Plugging agent as well as preparation method and application thereof

Abstract

The invention relates to a plugging agent as well as a preparation method and application thereof. The plugging agent is prepared from the following raw material components: acid-soluble resin, a bridging material, calcium carbonate, soil slurry and fibers, wherein relative to 100 parts by weight of the soil slurry, the content of the acid-soluble resin is 5-12 parts by weight, the content of the bridging material is 8-15 parts by weight, the content of the calcium carbonate is 2-6 parts by weight, and the content of the fiber is 0.5-2 parts by weight. The technical problem that an existing plugging agent is poor in pressure bearing performance is solved.

Description

Technical Field

[0001] The present application relates to the technical field of plugging for oil drilling, and in particular to a plugging agent and a preparation method and application thereof. Background Art

[0002] Well leakage seriously affects the development of oil and gas resources. There are many types of plugging agents. According to the composition of the plugging agents, they can be divided into single agents and composite agents. When a single agent is used for plugging, the plugging effect is poor, especially for complex well leakage. When plugging encounters large and numerous cracks in the leaking layer, it is difficult to form a good sealing layer around the wellbore, the pressure bearing performance is poor, and false plugging is easy to occur. After drilling is resumed, the false plugging layer is destroyed by the stirring of the drill bit and the flushing of the drilling fluid and leaks again.

[0003] Therefore, there is an urgent need for a plugging agent with excellent pressure-bearing performance to achieve the purpose of effectively plugging crack pores. Summary of the invention

[0004] The present application provides a plugging agent and a preparation method and application thereof, so as to solve the technical problem that the existing plugging agents have poor pressure bearing performance.

[0005] In a first aspect, the present application provides a plugging agent, wherein the raw material components of the plugging agent include:

[0006] Acid-soluble resin, bridging material, calcium carbonate, soil slurry and fiber; wherein, relative to 100 parts by weight of the soil slurry, the acid-soluble resin is 5 to 12 parts by weight, the bridging material is 8 to 15 parts by weight, the calcium carbonate is 2 to 6 parts by weight, and the fiber is 0.5 to 2 parts by weight.

[0007] Optionally, relative to 100 parts by weight of the soil slurry, the acid-soluble resin is 10 parts by weight, the bridging material is 8.1 parts by weight, the calcium carbonate is 2.1 parts by weight, and the fiber is 0.52 parts by weight.

[0008] Optionally, the acid-soluble resin includes at least one of the following: polyacrylic resin, phenolic resin, polyimide resin, and furan resin.

[0009] Optionally, the bridging material includes at least one of the following: walnut shell, quartz sand, ceramsite, calcite, and marble.

[0010] Optionally, the fiber includes at least one of the following: asbestos fiber, basalt fiber, carbon fiber.

[0011] Optionally, the soil raw material in the soil slurry includes at least one of the following: sodium-bentonite and calcium-bentonite.

[0012] Optionally, the mass fraction of the soil raw material in the soil slurry is 2% to 8%.

[0013] In a second aspect, the present application provides an application of the plugging agent described in any embodiment of the first aspect in oil drilling.

[0014] In a second aspect, the present application provides a method for preparing the plugging agent according to any one embodiment of the first aspect, the method comprising:

[0015] Under the action of the first stirring, adding a bridging material and calcium carbonate into the soil slurry to obtain a first suspension;

[0016] adding an acid-soluble resin to the first suspension, and performing a second stirring to obtain a second suspension;

[0017] Fibers are added to the second suspension, and a third stirring is performed to obtain a plugging agent.

[0018] Optionally, the first stirring rate is 600r / min to 1000r / min, and the second stirring rate is

[0019] 400r / min~800r / min, the rate of the third stirring is 400r / min~800r / min.

