss reducer is prepared by compounding cotton and linen cellulose, modified humic acid, quaternized chitosan, silane coupling agent and surfactant. The preparation method of cotton and linen cellulose is as follows: using cotton and linen as raw materials, adding cotton and linen into NaOH solution, the ratio of the two is 1:25, stirring at a temperature of 80-90°C for 2-2.5h, and then filtering, and the solid filter residue after filtration is then washed with distilled water until the solution filtered out of the filter residue reaches neutrality, and then the filter residue is dried to obtain cotton and linen cellulose.

[0069] Comparative Example

[0070] A method for preparing an environmentally friendly petroleum drilling fluid, which is used to prepare the drilling fluid, comprises the following steps:

[0071] S1. Preparation of base mud: Mix bentonite with water, disperse by ultrasonic and stir to mix evenly, and let stand naturally for 24 hours to obtain bentonite base mud;

[0072] S2, mixing additives, mixing the composite fluid loss agent and the plugging agent as the combined additive A added during the primary mixing, and mixing the vegetable oil lubricant and the organic ammonium salt as the combined additive B added during the secondary mixing;

[0073] S3, once mixing, adding the combined additive A to the bentonite-based slurry, stirring at a stirring speed of 1000-2000 r / min for 20-30 min to form a semi-finished drilling fluid;

[0074] S4, secondary mixing, adding the combined additive B to the semi-finished drilling fluid, stirring at a stirring speed of 4000-6000 r / min for 45-60 min to obtain a finished drilling fluid;

[0075] S5. Performance test: the performance of the finished drilling fluid is tested. The test items include the apparent viscosity and API filtration loss after standing at room temperature for 16 hours, the apparent viscosity and API filtration loss after hot rolling at 170℃ for 16 hours, and the high temperature and high pressure filtration loss.

[0076] The composite fluid loss reducer is made of modified humic acid, quaternized chitosan, silane coupling agent and surfactant, and does not contain cotton and linen cellulose.

[0077] The performance tests of the drilling fluids prepared in Examples 1-3 and the comparative examples show that the addition of silicone microspheres and cotton and linen cellulose effectively improves the rheological properties of the drilling fluid while ensuring environmental performance. At the same time, under the condition of high-temperature hot rolling for 16 hours, the viscosity and filtration loss of the drilling fluid change little, proving that the drilling fluid can still maintain good performance at a high temperature of 170 degrees, while the viscosity and filtration loss of the comparative example change greatly under the condition of high-temperature hot rolling for 16 hours, and the stability of the drilling fluid prepared by the method of the present application is obviously improved.

[0078]

[0079] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0080] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An environmentally friendly petroleum drilling fluid, characterized in that: The invention comprises 100 parts by weight of water, 10-15 parts by weight of bentonite, 0.5-1.5 parts by weight of organosilicon microspheres, 1-3 parts by weight of composite fluid loss reducer, 2-3 parts by weight of plugging agent, 5-8 parts by weight of vegetable oil lubricant and 1.5-2.5 parts by weight of organic amine salt.

2. A method for preparing an environmentally friendly petroleum drilling fluid, used for preparing the drilling fluid according to claim 1, characterized in that: The following steps are involved: S1. Preparation of base mud: Mix bentonite with water, disperse by ultrasonic and stir to mix evenly, and let stand naturally for 24 hours to obtain bentonite base mud; S2, mixing additives, mixing the organosilicon microspheres, the composite fluid loss agent and the plugging agent as the combined additive A added in the first mixing, and mixing the vegetable oil lubricant and the organic ammonium salt as the combined additive B added in the second mixing; S3, once mixing, adding the combined additive A to the bentonite-based slurry, stirring at a stirring speed of 1000-2000 r / min for 20-30 min to form a semi-finished drilling fluid; S4, secondary mixing, adding the combined additive B to the semi-finished drilling fluid, stirring at a stirring speed of 4000-6000 r / min for 45-60 min to obtain a finished drilling fluid; S5. Performance test: the performance of the finished drilling fluid is tested. The test items include the apparent viscosity and API filtration loss after standing at room temperature for 16 hours, the apparent viscosity and API filtration loss after hot rolling at 170℃ for 16 hours, and the high temperature and high pressure filtration loss.

3. The method for preparing an environmentally friendly petroleum drilling fluid according to claim 2, characterized in that: The organosilicon microspheres are made of the following raw materials in parts by weight: 0.4-0.8 parts of organosilicon resin, 1 part of emulsifier, 4-6 parts of organic solvent and 8-12 parts of water.

