Anti-corrosion and high-temperature-resistant sealing ring and preparation process thereof

Abstract

The invention provides a corrosion-resistant and high-temperature-resistant sealing ring and a preparation process thereof, and relates to the technical field of repeated opening and closing plugging circulation tools. The anti-corrosion and high-temperature-resistant sealing ring is prepared from the following raw materials in parts by weight: 100 parts of a perfluoroether rubber polymer, 2 to 8 parts of carbon black, 0.5 to 2 parts of a cross-linking agent, 20 to 40 parts of filler, 1 to 5 parts of a vulcanizing agent, 2 to 5 parts of a vulcanizing aid, 0.2 to 2 parts of an acid acceptor and 0.2 to 5 parts of a plasticizer. The perfluoroether rubber is adopted as the main raw material, and compared with a traditional silicon rubber sealing ring, the perfluoroether rubber has better corrosion resistance, so that the perfluoroether rubber can well resist chemical substances in drilling fluid, the chemical performance is stable under the condition, and the perfluoroether rubber has the advantage of being low in friction coefficient and is more suitable for sliding sealing of tools.

Description

Technical Field

[0001] The present application relates to the technical field of multiple-opening and closing leak plugging cycle tools, and in particular to a rust-proof and high-temperature-resistant sealing ring and a preparation process thereof. Background Art

[0002] The Multiple Switch Plug Circulation Tool (MCCS) is a tool used to deal with wellbore fluid loss during drilling, especially for deepwater operations and complex well leakage situations. The MCCS is located in the BHA (downhole tool assembly) and can deliver high-concentration plugging materials (such as LCM) to the wellbore through multiple switching cycles when fluid loss is encountered, thereby solidifying and maintaining wellbore control. The MCCS uses multiple switching cycles to flow the plugging material out of the bypass hole of the circulation short section to avoid clogging and corrosion of the bottom drilling tool assembly. This design makes the plugging process more efficient while reducing well control risks.

[0003] The development and application of MCCS began in 2019. With the increase of deepwater operations and complex well leakage problems, MCCS has gradually become an effective tool for dealing with these problems. Its structure is simple and suitable for wide use, especially in well sections that need to frequently deal with well leakage. The multiple-switch plugging circulation tool can plug leaks with high-concentration large-particle materials multiple times without drilling when well leakage accidents occur, as well as wash the well or clean the casing, effectively reducing the risk of on-site well control. The seals used in the multiple-switch plugging circulation tool are prone to corrosion and damage under oil drilling operation conditions. The multiple-switch plugging circulation tool has high requirements for sealing, especially the two sets of sliding seals outside the sliding sleeve. Damage will directly lead to tool failure.

[0004] The sealing rings of the current multiple-opening plugging and leaking circulation tools have the following main problems: 1. Due to the complex chemical composition of the drilling fluid, it is very easy to corrode and damage. 2. The sealing rings used in the multiple-opening plugging and leaking circulation tools have high temperature resistance requirements, and ordinary sealing rings cannot meet the on-site requirements. Summary of the invention

[0005] The purpose of the present application is to provide a rust-proof and high-temperature resistant sealing ring, which has the advantages of high-temperature resistance, good corrosion resistance, low friction and excellent aging resistance.

[0006] Another object of the present application is to provide a process for preparing a rust-proof and high-temperature resistant sealing ring, which is simple and safe.

[0007] In order to solve the above technical problems, the technical solution adopted in this application is:

[0008] On the one hand, the present application provides a rust-proof and high-temperature resistant sealing ring. The raw materials of the rust-proof and high-temperature resistant sealing ring include, by weight: 100 parts of perfluoroether rubber polymer, 2-8 parts of carbon black, 0.5-2 parts of cross-linking agent, 20-40 parts of filler, 1-5 parts of vulcanizing agent, 2-5 parts of vulcanizing aid, 0.2-2 parts of acid absorber and 0.2-5 parts of plasticizer.

[0009] On the other hand, the present application provides a process for preparing a rust-proof and high-temperature resistant sealing ring, comprising the following steps:

[0010] S1, first plasticize the perfluoroether rubber polymer in a mixer for 2-4 times, mix the carbon black, crosslinking agent, filler, vulcanizing agent, vulcanizing aid, acid absorber and plasticizer, and add them into the mixer for plasticization and mixing to obtain a rubber compound;

[0011] S2, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder;

[0012] S3, subjecting the semi-finished sealing ring to primary vulcanization and secondary vulcanization under the protection of an inert gas, and obtaining the finished sealing ring after cooling.

