A thermo-baric responsive plugging material for drilling, its preparation method and application

Abstract

This invention provides a temperature- and pressure-responsive plugging material for drilling, its preparation method, and its application. The temperature- and pressure-responsive plugging material, by weight, comprises: 60-80 parts of micron-sized inert particles, 8-20 parts of repairable resin, and 2-5 parts of lubricant. The repairable resin is obtained by curing resin monomers with a multifunctional cyclic anhydride curing agent, which is prepared by reacting polyhydroxyamines and cyclic anhydrides. This plugging material exhibits excellent plugging performance and low filtration loss during secondary plugging, making it suitable for complex microfracture formations.

Description

Technical Field

[0001] This invention belongs to the field of oil drilling plugging materials, specifically relating to a temperature and pressure responsive drilling plugging material, its preparation method, and its application. Background Technology

[0002] Well leakage and wellbore instability are common problems. Drilling plugging materials are the main drilling fluid additives for solving leakage and wellbore instability in complex micro-fractured formations. Most drilling fluid plugging agents are composed of emulsified asphalt, oxidized asphalt, rubber powder, asphalt resin or graphite microspheres. Most of these materials are not chemically active and have a certain physical plugging effect; however, they are only effective for pores of a certain size. When there are heterogeneous pores and fractures, their effect is limited. Summary of the Invention

[0003] To address the problem that drilling plugging materials in microfractured formations are not dense and are easily eroded and destroyed by drilling fluid, the present invention aims to provide a temperature and pressure responsive drilling plugging material, its preparation method, and its application. This plugging material has excellent plugging performance and low secondary plugging filtration loss, making it suitable for complex microfractured formations.

[0004] To achieve the above objectives, this invention provides a temperature and pressure responsive plugging material for drilling, comprising, by weight, 60-80 parts of micron-sized inert particles, 8-20 parts of repairable resin, and 2-5 parts of lubricant; wherein the repairable resin is obtained by curing resin monomers with a multifunctional cyclic anhydride curing agent, and the multifunctional cyclic anhydride curing agent is prepared by reacting polyhydroxyamines and cyclic anhydrides; the preparation method of the multifunctional cyclic anhydride curing agent includes the following steps: Under anaerobic conditions, a cyclic anhydride is added to a polyhydroxyamine, and the mixture is heated to 80-150℃ and reacted for 0.5-10 hours to obtain the multifunctional cyclic anhydride curing agent. The preparation method of the repairable resin includes the following steps: mixing the resin monomer and the multifunctional cyclic anhydride curing agent at 100-150℃, curing at 100-120℃ for 1-3 hours, curing at 140-160℃ for 1-3 hours, and curing at 180-220℃ for 2-5 hours to obtain the repairable resin.

[0005] According to a specific embodiment of the present invention, preferably, the micron-sized inert particles comprise quartz sand and / or calcium carbonate.

[0006] According to a specific embodiment of the present invention, preferably, the particle size of the micron-sized inert particles is 10-200 μm.

[0007] According to a specific embodiment of the present invention, preferably, the resin monomer includes one or a combination of two or more of hydrogenated bisphenol A type epoxy resin, bisphenol S type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, aliphatic glycidyl ether epoxy resin, and alicyclic epoxy resin.

[0008] According to a specific embodiment of the present invention, preferably, the polyhydroxyamine includes one or a combination of two or more of dihydroxyethylamine, triethanolamine, and N,N,N',N'-tetra(2-hydroxypropyl)ethylenediamine.

[0009] According to a specific embodiment of the present invention, preferably, the cyclic anhydride includes one or more of maleic anhydride, succinic anhydride, glutaric anhydride, and methyltetrahydrophthalic anhydride.

[0010] According to a specific embodiment of the present invention, preferably, in the preparation method of the multifunctional cyclic anhydride curing agent, the molar ratio of the polyhydroxyamine to the cyclic anhydride is 2:(2-15), more preferably 2:(3-12).

[0011] According to a specific embodiment of the present invention, the preparation method of the above-mentioned multifunctional cyclic anhydride curing agent includes the following specific steps: adding polyhydroxyamine to a three-necked flask, adding cyclic anhydride under oxygen-free conditions (e.g., passing nitrogen gas), heating to 120°C, stirring for 6 hours to obtain the reactant, and then washing and drying to obtain the target product; the drying conditions are preferably vacuum drying at 50°C for 30-60 hours.

[0012] According to a specific embodiment of the present invention, preferably, in the method for preparing the repairable resin, the mass ratio of the resin monomer to the multifunctional cyclic anhydride curing agent is 50-100:20-50.