[0020] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0021] The plugging agent provided by the embodiment of the present application has an acid-soluble resin with a certain deformation ability. After being added to the crack, the pressure wave propagation is reduced by mutual accumulation. When plugging, it is not limited by the leakage channel, and can enter the crack and hole space through extrusion deformation, and can better stay in the leakage layer to form a viscoelastic body to achieve the purpose of plugging; the bridging material forms a plugging layer by bridging, accumulation, filling and other effects in the leakage channel; calcium carbonate continuously migrates through the pressure difference, fills the gap of the plugging layer, and isolates the crack tip; the fiber and the bridging material produce a reinforcing effect, further improving the compressive resistance of the plugging layer; the bridging material and the acid-soluble resin are deposited inside the crack, and the crack tip is isolated through the continuous accumulation of calcium carbonate. The fiber and the bridging material increase the crack closure stress through the reinforcing effect, thereby improving the pressure bearing capacity of the formation. At the same time, it prevents the drilling fluid from transmitting pressure to the crack tip, increases the crack rupture pressure, and prevents the crack from extending. When the drilling fluid is lost in the formation, the bridging material and the acid-soluble resin form a sealing barrier near the crack tip to block the propagation of pressure waves and prevent the cracks from inducing cracks; the slurry has a suspension effect, which makes the plugging materials mix evenly. In summary, through the synergistic effect between the raw material components of the above plugging agent, the technical problem of the poor pressure bearing performance of the existing plugging agent is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 A schematic flow chart of a method for preparing a plugging agent provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0026] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0027] In this application, unless otherwise specified, directional words such as "upper" and "lower" used refer specifically to the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of this application, the terms "include", "comprise", etc. mean "including but not limited to". In this document, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and /

[0028] "Or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc or abc, where a, b, and c can be single or plural, respectively.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0030] In a first aspect, the present application provides a plugging agent, wherein the raw material components of the plugging agent include:

[0031] Acid-soluble resin, bridging material, calcium carbonate, soil slurry and fiber; wherein, relative to 100 parts by weight of the soil slurry, the acid-soluble resin is 5 to 12 parts by weight, the bridging material is 8 to 15 parts by weight, and the calcium carbonate is 2 to 6 parts by weight.

[0032] The fiber is 0.5 to 2 parts by weight.

[0033] In some embodiments, relative to 100 parts by weight of the soil slurry, the acid-soluble resin is 10 parts by weight, the bridging material is 8.1 parts by weight, the calcium carbonate is 2.1 parts by weight, and the fiber is 0.52 parts by weight.

[0034] In the embodiment of the present application, the bridging material and the acid-soluble resin are deposited inside the crack, and the crack tip is isolated by the continuous accumulation of calcium carbonate. The fiber and the bridging material increase the crack closure stress through the tensioning effect, thereby increasing the pressure bearing capacity of the formation. At the same time, it prevents the drilling fluid from transmitting pressure to the crack tip, increases the crack rupture pressure, and prevents the crack from extending. When the drilling fluid is lost in the formation, the bridging material and the acid-soluble resin form a sealing barrier near the crack tip to prevent the pressure wave from propagating and prevent the crack from generating induced cracks.

[0035] The above acid-soluble resin has good water absorption and expansion, elastic deformation ability, strong deformability, is not restricted by the leakage channel when plugging, can enter the cracks and hole space through extrusion deformation, can better stay in the leaking layer, form a viscoelastic body to achieve the purpose of plugging, improve the pressure bearing capacity of the formation, and effectively control the malignant leakage. Especially for low-pressure or depleted reservoirs with complex geological conditions, or induced fracture development formations, broken formation well leakage problems. An appropriate amount of acid-soluble resin allows the acid-soluble resin to be added to the cracks and piled up to reduce the propagation of pressure waves; if the content of the acid-soluble resin is too much, it will cause a certain degree of sealing; if the content of the acid-soluble resin is too little, a plugging layer will not be formed to a certain extent. Specifically, the acid-soluble resin can be 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, etc.

[0036] The above-mentioned bridging material forms a plugging layer by bridging, piling up, filling, etc. in the leakage channel. An appropriate amount of bridging material forms a stable plugging layer; if the content of the bridging material is too much, it will cause a door blocking phenomenon to a certain extent; if the content of the bridging material is too little, the bridging effect will be weak to a certain extent and a plugging layer cannot be formed. Specifically, the bridging material can be 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, etc.