[0013] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:

[0014] 1. This application uses perfluoroether rubber as the main raw material, which has better corrosion resistance than traditional silicone rubber sealing rings, so it can resist the chemical properties of chemicals in drilling fluids very well, and the low friction coefficient of perfluoroether rubber itself makes it more suitable for sliding seals of tools.

[0015] 2. This application uses carbon black, cross-linking agent, filler, vulcanizer, vulcanization aid, acid absorber and plasticizer to compound and modify perfluoroether rubber to improve the thermal conductivity, high temperature resistance and aging resistance of the sealing ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is the finished sealing ring prepared in the embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to specific embodiments.

[0020] A rust-proof and high-temperature resistant sealing ring. The raw materials of the rust-proof and high-temperature resistant sealing ring include, by weight: 100 parts of perfluoroether rubber polymer, 2-8 parts of carbon black, 0.5-2 parts of cross-linking agent, 20-40 parts of filler, 1-5 parts of vulcanizing agent, 2-5 parts of vulcanizing aid, 0.2-2 parts of acid absorbent and 0.2-5 parts of plasticizer.

[0021] In some embodiments of the present application, the cross-linking agent is one or more of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, triallyl isocyanurate, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0022] In some embodiments of the present application, the filler includes reinforcing fiber, modified mica powder and wollastonite, wherein the mass ratio of the reinforcing fiber, modified mica powder and wollastonite is (1-5):(1-5):1.

[0023] In some embodiments of the present application, the preparation method of the modified mica powder is as follows: add a silane coupling agent to anhydrous ethanol for dilution, then add mica powder, continue stirring for 1-2 hours, vacuum filter, and then dry the surface at 80-95°C; the mass ratio of the silane coupling agent to the mica powder is 1:(20-60). The present application uses a silane coupling agent to modify the surface of the mica powder. The hydrolyzable alkoxy group in the silane coupling agent reacts with the hydroxyl group on the surface of the mica to form a chemical bond Si-O-Si. The chemical bond is an active organic group, which reacts with the perfluoroether rubber polymer during the mixing and vulcanization process. The product plays a bridging role at the material interface between the polymer and the mica powder, making the connection between the small molecule filler and the polymer closer, reducing the interface defects between the matrix and the filler, and thereby reducing the scattering of phonons on the polymer surface, thereby improving the thermal conductivity of the material.

[0024] In some embodiments of the present application, the vulcanizing agent is hexamethylenediamine, tetraethylenepentamine or bisphenol A, and the vulcanizing aid is magnesium oxide.

[0025] In some embodiments of the present application, the acid absorber is zinc oxide; and the plasticizer is perfluoro oil.

[0026] A preparation process of a rust-proof and high-temperature-resistant sealing ring comprises the following steps:

[0027] S1, first plasticize the perfluoroether rubber polymer in a mixer for 2-4 times, mix the carbon black, crosslinking agent, filler, vulcanizing agent, vulcanizing aid, acid absorber and plasticizer, and add them into the mixer for plasticization and mixing to obtain a rubber compound;

[0028] S2, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder;

[0029] S3, subjecting the semi-finished sealing ring to primary vulcanization and secondary vulcanization under the protection of inert gas to improve its elasticity and durability, and obtaining the finished sealing ring after cooling.

[0030] In some embodiments of the present application, the mixing temperature of the above step S1 is 70-80° C., and the mixing time is 10-30 min.

[0031] In some embodiments of the present application, the primary vulcanization temperature in the above step S3 is 170-190° C. and the time is 10-20 min.

[0032] In some embodiments of the present application, the temperature of the secondary vulcanization in the above step S3 is 240-245° C., and the time is 12-24 hours.