[0013] According to a specific embodiment of the present invention, the preparation method of the above-mentioned repairable resin includes the following specific steps: (a) adding resin monomer and multifunctional cyclic anhydride curing agent sequentially to a three-necked flask, heating to 100°C, and stirring evenly; (b) pouring the product from step (a) into a mold, placing it at 120°C for 2 hours, at 160°C for 2 hours, and at 200°C for 4 hours to obtain the product, and pulverizing and sieving it to 50μm-1000μm.

[0014] According to a specific embodiment of the present invention, preferably, the lubricant includes one or a combination of two or more of calcium stearate, zinc stearate, and talc.

[0015] This invention also provides a method for preparing the above-mentioned temperature and pressure responsive drilling plugging material, which includes the following steps:

[0016] (1) The repairable resin is heated to 180-220°C to melt, and the micron-sized inert particles are added and mixed.

[0017] (2) Cool down to 70-90℃, add the lubricant, and mix;

[0018] (3) Cooling to obtain the temperature and pressure responsive drilling plugging material.

[0019] According to a specific embodiment of the present invention, preferably, in step (3), after cooling, the material is further pulverized to 10-200 μm.

[0020] According to a specific embodiment of the present invention, the preparation method of the above-mentioned temperature and pressure responsive drilling plugging material includes the following specific steps:

[0021] (1) Heat the repairable resin to 200°C using a heatable mixer and stir for 2-5 minutes until the resin is completely in a liquid molten state.

[0022] (2) While maintaining the heating conditions, mix the micron-sized inert particles with the molten high-temperature resistant resin in step (1) and stir for 3-5 minutes.

[0023] (3) Lower the temperature to 70-90℃, add lubricant and continue stirring for 1-2 minutes;

[0024] (4) Cool and crush the material obtained in step (3) and pass it through a sieve to obtain a temperature and pressure responsive drilling plugging material with a particle size of 10 μm to 200 μm.

[0025] This invention also provides the application of the above-mentioned temperature and pressure responsive plugging material in drilling fluid.

[0026] According to a specific embodiment of the present invention, preferably, the temperature-pressure responsive drilling plugging material exerts its plugging effect at 120-180°C.

[0027] The temperature- and pressure-responsive drilling plugging material of this invention consists of micron-sized inert particles coated with a self-healing resin. When the temperature- and pressure-responsive drilling plugging material accumulates in formation pores and fractures, the self-healing resin coating responds to formation temperature and pressure, melting and bonding to form a unified whole. The inner phase is micron-sized inert particles, and the outer phase is the self-healing resin, improving the stability of the plugging layer and enhancing the microfracture plugging effect. This temperature- and pressure-responsive drilling plugging material is suitable for formation temperatures from 120°C to 180°C, with a high-temperature, high-pressure PPA sandbox filtration loss of <6 mL and a secondary filtration loss of <10 mL after plugging, superior to conventional inert particle plugging materials. It is suitable for formations with pores and fractures at multiple scales. Attached Figure Description

[0028] Figure 1 Infrared spectrum of multifunctional cyclic anhydride curing agent;

[0029] Figure 2 This is a sand table diagram after the PPA high-temperature and high-pressure filtration test at 180℃;

[0030] Figure 3 This is a sand table diagram after the PPA high-temperature and high-pressure filtration test at 180℃;

[0031] Figure 4 This is a sand table diagram after the PPA high-temperature and high-pressure filtration test at 100℃. Detailed Implementation

[0032] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0033] Example 1

[0034] This embodiment provides a temperature and pressure responsive drilling plugging material, which is prepared from 73g of 20-40 micron silica sand powder, 18g of repairable resin, and 3g of calcium stearate using the following steps:

[0035] (1) Heat the repairable resin to 180°C using a heatable mixer and stir for 2 minutes until the resin is completely in a liquid molten state.

[0036] (2) While maintaining the heating conditions, mix the micron-sized inert particles with the molten high-temperature resistant resin in step (1) and stir for 5 minutes;

[0037] (3) Lower the temperature to 90℃, add lubricant and continue stirring for 2 minutes;

[0038] (4) Cool and crush the material obtained in step (3) and pass it through a sieve to obtain a temperature and pressure responsive drilling plugging material with a particle size of 20-40 micrometers.

