High-filtration-loss pressure-bearing plugging agent for oil-based drilling fluid and preparation method thereof

Abstract

The invention relates to the technical field of special plugging agents for oil-based drilling fluids, in particular to a high-filtration pressure-bearing plugging agent for oil-based drilling fluids and a preparation method thereof.The high-filtration pressure-bearing plugging agent for the oil-based drilling fluids is prepared from, by weight, 30-40 parts of bridging supporting materials, 10-15 parts of fiber materials, 40-50 parts of filling materials and 5-10 parts of filter aids, and uniformly mixing the required amounts of the bridging support material, the fiber material, the filling material and the filter aid to obtain the high-filtration pressure-bearing plugging agent for the oil-based drilling fluid. The preparation method is simple and convenient, the filter material is prepared by mixing various materials such as the bridging supporting material, the fiber material, the filling material and the filter aid, solid-phase particles are small in size and can easily enter leakage channels and spaces with various opening sizes, rapid filtration is performed under the action of pressure difference, and the more serious the leakage is, the faster the leakage speed is and the faster the filtration is. Therefore, the plugging agent is wide in application range, simple in plugging construction, high in safety, quick in effect and low in cost.

Description

Technical Field

[0001] The invention relates to the technical field of special plugging agents for oil-based drilling fluids, in particular to a high-filtration-loss pressure-bearing plugging agent for oil-based drilling fluids and a preparation method thereof. Background Art

[0002] In recent years, with the gradual depletion of shallow oil and gas reservoirs, oil and gas development has been fully developed towards deep oil and gas reservoirs, bringing new challenges to oil and gas extraction. The complex downhole conditions that occur during drilling and production are becoming more and more prominent, especially the problem of formation stability. Since the traditional water-based drilling fluid system is unstable under high temperature conditions and has poor inhibition of shale, it can no longer meet the requirements of drilling and production. The oil-based drilling fluid system has good temperature stability, strong inhibition and protective effect on oil and gas reservoirs. Therefore, the oil-based drilling fluid system has been widely promoted and applied in high-temperature deep wells and large-reach well drilling operations. Although the oil-based drilling fluid has good high-temperature stability and strong shale inhibition, which greatly improves the wellbore stability of the shale formation, the micro-cracks in the formation itself are widely developed, and there is induced fracturing leakage, which causes frequent leakage during the drilling process. Due to the high cost of preparing oil-based drilling fluids, the leakage of oil-based drilling fluids is bound to cause a lot of material waste, delay the drilling cycle, and cause huge economic losses. Therefore, the development of oil-based drilling fluid plugging agents is an urgent problem that needs to be solved in the application process of oil-based drilling fluids.

[0003] Currently, there are many types of water-based drilling fluid plugging products, but there are few special plugging agents for oil-based drilling fluid leakage plugging, especially special plugging agents for oil-based drilling fluids in high-permeability and micro-crack formations with serious leakage and pressure requirements.

[0004] High filtration plugging agent is a new type of plugging material developed in the past decade. It is commonly used in water-based drilling fluid plugging construction. It is popular on site for its convenient use, quick effect, high success rate, and wide application range. However, this type of plugging agent is rarely used in oil-based drilling fluid plugging construction. Therefore, the development of a high filtration plugging agent for oil-based drilling fluid for use in oil-based drilling has a good market prospect. Summary of the invention

[0005] The present invention provides a high-loss pressure-bearing plugging agent for oil-based drilling fluid and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of few existing special plugging agent products for plugging oil-based drilling fluid leakage during drilling and frequent leakage during drilling.

[0006] One of the technical solutions of the present invention is achieved through the following measures: a high-loss pressure-bearing plugging agent for oil-based drilling fluid, wherein the raw materials include 30 to 40 parts of bridging support materials, 10 to 15 parts of fiber materials, 40 to 50 parts of filling materials and 5 to 10 parts of filter aids in terms of weight, and the high-loss pressure-bearing plugging agent for oil-based drilling fluid is prepared according to the following method: the required amounts of bridging support materials, fiber materials, filling materials and filter aids are uniformly mixed to obtain the high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0007] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The bridging support material is a mixture of manganese calcite particles with a particle size of 120 meshes and manganese calcite particles with a particle size of 200 meshes; or / and, the fiber material is one or more of brucite fiber and sepiolite fiber; or / and, the filling material is a mixture of special rubber powder with a particle size of 400 meshes and quartz sand with a particle size of 800 meshes; or / and, the filter aid is activated clay powder with a particle size of 400 meshes.