[0033] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0034] Example 1

[0035] A rust-proof and high-temperature-resistant sealing ring is prepared by the following process:

[0036] S1. Weigh the raw materials in parts by weight: 100 parts of perfluoroether rubber polymer, 3 parts of carbon black, 1.2 parts of crosslinking agent (triallyl isocyanurate), 25 parts of filler (reinforced fiber, modified mica powder and wollastonite in a mass ratio of 2:2:1), 2 parts of vulcanizing agent (bisphenol A), 2 parts of vulcanizing aid (magnesium oxide), 1.5 parts of acid absorber (zinc oxide) and 3 parts of plasticizer (perfluoro oil); wherein the modified mica powder is prepared by the following method: adding silane coupling agent to anhydrous ethanol for dilution, the mass concentration after dilution is 4%, then adding mica powder, stirring continuously for 2 hours, vacuum filtering, and then drying the surface at 90°C; in this embodiment, the mass ratio of silane coupling agent to mica powder is 1:30;

[0037] S2, the perfluoroether rubber polymer is first plasticized twice in a mixer, and carbon black, a crosslinking agent, a filler, a vulcanizing agent, a vulcanizing aid, an acid absorber and a plasticizer are mixed and added into a mixer for plasticization and mixing, the mixing temperature is 75° C., and the mixing time is 20 min to obtain a rubber compound;

[0038] S3, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder;

[0039] S4, the semi-finished sealing ring is subjected to primary vulcanization and secondary vulcanization under the protection of nitrogen inert gas, wherein the primary vulcanization temperature is 175°C, the time is 15min, and the secondary vulcanization temperature is 240°C, the time is 18h; after cooling, the finished sealing ring of this embodiment is obtained, as shown Figure 1 shown.

[0040] Example 2

[0041] A rust-proof and high-temperature-resistant sealing ring is prepared by the following process:

[0042] S1. Weigh the raw materials in parts by weight: 100 parts of perfluoroether rubber polymer, 6 parts of carbon black, 1.5 parts of crosslinking agent (2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane), 30 parts of filler (reinforced fiber, modified mica powder and wollastonite in a mass ratio of 3:3:1), 2 parts of vulcanizing agent (hexamethylenediamine), 2 parts of vulcanizing aid (magnesium oxide), 2 parts of acid absorbent (zinc oxide) and 3.5 parts of plasticizer (perfluoro oil); wherein the modified mica powder is prepared by the following method: adding silane coupling agent to anhydrous ethanol for dilution, the mass concentration after dilution is 3.5%, then adding mica powder, stirring continuously for 1.5 hours, vacuum filtering, and then drying the surface at 90°C; in this embodiment, the mass ratio of silane coupling agent to mica powder is 1:40;

[0043] S2, the perfluoroether rubber polymer is first plasticized twice in a mixer, and carbon black, a crosslinking agent, a filler, a vulcanizing agent, a vulcanizing aid, an acid absorber and a plasticizer are mixed and added into the mixer for plasticization and mixing at a mixing temperature of 78° C. for 15 min to obtain a rubber compound;

[0044] S3, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder;

[0045] S4. Perform primary vulcanization and secondary vulcanization on the semi-finished sealing ring under the protection of nitrogen inert gas, wherein the primary vulcanization temperature is 172° C. and the time is 15 min, and the secondary vulcanization temperature is 240° C. and the time is 20 h; after cooling, the finished sealing ring of this embodiment is obtained.

[0046] Example 3

[0047] A rust-proof and high-temperature-resistant sealing ring is prepared by the following process:

[0048] S1. Weigh the raw materials in parts by weight: 100 parts of perfluoroether rubber polymer, 2 parts of carbon black, 0.5 parts of crosslinking agent (triallyl isocyanurate), 35 parts of filler (reinforced fiber, modified mica powder and wollastonite in a mass ratio of 2:5:1), 5 parts of vulcanizing agent (bisphenol A), 5 parts of vulcanizing aid (magnesium oxide), 1 part of acid absorber (zinc oxide) and 3.5 parts of plasticizer (perfluoro oil); wherein the modified mica powder is prepared by the following method: adding silane coupling agent to anhydrous ethanol for dilution, the mass concentration after dilution is 3.5%, then adding mica powder, stirring continuously for 1 hour, vacuum filtering, and then drying the surface at 85°C; in this embodiment, the mass ratio of silane coupling agent to mica powder is 1:20;

[0049] S2, the perfluoroether rubber polymer was first plasticized in a mixer for 3 times, and carbon black, crosslinking agent, filler, vulcanizing agent, vulcanizing aid, acid absorber and plasticizer were mixed and added into the mixer for plasticization and mixing at a mixing temperature of 78° C. for 20 min to obtain a rubber compound;

[0050] S3, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder;

[0051] S4. Perform primary vulcanization and secondary vulcanization on the semi-finished sealing ring under the protection of nitrogen inert gas, wherein the primary vulcanization temperature is 185° C. and the time is 12 min, and the secondary vulcanization temperature is 245° C. and the time is 24 h; after cooling, the finished sealing ring of this embodiment is obtained.