[0037] The calcium carbonate mentioned above is continuously transported by the pressure difference, filling the gaps in the plugging layer and isolating the crack tip. An appropriate amount of calcium carbonate forms a dense plugging layer by filling; if the content of the calcium carbonate is too much, it will affect the dispersibility of other materials in the plugging slurry to a certain extent, thereby affecting the formation of the plugging layer; if the content of the calcium carbonate is too little, the mechanical properties of the plugging layer will be poor to a certain extent, and it will be easy to break. Specifically, the calcium carbonate can be 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, etc.

[0038] The above-mentioned fibers and the bridging materials produce a reinforcement effect, further improving the compressive resistance of the plugging layer. The appropriate amount of fiber content improves the pressure bearing capacity of the plugging layer through the reinforcement effect. If the content of the fiber is too much, the plugging slurry will be thicker to a certain extent, affecting pumping; if the content of the fiber is too little, the strength of the plugging layer will be reduced to a certain extent. Specifically, the fiber can be 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, 2 parts by weight, etc.

[0039] In the embodiment of the present application, preferably, relative to 100 parts by weight of the soil slurry, the acid-soluble resin may be 10 parts by weight, the bridging material may be 8.1 parts by weight, the calcium carbonate may be 2.1 parts by weight, and the fiber may be 0.52 parts by weight.

[0040] In some embodiments, the acid-soluble resin includes at least one of the following: polyacrylic acid resin, phenolic resin, polyimide resin, furan resin.

[0041] In the embodiment of the present application, the above-mentioned furan resin is a polymer compound with modified sugar alcohol resin as the main body and compounded with other resins such as phenolic formaldehyde, urea formaldehyde, etc. The strong polar groups in the molecule (such as methyl, amide, etc.) have a strong affinity with the formation surface, which effectively solves the problems of low consolidation strength and severe heterogeneity, and improves the pressure-bearing performance of the plugging agent.

[0042] In some embodiments, the bridging material includes at least one of the following: walnut shell, quartz sand, ceramsite, calcite, and marble.

[0043] In the embodiments of the present application, the walnut shells, quartz sand, expanded clay, calcite, and marble have strong roughness, hardness, and rigidity, and are more likely to form a bridging effect between interfaces.

[0044] In some embodiments, the fiber includes at least one of the following: asbestos fiber, basalt fiber, carbon fiber.

[0045] In the embodiments of the present application, the above-mentioned asbestos fibers, basalt fibers, and carbon fibers have excellent mechanical properties and excellent strength after forming reinforcement.

[0046] In some embodiments, the soil raw material in the soil slurry includes at least one of the following: sodium-bentonite and calcium-bentonite.

[0047] In the embodiments of the present application, the sodium-bentonite and calcium-bentonite have excellent slurrying properties and are used to prepare drilling fluid suspensions with high rheological properties.

[0048] In some embodiments, the mass fraction of the soil raw material in the soil slurry is 2% to 8%.

[0049] In the embodiment of the present application, the bentonite slurry has a suspension effect, which can make the plugging materials mix evenly; if the content of the soil raw material is too much, the consistency will increase to a certain extent, affecting the pumping of the plugging slurry; if the content of the soil raw material is too little, the plugging material will not be suspended to a certain extent, and the configured plugging slurry will be uneven, affecting the plugging effect. Specifically, the mass fraction of the soil raw material in the soil slurry can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, etc.

[0050] In summary, the plugging agent provided in the embodiments of the present application has the following advantages:

[0051] 1) The plugging agent of the embodiment of the present application has the characteristic of slowly degrading under acidic or high temperature conditions. The plugging agent not only has a strong pressure-bearing capacity when plugging, but also has a high acid solubility rate, which can achieve acidification and unblocking, increase backflow efficiency, and improve reservoir protection capabilities. In addition, the grid of the plugging agent after degradation is converted into small molecules or linear polymers, and the residues are greatly reduced compared to inorganic temporary plugging materials, and most of them are soluble in water. The low damage and low residue unique to this acid-soluble resin ensure the recovery of the permeability of the reservoir after the target layer is uncovered;