[0008] The weight ratio of the above-mentioned manganese calcite particles with a particle size of 120 mesh to the manganese calcite particles with a particle size of 200 mesh is 2 to 3:3 to 4; or / and, the aspect ratio of the fiber material is 30 to 50:1, wherein the diameter is 20um to 40um; or / and, the weight ratio of the special rubber powder with a particle size of 400 mesh to the quartz sand with a particle size of 800 mesh is 1 to 2:2 to 3.

[0009] The above raw materials include 35 parts of bridging support material, 10 parts of fiber material, 45 parts of filling material and 10 parts of filter aid in terms of weight.

[0010] The bridging support material is a mixture of manganese calcite particles with a particle size of 120 meshes and manganese calcite particles with a particle size of 200 meshes; or / and, the fiber material is brucite fiber; or / and, the filling material is a mixture of special rubber powder with a particle size of 400 meshes and quartz sand with a particle size of 800 meshes; or / and, the filter aid is activated white clay powder with a particle size of 400 meshes.

[0011] The weight ratio of the above-mentioned manganese calcite particles with a particle size of 120 meshes to the manganese calcite particles with a particle size of 200 meshes is 2:4; or / and, the aspect ratio of the brucite fiber is 30 to 50:1, wherein the diameter is 20um to 40um; or / and, the weight ratio of the special rubber powder with a particle size of 400 meshes to the quartz sand with a particle size of 800 meshes is 2:3.

[0012] The above raw materials include 30 parts of bridging support material, 12 parts of fiber material, 50 parts of filling material and 8 parts of filter aid in terms of weight.

[0013] The above-mentioned bridging support material is a mixture of manganese calcite particles with a particle size of 120 meshes and manganese calcite particles with a particle size of 200 meshes; or / and, the fiber material is a mixture of brucite fiber and sepiolite fiber; or / and, the filling material is a mixture of special rubber powder with a particle size of 400 meshes and quartz sand with a particle size of 800 meshes; or / and, the filter aid is activated white clay powder with a particle size of 400 meshes.

[0014] The weight ratio of the above-mentioned manganese calcite particles with a particle size of 120 meshes to the manganese calcite particles with a particle size of 200 meshes is 3:4; or / and, the weight ratio of brucite fiber to sepiolite fiber is 1:1, and the aspect ratio of brucite fiber and sepiolite fiber are both 30 to 50:1, wherein the diameter is 20um to 40um; or / and, the weight ratio of special rubber powder with a particle size of 400 meshes to quartz sand with a particle size of 800 meshes is 1:3.

[0015] The second technical solution of the present invention is achieved through the following measures: a method for preparing a high-loss pressure-bearing plugging agent for oil-based drilling fluid, which is carried out according to the following method: the required amount of bridging support material, fiber material, filling material and filter aid are evenly mixed to obtain a high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0016] The preparation method of the present invention is simple and convenient. It is made by mixing various materials such as bridging support materials, fiber materials, filling materials, and filter aids. Since the solid phase particles therein are small in size, they are easy to enter leakage channels and spaces of various opening sizes and are quickly filtered out under the action of pressure difference. The more serious the leakage, the faster the leakage rate, and the faster the filter loss. Therefore, the present invention has a wide range of applications, simple plugging construction, high safety, quick effect, and low cost. DETAILED DESCRIPTION

[0017] 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.

[0018] The present invention will be further described below in conjunction with embodiments: Example 1: The high-loss pressure-bearing plugging agent for oil-based drilling fluid, the raw materials of which include, by weight, 30 to 40 parts of bridging support material, 10 to 15 parts of fiber material, 40 to 50 parts of filling material and 5 to 10 parts of filter aid, is prepared according to the following method: the required amounts of bridging support material, fiber material, filling material and filter aid are uniformly mixed to obtain the high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0019] Example 2: The high-loss pressure-bearing plugging agent for oil-based drilling fluid comprises 30 or 40 parts of bridging support material, 10 or 15 parts of fiber material, 40 or 50 parts of filling material and 5 or 10 parts of filter aid in terms of weight. The required amounts of bridging support material, fiber material, filling material and filter aid are uniformly mixed to obtain the high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0020] Embodiment 3: As an optimization of the above embodiment, the bridging support material is a mixture of manganese calcite particles with a particle size of 120 meshes and manganese calcite particles with a particle size of 200 meshes.

