A low-viscosity solvent-free epoxy resin gelling material, a preparation method and application thereof

Abstract

The application provides a low-viscosity solvent-free epoxy resin gelling material and a preparation method and application thereof. The solvent-free epoxy resin gelling material comprises the following components in parts by weight: 100 parts by weight of solvent-free modified epoxy resin, 5-100 parts by weight of a curing agent, 5-40 parts by weight of a viscosity regulator, 0.2-5 parts by weight of a curing regulator, 0-20 parts by weight of a toughening material and 0.1-1 parts by weight of a defoaming agent. The gelling material has low viscosity, a wide applicable temperature range, high strength and low elastic modulus, excellent mechanical properties, good toughness, good corrosion resistance, aging resistance and other abilities, and good sealing ability for cement ring microcracks, and can meet the annular pressure management requirements under complex working conditions such as deep and ultra-deep wells, complex natural gas wells, gas storage wells and CCUS wells, and has a wide application market.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well drilling, completion and downhole maintenance technology, and relates to a low-viscosity solvent-free epoxy resin cementing material, its preparation method and application. Background Technology

[0002] With my country's energy demand continuously increasing, the exploration and development of oil and gas resources is gradually moving towards deep and ultra-deep formations, natural gas, and unconventional energy sources. The number of natural gas wells and deep and ultra-deep wells is increasing daily, while unconventional oil and gas wells such as gas storage wells and carbon dioxide sealed-up (CCUS) wells are also developing rapidly. Various oil and gas wells face diverse downhole environments, including complex underground conditions, high formation pressure, easy gas escape, and corrosion from acidic gases (hydrogen sulfide, carbon dioxide). This leads to the formation of micro-annular gaps at the cement sheath interface and micro-cracks in the cement sheath itself, reducing the sealing capacity of the cement sheath and consequently causing increasingly prominent annular pressure problems, posing a severe challenge to the sealing integrity of the wellbore.

[0003] Annular pressure can have numerous adverse effects on oil and gas wells. Severe annular pressure not only affects the safe extraction of oil and gas, but if not effectively controlled, it can also lead to safety accidents such as well blowouts. Therefore, the treatment of annular pressure in oil and gas wells is essential, and there is an urgent need to develop new cementitious sealing material systems to improve the sealing capability of the wellbore throughout its entire life cycle. Currently, research on annular pressure treatment mainly focuses on expandable packers, the construction of self-healing cement slurry systems, and the optimization of cementing processes. Traditional cement slurries contain a large number of solid particles, making it difficult to penetrate into the micro-annulus and micro-cracks of the cement annulus, and the sealing strength cannot meet the requirements for long-term sealing, thus failing to form an efficient cementitious sealing material system. Therefore, researchers at home and abroad are committed to developing new wellbore sealing materials to improve the sealing effect of micro-annulus and micro-cracks in the cement annulus.

[0004] Due to its good fluidity, strong micro-annular injection capability, high compressive strength, and good toughness, resin materials are gradually becoming a good alternative for plugging leaks in oil and gas wells. CN 110016327 A discloses an oil and gas well plugging material composed of bisphenol A type epoxy resin, phenolic epoxy resin, viscosity modifier, curing agent, and accelerator. The thickening time is 120-260 min, and the compressive strength reaches 65-87.5 MPa. However, this technology requires curing at 60-80℃, resulting in a narrow applicable temperature range. Furthermore, the viscosity value of the plugging material is not described, making it impossible to determine its sealing ability against micro-annular gaps and micro-cracks in the cement sheath. Zhao Qingchen et al. prepared bisphenol A type epoxy resin DGEBA using epoxy resin, tackifier and curing agent as raw materials. The curing time of DGEBA is adjustable within 3-6 hours. The compressive strength of the cured body is greater than 40MPa and the sealing pressure exceeds 30MPa, which meets the requirements of shallow casing plugging. However, only a material suitable for one temperature environment has been developed, the applicable temperature range is small, and the curing time needs to be further improved to extend the on-site construction time. At present, this material cannot adapt to the complex working conditions of different regions and different wells.

