A branched epoxy resin pressure-bearing plugging material and oil-based drilling fluid

Abstract

The present invention discloses a branched epoxy resin pressure-bearing plugging material, which belongs to the field of oil and gas field drilling technology. The pressure-bearing plugging material has a branched structure, and the raw materials for synthesizing the material include epichlorohydrin, cycloenamine substances, graphene oxide, and a silane coupling agent, wherein the molar ratio of the epichlorohydrin to the cycloenamine substances is 1-2:2-3, wherein the silane coupling agent is glycidyltrimethoxysilane. The branched epoxy resin pressure-bearing material synthesized by the present invention has a compressive strength of up to 130-150 MPa, which is 2-3 times higher than that of traditional bisphenol A epoxy resin. It can be applied to drilling fluid plugging for pressure-bearing plugging.

Description

Technical Field

[0001] The invention relates to the field of oil and gas wells, and in particular to an epoxy resin pressure-bearing plugging material and an oil-based drilling fluid containing the plugging material. Background Art

[0002] During drilling operations, the complex distribution of underground formations, the development of fractures and karst caves, and other issues can easily lead to drilling fluid loss, resulting in direct economic losses. Serious fluid loss can even cause blowouts, formation collapses, and drill bit burials, directly threatening operator safety, impacting drilling cycles, and slowing oil and gas exploration and development. As drilling depth increases, formation pressure increases, placing greater pressure resistance demands on the plugging agent in the event of fluid loss.

[0003] Currently, a large number of conventional and novel plugging agents have achieved good results to a certain extent, but most of them have weak pressure-bearing capacity. Patent CN202010628354.6 discloses a plugging resin system and its application. The plugging agent is made by reacting an epoxy resin and a curing agent, and the material has a compressive strength of approximately 100 MPa. However, the number of deep and ultra-deep wells is increasing year by year, and the pressure-bearing capacity requirements of plugging materials are also increasing.

[0004] Since various cements and a small number of chemical agents and mixtures are the most commonly used plugging agents, and plugging practice shows that complete loss of drilling fluid in fractures, cave formations and large-pore and high-permeability formations is the most difficult to deal with, drilling workers at home and abroad have also developed some polymer plugging materials and supporting plugging processes from a chemical perspective, but no breakthrough progress has been made in dealing with fracture and cave leakage.

[0005] Epoxy resin molecules contain benzene rings, ether bonds, hydroxyl groups, and epoxy groups. The benzene rings impart excellent mechanical strength and heat resistance to epoxy resins, while the ether bonds impart excellent chemical resistance, making them a good choice for leak-proofing materials. However, most epoxy resins are synthesized from bisphenol A, resulting in chain-type epoxy resins with poor mechanical properties, making them ineffective for plugging leaks. Branched epoxy resins differ significantly from linear epoxy resins in structure and can effectively improve the material's mechanical properties, especially its pressure-bearing capacity. Adding graphene oxide, a rigid material, further enhances its compressive strength. Application to drilling fluids significantly enhances their sealing effectiveness. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide a branched epoxy resin pressure-bearing plugging material, which has high strength and can improve the pressure-bearing capacity of the formation, thereby performing good plugging.

[0007] To achieve the above object, the technical solution of the present invention is: a branched epoxy resin pressure-bearing plugging material, characterized in that the preparation steps of the branched epoxy resin pressure-bearing plugging material are as follows:

[0008] S1, add 200mL of ethanol to a three-necked flask, add cycloenamines and stir to mix evenly, add 50mL of ethanol and epichlorohydrin to a beaker and mix evenly, transfer to a constant pressure funnel, add dropwise to the three-necked flask, complete the addition, and react at room temperature overnight to obtain a diglycidylcycloenamine intermediate;

[0009] S2. Add 200 mL of ethanol to a three-necked flask, add the diglycidyl cycloenamine intermediate prepared in S1 to the three-necked flask and mix, add 30% sodium hydroxide solution, stir and react for 3 to 5 hours, stop the reaction, add appropriate amount of water and 60 mL of ethyl acetate, extract and separate, and purify by rectification to obtain diglycidyl cycloenamine;

[0010] S3. Graphene oxide (GO) was uniformly dispersed in 500 mL of dimethylformamide using ultrasonic dispersion, and the mixture was transferred to a three-necked flask. 0.15 mol of diphenylamine, 0.05 mol of N,N-dicyclohexylcarbodiimide, and 0.05 mol of dimethylolpropionic acid were added, and the mixture was mixed and the temperature was adjusted to 20-30°C. The mixture was stirred for 48 hours, and then filtered and dried to obtain D-GO.

