Resin oil well plugging agent, oil well plugging liquid and preparation method and application thereof

Abstract

The invention provides a resin oil well plugging agent, an oil well plugging liquid and a preparation method and application thereof. The resin oil well plugging agent comprises resin, a cross-linking agent, a reinforcing agent and a curing accelerator, the resin comprises any one or a combination of at least two of phenolic resin, epoxy resin, urea resin, alkyd resin and melamine-formaldehyde resin; the resin oil well plugging agent has the characteristics of high temperature resistance and high strength through actual compounding design, and can effectively solve the problem of steam channeling of steam injection exploitation of heavy oil reservoirs at present, improve the steam absorption profile and improve the reserve utilization degree, thereby improving the recovery rate of steam injection exploitation of heavy oil reservoirs.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to a resin-based oil well plugging agent, an oil well plugging liquid, and a preparation method and application thereof. Background Art

[0002] At present, the main measure for exploiting heavy oil reservoirs is steam recovery. However, due to factors such as the difference in mobility between steam and heavy oil, the gravity overlap of steam, and the heterogeneity of the reservoir, in actual production, it is easy to cause steam fingering and steam channeling in the high permeability layer, thereby reducing the steam sweep volume, resulting in poor steam injection recovery effect and reducing the heavy oil thermal recovery rate. In order to solve the problem of steam channeling during steam flooding, it is necessary to perform high-temperature profile adjustment on the steam injection thermal recovery wells, inject high-temperature plugging agents into the steam thermal recovery wells, and effectively block the large channels of steam channeling, including high-permeability layers, dominant seepage channels or high-production layers, so that the injected steam can enter the low-permeability channels or reservoirs with poor utilization, so as to achieve the purpose of improving the steam absorption profile and increasing the utilization of reserves. Solving the problems of severe water discharge in oil fields and steam channeling in heavy oil production is of great practical significance for maintaining stable production in my country's oil fields.

[0003] CN114479792A discloses a plugging agent, an oil-based drilling fluid, a preparation method and a drilling method, which belong to the field of drilling. The plugging agent includes the following components in mass ratio: water, asphalt, a first emulsifier, rubber micropowder and barite powder; wherein the mass ratio of the water, the asphalt, the first emulsifier, the rubber micropowder and the barite powder is 100:10-37:2-4:10-45:3-15. The plugging agent provided in the embodiment of the present invention uses rubber micropowder and asphalt to provide deformable flexible particles, and uses barite powder to provide rigid particles, wherein the rigid particles can be used to form stable bridges; the flexible particles can be deformed under high temperature and high pressure conditions, and multiple components work synergistically, so that the plugging agent provided in the embodiment of the present invention obtains a better plugging effect.

[0004] CN115247052A discloses an oil-based drilling fluid plugging agent and a preparation method thereof, belonging to the field of petrochemical industry. The preparation method of the oil-based drilling fluid plugging agent comprises: reacting divinyldimethylsilane and diphenylchloromethane in the presence of a catalyst and an initiator to obtain a crosslinking agent; mixing the crosslinking agent, emulsifier, high temperature resistant monomer, ester monomer, and polyene monomer evenly to form a pre-emulsion; in the presence of an initiator, polymerizing the pre-emulsion to obtain an oil-based drilling fluid plugging agent; the high temperature resistant monomer is selected from at least one of styrene, 2-acrylamido-2-methylpropane sulfonic acid, sodium styrene sulfonate, and N-vinyl pyrrolidone. The preparation method can prepare a plugging agent with excellent high temperature resistance and plugging properties. When used in an oil-based drilling fluid, it can be applied to ultra-deep oil and gas drilling, and is applicable to heterogeneous reservoirs containing more cracks and pores.

[0005] CN116063994A discloses a high-efficiency plugging agent for drilling fluid and a preparation method thereof. The plugging agent comprises a rigid material, a flexible material and an amphiphilic polyurethane elastomer; wherein the rigid material comprises silicon dioxide and / or titanium dioxide; and the flexible material comprises a reaction product of paraffin, fatty alcohol polyoxyethylene ether, polyethylene glycol, starch, stearic acid and calcium carbonate. The preparation method of the plugging agent comprises the following steps: mixing the rigid material, the flexible material and the amphiphilic polyurethane elastomer at 70-100°C for a period of time to obtain the plugging agent. The plugging agent provided by the present invention is a plugging agent that takes both rigidity and flexibility into consideration, which has both the good supporting force of a rigid plugging agent and the deformability and softness of a flexible material, as well as better resilience and better fit with rock cracks.