[0005] While existing technologies, represented by the aforementioned patents and literature, have developed novel resin-based gelling sealants with plugging capabilities, these sealants still have certain limitations: First, the viscosity of resin-based gelling sealants needs to be further reduced to enhance their ability to penetrate micro-annular gaps and micro-cracks in the cement sheath; second, the overall performance of the thickening time of the gelling material needs to be improved to extend its on-site construction performance; and third, the compressive strength and elastic modulus of the cured gelling sealant need further optimization to meet the requirements for wellbore integrity under various complex working conditions.

[0006] Therefore, in order to solve the annular pressure problem of complex oil and gas wells such as natural gas wells, gas storage wells and CCUS wells, ensure the bonding quality of the cement sheath interface, and improve the long-term sealing capability of the wellbore, it is of great significance to develop a new type of low-viscosity solvent-free epoxy resin cementing material. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a low-viscosity solvent-free epoxy resin cementitious material, its preparation method, and its application.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] On one hand, the present invention provides a solvent-free epoxy resin cementitious material, the solvent-free epoxy resin cementitious material comprising the following components in parts by weight:

[0010]

[0011] The solvent-free epoxy resin cementitious material of this invention uses solvent-free modified epoxy resin, which reduces the viscosity of the material. Furthermore, the use of a curing agent and a viscosity modifier works synergistically to adjust the viscosity and strength of the cementitious material, resulting in a viscosity of 50-800 mPa·s, a wide applicable temperature range (20-90℃), and characteristics of high strength and low elastic modulus. After curing, the compressive strength is greater than 16 MPa after 24 hours, greater than 35 MPa after 48 hours, and the elastic modulus is less than 5 GPa after 24 hours. It exhibits excellent mechanical properties, good toughness, and good sealing ability for micro-cracks in the cement sheath. It can meet the requirements for annular pressure treatment under complex conditions such as deep wells, ultra-deep wells, complex natural gas wells, gas storage wells, and CCUS wells, effectively ensuring the sealing integrity of the wellbore throughout its entire life cycle.

[0012] Preferably, the solvent-free modified epoxy resin is one or a combination of at least two of bisphenol A type E-51 epoxy resin or E-44 epoxy resin modified with reactive diluent. Using a solvent-free modified epoxy resin results in materials with low viscosity and stable performance.

[0013] Preferably, the active diluent is selected from any one or a combination of at least two of alkylene glycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

[0014] Preferably, the curing agent is selected from any one or a combination of at least two of aliphatic polyamines, aromatic polyamines, polyamides, polythiols, or polyanhydrides, with aliphatic polyamines being the most preferred.

[0015] Preferably, the aliphatic polyamine is selected from any one or a combination of at least two of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N,N-diethylaminopropylamine, and galvanic diamine;

[0016] Preferably, the aromatic polyamine is selected from any one or a combination of at least two of m-phenylenediamine, 4,4-diaminodiphenylmethane, 4,4-diaminodiphenyl sulfone, or m-phenylenediamine;

[0017] Preferably, the polybasic anhydride includes, but is not limited to, any one or a combination of at least two of phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadichotomous methyl anhydride, chlorogenic anhydride, or pyromellitic anhydride.

[0018] In this invention, the amount of curing agent used is 5 parts by weight, 8 parts by weight, 10 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, or 80 parts by weight.

[0019] Preferably, the tackifier is a tackifier containing epoxy groups and / or benzene rings, which has good curing activity. Preferably, the tackifier is selected from any one or a combination of at least two of phenyl glycidyl ether, benzyl glycidyl ether, cashew phenolic glyceryl ether, or epoxidized soybean oil.

[0020] In this invention, the amount of the viscosity modifier is 5 parts by weight, 8 parts by weight, 10 parts by weight, 20 parts by weight, 30 parts by weight, or 40 parts by weight.

[0021] Preferably, the curing modifier is selected from any one or a combination of at least two of the following: triethylamine, triethanolamine, o-hydroxybenzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, benzyl dimethylamine, N-(2-hydroxyphenyl)-N',N'-dimethylurea, phenol, resorcinol, o-cresol, nonylphenol, boron trifluoride complex, tertiary amines, imidazoles, or metal salts of acetylacetone.

[0022] In this invention, the amount of the curing regulator is 0.2 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, or 5 parts by weight.

