Composite temporary plugging agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of oilfield chemical materials, and particularly relates to a composite temporary plugging agent and a preparation method and application thereof. The composite temporary plugging agent comprises flexible material particles and rigid material particles, the flexible material particles comprise the following preparation raw materials in percentage by weight: 1%-3% of acrylate, 2%-5% of styrene, 50%-60% of sodium acrylate, 0.1%-1% of polyvinyl alcohol, 2%-4% of an emulsifier, 0.5%-1.5% of an initiator, 1%-4% of a demulsifier and the balance of water; the rigid material particles are prepared from the following raw materials in percentage by weight: 40%-45% of acrylamide, 20%-26% of silicate ester, 10%-13% of triethoxysilane, 10%-13% of polyhedral oligomeric silsesquioxane, 0.1%-1% of polyvinyl alcohol, 4%-6% of an emulsifier, 1%-2% of an initiator and the balance of water. The composite temporary plugging agent has the beneficial effects that the rigid material particles of the composite temporary plugging agent are stable in morphology, can provide high-strength support and resist high pressure; the flexible material particles deform under pressure to fill tiny gaps among the rigid particles, and efficient multi-scale plugging can be achieved through rigid-flexible cooperation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil field chemical materials, and particularly relates to a composite temporary plugging agent and a preparation method and application thereof. BACKGROUND

[0002] The temporary plugging agent is a functional material used for realizing temporary plugging of a formation in the field of oil and gas exploitation, and mainly includes three categories of degradable polymer, heat-sensitive material and composite chemical agent. The core function thereof is to form a low-permeability barrier through physical plugging or chemical action, to guide the fracturing fluid to divert to an unmodified area, and to be degradable or dissolved after construction to restore the permeability of the formation.

[0003] The traditional temporary plugging agent often adopts single-material particles, and cannot simultaneously plug multiple-scale cracks (such as micron-sized pores and millimeter-sized cracks), has poor plugging performance, and leads to high filtration loss. In addition, the traditional temporary plugging agent has weak performance and low pressure limit, and cannot effectively resist construction pressure fluctuation to maintain crack extension. SUMMARY

[0004] The application provides a composite temporary plugging agent and a preparation method and application thereof, and aims to solve the problems of poor plugging performance, high filtration loss, different solubility and dissolution rate of the existing temporary plugging agent, and limited use in hydraulic fracturing engineering.

[0005] The application provides a composite temporary plugging agent, which comprises flexible material particles and rigid material particles; the flexible material particles comprise the following preparation raw materials in the following weight percentage: 1%-3% of acrylate, 2%-5% of styrene, 50%-60% of sodium acrylate, 0.1%-1% of polyvinyl alcohol, 2%-4% of emulsifier, 0.5%-1.5% of initiator and 1%-4% of demulsifier, and the balance is water. The rigid material particles comprise the following preparation raw materials in the following weight percentage: 40%-45% of acrylamide, 20%-26% of silicate, 10%-13% of triethoxysilane, 10%-13% of cage-type poly silesquioxane, 0.1%-1% of polyvinyl alcohol, 4%-6% of emulsifier, 1%-2% of initiator, and the balance is water.

[0006] According to some embodiments of the composite temporary plugging agent, the particle size of the flexible material particles is 10-100 mesh.

[0007] According to some embodiments of the composite temporary plugging agent, the particle size of the rigid material particles is 10-100 mesh.

[0008] According to some embodiments of the composite temporary plugging agent, the mass ratio of the flexible material particles to the rigid material particles is (2-4):(5-8).

[0009] According to some embodiments of the composite temporary plugging agent, the pH of the rigid material particles is 8.5-9.

[0010] According to some embodiments of the composite temporary plugging agent, the acrylate includes ethyl acrylate and / or 2-ethylhexyl acrylate.

[0011] According to some embodiments of the composite temporary plugging agent, the silicate includes tetraethyl orthosilicate and / or tetramethyl orthosilicate.

[0012] According to some embodiments of the composite temporary plugging agent, the cage polysilsesquioxane includes a monofunctional cage polysilsesquioxane and / or a multifunctional cage polysilsesquioxane.