[0039] The synthesis process of the repairable resin is as follows:

[0040] (1) Synthesis of multifunctional cyclic anhydride curing agent: 0.1 mol of triethanolamine was added to a three-necked flask, stirred at room temperature in the absence of oxygen, and 0.5 mol of maleic anhydride was added. The mixture was heated to 120°C and reacted for 6 h. The mixture was then washed and dried at 50°C under vacuum for 12 h. Its infrared spectrum is shown below. Figure 1 As shown;

[0041] (2) Synthesis of repairable resin: 68g of bisphenol F type epoxy resin and 32g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask in sequence, heated to 100℃, stirred evenly, and then poured into a mold. The mold was placed at 110℃ for 2h, 150℃ for 2.5h, and 195℃ for 3.5h to obtain the product. The product was then crushed and sieved to form a 50μm-100μm repairable resin.

[0042] Example 2

[0043] This embodiment provides a temperature and pressure responsive drilling plugging material, which uses 78g of 10-20 micrometer calcium carbonate powder, 19g of repairable resin, and 3g of zinc stearate as raw materials. The preparation method is the same as in Example 1, and finally a 10-20 micrometer temperature and pressure responsive drilling plugging material is formed.

[0044] The synthesis process of the repairable resin is as follows:

[0045] (1) Synthesis of polyfunctional cyclic anhydride curing agent: 0.1 moles of dihydroxyethylamine were added to a three-necked flask, stirred at room temperature in the absence of oxygen, 0.38 moles of methyltetrahydrophthalic anhydride were added, and the mixture was heated to 120°C and reacted for 6 hours. Then the mixture was washed and dried at 50°C under vacuum for 12 hours.

[0046] (2) Synthesis of repairable resin: 82g of bisphenol S-type epoxy resin and 18g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask in sequence, heated to 100℃, stirred evenly, and then poured into a mold. The mold was placed at 120℃ for 2h, 160℃ for 2h, and 200℃ for 4h to obtain the product. The product was then crushed and sieved to form a 50μm-100μm repairable resin.

[0047] Example 3

[0048] This embodiment provides a temperature and pressure responsive drilling plugging material, which uses 71g of 60-80 micrometer quartz sand powder, 20g of repairable resin and 4g of talc powder as raw materials. The preparation method is the same as in Example 1, and finally a 60-80 micrometer temperature and pressure responsive drilling plugging material is formed.

[0049] The synthesis process of the repairable resin is as follows:

[0050] (1) Synthesis of polyfunctional cyclic anhydride curing agent: 0.1 mol N,N,N',N'-tetra(2-hydroxypropyl)ethylenediamine was added to a three-necked flask, stirred at room temperature in the absence of oxygen, 0.39 mol glutaric anhydride was added, heated to 120℃ and reacted for 6 h, then washed and dried at 50℃ under vacuum for 12 h.

[0051] (2) Synthesis of repairable resin: 75g of bisphenol A type epoxy resin and 25g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask, heated to 100℃, stirred evenly, and then poured into a mold. The mold was then placed at 120℃ for 2h, 160℃ for 2h, and 200℃ for 4h to obtain the product. The product was then crushed and sieved to form a 60μm-80μm repairable resin.

[0052] Example 4

[0053] This embodiment provides a temperature and pressure responsive drilling plugging material, which uses 67g of 100-200 micrometer calcium carbonate powder, 18g of repairable resin, 2g of zinc stearate, and 3g of talc powder as raw materials. The preparation method is the same as in Example 1 to form a 100-200 micrometer temperature and pressure responsive drilling plugging material.

[0054] The synthesis process of the repairable resin is as follows:

[0055] (1) Synthesis of polyfunctional cyclic anhydride curing agent: 0.1 mol N,N,N',N'-tetra(2-hydroxypropyl)ethylenediamine was added to a three-necked flask, stirred at room temperature in the absence of oxygen, 0.39 mol methyltetrahydrophthalic anhydride was added, heated to 120℃ and reacted for 6 h, then washed and dried at 50℃ under vacuum for 12 h.

[0056] (2) Synthesis of repairable resin: 66g of hydrogenated bisphenol A type epoxy resin and 34g of the multifunctional cyclic anhydride curing agent obtained in step (1) were added to a three-necked flask in sequence, heated to 100℃, stirred evenly, and then poured into a mold. The mixture was then cured at 120℃ for 2h, 160℃ for 2h, and 200℃ for 4h to obtain the product. The product was then crushed and sieved to form a 50μm-100μm repairable resin.

[0057] Comparative Example 1

[0058] Select 20μm-40μm quartz sand powder.

[0059] Comparative Example 2

[0060] Select calcium carbonate powder with a particle size of 10μm-20μm.

[0061] Comparative Example 3

[0062] This comparative example provides an epoxy resin-coated quartz sand powder cured with a conventional anhydride curing agent.