[0006] However, the oil well plugging agents disclosed in the prior art are degraded after plugging heavy oil wells with steam injection, resulting in problems such as short plugging validity period and poor plugging effect. It is necessary to develop a new type of resin oil well plugging agent, oil well plugging fluid and its preparation method and application. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a resin-based oil well plugging agent, an oil well plugging fluid, and a preparation method and application thereof. The resin-based oil well plugging agent comprises a resin, a cross-linking agent, a reinforcing agent, and a curing accelerator; the resin comprises any one of phenolic resin, epoxy resin, urea-formaldehyde resin, alkyd resin, and melamine-formaldehyde resin, or a combination of at least two thereof; the resin-based oil well plugging agent is compounded and designed based on actual conditions, and has the characteristics of high temperature resistance and high strength, and can effectively solve the current problem of steam channeling in steam injection production of heavy oil reservoirs, improve the steam absorption profile, and increase the degree of reserve utilization, thereby improving the recovery rate of steam injection production of heavy oil reservoirs.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] One of the purposes of the present invention is to provide a resin-based oil well plugging agent, which includes a resin, a cross-linking agent, a reinforcing agent and a curing accelerator; the resin includes any one of phenolic resin, epoxy resin, urea-formaldehyde resin, alkyd resin, and melamine-formaldehyde resin, or a combination of at least two of them.

[0010] In the resin-based oil well plugging agent of the present invention, on the one hand, the resin can form a three-dimensional network structure under the action of a cross-linking agent, with high strength and good stability, and the resin is easy to inject and has a sufficiently high strength to plug pores, cracks, holes, channeling grooves and blast holes; on the other hand, the resin is neutral after curing and does not react with downhole liquid, so it has a long effective period.

[0011] The resin oil well plugging agent of the present invention has the characteristics of high temperature resistance and high strength through actual compound design, can effectively solve the problems of severe water discharge in oil fields and steam channeling in heavy oil production, can greatly increase the area affected by steam injection in heavy oil wells, improve steam utilization rate, and improve the recovery rate of heavy oil wells.

[0012] It is worth noting that, in the resin-based oil well plugging agent of the present invention, the resin includes any one of phenolic resin, epoxy resin, urea-formaldehyde resin, alkyd resin, and melamine-formaldehyde resin, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of phenolic resin and epoxy resin, a combination of epoxy resin and urea-formaldehyde resin, a combination of urea-formaldehyde resin and alkyd resin, or a combination of alkyd resin and melamine-formaldehyde resin, etc.

[0013] As a preferred technical solution of the present invention, the resin oil well plugging agent comprises, by mass percentage, 79-85% of resin, such as 79%, 80%, 81%, 82%, 83%, 84% or 85%, etc., 0.5-1.5% of cross-linking agent, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4% or 1.5%, etc., and 10-15% of reinforcing agent, such as 1 0%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5% or 15%, etc.; curing accelerator 3-5%, for example 3%, 3.1%, 3.3%, 3.5%, 3.7%, 3.8%, 4%, 4.2%, 4.4%, 4.5%, 4.7%, 4.9% or 5%, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0014] As a preferred technical solution of the present invention, the cross-linking agent includes any one of dibasic acid, polyol, divinylbenzene, diisocyanate, N,N-methylenebisacrylamide or a combination of at least two thereof. Typical but non-limiting examples of the combination include: a combination of dibasic acid and polyol, a combination of polyol and divinylbenzene, a combination of divinylbenzene and diisocyanate, or a combination of diisocyanate and N,N-methylenebisacrylamide, etc.

[0015] In the resin-based oil well plugging agent of the present invention, the linear molecules of the resin generate chemical bonds after adding a cross-linking agent, so that the linear molecules are connected to each other to form a network structure, which can greatly improve the strength and elasticity of the molecular material and can greatly improve the heat resistance and strength of the resin.

[0016] As a preferred technical solution of the present invention, the reinforcing agent includes any one of light calcium carbonate, microsilica or fly ash, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of light calcium carbonate and microsilica, a combination of microsilica and fly ash, or a combination of light calcium carbonate and fly ash, etc.