[0011] S4. The D-GO prepared in S3 was uniformly dispersed in 500 mL of tetrahydrofuran solution by ultrasound, and then the tetrahydrofuran solution was transferred to a three-necked flask. Under nitrogen protection, 0.1 mol of triethanolamine was added dropwise to the tetrahydrofuran solution. After the addition was completed, the mixture was stirred for 1 to 3 hours, and then 3 g of hexachlorotriphosphazene was added. The mixture was stirred in an ice-water bath for 6 to 8 hours, and finally 20 mL of 1,3-propylenediamine was added. The mixture was reacted at room temperature for 8 to 12 hours to purify the modified graphene oxide.

[0012] S5. Mix the diglycidyl cycloalkenylamines and cycloalkenylamine substances prepared in S2, heat them to 140-160° C., and react them for 4-6 hours to prepare epoxy resin. Then, mix the epoxy resin with the modified graphene oxide and silane coupling agent prepared in S4, heat them to 160-180° C., and react them for 1-3 hours to prepare epoxy resin pressure-bearing plugging material.

[0013] The cycloalkenylamine substance is at least one of 1,3-cyclopentadienyl-5-amine, 1H-indene-1-amine, and 1H-indene-3-amine.

[0014] The silane coupling agent is glycidyl trimethoxysilane.

[0015] The mass of the graphene oxide is between 5 and 20 g.

[0016] The mass of the silane coupling agent is between 5 and 20 g.

[0017] An oil-based drilling fluid, characterized in that the drilling fluid contains the high-strength, strong adsorption plugging agent according to claims 1-4, and the drilling fluid comprises the following components by weight: 80 parts of base oil, 20 parts of CaCl2 brine, 2.5-4.5 parts of a primary emulsifier, 1.5-2.5 parts of an auxiliary emulsifier, 2.5-3 parts of organic soil, 0.5-0.8 parts of a wetting agent, 2-3 parts of quicklime, 1.5-4 parts of a fluid loss reducer, 1-5 parts of a high-strength, strong adsorption plugging agent, 15-230 parts of barite, and 1-5 parts of the branched epoxy resin pressure-bearing plugging material according to claim 1.

[0018] An oil-based drilling fluid, characterized in that the base oil is 3# white oil, the concentration of the calcium chloride solution is 25%, the primary emulsifier is HWPmul-1, the secondary emulsifier is HWSmul-1, the organic soil is HWGel-3, the wetting agent is HWWet-1, and the fluid loss additive is HWTrol-101, wherein HWPmul-1, HWSmul-1, HWGel-3, HWTrol-101 ​​and HWWet-1 are from Chengdu Xiyou Huawei Technology Co., Ltd.

[0019] The oil-based drilling fluid is adjusted to a density of 1.10-2.20 g / cm with barite. 3 .

[0020] The technical features and beneficial effects of the present invention are as follows: The branched epoxy resin pressure-bearing plugging material undergoes a cross-linking and curing reaction at formation temperature to form a high-strength solid polymer material; the high-strength solid formed by cross-linking and curing is suitable for high-pressure plugging. The monomer material used to synthesize the epoxy resin has a multi-benzene ring structure, which can improve the epoxy resin's compressive and temperature resistance, and the molecules are branched rather than linear during the polymerization reaction; cycloenols, epichlorohydrin, and cycloenamines contain multiple functional groups, which can increase the degree of cross-linking during the curing process; the rigid material and cross-linking agent can further improve the formation's pressure-bearing capacity and effectively plug deep and ultra-deep wells.