[0023] Preferably, the toughening material is selected from any one or a combination of at least two of cage-type polysilsesquioxane (POSS), nano-silica, microsilica, hollow glass microspheres or cenospheres, and the cage-type polysilsesquioxane (POSS) includes, but is not limited to, octacyclooxycyclohexylethyl-POSS, glycidyl etheroxypropyl-POSS, glycidyl etheroxypropylcyclotetrasiloxane, octaphenyl-POSS, octaoctyl-POSS, dimethylsiloxy-POSS or octaphenylaminopropyl-POSS.

[0024] In this invention, the amount of the toughening material is 0 parts by weight, 1 part by weight, 3 parts by weight, 5 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 15 parts by weight, 18 parts by weight, or 20 parts by weight.

[0025] Preferably, the defoamer is selected from polyether defoamers, silicone defoamers and their modified materials, including but not limited to polysiloxanes, modified polysiloxanes, polyether-modified silicones, and hydroxyl polydimethylsiloxanes;

[0026] In this invention, the amount of the defoamer is 0.1 parts by weight, 0.3 parts by weight, 0.5 parts by weight, 0.8 parts by weight, or 1 part by weight.

[0027] The solvent-free epoxy resin gelling material of the present invention can be used in an environment of 20-90°C (e.g., 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 60°C, 70°C, 80°C or 90°C).

[0028] On the other hand, the present invention provides a method for preparing the solvent-free epoxy resin cementitious material as described above, the method comprising the following steps:

[0029] The solvent-free modified epoxy resin, curing agent, tackifier, curing regulator, toughening material and defoamer are mixed to obtain the solvent-free epoxy resin gelling material.

[0030] Preferably, the mixing is carried out at a rotational speed of 200-1000 r / min (e.g., 200 r / min, 230 r / min, 250 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, 800 r / min, 900 r / min or 1000 r / min).

[0031] Preferably, the mixing time is 5-20 min, for example 5 min, 8 min, 10 min, 12 min, 15 min, 18 min or 20 min.

[0032] On the other hand, the present invention provides an oil and gas well plugging material, which includes the solvent-free epoxy resin cementing material as described above.

[0033] On the other hand, the present invention provides the application of the solvent-free epoxy resin cementing material or oil and gas well plugging material as described above in oil and gas resource exploration and development.

[0034] The low-viscosity solvent-free epoxy resin cementing material described in this invention is suitable for annular pressure treatment under complex working conditions such as complex natural gas wells, gas storage wells, and CCUS wells, as well as for sealing micro-annular gaps and micro-cracks in cement sheaths.

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

[0036] The solvent-free epoxy resin cementitious material of this invention has low viscosity (50-800 mPa·s), a wide applicable temperature range (20-90℃), and features high strength and low elastic modulus. After curing, its compressive strength is greater than 16 MPa after 24 hours, greater than 35 MPa after 48 hours, and can reach a maximum of 95 MPa. Its 24-hour elastic modulus is less than 5 GPa, exhibiting excellent mechanical properties, good toughness, and good resistance to corrosion and aging. It also provides excellent sealing capabilities for micro-cracks in the cement annulus, meeting the requirements for annular pressure control in complex conditions such as deep and ultra-deep wells, complex natural gas wells, gas storage wells, and CCUS wells, effectively ensuring the sealing integrity of the wellbore throughout its entire life cycle. The preparation method is simple, environmentally friendly, uses widely available raw materials, and is low-cost, with potential for large-scale production. It is applicable to various complex conditions and can meet the technical requirements for annular pressure control in complex wells such as natural gas wells, gas storage wells, and CCUS wells, with a broad application market. Attached Figure Description

[0037] Figure 1 This is a graph showing the relationship between the thickening time, 24-hour compressive strength and curing agent dosage of the epoxy resin cementitious material system at 90°C in Example 1.

[0038] Figure 2 This is a graph showing the relationship between the thickening time, 24-hour compressive strength, and the amount of curing regulator added to the epoxy resin cementitious material system at 60°C in Example 2. Detailed Implementation

[0039] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0040] Unless otherwise specified, the terminology used herein shall be understood as having the meaning commonly used in the art. In case of any discrepancy, this specification shall prevail.

[0041] Unless otherwise specified in this specification, all raw materials used in this invention can be purchased or prepared by existing methods, and all instruments and equipment used in this invention can be purchased.

[0042] The testing method and equipment used in this invention are as follows:

[0043] (1) The compressive strength of the cementitious material after curing was determined according to the test method specified in GB / T19139-2012 "Test Methods for Oil Well Cement". The test instrument was an oil well cement compressive strength tester.