[0021] In the present invention, the function of the bridging support material is to bridge the stratum gaps, increase the support strength and initially seal the stratum gaps.

[0022] Example 4: As an optimization of the above example, the weight ratio of manganese calcite particles with a particle size of 120 meshes to manganese calcite particles with a particle size of 200 meshes is 2 to 3:3 to 4.

[0023] Embodiment 5: As an optimization of the above embodiment, the fiber material is one or more of brucite fiber and sepiolite fiber.

[0024] Embodiment 6: As an optimization of the above embodiment, the aspect ratio of the fiber material is 30 to 50:1, wherein the diameter is 20 um to 40 um.

[0025] In the present invention, the brucite fiber and the sepiolite fiber have good toughness and can resist a temperature of up to 400°C. As monomer materials, they can be effectively dispersed in a diesel-based liquid to achieve the functions of suspending inert particles and weighting agents. As plugging materials, after entering the leaking layer, due to their large aspect ratio and good toughness, they can be well entangled and attached to bridging particles or well walls, thereby enhancing the bridging probability and plugging strength.

[0026] Example 7: As an optimization of the above example, the filling material is a mixture of special rubber powder with a particle size of 400 mesh and quartz sand with a particle size of 800 mesh.

[0027] Example 8: As an optimization of the above example, the weight ratio of the special rubber powder with a particle size of 400 meshes to the quartz sand with a particle size of 800 meshes is 1 to 2:2 to 3.

[0028] In the present invention, the function of the filling material is to enter into the micro-pores of the primary sealing plug formed by the bridging support particles to form a tight sealing plug and enhance the sealing pressure bearing capacity of the plug.

[0029] Example 9: As an optimization of the above example, the filter aid is activated clay powder with a particle size of 400 mesh.

[0030] In the present invention, the activated clay powder with a particle size of 400 meshes functions to adsorb the solid phase, change the surface properties of the solid and liquid phases, and quickly separate the solid phase from the liquid phase.

[0031] Example 10: As an optimization of the above example, the raw materials include 35 parts of bridging support material, 10 parts of fiber material, 45 parts of filling material and 10 parts of filter aid in terms of weight.

[0032] Example 11: As an optimization of the above-mentioned Example 10, the bridging support material is a mixture of manganese calcite particles with a particle size of 120 mesh and manganese calcite particles with a particle size of 200 mesh, and the weight ratio of the manganese calcite particles with a particle size of 120 mesh to the manganese calcite particles with a particle size of 200 mesh is 2:4.

[0033] Embodiment 12: As an optimization of the above embodiment, the fiber material is brucite fiber.

[0034] Example 13: As an optimization of the above example, the aspect ratio of the brucite fiber is 30 to 50:1, wherein the diameter is 20 um to 40 um.

[0035] Example 14: As an optimization of the above example, the filling material is a mixture of special rubber powder with a particle size of 400 mesh and quartz sand with a particle size of 800 mesh, and the weight ratio of the special rubber powder with a particle size of 400 mesh to the quartz sand with a particle size of 800 mesh is 2:3.

[0036] Example 15: As an optimization of the above example, the raw materials include 30 parts of bridging support material, 12 parts of fiber material, 50 parts of filling material and 8 parts of filter aid in terms of weight.

[0037] Example 16: As an optimization of the above-mentioned Example 15, the bridging support material is a mixture of manganese calcite particles with a particle size of 120 mesh and manganese calcite particles with a particle size of 200 mesh, and the weight ratio of the manganese calcite particles with a particle size of 120 mesh to the manganese calcite particles with a particle size of 200 mesh is 3:4.

[0038] Embodiment 17: As an optimization of the above embodiment, the fiber material is a mixture of brucite fiber and sepiolite fiber.

[0039] Example 18: As an optimization of the above example, the weight ratio of brucite fiber to sepiolite fiber is 1:1, and the aspect ratio of brucite fiber to sepiolite fiber is 30 to 50:1, wherein the diameter is 20 um to 40 um.

[0040] Example 19: As an optimization of the above example, the filling material is a mixture of special rubber powder with a particle size of 400 mesh and quartz sand with a particle size of 800 mesh, and the weight ratio of the special rubber powder with a particle size of 400 mesh to the quartz sand with a particle size of 800 mesh is 1:3.

