Drilling fluid pressure-bearing plugging and wall-protecting agent and preparation method thereof

Abstract

The present invention relates to the technical field of drilling fluid wall protectors, specifically to a drilling fluid pressure-bearing plugging wall protector and a preparation method thereof: the raw materials include the following parts by weight: 80 to 100 parts of distilled water, 20 to 30 parts of fiber materials, 10 to 20 parts of acrylamide, 10 to 20 parts of blending ingredients, 10 to 20 parts of bentonite, 8 to 10 parts of lubricants, 2 to 4 parts of stabilizers and 2 to 4 parts of carbonates. In the present invention, by adding activated carbon, zeolite, coconut shell and corn cob into the blending ingredients, the use performance of the drilling fluid pressure-bearing plugging wall protector is improved, wherein, by pre-treating the activated carbon, the corrosive potassium hydroxide solution can corrode the surface of the activated carbon into a pore structure, thereby increasing the specific surface area of ​​the activated carbon, and after high-temperature treatment, the zeolite optimizes the pore structure of the zeolite, thereby improving the adsorption performance of the zeolite, and can effectively improve the adhesion effect of the wall protector on the well wall in combination with the activated carbon.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluid wall protecting agents, in particular to a drilling fluid pressure-bearing leak-proofing wall protecting agent and a preparation method thereof. Background Art

[0002] Drilling fluid pressure-bearing plugging and wall-protecting agents are a type of chemical additives that play a key role in drilling projects. When drilling to deep formations or encountering complex formation structures, the formation pore pressure is relatively high, and dangerous situations such as well gushes and blowouts are prone to occur. Drilling fluid pressure-bearing plugging and wall-protecting agents can form a high-strength sealing layer around the well wall, enhancing the well wall's ability to withstand formation pressure.

[0003] In the prior art, a large amount of viscous raw materials are usually added during the preparation of drilling fluid pressure-bearing plugging and wall-protecting agents to improve the adhesion of drilling fluid to the well wall. However, the rapid flow of drilling fluid during drilling operations will affect the adhesion of drilling fluid to the well wall. Based on this, the present invention provides a drilling fluid pressure-bearing plugging and wall-protecting agent and a preparation method thereof. Summary of the invention

[0004] The purpose of the present invention is to provide a drilling fluid pressure-bearing plugging wall protecting agent and a preparation method thereof. The wall protecting agent prepared by the present invention not only has good apparent viscosity and bonding strength properties, but also has excellent filtration loss performance, thereby effectively improving the use performance of the drilling fluid pressure-bearing plugging wall protecting agent.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a drilling fluid pressure-bearing plugging and wall-protecting agent, comprising the following raw materials in parts by weight:

[0007] 80-100 parts of distilled water, 20-30 parts of fiber material, 10-20 parts of acrylamide, 10-20 parts of blending material, 10-20 parts of bentonite, 8-10 parts of lubricant, 2-4 parts of stabilizer and 2-4 parts of carbonate;

[0008] The raw materials of the fiber material are composed of deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol, and the mass ratio of the deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol is 1: (0.2-0.4): (0.1-0.3): (0.06-0.08): (0.06-0.08), and the polyester fiber and the polypropylene fiber are pretreated before the preparation of the fiber material;

[0009] The raw materials of the formulation are composed of activated carbon, zeolite, coconut shell and corn cob, and the mass ratio of the activated carbon, zeolite, coconut shell and corn cob is 1: (0.6-0.8): (0.6-0.8): (0.4-0.6). The activated carbon, zeolite, coconut shell and corn cob are pretreated before the preparation of the formulation.

[0010] Furthermore, the lubricant is selected from at least one of rosin pentaerythritol ester and octadecanoic acid.

[0011] Furthermore, the stabilizer is selected from at least one of methyl silicone oil, amino silicone oil, and oleic acid amide.