[0017] In the resin-based oil well plugging agent of the present invention, the reinforcing agent can not only make the resin material closely connected to achieve good mechanical strength, but also improve the dispersibility of the resin and the fluidity of the resin system.

[0018] As a preferred technical solution of the present invention, the curing accelerator includes an inorganic salt curing accelerator and / or an organic curing accelerator.

[0019] Preferably, the organic curing accelerator comprises any one of aliphatic amines, aromatic amines, modified amines or low molecular weight polyamides, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of aliphatic amines and aromatic amines, a combination of aromatic amines and modified amines, a combination of modified amines and low molecular weight polyamides, or a combination of aliphatic amines and low molecular weight polyamides, etc.

[0020] In the resin-based oil well plugging agent of the present invention, the curing accelerator can accelerate the curing speed of the resin and improve the curing rate.

[0021] A second object of the present invention is to provide an oil well plugging fluid, which comprises the resin oil well plugging agent according to one of the objects and water, and the mass ratio of the two is 1:10-15, for example, 1:10, 1:10.5, 1:11, 1:11.5, 1:12, 1:12.5, 1:13, 1:13.5, 1:14, 1:14.5 or 1:15, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0022] The third object of the present invention is to provide a method for preparing an oil well plugging fluid, wherein the resin oil well plugging agent described in the first object is mixed with water evenly, and the preparation method comprises the following steps: firstly, the resin and the cross-linking agent are added into water and dispersed evenly, and then the reinforcing agent and the curing accelerator are added and dispersed evenly; the resin comprises any one of phenolic resin, epoxy resin, urea-formaldehyde resin, alkyd resin, and melamine-formaldehyde resin, or a combination of at least two thereof.

[0023] In actual use, the oil well plugging fluid of the present invention is often prepared by mixing a resin oil well plugging agent with water.

[0024] As a preferred technical solution of the present invention, the preparation method comprises the following steps: under stirring conditions, firstly, adding the resin and the cross-linking agent into water and dispersing them evenly, and continuing to stir for 10-20 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, etc.; under stirring conditions, then adding the reinforcing agent and the curing accelerator and dispersing them evenly, and continuing to stir for 25-35 minutes, for example, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes or 35 minutes, etc., but it is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0025] A fourth object of the present invention is to provide an application of an oil well plugging fluid, wherein the oil well plugging fluid described in the second object, or the oil well plugging fluid prepared by the preparation method described in the third object, is applied to steam oil production.

[0026] As a preferred technical solution of the present invention, the application method includes the following steps: selecting a target well suitable for plugging, pre-injecting nitrogen foam water into the target well, injecting the oil well plugging fluid, injecting nitrogen again, and pushing the oil well plugging fluid to a remote well area to form a plug.

[0027] Specifically, the application method comprises the following steps:

[0028] (1) Selecting target wells for plugging based on RS optimization decision-making method: Based on the RS optimization decision-making method, factors such as wellhead pressure index, apparent water absorption index, water absorption profile, permeability variation coefficient, remaining oil reserves, recovery degree, average water content, and liquid production are considered, and the decision factors are calculated using a multi-factor formula. The target wells suitable for water plugging are selected based on the calculation results.

[0029] (2) Injecting nitrogen foam: Injecting nitrogen foam into the target well in advance to push water. Using high-pressure nitrogen foam non-miscible drive, the water near the wellbore is pushed away, the formation pressure is maintained to slow down the coning of bottom water, and at the same time, the dilution of the subsequent injection of plugging agents by the formation water is reduced;

[0030] (3) Injecting oil well plugging fluid: A resin-based oil well plugging agent is mixed evenly with water to obtain an oil well plugging fluid, which is prepared on site and injected into the target well;

[0031] (4) Inject nitrogen again to expand the plugging radius: Inject nitrogen into the target well again to push the plugging fluid to the far well area to form a plug and expand the plugging radius;

[0032] (5) Stew well;

[0033] (6) Start well production.

[0034] The resin-based oil well plugging agent of the present invention includes resin, cross-linking agent, reinforcing agent and curing accelerator. Through actual compound design, it has the characteristics of high temperature resistance and high strength, can effectively plug water-producing layers, dominant seepage channels, etc., realize effective displacement of subsequent steam injection, and increase the swept volume.