[0041] Example 20: The high-loss pressure-bearing plugging agent for oil-based drilling fluid comprises 10 parts of fiber material, 35 parts of bridging support material, 45 parts of filling material, and 10 parts of filter aid in terms of weight. The bridging support material is a mixture of 120-mesh manganese calcite particles and 200-mesh manganese calcite particles in a weight ratio of 3:4; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1, wherein the fiber material has an aspect ratio of 30 to 50:1 and a diameter of 20um to 40um; the filling material is a mixture of 400-mesh rubber powder and 800-mesh quartz sand in a weight ratio of 1:3. The above components are mixed evenly to obtain a high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0042] Example 21: The high-loss pressure-bearing plugging agent for oil-based drilling fluid, the raw materials include 12 parts of fiber material, 35 parts of bridging support material, 43 parts of filling material, and 10 parts of filter aid in terms of weight. The bridging support material is a mixture of 120-mesh manganese calcite particles and 200-mesh manganese calcite particles in a weight ratio of 2:4; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 2:1, wherein the fiber material has an aspect ratio of 30 to 50:1 and a diameter of 20um to 40um; the filling material is a mixture of 400-mesh rubber powder and 800-mesh quartz sand in a weight ratio of 2:3. The above components are mixed evenly to obtain a high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0043] Example 22: The high-loss pressure-bearing plugging agent for oil-based drilling fluid, the raw materials include 15 parts of fiber material, 30 parts of bridging support material, 50 parts of filling material, and 1 part of filter aid in terms of weight. The bridging support material is a mixture of 120-mesh manganese calcite particles and 200-mesh manganese calcite particles in a weight ratio of 2:3; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1, wherein the fiber material has an aspect ratio of 30 to 50:1 and a diameter of 20um to 40um; the filling material is a mixture of 400-mesh rubber powder and 800-mesh quartz sand in a weight ratio of 3:3. The above components are mixed evenly to obtain a high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0044] Example 23: The high-loss pressure-bearing plugging agent for oil-based drilling fluid, the raw materials include 10 parts of fiber material, 40 parts of bridging support material, 40 parts of filling material, and 10 parts of filter aid in terms of weight. The bridging support material is a mixture of 120-mesh manganese calcite particles and 200-mesh manganese calcite particles in a weight ratio of 2:4; the fiber material is a mixture of brucite fiber and sepiolite fiber in a weight ratio of 1:1, wherein the fiber material has an aspect ratio of 30 to 50:1 and a diameter of 20um to 40um; the filling material is a mixture of 400-mesh rubber powder and 800-mesh quartz sand in a weight ratio of 2:3. The above components are mixed evenly to obtain a high-loss pressure-bearing plugging agent for oil-based drilling fluid.

[0045] Comparative example: imported high filtration loss plugging agent Diaseal-M.

[0046] The oil-based drilling fluid obtained according to Examples 20 to 23 was subjected to performance testing using a high-loss pressure-bearing plugging agent, and an imported plugging agent Diaseal-M was selected as a comparative sample.

[0047] The oil-based drilling fluid obtained in Examples 20 to 23 was prepared into plugging slurry with high filtration loss pressure plugging agent and Diaseal-M and diesel respectively, and the preparation steps were as follows: (1) Take 5 cups of 300 ml white oil and place them on a high-speed stirrer; weigh 90 g of the samples prepared in Examples 20 to 23 and the imported plugging agent Diaseal-M and set them aside.

[0048] (2) Turn on the stirrer at 11000 rpm and add the five plugging agents into five cups of white oil respectively. Stir for 20 min. During this time, use a glass rod to scrape off the adherent materials on the wall of the cup.

[0049] The plugging slurry samples prepared above were subjected to the following tests: (1) Rapid filtration test Stir the sample evenly and pour it into the dry and clean medium-pressure filter loss meter slurry cup to the scale line, cover the filter loss meter slurry cup cover tightly, and place a 500 ml beaker at the lower outlet of the filter loss meter to receive the filtrate. Adjust the gas source to 0.7 MPa, and immediately open the air inlet valve, and start timing at the same time until gas is ejected from the discharge port, then stop timing immediately and record the filter loss time.

