Preparation method and application of anti-collapse plugging agent based on polyether nano polymer

Abstract

The invention relates to a preparation method and application of an anti-sloughing plugging agent based on a polyether nano polymer, and the method comprises the following steps: preparing the polyether nano polymer, melting, mixing, quenching, and subsequently washing and drying to form nanoscale powder; then, mixing with dolomite crystal powder, and preparing a modified polyether nano polymer by adopting a vulcanization modification process; then styrene and butadiene are copolymerized to form a copolymer a-PEGS; and mixing the polyether nano polymer, the copolymer a-PEGS, artificial graphite and amorphous soil to prepare the anti-collapse plugging agent finished product. The modified polyether nano-polymer shows excellent interface bonding capacity and nano-scale structural characteristics, can efficiently block micro-cracks, and ensures well wall stability under complex stratum conditions. Meanwhile, the proportion of the artificial graphite and the amorphous soil combined by the polyether nano polymer and the copolymer a-PEGS is optimized, so that the anti-collapse plugging agent shows excellent lubricity, plugging property and high-temperature and high-pressure resistance in the drilling fluid, and comprehensive protection is provided for drilling operation.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-collapse plugging agents, and particularly to a preparation method and application of an anti-collapse plugging agent based on polyether nanopolymers. Background Art

[0002] During the drilling process of resources such as oil and natural gas, wellbore collapse is one of the common and serious technical problems, which directly affects the safety and efficiency of drilling operations and the development cost of subsequent resources. Especially when drilling through complex formations such as shale formations, the problem of wellbore collapse is particularly prominent, often resulting in phenomena such as wellbore instability and caving, lost circulation, and stuck pipe, which not only delays the construction progress but also significantly increases the operation cost. To prevent wellbore collapse, plugging agents are usually added to the drilling fluid to fill micro-fractures and stabilize the wellbore. However, there are still many problems in the actual application of existing plugging agents, including insufficient plugging performance, weak resistance to high temperature and high pressure, poor compatibility with drilling fluids, high energy consumption in the preparation process, and insufficient environmental friendliness. These problems are particularly prominent under complex formation conditions such as high temperature and high pressure and high salinity environments, and it is difficult to meet the dual requirements of drilling operation stability and plugging efficiency.

[0003] Currently, domestic and foreign plugging agents mostly use silica or titanium dioxide as the core material and treat their surfaces with unsaturated hydrocarbon and unsaturated ester modifiers. However, these products have obvious deficiencies in plugging performance and adaptability and are difficult to meet the diverse needs of oilfield drilling sites, having certain limitations.

[0004] In recent years, the rapid development of nanomaterial technology has provided new ideas for improving the performance of plugging agents. Among them, nanopolymer materials have become a research hotspot for plugging agent preparation due to their high specific surface area, excellent interfacial bonding ability, and chemical stability. However, there are still deficiencies in the preparation process, modification treatment, and synergistic effect with other components of nanopolymers in the existing technology. For example, problems such as complex preparation processes, high energy consumption, and poor environmental friendliness restrict the wide application of nanopolymer plugging agents. In addition, how to further improve the comprehensive performance of plugging agents through material design, including lubricity, high temperature and high pressure resistance, and recycling ability, still requires in-depth research and exploration.

[0005] In view of the above problems, the present invention is specifically proposed. Summary of the Invention

[0006] The present invention discloses a preparation method and application of an anti-collapse plugging agent based on polyether nanopolymers, aiming to solve the technical problems existing in the prior art.

[0007] According to one aspect of the present invention, there is provided

[0008] A preparation method of an anti-collapse plugging agent based on polyether nanopolymers, comprising:

[0009] (1) Prepare polyether nanopolymer;

[0010] Add diphenyl sulfone to a reaction vessel. After heating until completely melted, sequentially add 4,4'-dihydroxybenzophenone, 1,4-bis(4-fluorobenzoyl)benzene, and sodium carbonate. After heating until viscous, pour the mixture into normal-temperature distilled water for quenching treatment to obtain a strip-shaped product. After crushing, washing, and drying the strip-shaped product, polyether nanopolymer powder is obtained;

[0011] (2) Prepare modified polyether nanopolymer;