[0012] Furthermore, the pretreatment method of the polyester fiber and the polypropylene fiber is: the polyester fiber and the polypropylene fiber are mixed and soaked in clean water for 20 to 30 minutes, the water is drained after soaking, the fibers are shaken and spread out and sent into an oven, set at 40 to 50° C. for treatment for 30 to 40 minutes, dried and sent into a fiber cutting machine, the cutting length is 1 to 3 mm, and the pretreatment of the polyester fiber and the polypropylene fiber is completed.

[0013] Furthermore, the fiber material is prepared by the following method: deionized water and pretreated polyester fiber and polypropylene fiber are added into a mixer, and the mixture is processed at 800-1000 r / min for 12-16 minutes to obtain a mixture, and the mixture is placed in a water bath, lignin sulfonate and polyethylene glycol are added, and after stirring evenly, the mixture is heated in a water bath to 60-70° C., and the reaction is kept warm for 14-18 minutes to obtain the fiber material.

[0014] Furthermore, the pretreatment method of the activated carbon is as follows: the activated carbon is crushed and ground, the particle size of the ground activated carbon is 40-50 μm, the ground activated carbon is sent to a water bath, potassium hydroxide solution is added, the mass of the potassium hydroxide solution is 20-30% of the mass of the activated carbon, the concentration of the potassium hydroxide solution is 0.6-0.8 mol / L, after stirring evenly, it is heated to 50-60°C in a water bath, kept warm for reaction for 4-6 minutes, rinsed with clean water for 5-7 times after the reaction, drained and sent to an oven, set at 70-80°C for treatment for 10-14 minutes, and the pretreatment of the activated carbon is completed.

[0015] Furthermore, the zeolite pretreatment method is as follows: the zeolite is crushed into zeolite particles with a particle size of ≤5 mm, the zeolite particles are sent to a kiln, and a high temperature treatment is set at 600-700°C for 2-4 hours. The zeolite particles after high temperature treatment are sent to a grinding mill after cooling, and the grinding particle size is 30-40 μm, thereby completing the zeolite pretreatment.

[0016] Furthermore, the coconut shell pretreatment method is: the coconut shell is hammered to break into large pieces, and then sent to a hammer mill, set at 1600-2000r / min and repeatedly crushed for 3-5 times to complete the coconut shell pretreatment. The corn cob pretreatment method is: the corn cob is crushed and ground, the corn cob powder particle size is 50-60μm, and the corn cob pretreatment is completed.

[0017] Furthermore, the blend is prepared by the following method: the pre-treated activated carbon, zeolite, coconut shell and corn cob are fed into a mixer, and the mixer is set at 80-100 r / min for 20-30 minutes to prepare the blend.

[0018] In a second aspect, the present invention also provides a method for preparing a drilling fluid pressure-bearing plugging and wall-protecting agent, comprising the following steps:

[0019] S1: The lubricant is divided into two equal parts by weight, one part of the lubricant and the blending material are fed into a mixer, and the mixer is set at 400-500 r / min for 8-10 minutes to obtain an additive;

[0020] S2: Add additives, distilled water, fiber material, acrylamide, bentonite, stabilizer, carbonate and the other half of the lubricant into the mixing equipment, set the speed to 120-160r / min for 20-30min, and prepare the drilling fluid pressure-bearing plugging and wall-protecting agent.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In the present invention, by adding activated carbon, zeolite, coconut shell and corn cob into the mixing ingredients, the purpose of improving the performance of the drilling fluid pressure-bearing plugging wall protecting agent is achieved. Among them, through the pretreatment of activated carbon, the corrosive potassium hydroxide solution can corrode the surface of the activated carbon into a pore structure, thereby increasing the specific surface area of ​​the activated carbon. After high-temperature treatment, the zeolite has an optimized pore structure and improved adsorption performance. The combination with activated carbon can effectively improve the adhesion effect of the wall protecting agent on the well wall and reduce the use loss of drilling fluid.

[0023] 2. In the present invention, by adding coconut shell and corn cob, the coarse fiber structure of coconut shell can be combined with corn cob, wherein a large number of cellulose molecules can combine with water molecules in drilling fluid to form hydrogen bonds, thereby increasing the cohesive force of drilling fluid molecules, thereby improving the apparent viscosity of drilling fluid, achieving the purpose of reducing filtration loss and improving drilling efficiency.