[0063] The following steps were taken to prepare the product using 73g of 20-40 micron silica sand powder, 26g of cured epoxy resin powder, and 3g of calcium stearate as raw materials:

[0064] (1) Use a heatable mixer to heat the cured epoxy resin powder to 200°C and stir for 2 minutes until the resin is completely in a liquid molten state.

[0065] (2) While maintaining the heating conditions, mix the micron-sized inert particles with the molten high-temperature resistant resin in step (1) and stir for 5 minutes;

[0066] (3) Lower the temperature to 90℃, add lubricant and continue stirring for 2 minutes;

[0067] (4) Cool and crush the material obtained in step (3) and pass it through a sieve to obtain the product of Comparative Example 3 with a particle size of 20-40 micrometers.

[0068] The synthesis process of the cured epoxy resin powder is as follows:

[0069] 68g of bisphenol F epoxy resin and 34g of hexahydrophthalic anhydride were heated to 100℃, stirred evenly, and then poured into a mold. The mixture was then cured at 110℃ for 2 hours and at 150℃ for 15 hours to obtain the product. The product was then pulverized and sieved to form a 50μm-100μm cured epoxy resin powder.

[0070] Comparative Example 4

[0071] Select 60μm-80μm quartz sand powder.

[0072] Comparative Example 5

[0073] Select calcium carbonate powder with a particle size of 100μm-200μm.

[0074] Performance testing

[0075] The compatibility and plugging performance of the samples from Examples 1-4 and Comparative Examples 1-5 with drilling fluid were evaluated using the following methods:

[0076] (1) Basic drilling fluid formulation:

[0077] ① Density is 1.6 g / cm³ 3 Water-based drilling fluid: 2% bentonite slurry, with the following added based on 100% of the bentonite slurry: 0.3% polymer thickener FA-367 + 1.5% polymer filtration loss reducer JT-888 + 3% sulfonated lignite + 7% KCl + 97% barite.

[0078] ② The density is 1.8 g / cm³ 3The oil-based drilling fluid is: No. 5 white oil + 40% calcium chloride solution (oil-water volume ratio, i.e., the volume ratio of white oil to calcium chloride solution is 8:2), and the following are added based on the total mass of white oil and calcium chloride solution as 100%: 4% organic clay + 4% primary emulsifier fatty acid amide DR-EM + 2% co-emulsifier alkanolamide DR-CO + 3% filtration loss reducer humic acid amide FLRA + 3% calcium oxide + 175% barite;

[0079] (2) Filtration loss reduction performance test: Based on drilling fluid mass of 100%, 3% of the samples from Examples 1-2 and Comparative Examples 1-3 were added to oil-based drilling fluid, respectively. After thorough mixing, the drilling fluid containing the plugging materials from Examples 1 and Comparative Examples 1 was aged at 160℃ for 16 hours, and the drilling fluid containing the plugging materials from Examples 2 and Comparative Examples 2 and 3 was aged at 180℃ for 16 hours. According to GB / T 29170-2012 "Laboratory Testing Standards for Drilling Fluids in Petroleum and Natural Gas Industry", the apparent viscosity AV, plastic viscosity PV, demulsification voltage, and high-temperature, high-pressure filtration loss FL of the aged sample slurry at 65℃ were tested. HTHP PPA sand disc filtration loss FL at different temperatures 砂盘 3% of the samples from Examples 3-4 and Comparative Examples 4-5 were added to water-based drilling fluids, respectively. After thorough mixing, the drilling fluids containing the plugging materials from Examples 3 and 4 were aged at 120°C for 16 hours, and the drilling fluids containing the plugging materials from Examples 4 and 5 were aged at 140°C for 16 hours. The apparent viscosity AV, plastic viscosity PV, and high-temperature high-pressure filtration loss FL of the aged sample slurry at 65°C were tested. HTHP PPA sand disc filtration loss FL at different temperatures 砂盘 The results are shown in Tables 1 and 2. The sand tray after the PPA high-temperature and high-pressure filtration test at 180℃ for the test sample in Example 3 is shown in... Figure 2 As shown, the surface filter cake is thin and dense; the sand tray of the test sample in Comparative Example 4 after the PPA high-temperature and high-pressure filtration loss experiment at 180℃ is as follows. Figure 3 As shown, the surface filter cake is of poor thickness; the sand tray of the test sample in Comparative Example 5 after the PPA high-temperature and high-pressure filtration loss test at 100℃ is as follows. Figure 4 As shown, the surface filter cake has a loose thickness.