[0013] According to some embodiments of the composite temporary plugging agent, the emulsifier in the flexible material particles and the rigid material particles each independently includes one or more of sodium dodecyl sulfate, myristoyl amidopropyl hydroxypropyl sulfonate betaine, and dodecylaminopropionic acid.

[0014] According to some embodiments of the composite temporary plugging agent, the initiator in the flexible material particles and the rigid material particles each independently includes one or more of potassium persulfate, ammonium persulfate, and azobisisobutyronitrile.

[0015] According to some embodiments of the composite temporary plugging agent, the demulsifier in the flexible material particles includes ethanol and / or isopropyl alcohol.

[0016] According to some embodiments of the composite temporary plugging agent, the adjusting agent for adjusting the pH of the rigid material particles includes hydrochloric acid and / or ammonia.

[0017] The second aspect of the present application provides a preparation method of the composite temporary plugging agent of the first aspect of the present application, including the following steps: (1) preparing flexible material particles The emulsifier, polyvinyl alcohol, acrylate, styrene, and water are mixed to form an emulsion; the initiator and sodium acrylate are added to the emulsion to react; after the reaction is completed, the demulsifier is added to the reaction solution for demulsification treatment; the reaction solution is centrifuged and separated; the precipitate is dried to obtain the flexible particles; (2) preparing rigid material particles The emulsifier, polyvinyl alcohol, silicate, triethoxysilane, cage polysilsesquioxane, and water are mixed to obtain a mixture; the pH of the mixture is adjusted to be acidic, so that the first reaction is carried out under acidic conditions; after the reaction is completed, the pH of the reaction solution is adjusted to be alkaline; the acrylamide and the initiator are added to the reaction solution to carry out the second reaction; after the reaction is completed, the reaction solution is centrifuged and separated; the precipitate is dried to obtain the rigid particles; (3) mixing the flexible material particles and the rigid material particles to obtain the composite temporary plugging agent.

[0018] According to some embodiments of the method for preparing the composite temporary plugging agent, in step (1), the temperature of the reaction is 70-80℃; and the time of the mixing reaction is 2-4h.

[0019] According to some embodiments of the method for preparing the composite temporary plugging agent, in step (1), the demulsification treatment comprises mixing the reaction solution and a demulsifier and performing the demulsification treatment.

[0020] According to some embodiments of the method for preparing the composite temporary plugging agent, the temperature of the demulsification treatment is 20-30℃, and the time of the demulsification treatment is 10-15min.

[0021] According to some embodiments of the method for preparing the composite temporary plugging agent, in step (1), the temperature of the drying is 110-130℃; and the time of the drying is 4-6h.

[0022] According to some embodiments of the method for preparing the composite temporary plugging agent, in step (2), the temperature of the first reaction is 60-70℃, the time of the first reaction is 1-2h, and the pH of the acidic condition of the first reaction is 3.7-4.3.

[0023] According to some embodiments of the method for preparing the composite temporary plugging agent, in step (2), the temperature of the second reaction is 80-85℃, the time of the second reaction is 1-3h, and the pH of the basic condition of the second reaction is 8.5-9.

[0024] The embodiments of the present application also provide an application of the composite temporary plugging agent of the first aspect of the present application or the composite temporary plugging agent obtained by the method of the second aspect of the present application in a fracturing fluid.

[0025] According to some embodiments of the application, the fracturing fluid comprises a fracturing fluid for coalbed methane exploitation, a fracturing fluid for geothermal development, or a fracturing fluid for oil and gas wells.

[0026] According to some embodiments of the application, the mass content of the composite temporary plugging agent in the fracturing fluid is 3%-8%.

[0027] The beneficial effects of the present application include that the rigid material particles of the composite temporary plugging agent are stable in form, can provide high-strength support, and resist high pressure; the flexible material particles deform under pressure, fill the small gaps between the rigid particles, and the combination of rigidity and flexibility can achieve efficient multi-scale plugging. DETAILED DESCRIPTION

[0028] Embodiments of the present application are described in detail below, examples of which are exemplary and intended to explain the present application, and cannot be understood as a limitation of the present application.