[0024] 3. In the present invention, the addition of polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol to the fiber material can improve the overall strength of the wall protecting agent. The rough fiber structure of the polyester fiber and the polypropylene fiber can adsorb the dust on the well wall, improve the adhesion of the drilling fluid to the well wall, and reduce the filtration loss of the drilling fluid. At the same time, the lignin sulfonate and the polyethylene glycol can disperse the polyester fiber and the polypropylene fiber, so that the polyester fiber and the polypropylene fiber are evenly mixed in the wall protecting agent, thereby improving the use effect of the fiber material. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 making creative work are within the scope of protection of the present invention.

[0026] This embodiment provides a drilling fluid pressure-bearing plugging and wall-protecting agent, comprising the following raw materials in parts by weight:

[0027] 80-100 parts of distilled water, 20-30 parts of fiber material, 10-20 parts of acrylamide, 10-20 parts of blending material, 10-20 parts of bentonite, 8-10 parts of lubricant, 2-4 parts of stabilizer and 2-4 parts of carbonate;

[0028] The raw materials of the fiber material are composed of deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol. The mass ratio of deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol is 1: (0.2-0.4): (0.1-0.3): (0.06-0.08): (0.06-0.08). Before preparing the fiber material, the polyester fiber and the polypropylene fiber are pretreated.

[0029] The raw materials of the formulation are composed of activated carbon, zeolite, coconut shell and corn cob. The mass ratio of activated carbon, zeolite, coconut shell and corn cob is 1: (0.6-0.8): (0.6-0.8): (0.4-0.6). The activated carbon, zeolite, coconut shell and corn cob are pretreated before the preparation of the formulation.

[0030] In some embodiments, the lubricant is selected from at least one of rosin pentaerythritol ester and octadecanoic acid.

[0031] In some embodiments, the stabilizer is selected from at least one of methyl silicone oil, amino silicone oil, and oleic acid amide.

[0032] In some embodiments, the pretreatment method of polyester fiber and polypropylene fiber is: the polyester fiber and polypropylene fiber are mixed and soaked in clean water for 20 to 30 minutes, the water is drained after soaking, and the fibers are shaken and spread out and sent into an oven, set at 40 to 50°C for treatment for 30 to 40 minutes, and then dried and sent into a fiber cutting machine with a cutting length of 1 to 3 mm to complete the pretreatment of the polyester fiber and polypropylene fiber.

[0033] In some embodiments, the fiber material is prepared by the following method: deionized water and pretreated polyester fiber and polypropylene fiber are added into a mixer, set to 800-1000r / min for 12-16 minutes to obtain a mixture, place the mixture in a water bath, add lignin sulfonate and polyethylene glycol, stir evenly, heat in a water bath to 60-70°C, keep warm for 14-18 minutes to obtain the fiber material.

[0034] In some embodiments, the pretreatment method of activated carbon is as follows: the activated carbon is crushed and ground, the particle size of the ground activated carbon is 40-50 μm, the ground activated carbon is sent to a water bath, potassium hydroxide solution is added, the mass of the potassium hydroxide solution is 20-30% of the mass of the activated carbon, the concentration of the potassium hydroxide solution is 0.6-0.8 mol / L, after stirring evenly, it is heated to 50-60°C in a water bath, kept warm for 4-6 minutes, rinsed with clean water 5-7 times after the reaction, drained and sent to an oven, set at 70-80°C for 10-14 minutes, and the pretreatment of the activated carbon is completed.

[0035] In some embodiments, the pretreatment method of zeolite is as follows: the zeolite is crushed into zeolite particles with a particle size of ≤5 mm, the zeolite particles are sent to a kiln, and a high temperature treatment of 600-700°C is set for 2-4 hours. The zeolite particles after high temperature treatment are sent to a grinding mill after cooling, and the grinding particle size is 30-40 μm, thereby completing the pretreatment of the zeolite.