[0052] 2) The acid-soluble resin in the embodiment of the present application has a deformable ability, can adapt to the size of the leakage formation channel, self-match into the formation under the fluid, and form a stable viscoelastic grid structure through compounding with bridging materials and fibers, thereby forming a stable bridge plugging structure in the leakage channel. The tough particle plugging structure can be released by acidic materials or high temperatures, and the particles are returned with the return fluid, and the particles can be recycled. The system has self-matching crack width, high plugging pressure strength, does not damage the reservoir, and has a simple operation method. It is suitable for processes such as fracture leakage drilling plugging, temporary plugging and fracturing transformation of oil and gas well reservoirs, etc.

[0053] In a second aspect, the present application provides an application of the plugging agent described in any embodiment of the first aspect in oil drilling.

[0054] In the embodiment of the present application, the degradable plugging agent for reservoir plugging is prepared by compounding bridging materials, acid-soluble resins, fibers, etc. The plugging agent can not only slowly degrade under acidic or high temperature conditions, but also has excellent pressure bearing capacity, can effectively increase the backflow efficiency, achieve efficient plugging of the reservoir and improve the reservoir protection ability, can be well applied in oil drilling, and ensure the exploration and development of oil and gas resources.

[0055] In the second aspect, the present application provides a method for preparing the plugging agent described in any embodiment of the first aspect, see Figure 1 , the method comprising:

[0056] S1. Under the action of the first stirring, adding a bridging material and calcium carbonate to the soil slurry to obtain a first suspension;

[0057] S2, adding an acid-soluble resin to the first suspension, and performing a second stirring to obtain a second suspension;

[0058] S3, adding fibers to the second suspension, and performing a third stirring to obtain a plugging agent.

[0059] In some embodiments, the first stirring rate is 600 r / min to 1000 r / min, the second stirring rate is 400 r / min to 800 r / min, and the third stirring rate is 400 r / min to 800 r / min.

[0060] In the embodiment of the present application, the rates of the first stirring, the second stirring and the third stirring are controlled respectively, and different plugging materials are mixed evenly without affecting the performance of the plugging materials. Specifically, the rate of the first stirring can be 600r / min, 700r / min, 800r / min, 900r / min, 1000r / min, the rate of the second stirring can be 400r / min, 500r / min, 600r / min, 700r / min, 800r / min, etc., and the rate of the third stirring can be 400r / min, 500r / min, 600r / min, 700r / min, 800r / min, etc. The bridging material and calcium carbonate are added to the soil slurry in sequence, followed by the acid-soluble resin, and finally the fiber, so that the plugging materials in the plugging slurry are evenly dispersed; if the order is disrupted, the plugging slurry may have a larger consistency, affecting the plugging effect.

[0061] The method for preparing a plugging agent is implemented based on the raw material components of the plugging agent. The specific steps of the raw material components of the plugging agent can refer to the above-mentioned embodiments. Since the method for preparing a plugging agent adopts part or all of the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0062] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0063] The present application example provides a plugging agent, and its raw material components are shown in Table 1.

[0064] Table 1 Raw material components of plugging agent (parts by weight)

[0065]

[0066]

[0067] The present application provides a method for preparing the above-mentioned plugging agent, the method comprising:

[0068] S11, under the action of the first stirring, adding a bridging material and calcium carbonate to the soil slurry to obtain a first suspension;

[0069] S21, adding an acid-soluble resin to the first suspension, and performing a second stirring to obtain a second suspension;

[0070] S31, adding fibers to the second suspension, and performing a third stirring to obtain a plugging agent. For specific process parameters, please refer to the following Examples 1 to 7.

[0071] Example 1

[0072] Add 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, and stir for 6 hours to obtain soil slurry.

[0073] Under mechanical stirring at 800 r / min, 80 parts by weight of calcium carbonate and 240 parts by weight of walnut shells were slowly added to the soil slurry, and stirred evenly for 4 hours to obtain a first suspension.

