Composite resin as well as preparation method and application thereof

Abstract

The invention provides composite resin as well as a preparation method and application thereof. The composite resin comprises the following raw materials: 30%-50% of epoxy resin, 10%-30% of a curing agent, 0.1%-5% of aerogel silicon dioxide, 3%-8% of a silane coupling agent, 5%-15% of a toughening agent, 3%-10% of a styrene-maleic anhydride copolymer, 3%-15% of a nano solid lubricant, 2%-10% of nano magnetic particles and 10%-40% of a diluent. The composite resin has the advantages of good sealing performance, high temperature resistance and strong adhesive force, and can meet the requirements of the inner surface of an underground pipe column on sealing, lubrication and service life.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas development, and specifically relates to a composite resin and a preparation method and application thereof. Background Art

[0002] The threaded joints of the pipe string used in oil and gas development mainly rely on the metal-metal interference sealing surface to provide sealing performance. If the tightening torque is not in place during field use or other reasons cause the sealing surface to not contact, the contact pressure is too low, or the downhole load conditions are too complicated, leakage may occur in the connection joint after a period of service, resulting in an abnormal increase in annular pressure. At present, there is no good way to deal with the leakage of threaded joints. Either the annulus is pressurized or the tubing string is taken out and replaced with a new string for use in the well. When working with annulus pressure, it is necessary to always consider whether the anti-squeezing strength of the string is sufficient. When the pressure reaches the critical value, it is necessary to go to the site to release part of the annular pressure, which brings the problem of the gradual reduction of the annular protection fluid. Replacing a new string is not only time-consuming and costly, but the premature well killing operation may also cause serious damage to the production layer, causing irreparable losses to the production of oil and gas wells. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a composite resin and its preparation method and application, which has good sealing performance, high temperature resistance, strong adhesion, and can meet the requirements of the inner surface of the downhole pipe for sealing, lubrication and service life.

[0004] In order to achieve the above object, the present invention provides a composite resin, and the raw material composition thereof includes:

[0005] Epoxy resin 30%-50%, curing agent 10%-30%, aerogel silica 0.1%-5%, silane coupling agent 3%-8%, toughening agent 5%-15%, styrene maleic anhydride copolymer 3%-10%, nano solid lubricant 3%-15%, nano magnetic particles 2%-10%, diluent 10%-40%.

[0006] According to a specific embodiment of the present invention, preferably, the epoxy resin is a liquid epoxy resin with a high temperature resistance of ≥180°C.

[0007] According to a specific embodiment of the present invention, preferably, the epoxy resin includes one or a combination of two or more of an organosilicon-modified alicyclic epoxy resin, an alicyclic epoxy resin, and an aliphatic epoxidized olefin compound.

[0008] According to a specific embodiment of the present invention, preferably, the nano magnetic particles include iron oxide magnetic powder and / or chromium dioxide magnetic powder.

[0009] According to a specific embodiment of the present invention, preferably, the nano solid lubricant includes one or a combination of two or more of molybdenum disulfide, manganese disulfide, polytetrafluoroethylene, and graphite.

[0010] According to a specific embodiment of the present invention, preferably, the curing agent includes one or a combination of two or more of diethylenetriamine, triethylenetetramine, and diethylaminopropylamine.

[0011] According to a specific embodiment of the present invention, preferably, the silane coupling agent includes one or a combination of two or more of aminosilane, vinylsilane, and methacryloxysilane.

[0012] According to a specific embodiment of the present invention, preferably, the toughening agent includes one or a combination of two or more of polyethersulfone (PES), polyetherketone (PEK), polyetheretherketone (PEEK), and polyetherimide (PEI).

[0013] According to a specific embodiment of the present invention, preferably, the diluent includes one or a combination of two or more of tert-butyl alcohol, isopropyl alcohol, and ethanol.

[0014] According to a specific embodiment of the present invention, preferably, the raw material composition of the composite resin includes: 30-50% epoxy resin, 10-30% curing agent, 0.1-0.5% aerogel silica, 3-5% silane coupling agent, 8-12% toughening agent, 3-7% styrene maleic anhydride copolymer, 5-8% nano solid lubricant, 2-5% nano magnetic particles, and 20-30% diluent.