[0036] In some embodiments, the coconut shell pretreatment method is: the coconut shell is hammered to break into large pieces, and then sent to a hammer mill, set at 1600-2000r / min and repeatedly crushed for 3-5 times to complete the coconut shell pretreatment. The corn cob pretreatment method is: the corn cob is crushed and ground, the corn cob powder particle size is 50-60μm, and the corn cob pretreatment is completed.

[0037] In some embodiments, the blend is prepared by the following method: the pretreated activated carbon, zeolite, coconut shell and corn cob are fed into a mixer, and the mixer is set at 80-100 r / min for 20-30 min to prepare the blend.

[0038] In some embodiments, a method for preparing a drilling fluid pressure-bearing plugging and wall-protecting agent comprises the following steps:

[0039] S1: The lubricant is divided into two equal parts by weight, one part of the lubricant and the blending material are fed into a mixer, and the mixer is set at 400-500 r / min for 8-10 minutes to obtain an additive;

[0040] S2: Add additives, distilled water, fiber material, acrylamide, bentonite, stabilizer, carbonate and the other half of the lubricant into the mixing equipment, set the speed to 120-160r / min for 20-30min, and prepare the drilling fluid pressure-bearing plugging and wall-protecting agent.

[0041] In this embodiment, the purpose of improving the performance of the drilling fluid pressure-bearing plugging and wall protecting agent is achieved by adding activated carbon, zeolite, coconut shell and corn cob into the formulation. Among them, through the pretreatment of the activated carbon, the corrosive potassium hydroxide solution can corrode the surface of the activated carbon to form a pore structure, thereby increasing the specific surface area of ​​the activated carbon. After high-temperature treatment, the zeolite has an optimized pore structure and improved its adsorption performance. The combination with activated carbon can effectively improve the adhesion effect of the wall protecting agent on the well wall and reduce the loss of drilling fluid.

[0042] By adding coconut shells and corn cobs, the coarse fiber structure of coconut shells can be combined with corn cobs, and a large number of cellulose molecules can combine with water molecules in the drilling fluid to form hydrogen bonds, increasing the cohesion of the drilling fluid molecules, thereby increasing the apparent viscosity of the drilling fluid, achieving the purpose of reducing filtration loss and improving drilling efficiency.

[0043] By adding polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol to the fiber material, the overall strength of the wall protecting agent can be improved. The rough fiber structure of polyester fiber and polypropylene fiber can adsorb dust on the well wall, improve the adhesion effect of drilling fluid to the well wall, and reduce the filtration loss of drilling fluid. At the same time, lignin sulfonate and polyethylene glycol can disperse the polyester fiber and polypropylene fiber, so that the polyester fiber and polypropylene fiber are evenly mixed in the wall protecting agent, thereby improving the use effect of the fiber material.

[0044] Based on the above embodiments, the following multiple experiments were also conducted:

[0045] It should be noted that the raw materials used in the following experiments are all commercially available raw materials.

[0046] Experiment 1:

[0047] The lubricant is rosin pentaerythritol ester, and the stabilizer is methyl silicone oil;

[0048] Pretreatment of polyester fiber and polypropylene fiber: Mix the polyester fiber and polypropylene fiber and soak them in clean water for 20 minutes. Drain the water after soaking, shake them loose and spread them flat into an oven. Set the oven to 40℃ for 30 minutes. Dry them and send them into a fiber cutting machine. The cutting length is 1mm.

[0049] Preparation of fiber material: deionized water and pretreated polyester fiber and polypropylene fiber are added into a mixer, and the mixture is processed at 800 r / min for 12 min to obtain a mixture, which is placed in a water bath, and lignin sulfonate and polyethylene glycol are added. After stirring evenly, the mixture is heated to 60°C in a water bath, and the reaction is kept warm for 14 min. The mass ratio of deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol is 1: (0.2): (0.1): (0.06): (0.06);

[0050] Activated carbon pretreatment: The activated carbon is crushed and ground to a particle size of 40 μm. The ground activated carbon is placed in a water bath, and potassium hydroxide solution is added. The mass of the potassium hydroxide solution is 20% of the mass of the activated carbon, and the concentration of the potassium hydroxide solution is 0.6 mol / L. After stirring evenly, the water bath is heated to 50°C and the reaction is kept warm for 4 minutes. After the reaction, it is rinsed with clean water for 5 times, drained, and placed in an oven, set at 70°C for 10 minutes.