[0074] 110 parts by weight of furan resin were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 1 hour to obtain a second suspension.

[0075] 20 parts by weight of basalt fiber were added to the second suspension, and the mixture was stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0076] Example 2

[0077] Add 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, and stir for 6 hours to obtain soil slurry.

[0078] Under mechanical stirring at 800 r / min, 80 parts by weight of calcium carbonate, 120 parts by weight of walnut shells and 120 parts by weight of quartz sand were slowly added to the soil slurry and stirred evenly for 4 hours to obtain a first suspension.

[0079] 110 parts by weight of furan resin were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 1 hour to obtain a second suspension.

[0080] Add 20 parts by weight of basalt fiber to the second suspension, and stir at a stirring rate of 800 r / min for 2 hours to prepare a plugging agent.

[0081] Example 3

[0082] Add 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, and stir for 6 hours to obtain soil slurry.

[0083] Under mechanical stirring at 800 r / min, 80 parts by weight of calcium carbonate, 80 parts by weight of walnut shells, 80 parts by weight of quartz sand and 80 parts by weight of ceramsite were slowly added to the soil slurry and stirred evenly for 4 hours to obtain a first suspension.

[0084] 110 parts by weight of furan resin were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 1 hour to obtain a second suspension.

[0085] 20 parts by weight of basalt fiber were added to the second suspension, and the mixture was stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0086] Example 4

[0087] Add 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, and stir for 6 hours to obtain soil slurry.

[0088] Under mechanical stirring at 800 r / min, 80 parts by weight of calcium carbonate, 120 parts by weight of walnut shells and 120 parts by weight of quartz sand were slowly added to the soil slurry and stirred evenly for 4 hours to obtain a first suspension.

[0089] 110 parts by weight of furan resin were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 1 hour to obtain a second suspension.

[0090] 20 parts by weight of asbestos fiber were added to the second suspension, and the mixture was stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0091] Example 5

[0092] Step S1, adding 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, stirring for 6 hours to obtain soil slurry.

[0093] Step S2, under mechanical stirring at 800 r / min, slowly add 80 parts by weight of calcium carbonate, 120 parts by weight of walnut shells and 120 parts by weight of quartz sand to the above soil slurry, and stir evenly for 4 hours to obtain a first suspension.

[0094] 200 parts by weight of furan resin were added to the first suspension, and stirred at a stirring rate of 800 r / min for 1 hour.

[0095] 20 parts by weight of basalt fiber were added to the second suspension, and the mixture was stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0096] Example 6

[0097] Add 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, and stir for 6 hours to obtain soil slurry.

[0098] Under mechanical stirring at 800 r / min, 120 parts by weight of calcium carbonate and 310 parts by weight of walnut shells were slowly added to the soil slurry, and stirred evenly for 4 hours to obtain a first suspension.

[0099] 250 parts by weight of furan resin were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 1 hour to obtain a second suspension.

[0100] 40 parts by weight of basalt fiber were added to the second suspension, and stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0101] Example 7

[0102] Add 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, and stir for 6 hours to obtain soil slurry.

[0103] Under mechanical stirring at 800 r / min, 45 parts by weight of calcium carbonate and 170 parts by weight of walnut shells were slowly added to the soil slurry, and stirred evenly for 4 hours to obtain a first suspension.

[0104] 210 parts by weight of furan resin were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 1 hour to obtain a second suspension.

[0105] 11 parts by weight of basalt fiber were added to the second suspension, and the mixture was stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0106] Comparative Example 1

[0107] Step S1, adding 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, stirring for 6 hours to obtain soil slurry.

[0108] Step S2, slowly adding 80 parts by weight of calcium carbonate and 320 parts by weight of walnut shells to the soil slurry under mechanical stirring at 800 r / min, and stirring evenly for 4 hours to obtain a first suspension.

[0109] 20 parts by weight of basalt fiber were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0110] Comparative Example 2

[0111] Add 100 parts by weight of sodium-bentonite to 2000 parts by weight of clean water, and stir for 6 hours to obtain soil slurry.