[0035] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0036] The resin-based oil well plugging agent of the present invention has the characteristics of high temperature resistance and high strength through actual compound design, and can effectively plug large steam channeling pores, including high permeability layers, dominant seepage channels or high production layers, so that the injected steam can enter low permeability channels or reservoirs with poor production, thereby achieving the purpose of improving the steam absorption profile and increasing the production degree of reserves. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of the method for applying oil well plugging fluid in field application example 1. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0039] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0040] The simulated water used in the examples of the present invention and the comparative examples is water with a mineralization of 2000 mg / L.

[0041] Example 1 Indoor preparation of oil well plugging fluid

[0042] The present embodiment provides a resin-based oil well plugging agent, which includes a resin, a cross-linking agent, a reinforcing agent, and a curing accelerator; the specific formula of the resin-based oil well plugging agent is as follows, in terms of mass percentage: 40% phenolic resin, 40% alkyd resin, 1% N,N-methylenebisacrylamide, 10% light calcium carbonate, 5% fly ash, 2% sodium carbonate, and 2% sodium hydroxide;

[0043] This embodiment also provides an oil well plugging fluid, which is composed of the above-mentioned resin oil well plugging agent and water, and the mass ratio of the two is 1:12;

[0044] The present embodiment also provides a preparation method of an oil well plugging fluid, which comprises the following steps: taking 300 g of simulated water into a 500 mL beaker, and slowly adding 10 g of phenolic resin, 10 g of alkyd resin, and 0.25 g of N,N-methylenebisacrylamide under stirring conditions to make them evenly dispersed, and continuing to stir for 15 minutes; under stirring conditions, adding 2.5 g of light calcium carbonate, 1.25 g of fly ash, 0.5 g of sodium carbonate, and 0.5 g of sodium hydroxide in sequence to make them evenly dispersed, and continuing to stir for 30 minutes; then sealing the beaker and placing it in a constant temperature water bath, setting the temperature to 100°C, and recording the initial setting time and the final setting time of curing.

[0045] Application Example 1 Sand filling pipe plugging experiment

[0046] Fill the stainless steel tube with quartz sand, evacuate and saturate it with simulated water. The filling and evaluation methods refer to the petroleum and natural gas industry standard SY / T5345-2007 "Method for Determining Relative Permeability of Two-Phase Fluids in Rocks". The initial porosity of the sand-filled tube is 30%, and the water permeability is 2.0D.

[0047] Plugging and scour resistance test. Prepare the oil well plugging fluid according to Example 1, seal the sand-filled pipe filled with the oil well plugging fluid, wait for condensation at 100°C for 24 hours, and then install it into the displacement equipment. After keeping the temperature at 100°C for 20 minutes, use simulated water at a displacement rate of 1mL / min to displace. When the first drop of liquid appears at the outlet, record the breakthrough pressure. Continue water flooding to 2PV, record the pressure difference at both ends of the sand-filled pipe, and calculate the liquid permeability K. n Compare the changes in the liquid permeability of the sand-filled pipe after flushing, and calculate the core plugging rate E according to the following formula.

[0048] E=(K0-K n ) / K0

[0049] Where, K0—permeability before plugging, mD; K n —Permeability after plugging, mD

[0050] Field application example 1

[0051] Liaohe Oilfield X32-Xing HX was put into production on May 21, 2008, with a well section of 1240-1507m and a production well section of 267m. It has been produced for 7 cycles, with a cumulative oil production of 8912t and a cumulative water production of 47268m 3 In January 2017, the well was shut down due to high water content. In the early stage, segmented steam injection and profile adjustment were implemented, and in the later stage, selective injection and production were implemented, but the effect was not obvious.

[0052] The oil well plugging fluid was re-prepared according to Example 1 and used immediately for steam oil recovery. Figure 1 As shown, the application method comprises the following steps:

[0053] (1) Selecting target wells for plugging based on RS optimization decision-making method: Based on the RS optimization decision-making method, factors such as wellhead pressure index, apparent water absorption index, water absorption profile, permeability variation coefficient, remaining oil reserves, recovery degree, average water content, and liquid production are considered, and the decision factors are calculated using a multi-factor formula. The target wells suitable for water plugging are selected based on the calculation results.