[0051] Zeolite pretreatment: The zeolite is crushed into zeolite particles with a particle size of ≤5mm. The zeolite particles are sent to the kiln and treated at 600℃ for 2h. After cooling, the zeolite particles after high temperature treatment are sent to the grinding machine, and the grinding particle size is 30μm;

[0052] Coconut shell pretreatment: The coconut shell is hammered to break into large pieces, and then sent to the hammer mill, set at 1600r / min and crushed three times;

[0053] Corncob pretreatment: The corncob is crushed and ground into powder, and the particle size of the corncob powder is 50 μm;

[0054] Preparation of ingredients: The pretreated activated carbon, zeolite, coconut shell and corn cob were fed into a mixer and processed at 80 r / min for 20 min. The mass ratio of activated carbon, zeolite, coconut shell and corn cob was 1: (0.6): (0.6): (0.4);

[0055] Preparation of drilling fluid pressure plugging and wall protection agent:

[0056] S1: 4 parts of lubricant and 10 parts of blending ingredients are fed into a mixer, set at 400r / min for 8min to obtain an additive;

[0057] S2: Add additives, 80 parts of distilled water, 20 parts of fiber materials, 10 parts of acrylamide, 10 parts of bentonite, 2 parts of stabilizer, 2 parts of carbonate and 4 parts of lubricant into the mixing equipment, set 120r / min for 20min, and prepare the drilling fluid pressure-bearing plugging and wall-protecting agent.

[0058] Experiment 2:

[0059] The lubricant is octadecanoic acid, and the stabilizer is amino silicone oil;

[0060] Pretreatment of polyester fiber and polypropylene fiber: Mix the polyester fiber and polypropylene fiber and soak them in clean water for 25 minutes. Drain the water after soaking, shake them loose and spread them flat into an oven. Set the oven to 45℃ for 35 minutes. Dry them and send them into a fiber cutting machine. The cutting length is 2 mm.

[0061] Preparation of fiber material: deionized water and pretreated polyester fiber and polypropylene fiber are added into a mixer, and the mixture is processed at 900 r / min for 14 min to obtain a mixture, which is placed in a water bath, and lignin sulfonate and polyethylene glycol are added. After stirring evenly, the mixture is heated to 65°C in a water bath, and the reaction is kept warm for 16 min. The mass ratio of deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol is 1: (0.3): (0.2): (0.07): (0.07);

[0062] Activated carbon pretreatment: The activated carbon is crushed and ground to a particle size of 45 μm. The ground activated carbon is placed in a water bath, and potassium hydroxide solution is added. The mass of the potassium hydroxide solution is 25% of the mass of the activated carbon, and the concentration of the potassium hydroxide solution is 0.7 mol / L. After stirring evenly, the water bath is heated to 55°C and the reaction is kept warm for 5 minutes. After the reaction, it is rinsed with clean water for 6 times, drained, and placed in an oven, set at 75°C for 12 minutes;

[0063] Zeolite pretreatment: The zeolite is crushed into zeolite particles with a particle size of ≤5mm. The zeolite particles are sent to the kiln and treated at 650℃ for 3h. After the high-temperature treatment, the zeolite particles are sent to the grinding machine after cooling. The grinding particle size is 35μm.