[0112] Under mechanical stirring at 800 r / min, 80 parts by weight of calcium carbonate were slowly added to the soil slurry, and stirred evenly for 4 hours to obtain a first suspension.

[0113] 320 parts by weight of furan resin were added to the first suspension, and the mixture was stirred at a stirring rate of 800 r / min for 1 hour to obtain a second suspension.

[0114] 20 parts by weight of basalt fiber were added to the second suspension, and the mixture was stirred at a stirring rate of 800 r / min for 2 h to obtain a plugging agent.

[0115] The plugging agents of Examples 1 to 7 and Comparative Examples 1 to 2 were tested for their compressive strength performance. Please see Table 2 for the test results.

[0116] Table 2 Pressure bearing strength of plugging agent

[0117] Serial number Seam width / mm Compression strength / MPa Example 1 3 10 Example 2 3 11.5 Example 3 3 12 Example 4 3 12.5 Example 5 3 10.5 Example 6 3 8.5 Example 7 3 14 Comparative Example 1 3 4 Comparative Example 2 3 3.5

[0118] As shown in Table 2, the plugging agent provided by the embodiment of the present application has good pressure-bearing strength, thus having excellent plugging performance, and can achieve the purpose of effectively plugging crack pores. In Comparative Example 1, the content of bridging material is too much, no acid-soluble resin is added, and the pressure-bearing strength is small, indicating that the resin material plays an important role in its plugging performance, and the high concentration of the bridging material easily causes the door-sealing phenomenon; in Comparative Example 2, the content of acid-soluble resin is too much, no bridging material is added, and the pressure-bearing strength is small, indicating that the bridging material has an important influence on the pressure-bearing capacity, although resin, fiber, etc. can enter the crack, but due to the low strength, a stable plugging layer cannot be formed, and then the pressure-bearing capacity is relatively low, and its plugging performance can be effectively improved by compounding with the bridging material.

[0119] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A plugging agent, characterized in that: The raw material components of the plugging agent include: Acid-soluble resin, bridging material, calcium carbonate, soil slurry and fiber; wherein, relative to 100 parts by weight of the soil slurry, The acid-soluble resin is 5 to 12 parts by weight, the bridging material is 8 to 15 parts by weight, the calcium carbonate is 2 to 6 parts by weight, and the fiber is 0.5 to 2 parts by weight.

2. The plugging agent according to claim 1, characterized in that: With respect to 100 parts by weight of the soil slurry, the acid-soluble resin is 10 parts by weight, the bridging material is 8.1 parts by weight, the calcium carbonate is 2.1 parts by weight, and the fiber is 0.52 parts by weight.

3. The plugging agent according to claim 1, characterized in that: The acid-soluble resin includes at least one of the following: polyacrylic acid resin, phenolic resin, polyimide resin, and furan resin.

4. The plugging agent according to claim 1, characterized in that: The bridging material includes at least one of the following: walnut shell, quartz sand, ceramsite, calcite, and marble.

5. The plugging agent according to claim 1, characterized in that: The fiber includes at least one of the following: asbestos fiber, basalt fiber, carbon fiber.

6. The plugging agent according to claim 1, characterized in that: The soil raw material in the soil slurry includes at least one of the following: sodium-bentonite and calcium-bentonite.

7. The plugging agent according to claim 1 or 6, characterized in that: The mass fraction of the soil raw material in the soil slurry is 2% to 8%.

8. Use of the plugging agent according to claims 1 to 7 in oil drilling.

9. A method for preparing the plugging agent according to claims 1 to 7, characterized in that: The method comprises: Under the action of the first stirring, adding a bridging material and calcium carbonate into the soil slurry to obtain a first suspension; adding an acid-soluble resin to the first suspension, and performing a second stirring to obtain a second suspension; Fibers are added to the second suspension, and a third stirring is performed to obtain a plugging agent.

10. The method according to claim 9, characterized in that The first stirring rate is 600 r / min to 1000 r / min, the second stirring rate is 400 r / min to 800 r / min, and the third stirring rate is 400 r / min to 800 r / min.

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