[0050] (2) Needle penetration test Place the plug formed after rapid filtration directly on the base of the cement standard consistency setting time measuring instrument, install the initial setting test needle with a diameter of 1.13 mm ± 0.05 mm and a length of 50 mm ± 1 mm, adjust the tightening screw so that the needle tip just touches the surface of the filter cake, adjust the tightening screw of the test rod so that it is just aligned with the "0" position of the scale, loosen the tightening screw, and read the scale value after the test needle is stable, which is the needle penetration.

[0051] The experimental results of the rapid filtration test and the needle penetration test are shown in Table 1. As can be seen from Table 1, Diaseal-M takes a long time in the API filtration process, and the mud cake formed is soft and not dense enough. However, Examples 20 to 23 can quickly filtrate in the API filtration process, and the filter cakes formed are dense, regular and have a certain initial strength.

[0052] (3) Oil-based drilling fluid compatibility test Oil-based drilling fluid formula: 240ml 5# white oil + 7.2g organic soil + 6ml primary emulsifier + 4ml auxiliary emulsifier + 4ml wetting agent + 4g calcium oxide + 60ml 25% calcium chloride solution + barite powder (density added to 1.50g / cm 3 ).

[0053] Preparation method of oil-based drilling fluid: Measure 240ml 5# white oil and add it to the preparation container, start stirring, set the speed to 11000rpm, add 7.2g organic soil under high-speed stirring, and stir for 10min; then use a syringe to extract 6ml of primary emulsifier, 4ml of auxiliary emulsifier, and 4ml of wetting agent, and add them to the preparation container in sequence, then add 4g of calcium oxide, add it under high-speed stirring, stir for 30min, then add 60ml of 25% calcium chloride solution, stir for 30min under high-speed stirring, and finally slowly add barite powder until the system density is 1.50g / cm 3 , stir for 30 minutes, use a densitometer to test the density, the measured density is 1.50g / cm 3 , that is, the oil-based drilling fluid base slurry is obtained. Among them, Table 2 is the required range of various performance data of the oil-based drilling fluid.

[0054] 400 ml of 6 parts of oil-based drilling fluid prepared according to the above method were measured respectively, and the high-speed stirrer was turned on and the speed was adjusted to 11000 rpm; 16 g of high filtration loss pressure plugging agent and imported plugging agent Diaseal-M for oil-based drilling fluid prepared in Examples 20 to 23 were weighed respectively, and added to 5 parts of oil-based drilling fluid respectively under stirring, and the remaining 1 part of oil-based drilling fluid was used as a blank sample, stirred for 10 minutes, and after stirring, the 6 samples were poured into an aging tank respectively, put into a roller furnace, aged at 150°C for 16 hours, and then tested for their performance. The performance test results of the oil-based drilling fluid after aging are shown in Table 3. In Table 3, the rheological test was tested when the temperature of the constant temperature heating jacket was controlled at 50°C. It can be seen from Table 3 that after adding the oil-based high filtration loss plugging agent, the rheological properties of the entire oil-based drilling fluid are less affected; after adding Diaseal-M to the oil-based drilling fluid, the demulsification voltage is significantly reduced and the rheology increases.

[0055] Therefore, it can be seen that the various properties of the high-loss pressure-bearing plugging agent for oil-based drilling fluid of the present invention are significantly better than the imported plugging agent Diaseal-M.

[0056] The present invention uses white oil as the base liquid to prepare the plugging slurry. After the plugging slurry enters the leaking formation, under the action of the pressure difference between the drilling fluid column pressure and the formation pressure, the plugging slurry is quickly filtered out, and a plug is quickly formed in the formation crack. The plug is continuously compacted under the action of the pressure difference, and a higher plugging strength can be formed, and the leaking channel is effectively filled, and the pressure bearing capacity of the formation is improved. At the same time, the formed plugging layer has some microporous structures and overall filling characteristics, and is permeable to air and liquid phase media. Since the drilling fluid contains a lot of solid phase substances, it cannot pass through this layer, but the continuous phase in the drilling fluid can be filtered out, just like the homogeneous seamless low-porosity sandstone formed by natural geology. The drilling fluid is quickly filtered out on the formed plug surface, and a thin, dense, smooth and flat mud cake is formed on the layer, which further plays the effect of plugging the leaking channel.