[0054] (2) Injecting nitrogen foam: Injecting nitrogen foam into the target well in advance to push water. Using high-pressure nitrogen foam non-miscible drive, the water near the wellbore is pushed away, the formation pressure is maintained to slow down the coning of bottom water, and at the same time, the dilution of the subsequent injection of plugging agents by the formation water is reduced;

[0055] (3) Injecting oil well plugging fluid: A resin-based oil well plugging agent is mixed evenly with water to obtain an oil well plugging fluid, which is prepared on site and injected into the target well;

[0056] (4) Inject nitrogen again to expand the plugging radius: Inject nitrogen into the target well again to push the plugging fluid to the far well area to form a plug and expand the plugging radius;

[0057] (5) Stew well;

[0058] (6) Start well production.

[0059] The well was plugged using the above-mentioned method and a total of 150,000 cubic meters of nitrogen and 1,200 cubic meters of oil well plugging fluid were injected. After the measures were taken, the well produced for a total of 426 days, with a cumulative increase of more than 4,000 tons of oil production, and a significant production increase effect.

[0060] Example 2

[0061] This embodiment provides a resin-based oil well plugging agent. Compared with the resin-based oil well plugging agent described in Example 1, the only difference is that, measured by mass percentage, the specific formula of the resin-based oil well plugging agent is: 30% phenolic resin, 30% alkyd resin, 1% N,N-methylenebisacrylamide, 20% light calcium carbonate, 15% fly ash, 2% sodium carbonate, and 2% sodium hydroxide.

[0062] This embodiment also provides an oil well plugging fluid, which is composed of the above-mentioned resin oil well plugging agent and water, and the mass ratio of the two is 1:12;

[0063] The present embodiment also provides a method for preparing an oil well plugging fluid, which comprises the following steps: taking 300 g of simulated water into a 500 mL beaker, and slowly adding 7.5 g of phenolic resin, 7.5 g of alkyd resin, and 0.25 g of N,N-methylenebisacrylamide under stirring conditions to make them evenly dispersed, and continuing to stir for 15 minutes; under stirring conditions, adding 5.0 g of light calcium carbonate, 3.75 g of fly ash, 0.5 g of sodium carbonate, and 0.5 g of sodium hydroxide in sequence to make them evenly dispersed, and continuing to stir for 30 minutes; then sealing the beaker and placing it in a constant temperature water bath, setting the temperature to 100°C, and recording the initial setting time and the final setting time of curing.

[0064] Example 3

[0065] This embodiment provides a resin-based oil well plugging agent. Compared with the resin-based oil well plugging agent described in Example 1, the only difference is that, measured by mass percentage, the specific formula of the resin-based oil well plugging agent is: 45% phenolic resin, 45% alkyd resin, 1% N,N-methylenebisacrylamide, 3% light calcium carbonate, 2% fly ash, 2% sodium carbonate, and 2% sodium hydroxide.

[0066] This embodiment also provides an oil well plugging fluid, which is composed of the above-mentioned resin oil well plugging agent and water, and the mass ratio of the two is 1:12;

[0067] The present embodiment also provides a preparation method of an oil well plugging fluid, which comprises the following steps: taking 300 g of simulated water into a 500 mL beaker, and slowly adding 11.25 g of phenolic resin, 11.25 g of alkyd resin, and 0.25 g of N,N-methylenebisacrylamide under stirring conditions to make them evenly dispersed, and continuing to stir for 15 minutes; under stirring conditions, adding 0.75 g of light calcium carbonate, 0.5 g of fly ash, 0.5 g of sodium carbonate, and 0.5 g of sodium hydroxide in sequence to make them evenly dispersed, and continuing to stir for 30 minutes; then sealing the beaker and placing it in a constant temperature water bath, setting the temperature to 100°C, and recording the initial setting time and the final setting time of curing.

[0068] Example 4

[0069] This embodiment provides a resin-based oil well plugging agent. Compared with the resin-based oil well plugging agent described in Example 1, the only difference is that, measured in percentage by mass, the specific formula of the resin-based oil well plugging agent is: 40% phenolic resin, 40% alkyd resin, 2% N,N-methylenebisacrylamide, 10% light calcium carbonate, 5% fly ash, 1% sodium carbonate, and 2% sodium hydroxide.