[0029] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0030] The embodiment of the present application provides a composite temporary plugging agent, which comprises flexible material particles and rigid material particles; the flexible material particles comprise the following preparation raw materials in percentage by weight: 1%-3% of acrylate, 2%-5% of styrene, 50%-60% of sodium acrylate, 0.1%-1% of polyvinyl alcohol, 2%-4% of emulsifier, 0.5%-1.5% of initiator, 1%-4% of demulsifier, and the balance is water; The rigid material particles comprise the following preparation raw materials in percentage by weight: 40%-45% of acrylamide, 20%-26% of silicate, 10%-13% of triethoxysilane, 10%-13% of cage polysilsesquioxane, 0.1%-1% of polyvinyl alcohol, 4%-6% of emulsifier, 1%-2% of initiator, and the balance is water.

[0031] The rigid material particles of the composite temporary plugging agent described in the present application are stable in form, can provide high-strength support, and resist high pressure; the flexible material particles deform under pressure, fill the tiny gaps between the rigid particles, and the cooperation of rigidity and flexibility can achieve efficient multi-scale plugging.

[0032] In some embodiments of the present application, the particle size of the flexible material particles is 10-100 mesh; for example, 10 mesh, 15 mesh, 20 mesh, 30 mesh, 50 mesh, 80 mesh, 100 mesh, etc.

[0033] In some embodiments of the present application, the particle size of the rigid material particles is 10-100 mesh; for example, 10 mesh, 15 mesh, 20 mesh, 30 mesh, 50 mesh, 80 mesh, 100 mesh, etc.

[0034] In some embodiments of the present application, the mass ratio of the flexible material particles and the rigid material particles is (2-4):(5-8), such as 2:5, 2:6, 2:8, 3:5, 3:6, 3:8, 4:5, 4:6, 4:8, etc. Controlling the mass ratio of the flexible material particles and the rigid material particles within this range can ensure the plugging effect of the temporary plugging agent.

[0035] In some embodiments of the present application, the pH of the rigid material particles is 8.5-9.

[0036] In some embodiments of the present application, the acrylate includes ethyl acrylate and / or 2-ethylhexyl acrylate.

[0037] In some embodiments of the present application, the silicate includes tetraethyl orthosilicate and / or tetramethyl orthosilicate.

[0038] In some embodiments of the present application, the cage polysilsesquioxane includes a monofunctional cage polysilsesquioxane and / or a multifunctional cage polysilsesquioxane; both the monofunctional cage polysilsesquioxane and the multifunctional cage polysilsesquioxane used in the embodiments of the present application are purchased from Guangzhou Yixin Technology Co., Ltd.

[0039] In some embodiments of the present application, the emulsifier in the flexible material particles and the rigid material particles each independently includes one or more of sodium dodecyl sulfate, myristoyl amidopropyl hydroxypropyl sulfonate betaine, and dodecylaminopropionic acid.

[0040] In some embodiments of the present application, the initiator in the flexible material particles and the rigid material particles each independently includes one or more of potassium persulfate, ammonium persulfate, and azobisisobutyronitrile.

[0041] In some embodiments of the present application, the demulsifier in the flexible material particles includes ethanol and / or isopropyl alcohol.

[0042] In some embodiments of the present application, the adjusting agent for adjusting the pH of the rigid material particles includes hydrochloric acid and / or ammonia.

[0043] The embodiments of the present application also provide a preparation method of the composite temporary plugging agent of the first aspect of the present application, including the following steps: (1) preparing flexible material particles The emulsifier, polyvinyl alcohol, acrylate, styrene, and water are mixed to form an emulsion; the initiator and sodium acrylate are added to the emulsion to react, and after the reaction is completed, the demulsifier is added to the reaction solution for demulsification treatment, centrifugal separation is performed, the precipitate is dried, and the flexible particles are obtained; (2) preparing rigid material particles Mixing emulsifier, polyvinyl alcohol, silicate, triethoxysilane, cage polysilsesquioxane and water to obtain a mixture; adjusting pH of the mixture to be acidic, allowing the mixture to undergo a first reaction under acidic conditions, adjusting pH of the reaction solution to be alkaline after the reaction is completed, adding acrylamide and initiator to the reaction solution to undergo a second reaction, centrifuging after the reaction is completed, drying the precipitate to obtain rigid particles; (3) mixing the flexible material particles and the rigid material particles to obtain the composite temporary plugging agent.

[0044] In some embodiments of the present application, in step (1), the temperature of the reaction is 70-80℃, for example, 70℃, 72℃, 75℃, 78℃, 80℃, etc., and the time of the mixing reaction is 2-4h.