[0015] The present invention also provides a method for preparing the composite resin, which comprises the following steps:

[0016] The styrene maleic anhydride copolymer and the diluent are mixed at 60-90°C, stirred at a speed of 150-300rpm, epoxy resin, toughening agent, silane coupling agent are added, and after mixing, aerogel silica, nano solid lubricant, nano magnetic particles and curing agent are added to obtain the composite resin.

[0017] According to a specific embodiment of the present invention, preferably, aerogel silica, nano solid lubricant, nano magnetic particles and curing agent are added, mixed and then left to stand for 2 hours or sealed and vacuumed to obtain the composite resin.

[0018] According to a specific embodiment of the present invention, the above preparation method comprises the following specific steps:

[0019] Styrene maleic anhydride copolymer is mixed with a diluent, heated to 60°C, and allowed to stand for 30 minutes to allow the two to completely dissolve; then, low-speed stirring is started with a stirrer with a maximum speed of not less than 3000rpm, and epoxy resin, toughening agent, and silane coupling agent are gradually added until all are mixed together, and then high-speed stirring is continued for 30 minutes. Then, the stirrer is switched to low-speed rotation, and aerogel silica, nano solid lubricant, nano magnetic particles, and curing agent are gradually added. After all are added, high-speed stirring is continued for 30 minutes, and then allowed to stand for 5 hours, or the mixed composite resin is sealed and vacuumed to allow the bubbles in the resin solution to escape as much as possible, thereby reducing the tiny pores in the epoxy resin after curing.

[0020] The present invention also provides a method for repairing and sealing leakage of a fluid pipeline, which adopts the composite resin for repairing and sealing.

[0021] According to a specific embodiment of the present invention, preferably, fluid pipeline leakage repair and plugging includes leakage repair and plugging of connection parts of high-pressure gas wells or gas storage injection and production wells.

[0022] According to a specific embodiment of the present invention, preferably, the temperature for repairing and sealing fluid pipeline leakage is no greater than 180°C.

[0023] According to a specific embodiment of the present invention, preferably, when repairing and plugging fluid pipeline leakage, the composite resin is applied to the pipeline leakage position within 3-5 hours after preparation, and the composite resin is cured at 20-180° C. for 10 minutes.

[0024] According to a specific embodiment of the present invention, preferably, during the curing process, a magnetic field is applied on both sides of the leakage gap at the connection part.

[0025] The composite resin of the present invention has high bonding strength, appropriate hardness and self-lubricating properties, and can be used for downhole in-situ repair of oil pipe string thread leakage. It can replace the operation of removing and replacing the pipe string, greatly saving costs, reducing interference with production, and obtaining greater economic benefits. The composite resin has good sealing performance, high temperature resistance up to 180°C, strong adhesion, and does not fall off after 40 stretching-compression cycles; when in use, the composite resin is cured around the entire circumference of the leaking threaded joint, which can not only seal the joint leakage, but also meet the requirements of non-destructive passage when other tools are lowered into the oil pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of applying a magnetic field to repair and seal a leak. DETAILED DESCRIPTION

[0027] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0028] Example 1

[0029] This embodiment provides a composite resin, which is prepared by the following steps:

[0030] Mix 50g of styrene maleic anhydride copolymer with 150g of isopropanol, heat to 60°C, let stand for 30 minutes, and slowly shake the container to completely dissolve the two. Then start low-speed stirring with a stirrer at a speed of 100rpm, gradually add 600g of aliphatic epoxidized olefin compound, 70g of polyetheretherketone, and 40g of aminosilane coupling agent until all are mixed together, and then stir at a high speed of 4000rpm for 30 minutes, then the stirrer turns to a low-speed rotation of 100rpm, and gradually add 3g of aerogel silica, 80g of nano polytetrafluoroethylene, 25g of nano iron oxide magnetic powder and 250g of diethylaminopropylamine curing agent. After all are added, stir at high speed for 30 minutes before use.