[0052] Example 4

[0053] A rust-proof and high-temperature-resistant sealing ring is prepared by the following process:

[0054] S1. Weigh the raw materials in parts by weight: 100 parts of perfluoroether rubber polymer, 3 parts of carbon black, 1.6 parts of crosslinking agent (5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 40 parts of filler (reinforced fiber, modified mica powder and wollastonite in a mass ratio of 3:4:1), 3 parts of vulcanizing agent (bisphenol A), 2 parts of vulcanizing aid (magnesium oxide), 1 part of acid absorber (zinc oxide) and 2 parts of plasticizer (perfluoro oil); wherein the modified mica powder is prepared by the following method: adding silane coupling agent to anhydrous ethanol for dilution, the mass concentration after dilution is 3.5%, then adding mica powder, stirring continuously for 2 hours, vacuum filtering, and then drying the surface at 92°C; in this embodiment, the mass ratio of silane coupling agent to mica powder is 1:40;

[0055] S2, the perfluoroether rubber polymer was first plasticized in a mixer for 3 times, and carbon black, crosslinking agent, filler, vulcanizing agent, vulcanizing aid, acid absorber and plasticizer were mixed and added into the mixer for plasticization and mixing, the mixing temperature was 75°C, the mixing time was 15min, and a rubber compound was obtained;

[0056] S3, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder;

[0057] S4. Perform primary vulcanization and secondary vulcanization on the semi-finished sealing ring under the protection of nitrogen inert gas, wherein the primary vulcanization temperature is 180° C. and the time is 12 min, and the secondary vulcanization temperature is 240° C. and the time is 24 h; after cooling, the finished sealing ring of this embodiment is obtained.

[0058] Example 5

[0059] A rust-proof and high-temperature-resistant sealing ring is prepared by the following process:

[0060] S1. Weigh the raw materials in parts by weight: 100 parts of perfluoroether rubber polymer, 3.5 parts of carbon black, 2 parts of crosslinking agent (5-dimethyl-2,5-bis(tert-butylperoxy)hexane), 40 parts of filler (reinforced fiber, modified mica powder and wollastonite in a mass ratio of 3:4:1), 2 parts of vulcanizing agent (bisphenol A), 2 parts of vulcanizing aid (magnesium oxide), 1.5 parts of acid absorber (zinc oxide) and 2 parts of plasticizer (perfluoro oil); wherein the modified mica powder is prepared by the following method: adding silane coupling agent to anhydrous ethanol for dilution, the mass concentration after dilution is 4%, then adding mica powder, stirring continuously for 2 hours, vacuum filtering, and then drying the surface at 90°C; in this embodiment, the mass ratio of silane coupling agent to mica powder is 1:40;

[0061] S2, the perfluoroether rubber polymer is first plasticized in a mixer for 4 times, and the carbon black, crosslinking agent, filler, vulcanizing agent, vulcanizing aid, acid absorber and plasticizer are mixed and added into the mixer for plasticization and mixing, the mixing temperature is 75° C., the mixing time is 20 min, and a rubber compound is obtained;

[0062] S3, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder;

[0063] S4. Perform primary vulcanization and secondary vulcanization on the semi-finished sealing ring under the protection of nitrogen inert gas, wherein the primary vulcanization temperature is 175° C. and the time is 15 min, and the secondary vulcanization temperature is 240° C. and the time is 15 h; after cooling, the finished sealing ring of this embodiment is obtained.

[0064] Comparative Example

[0065] The difference between this comparative example and Example 1 is that unmodified mica powder is used in this comparative example.

[0066] Experimental example

[0067] 1. The thermal conductivity of Examples 1-3 and Comparative Example 1 was tested, and the perfluoroether rubber polymer was used as a blank comparison. The results are shown in Table 1. The thermal conductivity was measured according to GB / T 11205-1989 (transient hot wire method).

[0068] Table 1

[0069]

[0070]

[0071] As can be seen from Table 1, the thermal conductivity of the products of the embodiment and the comparative example is significantly improved compared with the perfluoroether rubber of the blank group, especially the embodiment has a better effect, which shows that the modified mica powder has an outstanding effect in improving thermal conductivity.