[0012] Mix the polyether nanopolymer powder with dolomite crystal powder, and then add it to a sulfur trioxide pyridine solution for sulfonation treatment to obtain a modified polyether nanopolymer; the solvent of the sulfur trioxide pyridine solution is dimethylformamide;

[0013] (3) Prepare copolymer a-PEGS

[0014] Select styrene and butadiene in equimolar ratio for copolymerization reaction to obtain a block copolymer of styrene and butadiene. Screen the triblock product and continue heating reaction to obtain copolymer a-PEGS;

[0015] (4) Prepare the finished product of anti-collapse plugging agent

[0016] Mix the polyether nanopolymer and copolymer a-PEGS, and then add artificial graphite and amorphous soil, and stir to obtain the finished product of anti-collapse plugging agent.

[0017] As a preferred technical solution, in the preparation of the modified polyether nanopolymer, by weight, the polyether nanopolymer powder is 40-60 parts, the dolomite crystal powder is 40-60 parts, and the particle size of the dolomite crystal powder is ≤80 mesh.

[0018] As a preferred technical solution, in the preparation of the modified polyether nanopolymer, the sulfonation treatment temperature is 60-80 °C and the time is 1-2 h.

[0019] As a preferred technical solution, in the preparation of the polyether nanopolymer, by weight, diphenyl sulfone is 20-25 parts, 4,4'-dihydroxybenzophenone is 3-4 parts; 1,4-bis(4-fluorobenzoyl)benzene is 4-5 parts, and sodium carbonate is 2-3 parts.

[0020] As a preferred technical solution, the way of heating until viscous is to heat to 200-250 °C and keep for 0.5-1.5 h; then heat to 300-350 °C and continuously stir and heat until viscous.

[0021] As a preferred technical solution, in the preparation of polyether nano-polymer, the washing method is to wash successively with acetone, distilled water, and acetone.

[0022] As a preferred technical solution, in the preparation of copolymer a-PEGS, the reaction conditions for screening the triblock product for continued heating reaction are that the temperature is 80 - 90 °C and catalyst P4-t-Bu is added.

[0023] As a preferred technical solution, in the preparation of the finished anti-collapse plugging agent, by weight, 50 - 60 parts of polyether nano-polymer, 15 - 20 parts of copolymer a-PEGS, 5 - 10 parts of artificial graphite, and 5 - 10 parts of amorphous soil are used.

[0024] As a preferred technical solution, the amorphous soil is sodium-based bentonite.

[0025] According to another aspect of the present invention, there is also provided an application of the anti-collapse plugging agent prepared by the above preparation method in drilling fluid.

[0026] The technical solution adopted by the present invention can at least achieve one of the following beneficial effects:

[0027] 1. By preparing polyether nano-polymer and performing modification treatment, the present invention significantly improves the plugging performance and anti-collapse ability of the material. The surface activity of the modified polyether nano-polymer is significantly enhanced, forming a stronger interfacial bond with the particles in the drilling fluid, ensuring stability under complex formation conditions. At the same time, its nano-scale structure enables it to efficiently plug micro-cracks and prevent wellbore collapse.

[0028] 2. In the preparation process of the present invention, controllable reaction conditions and post-treatment processes, such as vulcanization modification and low-temperature drying, are adopted to avoid the energy consumption problems caused by high temperature and high pressure in traditional processes, significantly reducing the environmental burden. In addition, the selection of environmentally friendly materials such as dolomite crystal powder and amorphous soil further improves the sustainability and recycling performance of the anti-collapse plugging agent.

[0029] 3. The combination of polyether nano-polymer and copolymer a-PEGS in the present invention, together with the addition of artificial graphite and amorphous soil, enables the anti-collapse plugging agent to have excellent lubricity, plugging property, and high-temperature and high-pressure resistance performance in drilling fluid, providing comprehensive protection for complex downhole environments, improving drilling operation efficiency, and reducing non-productive time. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. These drawings form a part of the present invention. The schematic embodiments of the present invention and their explanations explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0031] Figure 1 Schematic flow chart of a method for preparing a collapse prevention and plugging agent based on polyether nanopolymer according to the present invention;

[0032] Figure 2 SEM photograph of the collapse prevention and plugging agent at a magnification of 1 μm according to an embodiment of the present invention;

[0033] Figure 3 SEM photograph of the collapse prevention and plugging agent at a magnification of 2 μm according to an embodiment of the present invention. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is generally used in the sense of including "and / or", unless otherwise clearly specified in the context.