[0031] When used, mix on the ground and immediately go down the well, and apply to the leaking location within 3-5 hours. The oil pipe threads are sealed in the laboratory, and a magnetic field is applied on both sides of the leaking gap during curing to simulate the working conditions of the gas storage pipe string. After 20 tensile-compression and internal pressure cycle loads at room temperature and 150°C, no leakage occurs in the threads. The specific coating and testing process is the same as in Example 2.

[0032] Example 2

[0033] This embodiment provides a composite resin, which is prepared by the following steps:

[0034] Mix 50g of styrene maleic anhydride copolymer with 150g of isopropanol, heat to 60°C, let stand for 30 minutes, and slowly shake the container to completely dissolve the two. Then start low-speed stirring with a stirrer at a speed of 100rpm, gradually add 600g of silicone-modified epoxy resin, 90g of polyetherimide, and 40g of methacryloxysilane coupling agent until all are mixed together, then stir at a high speed of 4000rpm for 30 minutes, then the stirrer turns to a low-speed rotation of 100rpm, gradually add 2g of aerogel silica, 90g of nano molybdenum disulfide, 30g of nano chromium dioxide magnetic powder and 350g of diethylaminopropylamine curing agent, and after all are added, stir at high speed for 30 minutes before use.

[0035] Under the condition that the ambient temperature is higher than 20°C, the mixed composite resin of Example 2 is applied to the inner surface of the oil pipe connection joint within 3-5 hours, and then the two poles of the electromagnet (such as Figure 1 As shown), the electromagnet is energized (the magnetic field strength is not less than 2 Tesla) for 10 minutes, the composite resin of Example 2 applied is basically cured, the electromagnet is stopped from being energized, and the next step of the test is carried out.

[0036] Test process: Both ends of the oil pipe are welded and sealed, and a gas pressurization hole is left on the plug. To simulate the environmental load of the gas storage, 20 tensile-compression loads are applied to the oil pipe at room temperature, and then the internal pressure is applied to the oil pipe through the reserved air holes to 80% of the rated internal pressure strength, and then the tensile load is slowly applied to the oil pipe to 35% of the rated tensile strength, and maintained for 30 minutes, while monitoring the release of gas in the pipe for leakage. If there is no leakage, remove the tensile and internal pressure loads, use induction heating to heat the oil pipe to 180°C, apply 20 tensile-compression loads to the oil pipe, and then apply the internal pressure to the oil pipe through the reserved air holes to 70% of the rated internal pressure strength, and then slowly apply the tensile load to the oil pipe to 30% of the rated tensile strength, and maintain for 30 minutes, while monitoring the release of gas in the pipe for leakage. No leakage, remove the tensile and internal pressure loads, saw off the plugs at both ends of the tubing, use a drift rod to simulate the downhole tool sliding back and forth 20 times at the curing resin position, and there is no obvious damage or shedding on the resin surface; the test parameter setting is calculated in reference to ISO10400:2018.

[0037] Comparative Example 1

[0038] This comparative example provides a composite resin, which is prepared by the following steps:

[0039] Mix 50g of styrene maleic anhydride copolymer with 150g of isopropanol, heat to 60°C, let stand for 30 minutes, and slowly shake the container to make the two completely dissolved. Then start low-speed stirring with a stirrer at a speed of 100rpm, gradually add 600g of bisphenol A epoxy resin, 90g of polyetherimide, and 30g of aminosilane coupling agent until all are mixed together, then stir at a high speed of 4000rpm for 30 minutes, then the stirrer is turned into a low-speed rotation of 100rpm, and gradually add 2g of aerogel silica, 90g of nano molybdenum disulfide, 30g of nano chromium dioxide magnetic powder and 350g of diethylaminopropylamine curing agent. After all are added, stir at high speed for 30 minutes before use.

[0040] The oil pipe threads were sealed in the laboratory, and a magnetic field was applied on both sides of the leakage gap during curing. After 12 tension-compression and internal pressure cycle loads were applied at room temperature, the threaded joint leaked. The cause was analyzed to be cracking of the curing resin. The specific coating and testing process was the same as Example 2.