[0070] This embodiment also provides an oil well plugging fluid, which is composed of the above-mentioned resin oil well plugging agent and water, and the mass ratio of the two is 1:12;

[0071] The present embodiment also provides a preparation method of an oil well plugging fluid, which comprises the following steps: taking 300 g of simulated water into a 500 mL beaker, and slowly adding 10 g of phenolic resin, 10 g of alkyd resin, and 0.5 g of N,N-methylenebisacrylamide under stirring conditions to make them evenly dispersed, and continuing to stir for 15 minutes; under stirring conditions, adding 2.5 g of light calcium carbonate, 1.25 g of fly ash, 0.25 g of sodium carbonate, and 0.5 g of sodium hydroxide in sequence to make them evenly dispersed, and continuing to stir for 30 minutes; then sealing the beaker and placing it in a constant temperature water bath, setting the temperature to 100°C, and recording the initial setting time and the final setting time of curing.

[0072] Example 5

[0073] This embodiment provides a resin-based oil well plugging agent. Compared with the resin-based oil well plugging agent described in Example 1, the only difference is that, measured by mass percentage, the specific formula of the resin-based oil well plugging agent is: 40% phenolic resin, 40% alkyd resin, 1% N,N-methylenebisacrylamide, 11% light calcium carbonate, 5% fly ash, 1% sodium carbonate, and 2% sodium hydroxide.

[0074] This embodiment also provides an oil well plugging fluid, which is composed of the above-mentioned resin oil well plugging agent and water, and the mass ratio of the two is 1:12;

[0075] The present embodiment also provides a method for preparing an oil well plugging fluid, which comprises the following steps: taking 300 g of simulated water into a 500 mL beaker, and slowly adding 10 g of phenolic resin, 10 g of alkyd resin, and 0.25 g of N,N-methylenebisacrylamide under stirring conditions to make them evenly dispersed, and continuing to stir for 15 minutes; under stirring conditions, adding 2.75 g of light calcium carbonate, 1.25 g of fly ash, 0.25 g of sodium carbonate, and 0.5 g of sodium hydroxide in sequence to make them evenly dispersed, and continuing to stir for 30 minutes; then sealing the beaker and placing it in a constant temperature water bath, setting the temperature to 100°C, and recording the initial setting time and the final setting time of curing.

[0076] Example 6

[0077] This embodiment provides a resin-based oil well plugging agent. Compared with the resin-based oil well plugging agent described in Example 1, the only difference is that, measured in percentage by mass, the specific formula of the resin-based oil well plugging agent is: 40% phenolic resin, 40% alkyd resin, 1% N,N-methylenebisacrylamide, 9% light calcium carbonate, 4% fly ash, 3% sodium carbonate, and 3% sodium hydroxide.

[0078] This embodiment also provides an oil well plugging fluid, which is composed of the above-mentioned resin oil well plugging agent and water, and the mass ratio of the two is 1:12;

[0079] The present embodiment also provides a preparation method of an oil well plugging fluid, which comprises the following steps: taking 300 g of simulated water into a 500 mL beaker, and slowly adding 10 g of phenolic resin, 10 g of alkyd resin, and 0.25 g of N,N-methylenebisacrylamide under stirring conditions to make them evenly dispersed, and continuing to stir for 15 minutes; under stirring conditions, adding 2.25 g of light calcium carbonate, 1 g of fly ash, 0.75 g of sodium carbonate, and 0.75 g of sodium hydroxide in sequence to make them evenly dispersed, and continuing to stir for 30 minutes; then sealing the beaker and placing it in a constant temperature water bath, setting the temperature to 100°C, and recording the initial setting time and the final setting time of curing.

[0080] Comparative Example 1

[0081] This comparative example provides a resin-based oil well plugging agent, which is different from the resin-based oil well plugging agent in Example 1 in that the cross-linking agent is completely omitted and replaced with an enhancer of equal mass; specifically, the resin-based oil well plugging agent comprises a resin, an enhancer and a curing accelerator; in terms of mass percentage, the specific formula of the resin-based oil well plugging agent is: 40% phenolic resin, 40% alkyd resin, 11% light calcium carbonate, 5% fly ash, 2% sodium carbonate, and 2% sodium hydroxide;

[0082] This comparative example also provides an oil well plugging fluid, which is composed of the above-mentioned resin oil well plugging agent and water, and the mass ratio of the two is 1:12;

[0083] This comparative example also provides a preparation method of an oil well plugging fluid, which comprises the following steps: taking 300 g of simulated water into a 500 mL beaker, slowly adding 10 g of phenolic resin and 10 g of alkyd resin under stirring conditions to make them evenly dispersed, and continuing to stir for 15 minutes; under stirring conditions, sequentially adding 2.75 g of light calcium carbonate, 1.25 g of fly ash, 0.5 g of sodium carbonate, and 0.5 g of sodium hydroxide to make them evenly dispersed, and continuing to stir for 30 minutes; then sealing the beaker and placing it in a constant temperature water bath, setting the temperature to 100°C, and recording the initial setting time and the final setting time of curing.