[0057] In summary, the preparation method of the present invention is simple and convenient, and is made by mixing various materials such as bridging support materials, fiber materials, filling materials, and filter aids. Since the solid phase particles therein are small in size, they are easy to enter leakage channels and spaces of various opening sizes, and are quickly filtered out under the action of pressure difference. The more serious the leakage, the faster the leakage rate, and the faster the filtration. Therefore, the present invention has a wide range of applications, simple plugging construction, high safety, quick results, and low cost.

[0058] 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. A high-loss pressure-bearing plugging agent for oil-based drilling fluid, characterized in that The raw materials include 30 to 40 parts of bridging support material, 10 to 15 parts of fiber material, 40 to 50 parts of filling material and 5 to 10 parts of filter aid in terms of weight, and are prepared according to the following method: required amounts of bridging support material, fiber material, filling material and filter aid are uniformly mixed to obtain a high filtration loss pressure-bearing plugging agent for oil-based drilling fluid.

2. The high filtration loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 1, characterized in that The bridging support material is a mixture of manganese calcite particles with a particle size of 120 meshes and manganese calcite particles with a particle size of 200 meshes; or / and, the fiber material is one or more of brucite fiber and sepiolite fiber; or / and, the filling material is a mixture of special rubber powder with a particle size of 400 meshes and quartz sand with a particle size of 800 meshes; or / and, the filter aid is activated clay powder with a particle size of 400 meshes.

3. The high filtration loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 2, characterized in that The weight ratio of manganese calcite particles with a particle size of 120 mesh to manganese calcite particles with a particle size of 200 mesh is 2 to 3:3 to 4; or / and, the aspect ratio of the fiber material is 30 to 50:1, wherein the diameter is 20um to 40um; or / and, the weight ratio of special rubber powder with a particle size of 400 mesh to quartz sand with a particle size of 800 mesh is 1 to 2:2 to 3.

4. The high filtration loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 1, 2 or 3, characterized in that The raw materials include 35 parts of bridging support material, 10 parts of fiber material, 45 parts of filling material and 10 parts of filter aid in terms of weight.

5. The high filtration loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 4, characterized in that The bridging support material is a mixture of manganese calcite particles with a particle size of 120 meshes and manganese calcite particles with a particle size of 200 meshes; or / and, the fiber material is brucite fiber; or / and, the filling material is a mixture of special rubber powder with a particle size of 400 meshes and quartz sand with a particle size of 800 meshes; or / and, the filter aid is activated white clay powder with a particle size of 400 meshes.

6. The high filtration loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 5, characterized in that The weight ratio of manganese calcite particles with a particle size of 120 meshes to manganese calcite particles with a particle size of 200 meshes is 2:4; or / and, the aspect ratio of brucite fiber is 30 to 50:1, wherein the diameter is 20um to 40um; or / and, the weight ratio of special rubber powder with a particle size of 400 meshes to quartz sand with a particle size of 800 meshes is 2:

3.

7. The high fluid loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 1, 2, 3, 5 or 6, characterized in that The raw materials include 30 parts of bridging support material, 12 parts of fiber material, 50 parts of filling material and 8 parts of filter aid in terms of weight.

8. The high filtration loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 7, characterized in that The bridging support material is a mixture of manganese calcite particles with a particle size of 120 meshes and manganese calcite particles with a particle size of 200 meshes; or / and, the fiber material is a mixture of brucite fiber and sepiolite fiber; or / and, the filling material is a mixture of special rubber powder with a particle size of 400 meshes and quartz sand with a particle size of 800 meshes; or / and, the filter aid is activated white clay powder with a particle size of 400 meshes.

9. The high filtration loss pressure-bearing plugging agent for oil-based drilling fluid according to claim 8, characterized in that The weight ratio of manganese calcite particles with a particle size of 120 meshes to manganese calcite particles with a particle size of 200 meshes is 3:4; or / and, the weight ratio of brucite fiber to sepiolite fiber is 1:1, and the aspect ratio of brucite fiber and sepiolite fiber are both 30 to 50:1, wherein the diameter is 20um to 40um; or / and, the weight ratio of special rubber powder with a particle size of 400 meshes to quartz sand with a particle size of 800 meshes is 1:

3.

10. A method for preparing a high fluid loss pressure-bearing plugging agent for oil-based drilling fluid according to any one of claims 2 to 9, characterized in that The method is as follows: the required amount of bridging support material, fiber material, filling material and filter aid are mixed evenly to obtain a high filtration loss pressure-bearing plugging agent for oil-based drilling fluid.

Images