[0041] Comparative Example 2

[0042] The composite resin obtained in Example 2 was tested as follows:

[0043] When used, simulate the downhole test immediately after mixing on the ground, and apply it to the leaking position within 3-5 hours. The oil pipe threads were sealed in the laboratory. No magnetic field was applied on both sides of the leaking gap during curing. After loading 7 tensile-compression and internal pressure cycle loads at room temperature, the threaded joint leaked. The reason was analyzed to be that the thickness of the cured resin on the leaking gap was not enough, resulting in insufficient pressure bearing strength. The specific coating and testing process was the same as Example 2.

Claims

1. A composite resin, wherein the raw material composition of the composite resin is 100% by weight: Epoxy resin 30%-50%, curing agent 10%-30%, aerogel silica 0.1%-5%, silane coupling agent 3%-8%, toughening agent 5%-15%, styrene maleic anhydride copolymer 3%-10%, nano solid lubricant 3%-15%, nano magnetic particles 2%-10%, diluent 10%-40%.

2. The composite resin according to claim 1, wherein The epoxy resin is a liquid epoxy resin with a high temperature resistance of ≥180°C.

3. The composite resin according to claim 1, wherein The epoxy resin includes one or a combination of two or more of silicone-modified alicyclic epoxy resin, alicyclic epoxy resin, and aliphatic epoxidized olefin compounds.

4. The composite resin according to claim 1, wherein The nano magnetic particles include iron oxide magnetic powder and / or chromium dioxide magnetic powder.

5. The composite resin according to claim 1, wherein The nano solid lubricant includes one or a combination of two or more of molybdenum disulfide, manganese disulfide, polytetrafluoroethylene and graphite.

6. The composite resin according to claim 1, wherein The curing agent includes one or a combination of two or more of diethylenetriamine, triethylenetetramine and diethylaminopropylamine.

7. The composite resin according to claim 1, wherein The silane coupling agent includes one or a combination of two or more of aminosilane, vinylsilane and methacryloxysilane.

8. The composite resin according to claim 1, wherein The toughening agent includes one or a combination of two or more of polyethersulfone, polyetherketone, polyetheretherketone and polyetherimide.

9. The composite resin according to claim 1, wherein The diluent includes one or a combination of two or more of tert-butyl alcohol, isopropyl alcohol and ethanol.

10. The composite resin according to claim 1, wherein The raw materials of the composite resin include: 30-50% epoxy resin, 10-30% curing agent, 0.1-0.5% aerogel silica, 3-5% silane coupling agent, 8-12% toughening agent, 3-7% styrene maleic anhydride copolymer, 5-8% nano solid lubricant, 2-5% nano magnetic particles and 20-30% diluent.

11. A method for preparing a composite resin according to any one of claims 1 to 10, comprising the following steps: The styrene maleic anhydride copolymer and the diluent are mixed at 60-90° C., stirred at a speed of 150-300 rpm, epoxy resin, toughening agent, silane coupling agent are added, and after mixing, aerogel silica, nano solid lubricant, nano magnetic particles and curing agent are added, and after mixing, the composite resin is obtained; Preferably, aerogel silica, nano solid lubricant, nano magnetic particles and curing agent are added, mixed and then left to stand for 2 hours or sealed and vacuumed to obtain the composite resin.

12. A method for repairing and sealing fluid pipeline leakage, which uses the composite resin according to any one of claims 1 to 10 for repairing and sealing.

13. The method according to claim 12, wherein: Fluid pipeline leakage repair and plugging include leakage repair and plugging of the connection parts of high-pressure gas wells or gas storage injection and production wells.

14. The method according to claim 12, wherein: The temperature for repairing and sealing fluid pipeline leakage shall not exceed 180℃.

15. The method according to claim 12, wherein: When repairing and plugging fluid pipeline leakage, the composite resin is applied to the pipeline leakage position within 3-5 hours after preparation, and the composite resin is cured at 20-180° C. for 10 minutes.

16. The method according to claim 15, wherein: During the curing process, a magnetic field is applied on both sides of the leakage gap at the connection.

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