[0035] Unless clearly indicated to the contrary, the numerical parameters in this specification and the appended claims may be approximate values, which can be changed according to the required characteristics obtained through the content of the present invention. Specifically, all the numbers representing the contents of components, reaction conditions, etc. used in the specification and claims should be understood to be modified by the term "about" in all cases. Generally, the meaning expressed is that it includes a change of ±10% in some embodiments, a change of ±5% in some embodiments, a change of ±1% in some embodiments, and a change of ±0.5% in some embodiments for a specific quantity.

[0036] Furthermore, the word "comprising" does not exclude the presence of materials or steps not listed in the claims. Ordinal numbers such as "first", "second", "third", and Arabic numerals, letters, etc. used in the specification and claims to modify the corresponding elements or steps do not themselves imply an order in the manufacturing method, and the use of these ordinal numbers is only used to clearly distinguish the steps.

[0037] In addition, unless specifically described or steps that must occur in sequence, the order of the above steps is not limited to the above-listed order, and can be changed or rearranged according to the required design. And the above embodiments can be mixed and used with each other or mixed and used with other embodiments based on considerations of design and reliability, that is, the technical features in different embodiments can be freely combined to form more embodiments.

[0038] Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0039] To solve the problems existing in the prior art, an embodiment of the present invention provides a method for preparing an anti-collapse plugging agent based on polyether nanopolymer, as Figure 1 shown, which includes the following steps:

[0040] S1: Prepare polyether nanopolymer;

[0041] S11: Add 20 - 25 parts of diphenyl sulfone into a three-necked flask, and slowly heat it to 155 - 165 °C under nitrogen protection; as the temperature rises, diphenyl sulfone gradually changes from solid state to liquid state; when the temperature reaches 155 - 165 °C, diphenyl sulfone is completely melted and presents as a semi-transparent pale yellow liquid;

[0042] S12: Sequentially add 3 - 4 parts of 4,4'-dihydroxybenzophenone, 4 - 5 parts of 1,4-bis(4-fluorobenzoyl)benzene and 2 - 3 parts of sodium carbonate into the three-necked flask, and continuously stir to ensure uniform distribution of raw materials; under stirring state and nitrogen protection, gradually raise the temperature to 200 - 250 °C. As the temperature rises, the raw materials are gradually dissolved and the first reaction occurs. The system of the first reaction gradually changes from turbid to a bright yellow liquid; maintain the reaction temperature of 200 - 250 °C for 0.5 - 1.5 hours to ensure complete progress of the first reaction;

[0043] S13: After the above first reaction reaches the predetermined time, discharge the water in the first reaction system through continuous heating to ensure complete escape of water to avoid its influence on subsequent reactions; on this basis, continue to gradually raise the temperature in the first reaction system to 300 - 350 °C, and keep stirring, and continuously react for 2 - 3.5 hours. During the heating process, as the temperature rises, significant changes gradually occur in the first reaction system: the mixture of the first reaction gradually changes from the initial liquid state to off-white, and the viscosity significantly increases until the first reaction system shows a high viscosity, reflecting the in-depth progress of the polymerization reaction in the first reaction system;

[0044] S14: Quickly pour the mixture (the first mixed material) in the three-necked flask into a large amount of normal-temperature distilled water for quenching treatment. The distilled water can quickly reduce the temperature of the first mixed material and make it quickly solidify from the liquid state to form a strip-shaped product;

[0045] S15: Place the strip-shaped product in a high-speed blender for crushing treatment to convert the strip-shaped product from large pieces or strips into a uniform powder form, providing a suitable material form for subsequent processing or application;

[0046] S16: Wash the strip-shaped product powder three times in acetone to remove diphenyl sulfone and excess monomers, then wash it five times with distilled water to remove sodium carbonate, and finally wash it three times with acetone again. Remove the residual impurities in the strip-shaped product powder through sequential solvent cleaning to ensure the purity and quality of the strip-shaped product powder;