[0045] In some embodiments of the present application, in step (1), the demulsification treatment includes mixing the reaction solution and a demulsifier to perform the demulsification treatment.

[0046] In some embodiments of the present application, the temperature of the demulsification treatment is 20-30℃, for example, 20℃, 25℃, 28℃, 30℃, etc., and the time of the demulsification treatment is 10-15min.

[0047] In some embodiments of the present application, in step (1), the temperature of the drying is 110-130℃, for example, 110℃, 115℃, 118℃, 120℃, 123℃, 126℃, 130℃, etc., and the time of the drying is 4-6h.

[0048] In some embodiments of the present application, in step (2), the temperature of the first reaction is 60-70℃, for example, 60℃, 62℃, 65℃, 68℃, 70℃, etc., the time of the first reaction is 1-2h, and the pH of the acidic condition of the first reaction is 3.7-4.3.

[0049] In some embodiments of the present application, in step (2), the temperature of the second reaction is 80-85℃, for example, 80℃, 83℃, 85℃, etc., the time of the second reaction is 1-3h, and the pH of the alkaline condition of the second reaction is 8.5-9.

[0050] The present application also provides an application of the composite temporary plugging agent of the first aspect of the present application or the composite temporary plugging agent obtained by the preparation method of the second aspect of the present application in a fracturing fluid.

[0051] In some embodiments of the present application, the fracturing fluid includes a fracturing fluid for coalbed methane development, a fracturing fluid for geothermal development, or a fracturing fluid for oil and gas wells.

[0052] In some embodiments of the present application, the mass content of the composite temporary plugging agent in the fracturing fluid is 3%-8%, such as 3%, 5%, 6%, 8%, etc.

[0053] The technical solutions of the present application are further described below in combination with specific embodiments.

[0054] Embodiment 1 A preparation method of a composite temporary plugging agent, comprising the following steps: (1) Preparation of flexible material particles Add 2 g of ethyl acrylate, 3 g of styrene, 0.5 g of polyvinyl alcohol, 3 g of emulsifier (sodium dodecyl sulfate), and 150 g of water into a reaction kettle, and stir to dissolve. Stir at a speed of 200 rpm for 20 minutes to form a milky white emulsion. Increase the temperature to 75°C and pass nitrogen gas. Add an aqueous solution containing 1 g of initiator (potassium persulfate) and 55 g of sodium acrylate (add in portions, about 1 / 3 of the total amount of the aqueous solution), and after observing the reaction, drop the remaining aqueous solution into the mixture within 1.5 hours. Keep the reaction for 1 hour, cool to room temperature 25°C, add 6 g of ethanol for demulsification treatment for 10 minutes, centrifugal separation, and dry at 120°C for 5 hours. Grind to obtain 10-100 mesh flexible particles.

[0055] (2) Preparation of rigid material particles Mix 5 g of emulsifier (sodium dodecyl sulfate), 0.5 g of polyvinyl alcohol, 23 g of silicate (tetraethyl orthosilicate), 11 g of triethoxysilane, 11 g of monofunctional cage-type polysilsesquioxane (POSS), and 150 g of water at high speed (800 rpm) for 12 minutes. Increase the temperature to 65°C, add a pH adjuster (dilute hydrochloric acid) to adjust the pH to 3.8, and keep the reaction for 1.5 hours. Adjust the pH to 8.5 again, and increase the temperature to 85°C. Dissolve 42 g of acrylamide in 50 g of water, and drop the solution into the above mixture within 50 minutes. Add 1.5 g of initiator (azobisisobutyronitrile), and keep the reaction for 1.5 hours. Cool to room temperature, centrifugal separation, and dry, and grind to obtain 10-100 mesh rigid particles.

[0056] (3) Mix the flexible material particles and the rigid material particles in a mass ratio of 2:8 to obtain the composite temporary plugging agent.

[0057] Embodiment 2 The preparation method of the composite temporary plugging agent in Embodiment 2 is different from that in Embodiment 1 only in that the amounts of acrylate, styrene, and silicate used in the preparation process of the composite temporary plugging agent in Embodiment 2 are different from those in Embodiment 1.