[0084] The initial setting time and final setting time of solidification obtained in the above Examples 1-6 and Comparative Example 1 are summarized in Table 1. The oil well plugging fluids prepared indoors in Examples 2-6 and Comparative Example 1 were subjected to sand filling pipe plugging experiments according to the sand filling pipe plugging experiment described in Application Example 1, and the calculated core plugging rates E are also summarized in Table 1.

[0085] Table 1

[0086] project Initial setting time of curing (h) Final setting time (h) Core plugging rate E(%) Example 1 16 24 95 Example 2 16 24 90 Example 3 16 24 87 Example 4 16 25 92 Example 5 18 26 93 Example 6 12 22 88 Comparative Example 1 24 48 75

[0087] In summary, the resin-based oil well plugging agent of the present invention has the characteristics of high temperature resistance and high strength through actual compound design, and can effectively plug large steam channeling pores, including high permeability layers, dominant seepage channels or high production layers, so that the injected steam can enter low permeability channels or reservoirs with poor production, thereby achieving the purpose of improving the steam absorption profile and increasing the production degree of reserves.

[0088] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0089] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0091] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A resin-based oil well plugging agent, characterized in that: The resin-based oil well plugging agent comprises resin, a cross-linking agent, a reinforcing agent and a curing accelerator; the resin comprises any one of phenolic resin, epoxy resin, urea-formaldehyde resin, alkyd resin and melamine-formaldehyde resin or a combination of at least two thereof.

2. The resin-based oil well plugging agent according to claim 1, characterized in that: The resin-based oil well plugging agent comprises, by weight percentage, 79-85% of resin, 0.5-1.5% of cross-linking agent, 10-15% of reinforcing agent and 3-5% of curing accelerator.

3. The resin-based oil well plugging agent according to claim 1 or 2, characterized in that: The crosslinking agent includes any one of dibasic acid, polyol, divinylbenzene, diisocyanate, and N,N-methylenebisacrylamide, or a combination of at least two thereof.

4. The resin-based oil well plugging agent according to any one of claims 1 to 3, characterized in that: The reinforcing agent includes any one of light calcium carbonate, microsilica powder or fly ash, or a combination of at least two of them.

5. The resin-based oil well plugging agent according to any one of claims 1 to 4, characterized in that: The curing accelerator includes an inorganic salt curing accelerator and / or an organic curing accelerator; Preferably, the organic curing accelerator includes any one of aliphatic amine, aromatic amine, modified amine or low molecular weight polyamide, or a combination of at least two thereof.

6. An oil well plugging fluid, characterized in that: The oil well plugging fluid comprises the resin oil well plugging agent according to any one of claims 1 to 5 and water, and the mass ratio of the two is 1:10-15.

7. A method for preparing an oil well plugging fluid, characterized in that: The resin oil well plugging agent according to any one of claims 1 to 5 is mixed with water evenly, and the preparation method comprises the following steps: firstly, the resin and the cross-linking agent are added into water and dispersed evenly, and then the reinforcing agent and the curing accelerator are added and dispersed evenly; the resin comprises any one of phenolic resin, epoxy resin, urea-formaldehyde resin, alkyd resin, and melamine-formaldehyde resin, or a combination of at least two thereof.

8. The preparation method according to claim 7, characterized in that: The preparation method comprises the following steps: firstly, adding the resin and the crosslinking agent into water and dispersing them uniformly under stirring conditions, and continuing to stir for 10-20 minutes; then, adding the reinforcing agent and the curing accelerator and dispersing them uniformly under stirring conditions, and continuing to stir for 25-35 minutes.

9. An application of an oil well plugging fluid, characterized in that: The oil well plugging fluid according to claim 6, or the oil well plugging fluid prepared by the preparation method according to claim 7 or 8, is applied to steam oil production.

10. The use according to claim 9, characterized in that: The application method comprises the following steps: selecting a target well suitable for plugging, pre-injecting nitrogen foam water-pushing into the target well, injecting the oil well plugging fluid, injecting nitrogen again, and pushing the oil well plugging fluid to a remote well area to form a plug.

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