[0047] S17: Place the washed strip-shaped product powder in a vacuum environment at 70 - 90 °C for drying for 9 - 11 hours to remove the residual solvent and moisture, and obtain off-white polyether nanopolymer powder;

[0048] S2: Modify the polyether nanopolymer;

[0049] S21: Grind 40 - 60 parts of dolomite crystals into powder with a particle size ≤ 80 mesh to ensure uniform particle size and reasonable distribution, and then evenly spray the dolomite powder on the surface of the above polyether nanopolymer by spraying to obtain the second mixed material; Preferably, the particle size of the dolomite crystal powder is 20 - 40 mesh to ensure that the powder particles are not too small to prevent powder agglomeration;

[0050] S22: Carry out low-temperature drying treatment on the second mixed material in an environment at 40 - 60 °C to remove the residual moisture or other volatile substances during the mixing process and ensure the uniformity of the second mixed material;

[0051] S23: Use dimethylformamide (DMF) as the solvent, stir and mix the second mixed material with the sulfonating agent pyridine sulfur trioxide in the solvent, and carry out the second reaction, i.e., sulfonation reaction, at a temperature of 60 - 80 °C for 1 - 2 hours. During this process, the active groups of the sulfonating agent chemically react with the active sites of the second mixed material to introduce sulfonic acid groups and obtain the modified polyether nanopolymer;

[0052] S3: Prepare copolymer a-PEGS;

[0053] S31: Select styrene and butadiene in equimolar ratio as raw materials, and carry out the third reaction, i.e., copolymerization reaction, under mild temperature conditions of 75 - 85 °C. By controlling the time of the third reaction, obtain the block copolymer of styrene and butadiene;

[0054] S32: Screen out the triblock copolymer, place it in a blending kettle, add the catalyst P4-t-Bu, and carry out the fourth reaction under mild conditions of 80 - 90 °C; Through the uniform mixing and precise temperature control of the blending kettle, promote the fourth reaction to proceed under optimal conditions to obtain the high-performance copolymer a-PEGS. The structural formula of a-PEGS is as follows:

[0055]

[0056] S4: Prepare the finished anti-collapse plugging agent based on the modified polyether nanopolymer;

[0057] Add 50 - 60 parts of the modified polyether nanopolymer and 15 - 20 parts of α-PEGS into a blending kettle, then add 5 - 10 parts of artificial graphite and 5 - 10 parts of amorphous soil, and make each component evenly mixed through sufficient stirring to obtain the finished anti-collapse plugging agent; Preferably, the amorphous soil is sodium-based bentonite, that is, a water-containing clay mineral with montmorillonite as the main mineral component, and the exchangeable cations between its layers are mainly sodium ions (Na+).

[0058] Through the above design, based on the synergistic effect of the modified polyether nanopolymer and the block copolymer, the embodiments of the present invention prepare an anti-collapse plugging agent with excellent performance through multi-step precisely controlled chemical and physical treatments. First, through strict temperature control, multi-step polymerization and vacuum drying processes, high-purity polyether nanopolymers are prepared; Subsequently, dolomite powder spraying and sulfonation modification technologies are adopted to endow the material with stronger adsorption, chemical stability and hydrophilicity; At the same time, styrene-butadiene block copolymer and platinum-based catalyst are introduced to enhance the mechanical toughness and functional diversity of the product; Finally, through the synergistic compounding of artificial graphite and amorphous soil, the conductivity, mechanical properties and environmental adaptability of the material are further improved. The embodiments of the present invention significantly improve the wellbore stability performance and applicability of the plugging agent. The product has excellent high temperature resistance, corrosion resistance and dispersibility, and can effectively cope with the challenges of complex downhole environments; At the same time, the preparation process is efficient and environmentally friendly, with a high solvent recovery rate and significant industrialization potential, providing a reliable and economical anti-collapse solution for drilling operations.

[0059] In some preferred embodiments, in step S31, in order to ensure that the block copolymer has an ideal block structure and a uniform molecular weight distribution, the time of the third reaction is 4 - 6 h.