[0072] 2. The acid and alkali resistance of Example 1, Comparative Example 1, perfluoroether rubber polymer (blank group) and traditional silicone rubber sealing ring (control group) were tested; the samples were immersed in a nitric acid solution at 70°C and a mass fraction of 0.6 for 3 days and in a sodium hydroxide solution at 100°C and a mass fraction of 0.5 for 3 days, and the volume change rate was measured, as shown in Table 2.

[0073] Table 2

[0074]

[0075]

[0076] It can be seen from Table 2 that compared with traditional silicone rubber sealing rings and ordinary perfluoroether rubber sealing rings, the rust-resistant and high-temperature resistant sealing rings prepared in the present application have better acid and alkali resistance, and are not easily corroded in the complex chemical system of drilling fluid.

[0077] In summary, the rust-proof and high-temperature-resistant sealing ring and its preparation process of the embodiment of the present application have the following advantages: 1. The present application adopts perfluoroether rubber as the main raw material, which has better corrosion resistance than traditional silicone rubber sealing rings, so it can resist the chemical properties of chemicals in drilling fluids well and has stable chemical properties. The advantage of perfluoroether rubber itself with low friction coefficient makes it more suitable for sliding sealing of tools.

[0078] 2. This application uses carbon black, cross-linking agent, filler, vulcanizer, vulcanization aid, acid absorber and plasticizer to compound and modify perfluoroether rubber to improve the thermal conductivity, high temperature resistance and aging resistance of the sealing ring.

[0079] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present application.

Claims

1. A rust-proof and high-temperature resistant sealing ring, characterized in that: The raw materials of the rust-proof and high-temperature-resistant sealing ring include, by weight: 100 parts of perfluoroether rubber polymer, 2-8 parts of carbon black, 0.5-2 parts of crosslinking agent, 20-40 parts of filler, 1-5 parts of vulcanizing agent, 2-5 parts of vulcanizing aid, 0.2-2 parts of acid absorbent and 0.2-5 parts of plasticizer.

2. The anti-corrosion and high temperature resistant sealing ring according to claim 1, characterized in that: The crosslinking agent is one or more of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, triallyl isocyanurate, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

3. The anti-corrosion and high temperature resistant sealing ring according to claim 3, characterized in that: The filler comprises reinforcing fiber, modified mica powder and wollastonite, wherein the mass ratio of the reinforcing fiber, the modified mica powder and the wollastonite is (1-5):(1-5):

1.

4. The anti-corrosion and high temperature resistant sealing ring according to claim 3, characterized in that: The preparation method of the modified mica powder is: adding a silane coupling agent to anhydrous ethanol for dilution, then adding mica powder, continuously stirring for 1-2 hours, vacuum filtering, and then drying the surface at 80-95° C.; the mass ratio of the silane coupling agent to the mica powder is 1:(20-60).

5. The anti-corrosion and high temperature resistant sealing ring according to claim 3, characterized in that: The vulcanizing agent is hexamethylenediamine, tetraethylenepentamine or bisphenol A, and the vulcanizing aid is magnesium oxide.

6. The anti-corrosion and high temperature resistant sealing ring according to claim 3, characterized in that: The acid absorbent is zinc oxide; the plasticizer is perfluoro oil.

7. A process for preparing a corrosion-resistant and high-temperature-resistant sealing ring according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, first plasticize the perfluoroether rubber polymer in a mixer for 2-4 times, mix the carbon black, crosslinking agent, filler, vulcanizing agent, vulcanizing aid, acid absorber and plasticizer, and add them into the mixer for plasticization and mixing to obtain a rubber compound; S2, extruding the mixed rubber into a semi-finished sealing ring of a specific shape through an extruder; S3, subjecting the semi-finished sealing ring to primary vulcanization and secondary vulcanization under the protection of an inert gas, and obtaining the finished sealing ring after cooling.

8. The process for preparing the anti-corrosion and high temperature resistant sealing ring according to claim 7, characterized in that: The mixing temperature of step S1 is 70-80° C., and the mixing time is 10-30 min.

9. The process for preparing the anti-corrosion and high temperature resistant sealing ring according to claim 7, characterized in that: The primary vulcanization temperature in step S3 is 170-190° C. and the time is 10-20 min.

10. The process for preparing the anti-corrosion and high temperature resistant sealing ring according to claim 9, characterized in that: The temperature of the secondary vulcanization in step S3 is 240-245° C. and the time is 12-24 hours.

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