[0058] The specific operation steps include: (1) Preparation of flexible material particles Into a reaction kettle, 1.5 g of ethyl acrylate, 2.5 g of styrene, 0.3 g of polyvinyl alcohol, 2.5 g of emulsifier (sodium dodecyl sulfate), and 150 g of water were added and stirred and dissolved. After stirring for 20 minutes at a speed of 200 rpm, a milky white emulsion was formed. The temperature was raised to 75°C, and nitrogen was introduced. An aqueous solution containing 0.8 g of initiator (potassium persulfate) and 58 g of sodium acrylate was added (the amount of addition was one-third of the total amount of the aqueous solution), and after the reaction was observed, the remaining aqueous solution was added dropwise over a period of 1.5 hours. The reaction was maintained for 1 hour, the temperature was cooled to room temperature (25°C), 5 g of ethanol was added for demulsification treatment for 10 minutes, and centrifugal separation was performed. The product was dried at 120°C for 5 hours, and was pulverized to obtain 10-100 mesh flexible particles.

[0059] (2) Preparation of rigid material particles Into a reaction kettle, 4.5 g of emulsifier (sodium dodecyl sulfate), 0.3 g of polyvinyl alcohol, 24 g of silicate (tetraethyl orthosilicate), 12 g of triethoxysilane, 12 g of monofunctional cage-type polyhedral oligomeric silsesquioxane (POSS), and 150 g of water were mixed and sheared at a high speed (800 rpm) for 12 minutes. The temperature was raised to 65°C, and a pH adjuster (dilute hydrochloric acid) was added dropwise to adjust the pH to 3.8. The reaction was maintained for 1.5 hours. The pH was adjusted to 8.5, and the temperature was raised to 85°C. 41 g of acrylamide was dissolved in 50 g of water, and was added dropwise to the above mixture over a period of 50 minutes. 1.2 g of initiator (azobisisobutyronitrile) was further added, and the reaction was maintained for 1.5 hours. The temperature was cooled to room temperature, centrifugal separation was performed, and the product was dried and pulverized to obtain 10-100 mesh rigid particles.

[0060] (3) The flexible material particles and the rigid material particles were mixed in a mass ratio of 2:8 to obtain the composite temporary plugging agent.

[0061] Example 3 The preparation method of the composite temporary plugging agent of Example 3 is different from that of Example 1 only in that the amounts of ethyl acrylate, styrene, and silicate used in the preparation process of the composite temporary plugging agent of Example 3 are different from those of Example 1.

[0062] The specific operation steps include: (1) Preparation of flexible material particles Into a reaction kettle, 3 g of ethyl acrylate, 5 g of styrene, 1 g of polyvinyl alcohol, 4 g of emulsifier (sodium dodecyl sulfate) and 150 g of water were added and stirred and dissolved. After stirring for 20 minutes at a speed of 200 rpm, a milky white emulsion was formed. The temperature was raised to 75°C and nitrogen was introduced. An aqueous solution containing 1.5 g of initiator (potassium persulfate) and 50 g of sodium acrylate was added (the amount of addition was one-third of the total amount of the aqueous solution), and after observing the reaction, the remaining aqueous solution was added dropwise over 1.5 hours. The reaction was maintained for 1 hour, the temperature was cooled to room temperature (25°C), 6 g of ethanol was added for demulsification for 10 minutes, centrifugal separation was performed, and drying was performed at 120°C for 5 hours to obtain 10-100 mesh flexible particles.

[0063] (2) Preparation of rigid material particles Into a reaction kettle, 6 g of emulsifier (sodium dodecyl sulfate), 1 g of polyvinyl alcohol, 20 g of silicate (tetraethyl orthosilicate), 10 g of triethoxysilane, 10 g of monofunctional cage-type polyhedral oligomeric silsesquioxane (POSS) and 150 g of water were mixed and high-speed sheared (800 rpm) for 12 minutes. The temperature was raised to 65°C, a pH adjuster (dilute hydrochloric acid) was added dropwise to adjust the pH to 3.8, and the reaction was maintained for 1.5 hours. The pH was adjusted to 8.5 again, and the temperature was raised to 85°C. 45 g of acrylamide was dissolved in 50 g of water and added dropwise to the above mixture over 50 minutes. 2 g of initiator (azobisisobutyronitrile) was added, and the reaction was maintained for 1.5 hours. The temperature was cooled to room temperature, centrifugal separation was performed, and drying and pulverization were performed to obtain 10-100 mesh rigid particles.