[0060] In some preferred embodiments, in step S32, the platinum-based catalyst is P4-t-Bu, that is, phosphazene ligand P4-tert-butyl (P4-t-Bu); Preferably, the dosage of the P4-t-Bu catalyst is 2 - 5 parts, which can ensure the reaction efficiency while minimizing the usage amount of the catalyst to achieve the balance between economy and efficiency.

[0061] The embodiments of the present invention also provide an application of the above anti-collapse plugging agent, that is, as a functional additive applied to drilling fluids. By adding the above anti-collapse plugging agent into the drilling fluid, the stability of the wellbore can be significantly improved, effectively preventing formation collapse or pore leakage, and at the same time improving the rheological properties and plugging effect of the drilling fluid.

[0062] The following will refer to the drawings and combine with embodiments to detail the anti-collapse plugging agent prepared by the present invention and the drilling fluid prepared based on the above anti-collapse plugging agent.

[0063] Anti-collapse plugging agent:

[0064] Example 1

[0065] This example provides an anti-collapse plugging agent based on polyether nanopolymer, obtained based on the above preparation method. Among them, the raw material components (by weight) are: 20 parts of diphenyl sulfone, 4 parts of 4,4'-dihydroxybenzophenone, 4 parts of 1,4-bis(4-fluorobenzoyl)benzene, 3 parts of sodium carbonate; 50 parts of dolomite crystals; 60 parts of modified polyether nanopolymer, 15 parts of a-PEGS; 5 parts of artificial graphite; 5 parts of amorphous soil.

[0066] The preparation process parameters are as follows: In step S11, the temperature is 160 °C; in step S12, the temperature is 220 °C, and the time for maintaining the reaction temperature of 220 °C is 1 hour; in step S13, the temperature is 320 °C, and the continuous reaction time is 3 hours; in step S17, the temperature is 80 °C, and the continuous time is 10 hours; in step S22, the temperature is 50 °C; in step S23, the temperature is 70 °C, and the continuous time is 1.5 hours; in step S31, the temperature is 80 °C; in step S32, the temperature is 85 °C.

[0067] As Figure 2 and Figure 3 shown, by observing the scanning electron microscope (SEM) photo of the anti-collapse plugging agent prepared in this example, it can be seen that the modified polyether nanopolymer is well wrapped by the particle mixture such as a-PEGS, artificial graphite, and amorphous soil.

[0068] Example 2

[0069] The difference between this example and Example 1 lies in the raw material components and preparation process parameters, as follows:

[0070] The raw material components (by weight) used are: 25 parts of diphenyl sulfone, 3.5 parts of 4,4'-dihydroxybenzophenone, 5 parts of 1,4-bis(4-fluorobenzoyl)benzene, 2 parts of sodium carbonate; 40 parts of dolomite crystals; 55 parts of modified polyether nanopolymer, 20 parts of a-PEGS; 7 parts of artificial graphite; 10 parts of amorphous soil.

[0071] The preparation process parameters are: In step S11, the temperature is 155 °C; in step S12, the temperature is 250 °C, and the time for maintaining the reaction temperature of 250 °C is 0.5 hour; in step S13, the temperature is 350 °C, and the continuous reaction time is 2 hours; in step S17, the temperature is 70 °C, and the continuous time is 11 hours; in step S22, the temperature is 60 °C; in step S23, the temperature is 80 °C, and the continuous time is 1 hour; in step S31, the temperature is 75 °C; in step S32, the temperature is 80 °C.

[0072] Example 3

[0073] The difference between this example and Example 1 lies in the raw material components and preparation process parameters, as follows:

[0074] The raw material components used (by weight) are: 23 parts of diphenyl sulfone, 3 parts of 4,4'-dihydroxybenzophenone, 4.5 parts of 1,4-bis(4-fluorobenzoyl)benzene, 2.5 parts of sodium carbonate; 60 parts of dolomite crystals; 50 parts of modified polyether nanopolymer, 18 parts of a-PEGS; 10 parts of artificial graphite; 8 parts of amorphous soil.