[0021] Figures in the specification

[0022] The above-mentioned partial reaction process is shown in the attached figure. Figure 1 is the schematic diagram of S1 reaction, Figure 2 is the schematic diagram of S2 reaction, Figure 3 A partial schematic diagram of the polymer. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0024] The embodiments of the present invention are as follows:

[0025] 1. Preparation of branched epoxy resin pressure-bearing plugging material

[0026] Example 1

[0027] S1. Add 200 mL of ethanol to a three-necked flask, then add 0.05 mol of 1,3-cyclopentadiene-5-amine and stir to mix evenly. Add 50 mL of ethanol and 0.2 mol of epichlorohydrin to a beaker and mix evenly. Transfer to a constant pressure funnel and add dropwise to the three-necked flask. After the addition is complete, react at room temperature overnight to prepare a 1,3-cyclopentadiene-5-diepoxypropylamine intermediate.

[0028] S2. Add 200 mL of ethanol to a three-necked flask, add the intermediate product of 1,3-cyclopentadiene-5-diepoxypropylamine prepared in S1 to the three-necked flask and mix, add 30% sodium hydroxide solution, stir and react for 4 h, stop the reaction, add appropriate amount of water and 60 mL of ethyl acetate, extract and separate, and purify by rectification to obtain 1,3-cyclopentadiene-5-diepoxypropylamine;

[0029] S3. 5 g of graphene oxide (GO) was uniformly dispersed in 500 mL of dimethylformamide using ultrasonic dispersion, and the mixture was transferred to a three-necked flask. 0.15 mol of diphenylamine, 0.05 mol of N,N-dicyclohexylcarbodiimide, and 0.05 mol of dimethylolpropionic acid were added, and the mixture was mixed and the temperature was adjusted to 25°C. The mixture was stirred for 48 h, and filtered and dried to obtain D-GO.

[0030] S4. The D-GO prepared in S3 was uniformly dispersed in 500 mL of tetrahydrofuran solution by ultrasound, and then the tetrahydrofuran solution was transferred to a three-necked flask. Under nitrogen protection, 0.1 mol of triethanolamine was added dropwise to the tetrahydrofuran solution. After stirring for 2 h, 3 g of hexachlorotriphosphazene was added, and then stirred in an ice-water bath for 6 h. Finally, 20 mL of 1,3-propylenediamine was added, and the mixture was reacted at room temperature for 12 h to purify and obtain modified graphene oxide;

[0031] S5. Mix the 1,3-cyclopentadiene-5-diepoxypropylamine and 1H-indene-1-amine prepared in S2, heat it to 150°C, and react for 5 hours to prepare an epoxy resin. Then, mix the epoxy resin with the modified graphene oxide prepared in S4 and 5 g of glycidyltrimethoxysilane, heat it to 180°C, and react for 2 hours to prepare an epoxy resin pressure-bearing plugging material.

[0032] Example 2

[0033] S1, add 200mL of ethanol to a three-necked flask, then add 0.05mol1H-indene-1-amine and stir to mix evenly, add 50mL of ethanol and 0.2mol of epichlorohydrin to a beaker and mix evenly, transfer to a constant pressure funnel, add dropwise to the three-necked flask, complete the addition, and react at room temperature overnight to prepare a 1H-indene-1-diepoxypropylamine intermediate;

[0034] S2. Add 200 mL of ethanol to a three-necked flask, add the intermediate product of 1H-indene-1-diepoxypropylamine prepared in S1 to the three-necked flask and mix, add 30% sodium hydroxide solution, stir and react for 4 h, stop the reaction, add appropriate amount of water and 60 mL of ethyl acetate, extract and separate, and purify by rectification to obtain 1H-indene-1-diepoxypropylamine;

[0035] S3. 10 g of graphene oxide (GO) was uniformly dispersed in 500 mL of dimethylformamide using ultrasonic dispersion, and the mixture was transferred to a three-necked flask. 0.15 mol of diphenylamine, 0.05 mol of N,N-dicyclohexylcarbodiimide, and 0.05 mol of dimethylolpropionic acid were added. The mixture was mixed and the temperature was adjusted to 25°C. The mixture was stirred for 48 h, and filtered and dried to obtain D-GO.