[0064] (3) The flexible material particles and the rigid material particles were mixed in a mass ratio of 2:8 to obtain the composite temporary plugging agent.

[0065] Example 4 The preparation method of the composite temporary plugging agent described in Example 4 is different from that of Example 1 only in that the amounts of acrylate, styrene and silicate used in the preparation process of the composite temporary plugging agent described in Example 4 are different from those of Example 1.

[0066] The specific operation steps include: (1) Preparation of flexible material particles Into a reaction kettle, 1 g of ethyl acrylate, 2 g of styrene, 0.1 g of polyvinyl alcohol, 2 g of emulsifier (sodium dodecyl sulfate), and 150 g of water were added and stirred and dissolved. After stirring for 20 minutes at a speed of 200 rpm, a milky white emulsion was formed. The temperature was raised to 75°C and nitrogen was introduced. An aqueous solution containing 0.5 g of initiator (potassium persulfate) and 60 g of sodium acrylate was added (the amount of addition was a partial addition, about 1 / 3 of the total amount of the aqueous solution), and after the reaction was observed, the remaining aqueous solution was added dropwise over 1.5 hours. The reaction was maintained for 1 hour, and the temperature was cooled to room temperature 25°C. 4 g of ethanol was added for demulsification for 10 minutes, centrifuged, and dried at 120°C for 5 hours, and then pulverized to obtain 10-100 mesh flexible particles.

[0067] (2) Preparation of rigid material particles Into a reaction kettle, 4 g of emulsifier (sodium dodecyl sulfate), 0.1 g of polyvinyl alcohol, 26 g of silicate (tetraethyl orthosilicate), 13 g of triethoxysilane, 13 g of monofunctional cage-type polyhedral oligomeric silsesquioxane (POSS), and 150 g of water were mixed and sheared at high speed (800 rpm) for 12 minutes. The temperature was raised to 65°C, and a pH adjuster (dilute hydrochloric acid) was added dropwise to adjust the pH to 3.8, and the reaction was maintained for 1.5 hours. The pH was adjusted to 8.5, and the temperature was raised to 85°C. 40 g of acrylamide was dissolved in 50 g of water and added dropwise to the above mixture over 50 minutes. 1 g of initiator (azobisisobutyronitrile) was further added, and the reaction was maintained for 1.5 hours. The temperature was cooled to room temperature, centrifuged, dried, and pulverized to obtain 10-100 mesh rigid particles.

[0068] (3) The flexible material particles and the rigid material particles were mixed in a mass ratio of 2:8 to obtain the composite bridging agent. Example 5 The preparation method of the composite bridging agent of Example 5 is different from that of Example 1 only in that the mass ratio of the flexible material particles to the rigid material particles in the preparation process of the composite bridging agent of Example 5 is 1:1, and the mesh size ratio of the composite bridging agent is 60 mesh:20 mesh:10 mesh=6:2:2.

[0069] Example 6 The preparation method of the composite bridging agent of Example 6 is different from that of Example 1 only in that the mass ratio of the flexible material particles to the rigid material particles in the preparation process of the composite bridging agent of Example 6 is 1:1, and the mesh size ratio of the composite bridging agent is 60 mesh:30 mesh:10 mesh=2:3:5.

[0070] Example 7 The preparation method of the composite bridging agent of Example 7 is different from that of Example 1 only in that the mass ratio of the flexible material particles to the rigid material particles in the preparation process of the composite bridging agent of Example 7 is 1:1, and the mesh size ratio of the composite bridging agent is 80 mesh:20 mesh:10 mesh=3:2:5.

[0071] Example 8 The difference between the preparation method of the composite bridging agent in Example 8 and Example 1 is only that the mass ratio of the flexible material particles and the rigid material particles in the preparation process of the composite bridging agent in Example 8 is 1:1, and the mesh ratio of the composite bridging agent is 80 mesh:30 mesh:10 mesh = 7:2:1.