[0075] The preparation process parameters are: in step S11, the temperature is 165°C; in step S12, the temperature is 200°C, and the time for maintaining the reaction temperature of 200°C is 1.5 hours; in step S13, the temperature is 300°C, and the continuous reaction time is 3.5 hours; in step S17, the temperature is 90°C, and the continuous time is 9 hours; in step S22, the temperature is 40°C; in step S23, the temperature is 60°C, and the continuous time is 2 hours; in step S31, the temperature is 85°C; in step S32, the temperature is 90°C.

[0076] After screening the anti-collapse plugging agents of Examples 1-3, the anti-collapse plugging agent in Example 1 was selected as one of the raw materials to prepare drilling fluid:

[0077] Example 4

[0078] This example provides a high-performance polymer drilling fluid system prepared based on the anti-collapse plugging agent of Example 1. Its raw material components (by weight) are: 30 parts of the above anti-collapse plugging agent, 5 parts of coating agent, 15 parts of fluid loss reducer, 1-2 parts of pH regulator, 2-3 parts of flow pattern regulator, 30 parts of bentonite, 600 parts of weighting agent. Preferably, the coating agent is PHPA, the fluid loss reducer is PAC-LV and MAN101, the pH regulator is NaOH, the flow pattern regulator is xanthan gum XC, and the weighting agent is barite. The density of this polymer drilling fluid system is 1.40 g / cm 3 .

[0079] Example 5

[0080] This embodiment provides a high-performance soil-free drilling fluid system prepared based on the anti-collapse plugging agent of Embodiment 1. Its raw material components (by weight) are: 25 parts of the above anti-collapse plugging agent, 25 parts, 5 parts of a coating agent, 30 parts of a fluid loss reducer, 50 parts of an inhibitor, 3 parts of a pH regulator, 3 - 5 parts of a flow pattern regulator, and 600 parts of a weighting agent. Preferably, the coating agent is PHPA, the fluid loss reducer is PAC-LV and STARCH, the inhibitor is KL, the pH regulator is NaOH, the flow pattern regulator is xanthan gum XC, and the weighting agent is barite. This soil-free drilling fluid system has a density of 1.40 - 1.42 g / cm 3 .

[0081] Example 6

[0082] This embodiment provides a polysulfonate potassium-based drilling fluid system prepared based on the anti-collapse plugging agent of Embodiment 1. Its raw material components (by weight) are: 30 parts of the above anti-collapse plugging agent, 5 parts of a coating agent, 70 parts of a fluid loss reducer, 50 parts of an inhibitor, 3 parts of a pH regulator, 2 - 3 parts of a flow pattern regulator, and 600 parts of a weighting agent. Preferably, the coating agent is PHPA, the fluid loss reducer is PAC-LV, SMP and SPANH, with a ratio of 1:3:3, the inhibitor is KL, the pH regulator is NaOH, the flow pattern regulator is xanthan gum XC, and the weighting agent is barite. This polysulfonate potassium-based drilling fluid system has a density controlled at 1.40 - 1.45 g / cm 3 .

[0083] Comparative Example 1

[0084] This comparative example provides a water-based drilling fluid system. Its raw material components (by weight) are: 700 parts of a water-based slurry, 20 parts of organic clay, 5 parts of a polymer thickener, 200 parts of calcium carbonate particles (average particle size 5 μm), 50 parts of a chemical plugging agent (polymer particles), and an appropriate amount of a pH regulator (potassium hydroxide, adjusted to pH 9.5).

[0085] Perform a plugging evaluation on the anti-collapse plugging agent of Embodiment 1 and the drilling fluids of Examples 4, 5 and 6.

[0086] Plugging Evaluation 1

[0087] In order to investigate the microscopic distribution state of the above anti-collapse plugging agent, perform a scanning electron microscope (SEM) experiment on the anti-collapse plugging agent of Embodiment 1, as Figure 2 and Figure 3 shown. The core of the modified polyether nanopolymer is well wrapped by a mixture of particles such as a-PEGS, graphite, and amorphous soil, and can form a good continuous dispersion plugging film in the drilling fluid, increasing the plugging effect.

[0088] Plugging Evaluation 2

[0089] The relevant performance tests of the drilling fluids in Examples 4 - 6 were carried out, and the plugging evaluation results are shown in Table 1.