[0036] S4. The D-GO prepared in S3 was uniformly dispersed in 500 mL of tetrahydrofuran solution by ultrasound, and then the tetrahydrofuran solution was transferred to a three-necked flask. Under nitrogen protection, 0.1 mol of triethanolamine was added dropwise to the tetrahydrofuran solution. After stirring for 2 h, 3 g of hexachlorotriphosphazene was added, and then stirred in an ice-water bath for 6 h. Finally, 20 mL of 1,3-propylenediamine was added, and the mixture was reacted at room temperature for 12 h to purify and obtain modified graphene oxide;

[0037] S5. Mix the 1H-indene-1-diepoxypropylamine and 1,3-cyclopentadienyl-5-amine prepared in S2, heat the mixture to 150°C, and react for 5 hours to prepare an epoxy resin. Then, mix the epoxy resin with the modified graphene oxide prepared in S4 and 10 g of glycidyltrimethoxysilane, heat the mixture to 180°C, and react for 2 hours to prepare an epoxy resin pressure-bearing plugging material.

[0038] Example 3

[0039] S1, add 200mL of ethanol to a three-necked flask, then add 0.05mol1H-indene-3-amine and stir to mix evenly, add 50mL of ethanol and 0.2mol of epichlorohydrin to a beaker and mix evenly, transfer to a constant pressure funnel, add dropwise to the three-necked flask, complete the addition, and react at room temperature overnight to prepare a 1H-indene-3-diepoxypropylamine intermediate;

[0040] S2. Add 200 mL of ethanol to a three-necked flask, add the intermediate product of 1H-indene-3-diepoxypropylamine prepared in S1 to the three-necked flask and mix, add 30% sodium hydroxide solution, stir and react for 4 h, stop the reaction, add appropriate amount of water and 60 mL of ethyl acetate, extract and separate, and purify by rectification to obtain 1H-indene-3-diepoxypropylamine;

[0041] S3. 15 g of graphene oxide (GO) was uniformly dispersed in 500 mL of dimethylformamide using ultrasonic dispersion, and the mixture was transferred to a three-necked flask. 0.15 mol of diphenylamine, 0.05 mol of N,N-dicyclohexylcarbodiimide, and 0.05 mol of dimethylolpropionic acid were added. The mixture was mixed and the temperature was adjusted to 25°C. The mixture was stirred for 48 h, and filtered and dried to obtain D-GO.

[0042] S4. The D-GO prepared in S3 was uniformly dispersed in 500 mL of tetrahydrofuran solution by ultrasound, and then the tetrahydrofuran solution was transferred to a three-necked flask. Under nitrogen protection, 0.1 mol of triethanolamine was added dropwise to the tetrahydrofuran solution. After stirring for 2 h, 3 g of hexachlorotriphosphazene was added, and then stirred in an ice-water bath for 6 h. Finally, 20 mL of 1,3-propylenediamine was added, and the mixture was reacted at room temperature for 12 h to purify and obtain modified graphene oxide;

[0043] S5. Mix the 1H-indene-3-diepoxypropylamine and 1H-indene-1-amine prepared in S2, heat them to 150°C, and react for 5 hours to prepare an epoxy resin. Then, mix the epoxy resin with the modified graphene oxide prepared in S4 and 15g of glycidyltrimethoxysilane, heat them to 180°C, and react for 2 hours to prepare an epoxy resin pressure-bearing plugging material.

[0044] Comparative Example

[0045] 100 g of bisphenol A epoxy resin and 20 g of polyethylene glycol 200 were stirred for 30 minutes, and then 5 g of curing agent aromatic amine G3 was added. The mixture was stirred at 65° C. for 12 hours to uniformly disperse the mixture to obtain a bisphenol A epoxy resin plugging material.