[0044] (2) The thickening time of cementitious materials shall be determined according to the test method specified in GB / T19139-2012 "Test Methods for Cement in Oil Wells".

[0045] (3) Viscosity was determined according to GB / T10247-2008 "Viscosity Measurement Methods". The testing instrument was a Brookfield viscometer from the United States.

[0046] (4) The elastic modulus of the cementitious material after curing under different curing conditions (temperature, time) was tested using a cement stone triaxial test system.

[0047] In addition to the above, based on the curing characteristics of resin materials, the epoxy resin gelling material of the present invention has been optimized through system design parameters.

[0048] Furthermore, based on the curing mechanism, the gelling material of the present invention can have its viscosity and thickening time controlled by optimizing system parameters, thereby meeting the personalized needs of different temperatures and working conditions.

[0049] Example 1

[0050] Weigh 100 parts by weight of solvent-free epoxy resin, and add 30 parts by weight of curing agent, 30 parts by weight of tack modifier, 0.5 parts by weight of curing regulator, and 0.5 parts by weight of defoamer in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100. The curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure 305LC. The tack modifier is epoxidized soybean oil. The curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol. The defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1) purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103.

[0051] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: At 25℃, the viscosity was 386 mPa·s; under normal pressure curing conditions in a 90℃ water bath, the compressive strength was 55.6 MPa after 24 hours, 82.3 MPa after 48 hours, and the elastic modulus was 3.5 GPa after 24 hours; the thickening time was 240 min under normal pressure thickening conditions at 90℃. This indicates that the cementitious material can ensure smooth construction and effective sealing of the cement ring.

[0052] Example 2:

[0053] Weigh 100 parts by weight of solvent-free epoxy resin, and add 20 parts by weight of curing agent, 30 parts by weight of tack modifier, 0.5 parts by weight of curing regulator, and 1 part by weight of defoamer in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100. The curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure 305LC. The tack modifier is epoxidized soybean oil. The curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol. The defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1) purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103.

[0054] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: At 25℃, the viscosity was 475 mPa·s; under normal pressure curing conditions in an 80℃ water bath, the 24-hour compressive strength was 42.5 MPa, the 48-hour compressive strength was 76.4 MPa, and the 24-hour elastic modulus was 3.1 GPa; under normal pressure thickening conditions at 80℃, the thickening time was 330 min. This indicates that the cementitious material can ensure smooth construction and effective sealing of the cement ring.

[0055] Example 3:

[0056] Weigh 100 parts by weight of solvent-free epoxy resin, and add 40 parts by weight of curing agent, 30 parts by weight of tack modifier, 0.5 parts by weight of curing regulator, and 0.5 parts by weight of defoamer in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100. The curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure 305LC. The tack modifier is epoxidized soybean oil. The curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol. The defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1) purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103.

[0057] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: at 25℃, the viscosity was 315 mPa·s; under normal pressure curing in a 90℃ water bath, the 24-hour compressive strength was 37.6 MPa, and the 24-hour elastic modulus was 2.5 GPa; under normal pressure thickening conditions at 90℃, the thickening time was 180 min. This indicates that the cementitious material can ensure smooth construction and effective sealing of the cement ring.

[0058] Example 4:

[0059] Weigh 100 parts by weight of solvent-free epoxy resin, and under stirring conditions, add 30 parts by weight of curing agent, 20 parts by weight of tackifier, 0.5 parts by weight of curing regulator, 0.5 parts by weight of defoamer, and 5 parts by weight of toughening material in sequence. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain a solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100, and the curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure. 305LC, the viscosity modifier is benzyl glycidyl ether, the curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol, the defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1), purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103, and the toughening material is octacyclooxycyclohexylethyl-POSS.

[0060] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: at 25℃, the viscosity was 120 mPa·s; under normal pressure curing in a 90℃ water bath, the 24-hour compressive strength was 21.2 MPa, and the 24-hour elastic modulus was 2.3 GPa; under normal pressure thickening conditions at 90℃, the thickening time was 160 min. This indicates that the cementitious material can ensure smooth construction and effective sealing of the cement ring.