4. The method for preparing an environmentally friendly petroleum drilling fluid according to claim 3, characterized in that: The preparation method of the organosilicon microspheres is as follows: an emulsifier is added to an organic solvent to prepare a mixed solution, and then an organosilicon resin is added to water to prepare an organosilicon resin solution, and then the organosilicon resin solution is added to the mixed solution, and ultrasonically dispersed at 80kHz-120kHz for 5-8min to obtain a uniformly mixed milky white mixed solution; Add an alkaline solution to the milky white mixed solution at 200-300 rpm to obtain a mixed solution with a pH value of 9-11, continue stirring at 200-300 rpm for 6-10 minutes to obtain a uniform mixed solution, seal the reaction container of the uniform mixed solution at 500-600 rpm, and heat it in a water bath at 60°C-70°C for 18-20 hours to obtain a crude product of hollow silicone microspheres, then wash it once by centrifugation with an organic solvent, finally wash it once with distilled water, and freeze-dry it at -40°C - -60°C for 18h-22h to obtain a finished product of hollow silicone microspheres, wherein the silicone resin is any one of methylphenyl silicone resin, acryl silicone resin, vinyl silicone resin or methylphenylvinyl silicone resin.

5. The method for preparing an environmentally friendly petroleum drilling fluid according to claim 2, characterized in that: The composite fluid loss reducer is prepared by compounding cotton and linen cellulose, modified humic acid, quaternized chitosan, a silane coupling agent and a surfactant. The preparation method of the modified humic acid is as follows: adding humic acid and a potassium persulfate aqueous solution into a reactor, then controlling the internal temperature of the reactor to rise to 80-90° C., and starting to stir the solution in the reactor at the same time, and slowly dropping a mixed monomer aqueous solution of sodium p-styrene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid while stirring, and keeping the temperature for reaction for 2.5-4 hours after the dropping is completed, so as to prepare the modified humic acid. The mass ratio of the humic acid, sodium p-styrene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid is 2:0.5:

1.

6. The method for preparing an environmentally friendly petroleum drilling fluid according to claim 5, characterized in that: The preparation method of cotton and linen cellulose is as follows: cotton and linen are used as raw materials, and the cotton and linen are added into a NaOH solution in a ratio of 1:20-25, and stirred at a temperature of 80-90° C. for 2-2.5 hours, and then filtered, and the solid filter residue after filtration is washed with distilled water until the solution filtered out of the filter residue reaches neutrality, and then the filter residue is dried to obtain cotton and linen cellulose.

7. The method for preparing an environmentally friendly petroleum drilling fluid according to claim 2, characterized in that: The plugging agent is any one or more of rosin emulsion, sodium cyclopentaneate and sodium fatty acid.

8. The method for preparing an environmentally friendly petroleum drilling fluid according to claim 2, characterized in that: The preparation method of the plant-based lubricant is as follows: tung oil, dimethylphenylphosphine and acetone are preliminarily mixed, mercapto silicone oil is added, and then the mixture is fully mixed, nitrogen is introduced for protection, the mixture is heated to 40-42° C., stirred again, and irradiated for 2-2.5 hours, and then vacuum dried to recover acetone to obtain an organosilicon oligomer; Mix the organosilicon oligomer, diethanolamine and tetrahydrofuran, pass nitrogen protection, heat to 55-58°C, stir and add sodium hydride several times at regular intervals, recover tetrahydrofuran by rotary evaporation after the reaction is completed, wash the substrate with water, remove the aqueous phase and vacuum dry to obtain an aminolysis precursor, mix the aminolysis precursor, trimethylene chlorohydrin and ethanol, first heat to 70-72°C, stir and pressurize to 2.5-3.5 bar, heat to 90-100°C and reflux for 1.5-2h, then remove ethanol by rotary evaporation to obtain a plant-based lubricant.

9. The method for preparing an environmentally friendly petroleum drilling fluid according to claim 2, characterized in that: The organic amine salt is any one or more of piperazine acetate, N-ethylpiperazine acetate, N-methylpiperazine acetate, 2-methylpiperazine acetate, piperazine citrate, N-ethylpiperazine citrate, N-methylpiperazine citrate and 2-methylpiperazine citrate.

10. Use of the environmentally friendly petroleum drilling fluid and the preparation method thereof according to any one of claims 1 to 9 in the field of petroleum drilling.

Images