[0046] 2. Preparation of oil-based drilling fluid

[0047] Example 4

[0048] 10.0g of main emulsifier HWPmul-1, 10.0g of auxiliary emulsifier HWSmul-1, and 3.2g of wetting agent HWWet-1 were directly weighed in a high-stirring cup; 320mL of 3# white oil was introduced into the high-stirring cup, and the high-stirring cup was placed on a high-stirring machine and stirred at a high speed of 11000 rpm for 10 minutes; 12.0g of organic soil HWGel-3 was weighed with cellophane and slowly added to the high-stirring cup under high stirring to prevent splashing, and stirred at high speed for 10 minutes. n; Under high stirring, measure 80mL of 25% CaCl2 aqueous solution and add it to the high stirring cup to prevent splashing, and stir at high speed for 10 minutes; Under high stirring, slowly add 10.0g of quicklime to the high stirring cup and stir at high speed for 10 minutes; Under high stirring, slowly add 14.0g of filtration agent HWTrol-101 ​​to the high stirring cup and stir for 10 minutes; Under high stirring, slowly add 420.0g of barite to the high stirring cup and continue stirring for 30 minutes to prepare the base slurry.

[0049] In order to further illustrate the effects of the branched epoxy resin pressure-bearing plugging material and the oil-based drilling fluid of the present invention, plugging performance tests were conducted on the branched epoxy resin pressure-bearing plugging material, conventional bisphenol A epoxy resin plugging material and oil-based drilling fluid in Examples 1 to 4.

[0050] 1. Compressive performance test of plugging materials

[0051] Example 5

[0052] The final products of Examples 1-3, as well as samples from the comparative example, were subjected to compression testing, with three samples collected for each material. The compression test followed ASTM D6641. Two strain gauges, one vertical and one horizontal, were attached to the front and back surfaces of the specimens to obtain the average compressive strain and Poisson's ratio for both surfaces. An Instron 5882 testing machine (100 kN range) was used with a combined loading and compression fixture (CLC) to apply compressive loads to the specimens, and the resulting data were averaged.

[0053] Table 1 is prepared based on the experimental data and the compressive strength of the comparative example. It can be seen from Table 1 that compared with the bisphenol A epoxy resin with a chain molecular structure, the pressure bearing capacity of the branched epoxy resin is significantly improved, and as the amount of rigid material particles increases, the compressive capacity will also be correspondingly improved.

[0054] Table 1 Compression performance test of branched epoxy resin plugging material

[0055] Example 1 Example 2 Example 3 Comparative Example 1 Compressive strength (MPa) 143.8 148.5 138.9 54.6

[0056] 2. Wedge-shaped 1mm-3mm crack sealing test

[0057] Different amounts of the branched epoxy resin pressure-bearing plugging materials of Examples 1 to 3 and the plugging materials of the comparative example were added to the base slurry configured in Example 4 to conduct plugging effect experiments.

[0058] Example 6

[0059] Three drilling fluid systems were prepared: base slurry + 1% Example 1, base slurry + 3% Example 1, and base slurry + 5% Example 1, and wedge plate crack plugging experiments were carried out.

[0060] Example 7

[0061] Three drilling fluid systems were prepared: base slurry + 1% of Example 2, base slurry + 3% of Example 2, and base slurry + 5% of Example 2, and wedge plate crack plugging experiments were carried out.

[0062] Example 8

[0063] Three drilling fluid systems were prepared: base slurry + 1% Example 3, base slurry + 3% Example 3, and base slurry + 5% Example 3, and wedge plate crack plugging experiments were carried out.

[0064] Example 9

[0065] Three drilling fluid systems were prepared: base slurry + 1% comparative plugging material, base slurry + 3% comparative plugging material, and base slurry + 5% comparative plugging material, and wedge plate crack plugging experiments were carried out.

[0066] According to Table 2, after adding the plugging material to the base slurry, wedge-shaped cracks with a diameter of 1 to 3 mm can be plugged. As the amount of plugging material increases, the plugging effect improves, and the plugging position is concentrated in the range of 15 to 30 mm. The formula with the best plugging effect is: base slurry + 5% Example 2.