[0080] (3) Secondary plugging filtration loss test: The sand tray tested in (2) was taken out and rinsed, and ultrasonically treated in clean water or white oil for 10 minutes to simulate the flushing of downhole drilling fluid. White oil was used for the group that added the plugging materials of Examples 1-2 and Comparative Examples 1-3, and clean water was used for the group that added the plugging materials of Examples 3-4 and Comparative Examples 4-5. After ultrasonic treatment, the sand tray was taken out and placed in the PPA plugging instrument in reverse. Oil-based drilling fluid base formula ② (without barite) was used for Examples 1-2 and Comparative Examples 1-3, and water-based drilling fluid base formula ① (without barite) was used for Examples 3-4 and Comparative Examples 4-5. The high-temperature and high-pressure sand tray filtration loss FL was tested again according to GB / T 29170-2012 "Laboratory Testing Standard for Drilling Fluids in Petroleum and Natural Gas Industry". 二次砂盘 .

[0081] Table 1. Basic and plugging properties of oil-based drilling fluids in Examples 1-2 and Comparative Examples 1-3

[0082]

[0083]

[0084] Table 2. Basic and plugging properties of water-based drilling fluids in Examples 3-4 and Comparative Examples 4-5

[0085]

[0086] As can be seen from Tables 1 and 2, the plugging material of the present invention has good compatibility with water-based and oil-based drilling fluids and has excellent plugging performance. In particular, the secondary plugging filtration loss is low, indicating that the plugging layer formed has a good anti-drilling fluid erosion effect.

Claims

1. A temperature- and pressure-responsive plugging material for drilling, comprising, by weight, the following raw materials: 60-80 parts micron-sized inert particles, 8-20 parts repairable resin, and 2-5 parts lubricant; The repairable resin is obtained by curing resin monomers with a multifunctional cyclic anhydride curing agent, wherein the multifunctional cyclic anhydride curing agent is prepared by reacting polyhydroxyamines and cyclic anhydrides; wherein the mass ratio of the resin monomer to the multifunctional cyclic anhydride curing agent is 50-100:20-50, and the resin monomer includes one or more of hydrogenated bisphenol A type epoxy resin, bisphenol S type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, aliphatic glycidyl ether epoxy resin, and alicyclic epoxy resin. The preparation method of the multifunctional cyclic anhydride curing agent includes the following steps: Under anaerobic conditions, a cyclic anhydride is added to a polyhydroxyamine, and the mixture is heated to 80-150℃ and reacted for 0.5-10 hours to obtain the polyfunctional cyclic anhydride curing agent. The molar ratio of the polyhydroxyamine to the cyclic anhydride is 2:(2-15). The polyhydroxyamine includes one or more of bis(hydroxyethyl)amine, triethanolamine, and N,N,N',N'-tetra(2-hydroxypropyl)ethylenediamine. The cyclic anhydride includes one or more of maleic anhydride, succinic anhydride, glutaric anhydride, and methyltetrahydrophthalic anhydride. The method for preparing the repairable resin includes the following steps: The resin monomer and the multifunctional cyclic anhydride curing agent are mixed at 100-150°C, cured at 100-120°C for 1-3 hours, cured at 140-160°C for 1-3 hours, and cured at 180-220°C for 2-5 hours to obtain the repairable resin.

2. The temperature- and pressure-responsive plugging material according to claim 1, wherein, The micron-sized inert particles include quartz sand and / or calcium carbonate.

3. The temperature- and pressure-responsive plugging material according to claim 1, wherein, The particle size of the micron-sized inert particles is 10-200 μm.

4. The temperature- and pressure-responsive plugging material according to claim 1, wherein, In the preparation method of the multifunctional cyclic anhydride curing agent, the molar ratio of the polyhydroxyamine to the cyclic anhydride is 2:(3-12).

5. The temperature- and pressure-responsive plugging material according to claim 1, wherein, The lubricant includes one or more of calcium stearate, zinc stearate, and talc.

6. A method for preparing the temperature-pressure responsive plugging material as described in any one of claims 1-5, comprising the following steps: (1) The repairable resin is heated to 180-220°C to melt, and the micron-sized inert particles are added and mixed. (2) Cool down to 70-90℃, add the lubricant, and mix; (3) Cooling to obtain the temperature and pressure responsive drilling plugging material.

7. The preparation method according to claim 6, wherein, In step (3), after cooling, the material is further pulverized to 10-200 μm.

8. The application of the temperature and pressure responsive plugging material according to any one of claims 1-5 in drilling fluid.

9. The application according to claim 8, wherein, The temperature- and pressure-responsive plugging material used in drilling exerts its plugging effect at 120-180℃.

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