[0064] Coconut shell pretreatment: The coconut shell is hammered to break into large pieces, and then sent to the hammer mill, set at 1800r / min and repeatedly crushed 4 times;

[0065] Corncob pretreatment: The corncob is crushed and ground into powder, and the particle size of the corncob powder is 55 μm;

[0066] Preparation of ingredients: The pretreated activated carbon, zeolite, coconut shell and corn cob were fed into a mixer and processed at 90 r / min for 25 min. The mass ratio of activated carbon, zeolite, coconut shell and corn cob was 1: (0.7): (0.7): (0.5);

[0067] Preparation of drilling fluid pressure plugging and wall protection agent:

[0068] S1: 4.5 parts of lubricant and 15 parts of blending materials are fed into a mixer, set at 450r / min for 9 minutes to obtain an additive;

[0069] S2: Add additives, 90 parts of distilled water, 25 parts of fiber material, 15 parts of acrylamide, 15 parts of bentonite, 3 parts of stabilizer, 3 parts of carbonate and 4.5 parts of lubricant into the mixing equipment, set 140r / min for 25 minutes, and prepare the drilling fluid pressure-bearing plugging and wall-protecting agent.

[0070] Experiment 3:

[0071] The lubricant is rosin pentaerythritol ester, and the stabilizer is oleic acid amide;

[0072] Pretreatment of polyester fiber and polypropylene fiber: Mix the polyester fiber and polypropylene fiber and soak them in clean water for 30 minutes. Drain the water after soaking, shake them loose and spread them flat into an oven. Set the oven to 50℃ for 40 minutes. Dry them and send them into a fiber cutting machine. The cutting length is 3mm.

[0073] Preparation of fiber material: deionized water and pretreated polyester fiber and polypropylene fiber are added into a mixer, and the mixture is processed at 1000 r / min for 16 min to obtain a mixture, which is placed in a water bath, and lignin sulfonate and polyethylene glycol are added. After stirring evenly, the mixture is heated to 70°C in a water bath, and the reaction is kept warm for 18 min. The mass ratio of deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol is 1: (0.4): (0.3): (0.08): (0.08);

[0074] Activated carbon pretreatment: The activated carbon is crushed and ground to a particle size of 50 μm. The ground activated carbon is placed in a water bath, and potassium hydroxide solution is added. The mass of the potassium hydroxide solution is 30% of the mass of the activated carbon, and the concentration of the potassium hydroxide solution is 0.8 mol / L. After stirring evenly, the water bath is heated to 60°C and the reaction is kept warm for 6 minutes. After the reaction, it is rinsed with clean water for 7 times, drained, and placed in an oven, set at 80°C for 14 minutes.

[0075] Zeolite pretreatment: The zeolite is crushed into zeolite particles with a particle size of ≤5mm. The zeolite particles are sent to the kiln and treated at 700℃ for 4h. After the high-temperature treatment, the zeolite particles are sent to the grinding machine after cooling. The grinding particle size is 40μm.

[0076] Coconut shell pretreatment: The coconut shell is hammered to break into large pieces, and then sent to the hammer mill, set at 2000r / min and repeatedly crushed for 5 times;

[0077] Corncob pretreatment: The corncob is crushed and ground into powder, and the particle size of the corncob powder is 60 μm;

[0078] Preparation of ingredients: The pretreated activated carbon, zeolite, coconut shell and corn cob were fed into a mixer and processed at 100 r / min for 30 min. The mass ratio of activated carbon, zeolite, coconut shell and corn cob was 1: (0.8): (0.8): (0.6);

[0079] Preparation of drilling fluid pressure plugging and wall protection agent:

[0080] S1: 5 parts of lubricant and 20 parts of blending ingredients are fed into a mixer, set at 500r / min for 10min to obtain an additive;

[0081] S2: Add additives, 100 parts of distilled water, 30 parts of fiber materials, 20 parts of acrylamide, 20 parts of bentonite, 4 parts of stabilizer, 4 parts of carbonate and 5 parts of lubricant into the mixing equipment, set 160r / min for 30 minutes, and prepare the drilling fluid pressure-bearing plugging and wall-protecting agent.

[0082] Comparative Example 1: The difference between this comparative example and Experiment 1 is that:

[0083] In this comparative example, only the raw materials of the blending ingredients are crushed and ground.