[0061] Example 5:

[0062] Weigh 100 parts by weight of solvent-free epoxy resin, and under stirring conditions, add 30 parts by weight of curing agent, 40 parts by weight of tackifier, 1.0 part by weight of curing regulator, 0.5 parts by weight of defoamer, and 5 parts by weight of toughening material in sequence. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain a solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100, and the curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure. 305LC, the viscosity modifier is benzyl glycidyl ether, the curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol, the defoamer is a mixture of polyether and organosilicon (mixing ratio is 1:1), purchased from Dongguan Defeng Defoamer Co., Ltd., model number DF-103, and the toughening material is glycidyl etheroxypropyl-POSS.

[0063] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: at 25℃, the viscosity was 50 mPa·s; under normal pressure curing in a 90℃ water bath, the 24-hour compressive strength was 20.2 MPa, and the 24-hour elastic modulus was 2.1 GPa; under normal pressure thickening conditions at 90℃, the thickening time was 240 min. This indicates that the cementitious material can ensure smooth construction and effective sealing of the cement ring.

[0064] Example 6:

[0065] Weigh 100 parts by weight of solvent-free epoxy resin, and under stirring conditions, add 20 parts by weight of curing agent, 30 parts by weight of tackifier, 1.0 part by weight of curing regulator, 0.5 parts by weight of defoamer, and 5 parts by weight of toughening material in sequence. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain a solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100, and the curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure. 305LC, the viscosity modifier is benzyl glycidyl ether, the curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol, the defoamer is a mixture of polyether and organosilicon (mixing ratio is 1:1), purchased from Dongguan Defeng Defoamer Co., Ltd., model number DF-103, and the toughening material is glycidyl etheroxypropyl-POSS.

[0066] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: at 25℃, the viscosity was 109 mPa·s; under normal pressure curing in a 90℃ water bath, the 24-hour compressive strength was 16.8 MPa, and the 24-hour elastic modulus was 1.9 GPa; under normal pressure thickening conditions at 90℃, the thickening time was 296 min. This indicates that the cementitious material can ensure smooth construction and effective sealing of the cement ring.

[0067] Example 7:

[0068] Weigh 100 parts by weight of solvent-free epoxy resin, and add 60 parts by weight of curing agent, 3.0 parts by weight of curing regulator, and 0.5 parts by weight of defoamer in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100. The curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure 305LC. The curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol. The defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1) purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103.

[0069] The viscosity, thickening time, and compressive strength of the cementitious material were measured: at 25℃, the viscosity was 324 mPa·s; under normal pressure curing conditions in a 25℃ water bath, the compressive strength was 21.3 MPa after 24 hours and 33.6 MPa after 48 hours; and the thickening time was 420 min under normal pressure thickening conditions at 25℃. This indicates that the cementitious material can ensure smooth construction and effective sealing of the cement ring.

[0070] Comparative Example 1:

[0071] According to Example 1, the difference is that the epoxy resin is replaced with conventional E-51 epoxy resin.

[0072] Weigh 100 parts by weight of epoxy resin, and add 30 parts by weight of curing agent, 30 parts by weight of tackifier, 0.5 parts by weight of curing regulator, and 0.5 parts by weight of defoamer in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain epoxy resin gelling material. Among them, the curing agent is modified fatty amine, purchased from Fujian Wangpai New Material Co., Ltd., model Kingcure 305LC; the tackifier is epoxidized soybean oil; the curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol; and the defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1), purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103.

[0073] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: at 25℃, the viscosity was 3236 mPa·s; under normal pressure curing in a 90℃ water bath, the 24-hour compressive strength was 65.4 MPa, and the 24-hour elastic modulus was 4.6 GPa; under normal pressure thickening at 90℃, the thickening time was 190 min. This indicates that the cementitious material based on unmodified conventional E-51 epoxy resin has a high viscosity, which cannot meet the requirements for on-site pumping into microcracks in cement rings. Furthermore, its elasticity and toughness are poor after curing.

[0074] Comparative Example 2:

[0075] According to Example 4, the difference is that no tackifier is used, and the amount of curing agent is the sum of the amounts of tackifier and curing agent in Example 4.