[0067] Table 2 Results of wedge-shaped 1mm-3mm crack plugging test

[0068]

[0069]

[0070] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A branched epoxy resin pressure-bearing plugging material, characterized in that The main raw materials of the material include: epichlorohydrin, cycloenamine substances, graphene oxide, and a silane coupling agent. The molar ratio of the epichlorohydrin to the cycloenamine substances is 1-2:2-3, wherein the silane coupling agent is glycidyl trimethoxysilane. The branched epoxy resin pressure-bearing plugging material adopts the following synthesis steps: S1, add 200mL of ethanol to a three-necked flask, add cycloenamines and stir to mix evenly, add 50mL of ethanol and epichlorohydrin to a beaker and mix evenly, transfer to a constant pressure funnel, add dropwise to the three-necked flask, complete the addition, and react at room temperature overnight to obtain a diglycidylcycloenamine intermediate; S2. Add 200 mL of ethanol to a three-necked flask, add the diglycidyl cycloenamine intermediate prepared in S1 to the three-necked flask and mix, add 30% sodium hydroxide solution, stir and react for 3 to 5 hours, stop the reaction, add appropriate amount of water and 60 mL of ethyl acetate, extract and separate, and purify by rectification to obtain diglycidyl cycloenamine; S3. Graphene oxide (GO) was uniformly dispersed in 500 mL of dimethylformamide using ultrasonic dispersion, and the mixture was transferred to a three-necked flask. 0.15 mol of diphenylamine, 0.05 mol of N,N-dicyclohexylcarbodiimide, and 0.05 mol of dimethylolpropionic acid were added, and the mixture was mixed and the temperature was adjusted to 20-30°C. The mixture was stirred for 48 hours, and then filtered and dried to obtain D-GO. S4. The D-GO prepared in S3 was uniformly dispersed in 500 mL of tetrahydrofuran solution by ultrasonication, and then the tetrahydrofuran solution was transferred to a three-necked flask. Under nitrogen protection, 0.1 mol of triethanolamine was added dropwise to the tetrahydrofuran solution. After the addition was completed, the mixture was stirred for 1 to 3 hours, and then 3 g of hexachlorotriphosphazene was added. The mixture was stirred in an ice-water bath for 6 to 8 hours, and finally 20 mL of 1,3-propylenediamine was added. The mixture was reacted at room temperature for 8 to 12 hours to purify the modified graphene oxide. S5. Mix the diglycidyl cycloalkenylamines and cycloalkenylamines prepared in S2, heat them to 140-160° C., and react them for 4-6 hours to prepare an epoxy resin. Then, mix the epoxy resin with the modified graphene oxide and silane coupling agent prepared in S4, heat them to 160-180° C., and react them for 1-3 hours to prepare an epoxy resin pressure-bearing plugging material. S6. The cycloalkenylamine substance is at least one of 1,3-cyclopentadien-5-amine, 1H-indene-1-amine, and 1H-indene-3-amine.

2. An oil-based drilling fluid, characterized in that: The drilling fluid contains the branched epoxy resin pressure-bearing plugging material according to claim 1, and the drilling fluid comprises the following components by weight: 80 parts of base oil, 20 parts of CaCl2 brine, 2.5 to 4.5 parts of primary emulsifier, 1.5 to 2.5 parts of auxiliary emulsifier, 2.5 to 3 parts of organic soil, 0.5 to 0.8 parts of wetting agent, 2 to 3 parts of quicklime, 1.5 to 4 parts of fluid loss reducer, 15 to 230 parts of barite, and 1 to 5 parts of the branched epoxy resin pressure-bearing plugging material according to claim 1.

3. The oil-based drilling fluid according to claim 2, characterized in that The base oil is 3# white oil, the concentration of calcium chloride solution is 25%, the main emulsifier is HWPmul-1, the auxiliary emulsifier is HWSmul-1, the organic soil is HWGel-3, the wetting agent is HWWet-1, and the fluid loss reducer is HWTrol-101. Among them, HWPmul-1, HWSmul-1, HWGel-3, HWTrol-101 ​​and HWWet-1 are from Chengdu Xiyou Huawei Technology Co., Ltd.

4. The oil-based drilling fluid according to claim 2, characterized in that The oil-based drilling fluid is adjusted to a density of 1.10-2.20 g / cm with barite. 3 .

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