[0072] Example 9 The difference between the preparation method of the composite bridging agent in Example 9 and Example 1 is only that the mass ratio of the flexible material particles and the rigid material particles in the preparation process of the composite bridging agent in Example 9 is 1:1, and the mesh ratio of the composite bridging agent is 100 mesh:80 mesh:40 mesh = 4:3:3.

[0073] Example 10 The difference between the preparation method of the composite bridging agent in Example 10 and Example 1 is only that the mass ratio of the flexible material particles and the rigid material particles in the preparation process of the composite bridging agent in Example 10 is 1:1, and the mesh ratio of the composite bridging agent is 100 mesh:60 mesh:40 mesh = 3:2:5.

[0074] 1. The drag reduction rate and plugging effect of the composite bridging agent in Example 1 of the present application The test method is as follows: the drag reduction rate and plugging performance of the different mesh rigid-flexible bridging agents obtained in Example 1 are tested, the test method is based on NB / T14003.1-2015 "Shale gas fracturing fluid slick water performance index and test method", the slick water is used as the base fluid, the pipe friction instrument is used, the base fluid friction ΔP0 without adding the composite bridging agent is recorded, and the friction ΔP1 after adding the composite bridging agent with different gradations. The drag reduction rate calculation formula is as follows:

[0075] The plugging effect test adopts the static filtration test, which is based on GB / T19139-2012 "Oil well cement test method", and the filtration amount is tested, and the results are shown in Table 1.

[0076] Table 1

[0077] As can be seen from Table 1, the flexible material particles and the rigid material particles with different particle sizes have little effect on the overall drag reduction rate of the fracturing fluid bridging agent, and the high mesh rigid-flexible material can reduce the filtration loss of the fracturing fluid.

[0078] 2. The drag reduction rate and plugging effect of the composite bridging agent in Examples 1-4 of the present application The research test method is that the composite temporary plugging agent prepared by using different component weight proportions in examples 1-4 is respectively tested in terms of the resistance reduction rate and the plugging performance, the test method is based on NB / T14003.1-2015 "Shale gas fracturing fluid slick water performance index and test method", the slick water is used as a base fluid, the pipe friction instrument is used, the base fluid friction ΔP0 when the composite temporary plugging agent is not added is recorded, and the friction ΔP1 after the composite temporary plugging agent with different gradations is added. The resistance reduction rate calculation formula is as follows:

[0079] The plugging effect test adopts the static filtration test, the filtration loss is tested according to GB / T19139-2012 "Oil well cement test method", and the results are shown in Table 2.

[0080] Table 2

[0081] It can be seen from Table 2 that the composite temporary plugging agent described in the examples produces a high resistance reduction rate and a low filtration loss effect.

[0082] 3. The influence of the particle size and mesh ratio of the composite temporary plugging agent on the plugging performance.

[0083] The test method is that the composite temporary plugging agent with different mesh ratios in the particle size range in examples 5-10 is respectively tested in terms of the resistance reduction rate and the plugging performance, the test method is based on NB / T14003.1-2015 "Shale gas fracturing fluid slick water performance index and test method", the slick water is used as a base fluid, the pipe friction instrument is used, the base fluid friction ΔP0 when the composite temporary plugging agent is not added is recorded, and the friction ΔP1 after the composite temporary plugging agent with different mesh ratios is added. The resistance reduction rate calculation formula is as follows:

[0084] The plugging effect test adopts the static filtration test, the filtration loss is tested according to GB / T19139-2012 "Oil well cement test method", and the results are shown in Table 3.

[0085] Table 3

[0086] It can be seen from Table 3 that when the composite temporary plugging agent with a particle size of 10-100 meshes is mixed, the resistance reduction rate reaches 80% or above when the mesh ratio is different, and the filtration loss shows a good plugging effect.

[0087] Although the above examples have been shown and described, it can be understood that the above examples are exemplary and cannot be understood as limiting the application, and the changes, modifications, replacements and variations of the above examples made by those skilled in the art are within the protection scope of the application.

Claims

1. A composite bridging agent, characterized in that, The flexible material particles comprise the following weight percentage of raw materials: 1-3% of acrylate, 2-5% of styrene, 50-60% of sodium acrylate, 0.1-1% of polyvinyl alcohol, 2-4% of emulsifier, 0.5-1.5% of initiator, 1-4% of demulsifier, and the rest is water. The rigid material particles comprise the following weight percentage of raw materials: 40-45% of acrylamide, 20-26% of silicate, 10-13% of triethoxysilane, 10-13% of cage polysilsesquioxane, 0.1-1% of polyvinyl alcohol, 4-6% of emulsifier, 1-2% of initiator, and the rest is water.