[0076] Weigh 100 parts by weight of solvent-free epoxy resin, and add 50 parts by weight of curing agent, 0.5 parts by weight of curing regulator, 0.5 parts by weight of defoamer, and 5 parts by weight of toughening material in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100. The curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure 305LC. The curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol. The defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1) purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103. The toughening material is octaepoxycyclohexylethyl-POSS.

[0077] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were measured: At 25℃, the viscosity was 458 mPa·s; under normal pressure curing in a 90℃ water bath, the 24-hour compressive strength was 28.4 MPa, and the 24-hour elastic modulus was 2.8 GPa; under normal pressure thickening conditions at 90℃, the thickening time was 105 min. The thickening time of this cementitious material is relatively short and cannot meet construction requirements. This indicates that the viscosity modifier plays an important role in this cementitious material: firstly, it can reduce the viscosity of the cementitious material, facilitating pumping and injection into microcracks; secondly, it can extend the thickening time, improving on-site construction performance.

[0078] Comparative Example 3

[0079] According to Example 4, the difference is that no curing agent is used, and the amount of tackifier is the sum of the amounts of tackifier and curing agent in Example 4.

[0080] Weigh 100 parts by weight of solvent-free epoxy resin, and add 0.5 parts by weight of curing regulator, 50 parts by weight of tack modifier, 0.5 parts by weight of defoamer, and 5 parts by weight of toughening material in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain solvent-free epoxy resin gelling material. Among them, the solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100; the tack modifier is benzyl glycidyl ether; the curing regulator is 2,4,6-tris(dimethylaminomethyl)phenol; the defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1), purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103; and the toughening material is octaepoxycyclohexylethyl-POSS.

[0081] The viscosity, thickening time, and compressive strength of the cementitious material were measured: at 25℃, the viscosity of the cementitious material was 365 mPa·s; under normal pressure curing in a 90℃ water bath, the cementitious material remained fluid and had no strength after 24 hours; under normal pressure thickening at 90℃, the cementitious material could not be cured.

[0082] Comparative Example 4:

[0083] According to Example 3, the difference is that no curing modifier is used.

[0084] Weigh 100 parts by weight of solvent-free epoxy resin, and add 40 parts by weight of curing agent, 30 parts by weight of tackifier, and 0.5 parts by weight of defoamer in sequence under stirring. Mix the above raw materials evenly at a drilling speed of 500 r / min to obtain solvent-free epoxy resin gelling material. The solvent-free epoxy resin is a modified low-viscosity solvent-free epoxy resin purchased from Baling Petrochemical, model CYDW-100. The curing agent is a modified fatty amine purchased from Fujian Wangpai New Materials Co., Ltd., model Kingcure 305LC. The tackifier is epoxidized soybean oil. The defoamer is a mixture of polyether and organosilicon (mixing ratio of 1:1) purchased from Dongguan Defeng Defoamer Co., Ltd., model DF-103.

[0085] The viscosity, thickening time, compressive strength, and elastic modulus of the cementitious material were determined: at 25℃, the viscosity of the cementitious material was 317 mPa·s; under normal pressure curing in a 90℃ water bath, the compressive strength of the cementitious material was 0 MPa after 24 hours and 1.5 MPa after 48 hours; under normal pressure thickening at 90℃, the thickening time of the cementitious material exceeded 24 hours.

[0086] In summary, the low-viscosity solvent-free epoxy resin cementitious material of this invention has excellent comprehensive performance. By optimizing the selection of external additives and system parameters, the viscosity, applicable temperature, and thickening time of the cementitious material can be controlled, resulting in good field construction performance. It meets the sealing capacity requirements of domestic natural gas wells, gas storage wells, and CCUS wells for cement sheaths, effectively sealing micro-annular gaps and micro-cracks in cement sheaths, improving wellbore sealing integrity, and efficiently addressing annular pressure issues.