[0084] Comparative Example 2: The difference between this comparative example and Experiment 1 is that:

[0085] In this comparative example, no potassium hydroxide solution was added during the pretreatment of the activated carbon.

[0086] Comparative Example 3: The difference between this comparative example and Experiment 1 is that:

[0087] This comparative example does not contain fiber material.

[0088] Comparative Example 4: The difference between this comparative example and Experiment 1 is that:

[0089] In this comparative example, an equal amount of zeolite powder was used to replace the blending ingredients.

[0090] Performance test: Performance test was carried out on the drilling fluid pressure-bearing plugging and wall-protecting agents prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4.

[0091] In the performance test, the drilling fluid pressure plugging and wall protecting agents prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were added to the standard base slurry at a mass of 5wt%, and the closed filtration loss was measured. The obtained test data are recorded in the following table:

[0092]

[0093] Among them, the apparent viscosities of the drilling fluid pressure plugging and wall protecting agents prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were 16.1 mPa·s, 16.3 mPa·s, 15.8 mPa·s, 12.4 mPa·s, 11.3 mPa·s, 11.1 mPa·s and 10.7 mPa·s, respectively;

[0094] The filtration loss of the drilling fluid pressure plugging and wall protecting agent prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 were 8.4%, 8.5%, 8.1%, 16.4%, 18.5%, 23.6% and 28.7% respectively;

[0095] The bonding strengths of the drilling fluid pressure-bearing plugging and wall protective agents prepared in Experiment 1, Experiment 2, Experiment 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 are 58KPa, 54KPa, 57KPa, 31KPa, 36KPa, 23KPa and 25KPa respectively.

[0096] It can be seen that the apparent viscosity and bonding strength of the wall protective agent prepared in Comparative Examples 1, 2, 3, and 4 are lower than those in Experiments 1, 2, and 3, and the filtration loss of the wall protective agent prepared in Comparative Examples 1, 2, 3, and 4 is higher than that in Experiments 1, 2, and 3. This shows that the addition of activated carbon, zeolite, coconut shell, and corn cob in the formulation has the purpose of improving the performance of the drilling fluid pressure-bearing plugging wall protective agent. Among them, by pre-treating the activated carbon, the corrosive potassium hydroxide solution can corrode the surface of the activated carbon into a pore structure, thereby increasing the specific surface area of ​​the activated carbon. After high-temperature treatment, the pore structure of zeolite is optimized and the adsorption performance of zeolite is improved. When combined with activated carbon, it can effectively improve the adhesion effect of the wall protective agent on the well wall and reduce the loss of drilling fluid. By adding coconut shell and corn cob, the coarse fiber structure of coconut shell can be combined with corn cob, and a large number of cellulose molecules can combine with water molecules in the drilling fluid to form hydrogen bonds, which increases the cohesion of drilling fluid molecules and then improves the apparent viscosity of the drilling fluid, thereby achieving the purpose of reducing filtration loss and improving drilling efficiency.

[0097] By comparing and analyzing the relevant data in the table, it can be seen that the wall protecting agent prepared by the present invention not only has good apparent viscosity and cementing strength performance, but also has excellent filtration loss performance. This shows that the drilling fluid pressure plugging wall protecting agent and preparation method provided by the present invention have a broader market prospect and are more suitable for promotion.

[0098] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0099] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. Drilling fluid pressure plugging and wall protection agent, characterized by: It includes the following raw materials in parts by weight: 80-100 parts of distilled water, 20-30 parts of fiber material, 10-20 parts of acrylamide, 10-20 parts of blending material, 10-20 parts of bentonite, 8-10 parts of lubricant, 2-4 parts of stabilizer and 2-4 parts of carbonate; The raw materials of the fiber material are composed of deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol, and the mass ratio of the deionized water, polyester fiber, polypropylene fiber, lignin sulfonate and polyethylene glycol is 1: (0.2-0.4): (0.1-0.3): (0.06-0.08): (0.06-0.08); The raw materials of the formulation are composed of activated carbon, zeolite, coconut shell and corn cob, and the mass ratio of the activated carbon, zeolite, coconut shell and corn cob is 1: (0.6-0.8): (0.6-0.8): (0.4-0.6).

2. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 1, characterized in that: The lubricant is selected from at least one of rosin pentaerythritol ester and octadecanoic acid.

3. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 1, characterized in that: The stabilizer is selected from at least one of methyl silicone oil, amino silicone oil and oleic acid amide.

4. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 1, characterized in that: Before the fiber material is prepared, the polyester fiber and the polypropylene fiber are pretreated. The pretreatment method of the polyester fiber and the polypropylene fiber is as follows: the polyester fiber and the polypropylene fiber are mixed and soaked in clean water for 20 to 30 minutes, the water is drained after soaking, the fibers are shaken and spread out and sent into an oven, set at 40 to 50° C. for treatment for 30 to 40 minutes, dried and sent into a fiber cutting machine, and the cutting length is 1 to 3 mm, thereby completing the pretreatment of the polyester fiber and the polypropylene fiber.

5. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 4, characterized in that: The fiber material is prepared by the following method: deionized water and pretreated polyester fiber and polypropylene fiber are added into a mixer, and the mixture is processed at 800-1000 r / min for 12-16 minutes to obtain a mixture, and the mixture is placed in a water bath, lignin sulfonate and polyethylene glycol are added, and the mixture is stirred evenly and then heated in a water bath to 60-70° C., and the mixture is kept warm for reaction for 14-18 minutes to obtain the fiber material.

6. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 1, characterized in that: Before the preparation of the blend, the activated carbon, zeolite, coconut shell and corn cob are pretreated. The pretreatment method of the activated carbon is as follows: the activated carbon is crushed and ground, the particle size of the ground activated carbon is 40-50 μm, the ground activated carbon is sent to a water bath, potassium hydroxide solution is added, the mass of the potassium hydroxide solution is 20-30% of the mass of the activated carbon, the concentration of the potassium hydroxide solution is 0.6-0.8 mol / L, after stirring evenly, the water bath is heated to 50-60° C., the temperature is kept for reaction for 4-6 minutes, and after the reaction, it is rinsed with clean water for 5-7 times, and after draining the water, it is sent to an oven, set at 70-80° C. for treatment for 10-14 minutes, and the pretreatment of the activated carbon is completed.

7. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 1, characterized in that: The zeolite pretreatment method is as follows: the zeolite is crushed into zeolite particles with a particle size of ≤5 mm, the zeolite particles are sent to a kiln, and a high temperature treatment is set at 600-700°C for 2-4 hours, and the zeolite particles after high temperature treatment are sent to a grinding mill after cooling, and the grinding particle size is 30-40 μm, thereby completing the zeolite pretreatment.

8. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 1, characterized in that: The coconut shell pretreatment method is as follows: the coconut shell is hammered to break into large pieces, and then sent to a hammer mill, set at 1600-2000r / min and repeatedly crushed for 3-5 times to complete the coconut shell pretreatment. The corn cob pretreatment method is as follows: the corn cob is crushed and ground to a powder with a particle size of 50-60μm to complete the corn cob pretreatment.

9. The drilling fluid pressure-bearing plugging and wall-protecting agent according to claim 1, characterized in that: The blend is prepared by the following method: pre-treated activated carbon, zeolite, coconut shell and corn cob are fed into a mixer, and the mixer is set at 80-100 r / min for 20-30 minutes to prepare the blend.

10. The method for preparing the drilling fluid pressure-bearing plugging and wall-protecting agent according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: The lubricant is divided into two equal parts by weight, one part of the lubricant and the blending material are fed into a mixer, and the mixer is set at 400-500 r / min for 8-10 minutes to obtain an additive; S2: Add additives, distilled water, fiber material, acrylamide, bentonite, stabilizer, carbonate and the other half of the lubricant into the mixing equipment, set the speed to 120-160r / min for 20-30min, and prepare the drilling fluid pressure-bearing plugging and wall-protecting agent.

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