2. The composite bridge plug of claim 1, wherein, The particle size of the flexible material particles is 10-100 mesh; And / or, the particle size of the rigid material particles is 10-100 mesh; And / or, the mass ratio of the flexible material particles to the rigid material particles is (2-4):(5-8); And / or, the pH of the rigid material particles is 8.5-9.

3. The composite bridge plug of claim 1, wherein, The acrylate comprises ethyl acrylate and / or 2-ethylhexyl acrylate; And / or, the silicate comprises ethyl orthosilicate and / or methyl orthosilicate; And / or, the cage polysilsesquioxane comprises monofunctional cage polysilsesquioxane and / or multifunctional cage polysilsesquioxane; And / or, the emulsifier in the flexible material particles and the rigid material particles each independently comprises one or more of sodium dodecyl sulfate, myristoylpropylhydroxypropyl sulfobetaine, and dodecylaminopropionic acid; And / or, the initiator in the flexible material particles and the rigid material particles each independently comprises one or more of potassium persulfate, ammonium persulfate, and azobisisobutyronitrile; And / or, the demulsifier in the flexible material particles comprises ethanol and / or isopropyl alcohol; And / or, the adjusting agent for adjusting the pH of the rigid material particles comprises hydrochloric acid and / or ammonia.

4. A method of preparing the composite temporary plugging agent according to any one of claims 1-3, characterized in that, The method comprises the following steps: (1) preparing flexible material particles Mixing the emulsifier, polyvinyl alcohol, acrylate, styrene, and water to form an emulsion; adding the initiator and sodium acrylate to the emulsion for reaction; after the reaction is completed, demulsifying the reaction solution with the demulsifier, centrifuging, and drying the precipitate to obtain the flexible particles; (2) preparing rigid material particles Mixing the emulsifier, polyvinyl alcohol, silicate, triethoxysilane, cage polysilsesquioxane, and water to obtain a mixture; adjusting the pH of the mixture to be acidic to make it react under acidic conditions for a first reaction; after the reaction is completed, adjusting the pH of the reaction solution to be alkaline, and adding acrylamide and an initiator to the reaction solution for a second reaction; after the reaction is completed, centrifuging, and drying the precipitate to obtain the rigid particles; (3) mixing the flexible material particles and the rigid material particles to obtain the composite temporary plugging agent.

5. The method of claim 4, wherein the composite temporary plugging agent is prepared by mixing the first temporary plugging agent and the second temporary plugging agent. In step (1), the temperature of the reaction is 70-80°C; and the mixing reaction time is 2-4h.

6. The method of claim 4, wherein the composite temporary plugging agent is prepared by mixing the first temporary plugging agent and the second temporary plugging agent. In step (1), the demulsification treatment comprises mixing the reaction solution and the demulsifier for demulsification treatment. Preferably, the temperature of the demulsification treatment is 20-30℃, and the time of the demulsification treatment is 10-15min. And / or, in step (1), the temperature of the drying is 110-130℃, and the time of the drying is 4-6h.

7. The method for preparing the composite temporary plugging agent according to claim 4, characterized in that, In step (2), the temperature of the first reaction is 60-70℃, the time of the first reaction is 1-2h, and the pH of the acidic condition of the first reaction is 3.7-4.

3.

8. The method for preparing the composite temporary plugging agent according to claim 4, characterized in that, In step (2), the temperature of the second reaction is 80-85℃, the time of the second reaction is 1-3h, and the pH of the basic condition of the second reaction is 8.5-9.

9. The use of the composite temporary plugging agent of any one of claims 1-3 or the composite temporary plugging agent obtained by the preparation method of any one of claims 4-8 in a fracturing fluid. Preferably, the fracturing fluid comprises a fracturing fluid for coalbed methane exploitation, a fracturing fluid for geothermal development, or a fracturing fluid for oil and gas wells.

10. Use according to claim 9, characterized in that, The mass content of the composite temporary plugging agent in the fracturing fluid is 3%-8%.

Images