[0087] The applicant declares that this invention illustrates the solvent-free epoxy resin cementitious material, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A solvent-free epoxy resin cementitious material, characterized in that, The solvent-free epoxy resin cementitious material is composed of the following components in parts by weight: 100 parts by weight of solvent-free modified epoxy resin 20-40 parts by weight of curing agent 20-40 parts by weight of tackifier Curing modifier 0.2-5 parts by weight 5-20 parts by weight of toughening material Defoamer 0.1-1 parts by weight; The solvent-free modified epoxy resin is one or a combination of at least two of bisphenol A type E-51 epoxy resin or E-44 epoxy resin modified with an active diluent. The toughening material is selected from cage-type polysilsesquioxanes, which are selected from octacyclooxycyclohexylethyl cage-type polysilsesquioxanes, glycidyl etheroxypropyl cage-type polysilsesquioxanes, octaphenyl cage-type polysilsesquioxanes, octaoctyl cage-type polysilsesquioxanes, dimethylsiloxy cage-type polysilsesquioxanes, or octaphenylaminopropyl cage-type polysilsesquioxanes.

2. The solvent-free epoxy resin cementitious material according to claim 1, characterized in that, The active diluent is selected from any one or a combination of at least two of the following: alkylene diglycidyl ether, butyl diglycidyl ether, 1,4-butanediol diglycidyl ether, ethylene glycol diglycidyl ether, phenyl diglycidyl ether, neopentyl glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

3. The solvent-free epoxy resin cementitious material according to claim 1, characterized in that, The curing agent is selected from any one or a combination of at least two of aliphatic primary amines, aromatic primary amines, polyamides, polythiols, or polyacid anhydrides.

4. The solvent-free epoxy resin cementitious material according to claim 3, characterized in that, The curing agent is selected from aliphatic polyamines.

5. The solvent-free epoxy resin cementitious material according to claim 4, characterized in that, The aliphatic polyamine is selected from any one or a combination of at least two of diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or N,N-diethylaminopropylamine.

6. The solvent-free epoxy resin cementitious material according to claim 3, characterized in that, The aromatic polyamine is selected from any one or a combination of at least two of m-phenylenediamine, 4,4-diaminodiphenylmethane, 4,4-diaminodiphenyl sulfone, or m-phenylenediamine.

7. The solvent-free epoxy resin cementitious material according to claim 3, characterized in that, The polybasic anhydride includes any one or a combination of at least two of phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadiq methyl anhydride, chlorine anhydride, or pyromellitic anhydride.

8. The solvent-free epoxy resin cementitious material according to claim 1, characterized in that, The viscosity modifier is a viscosity modifier containing epoxy groups and / or benzene rings.

9. The solvent-free epoxy resin cementitious material according to claim 8, characterized in that, The viscosity modifier is selected from any one or a combination of at least two of phenyl glycidyl ether, benzyl glycidyl ether, cashew phenol glycidyl ether, or epoxidized soybean oil.

10. The solvent-free epoxy resin cementitious material according to claim 1, characterized in that, The curing modifier is selected from any one or a combination of at least two of the following: triethylamine, triethanolamine, o-hydroxybenzyl dimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, benzyl dimethylamine, N-(2-hydroxyphenyl)-N',N'-dimethylurea, phenol, resorcinol, o-cresol, nonylphenol, boron trifluoride complex, imidazoles, or metal salts of acetylacetone.

11. The solvent-free epoxy resin cementitious material according to claim 1, characterized in that, The defoamer is selected from polyether defoamers, silicone defoamers, and their modified materials.

12. The solvent-free epoxy resin cementitious material according to claim 11, characterized in that, The defoamer is selected from any one or a combination of at least two of polysiloxane, modified polysiloxane, polyether-modified organosilicon, or hydroxyl polydimethylsiloxane.

13. The solvent-free epoxy resin cementitious material according to claim 1, characterized in that, The solvent-free epoxy resin cementitious material is used in an environment of 20-90℃.

14. A method for preparing a solvent-free epoxy resin cementitious material according to any one of claims 1-13, characterized in that, The preparation method includes the following steps: The solvent-free modified epoxy resin, curing agent, tackifier, curing regulator, toughening material and defoamer are mixed to obtain the solvent-free epoxy resin gelling material.

15. The preparation method according to claim 14, characterized in that, The mixing is carried out at a rotation speed of 200-1000 r / min.

16. The preparation method according to claim 14, characterized in that, The mixing time is 5-20 minutes.

17. A plugging material for oil and gas wells, characterized in that, The oil and gas well plugging material includes the solvent-free epoxy resin cementing material as described in any one of claims 1-13.

18. The application of the solvent-free epoxy resin cementing material according to any one of claims 1-13 or the oil and gas well plugging material according to claim 17 in oil and gas resource exploration and development.

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