[0090] Table 1 Plugging Evaluation Index Table

[0091]

[0092]

[0093] As shown in Table 1, the drilling fluids in Examples 4 - 6 have excellent rheological properties and plugging properties. In terms of rheology, the change values of apparent viscosity and plastic viscosity do not exceed 2 mPa·s and 3 mPa·s respectively, ensuring the stability and fluidity of the drilling fluid under complex conditions; in terms of plugging properties, the leakage volume of the base slurry reaches more than 150 mL, the leakage volume of the specimens is lower than 45 mL, and the plugging efficiency is as high as more than 95%. At the same time, the instantaneous loss reduction rate of the plugging performance of the sand disk reaches more than 75%. These performance indicators show that the above drilling fluids have high - efficiency plugging ability and good rheological properties, and can meet the usage requirements under complex drilling environments.

[0094] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above - mentioned specific embodiments. The above - mentioned specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the spirit and scope protected by the claims of the present invention, and all of them belong to the protection scope of the present invention.

Claims

1. A method for preparing an anti-collapse plugging agent based on polyether nanopolymer, characterized in that: include: (1) preparing polyether nanopolymers; Add diphenyl sulfone to a reaction container, heat until completely melted, then add 4,4'-dihydroxybenzophenone, 1,4-bis(4-fluorobenzoyl)benzene and sodium carbonate in sequence, heat until viscous, pour the mixture into distilled water at room temperature for quenching, and obtain a strip product; crush, wash and dry the strip product to obtain a polyether nanopolymer powder; (2) preparing modified polyether nanopolymers; The polyether nanopolymer powder is mixed with dolomite crystal powder, and then added to a sulfur trioxide pyridine solution for sulfonation to obtain a modified polyether nanopolymer; the solvent of the sulfur trioxide pyridine solution is dimethylformamide; (3) Preparation of copolymer a-PEGS Selecting styrene and butadiene in equal molar proportions for copolymerization to obtain a block copolymer of styrene and butadiene, selecting a triblock product and continuing heating the product for reaction to obtain a copolymer a-PEGS; (4) Preparation of anti-collapse plugging agent finished product After the modified polyether nano polymer and the copolymer a-PEGS are mixed, artificial graphite and amorphous soil are added, and the mixture is stirred to obtain a finished anti-collapse plugging agent.

2. The preparation method according to claim 1, characterized in that: In the preparation of the modified polyether nanopolymer, the polyether nanopolymer powder is 40-60 parts by weight, the dolomite crystal powder is 40-60 parts by weight, and the dolomite crystal powder has a particle size of ≤80 meshes.

3. The preparation method according to claim 2, characterized in that: In the preparation of the modified polyether nanopolymer, the sulfonation treatment temperature is 60-80° C. and the time is 1-2 hours.

4. The preparation method according to claim 1, characterized in that: In the preparation of the polyether nanopolymer, by weight, the diphenyl sulfone is 20-25 parts, the 4,4'-dihydroxybenzophenone is 3-4 parts, the 1,4-bis(4-fluorobenzoyl)benzene is 4-5 parts, and the sodium carbonate is 2-3 parts.

5. The method according to claim 4, characterized in that The method of heating to viscosity is: heating to 200-250° C., maintaining for 0.5-1.5 hours; and then heating to 300-350° C., continuously stirring and heating until viscosity.

6. The preparation method according to claim 5, characterized in that: In the preparation of the polyether nanopolymer, the washing method is to use acetone, distilled water and acetone in sequence for washing.

7. The preparation method according to claim 1, characterized in that: In the preparation of the copolymer a-PEGS, the reaction conditions for continuing the heating reaction of the selected triblock product are as follows: the temperature is 80-90° C., and the catalyst P4-t-Bu is added.

8. The preparation method according to claim 1, characterized in that: In the preparation of the anti-collapse plugging agent finished product, by weight, the modified polyether nanopolymer is 50-60 parts, the copolymer a-PEGS is 15-20 parts, the artificial graphite is 5-10 parts, and the amorphous soil is 5-10 parts.

9. The preparation method according to claim 8, characterized in that: The amorphous soil is sodium bentonite.

10. Use of the anti-collapse plugging agent prepared by the preparation method according to any one of claims 1 to 9 in drilling fluid.

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