Processing method for cloth-wrapped fracturing packing

Abstract

The present invention relates to a processing method for a cloth-wrapped fracturing packing. The processing method for cloth wrapping comprises the following steps: S1, preparing a slurry; S2, slurry coating: scrape-coating a cloth with the rubber slurry in step S1 to obtain a rubber-coated cloth; S3, cutting the cloth; S4, forming a rubber green body: extruding a green body according to the shape and the weight of a rubber packing; S5, forming the green body: wrapping the rubber green body with the cut rubber-coated cloth to make a rubber packing green body; S6, vulcanization: performing pressurized and heating vulcanization on the rubber packing green body; S7, trimming: trimming the product to remove burrs; and S8, inspection: inspecting the appearance of the product according to specifications. The present invention adds a protective layer to the surface of the rubber packing in a fracturing packing assembly without changing the original fracturing packing structure, so as to improve the wear resistance, tear resistance and corrosion resistance of the fracturing packing, thereby prolonging the service life thereof.

Description

Treatment method of wrapped fracturing packing

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202311813724.3 filed on December 27, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The invention relates to a fracturing packing for a fracturing pump used in oil and gas development, and in particular to a method for processing a cloth-wrapped fracturing packing. Background Art

[0004] Oilfield fracturing trucks are used to increase oil and gas well production. Fracturing involves the artificial use of hydraulic forces during the oil or gas extraction process to create cracks in the oil and gas layers. This improves the underground flow environment, enhances flow conditions at the bottom of the well, slows interlayer movement, and improves reservoir movement, ultimately increasing well production. The primary power source for fracturing is the fracturing pump, the heart of the fracturing truck and the key to its quality. The hydraulic end of the pump is its power source, and the fracturing packing is one of the key components that provides continuous power to the fracturing pump.

[0005] The life of fracturing packing assemblies is a key indicator of fracturing pump performance. Fracturing pumps operate in an extremely harsh environment: extremely high operating pressures; the fracturing fluid contains a large amount of extremely hard sand particles; the fracturing fluid is highly acidic, has low viscosity, and exhibits poor self-lubrication; and the plunger moves at high speeds, which severely wears and corrodes the packing assembly. Because the rubber packing in fracturing packing assemblies is made of pure rubber, it is more susceptible to wear and corrosion than the cloth-reinforced packing in other packing assemblies. This results in a short lifespan for the fracturing packing assembly, requiring frequent replacement. This increases the cost and risk of fracturing operations and impacts oil recovery efficiency.

[0006] Several methods have been proposed to improve the wear and corrosion resistance of rubber packing in fracturing packing assemblies. For example, the material of the fracturing packing assembly has been continuously changed, with rubber packing transitioning from NBR to a rubber-plastic combination, and then to HNBR. While HNBR offers excellent temperature and chemical resistance, effectively reducing friction and wear, and extending the packing's service life, its wear, tear, and corrosion resistance are still significantly lower than those of cloth packing. Leakage in fracturing packing assemblies is often caused by damage to the rubber packing, which is the most susceptible to damage within the assembly. Summary of the Invention

[0007] To solve the above problems, the present invention provides a method for processing cloth-wrapped fracturing packing, which improves the wear resistance, tear resistance and corrosion resistance of the fracturing packing without changing the original structure of the fracturing packing assembly, thereby extending the service life of the fracturing packing assembly.

[0008] The technical solution adopted by the present invention is: a method for processing cloth-wrapped fracturing packing, comprising the following steps:

[0009] S1. Pulping: Soak HNBR slurry with solvent until it is fully dissolved;

[0010] S2. Sizing: Evenly scrape the HNBR slurry soaked in step S1 onto the coating, cool and dry it, and make a spare rubberized cloth;

[0011] S3. Cutting cloth: Use an electric cutting machine to cut the prepared rubberized cloth into the required size;

[0012] S4. Rubber blank molding: Use a rubber extruder to extrude the blank according to the shape and weight of the rubber packing;

[0013] S5, blank forming: Wrap the rubberized cloth cut in step S3 on the surface of the rubber blank formed in step S4, and use a forming tool to cold-press and shape it to form a rubber packing blank;

[0014] S6. Vulcanization: Put the formed rubber packing blank into the mold, push it into the flat vulcanizer according to the process requirements, and vulcanize the rubber packing blank under pressure and temperature;

[0015] S7, trimming: trimming the burrs of the product;

[0016] S8. Inspection: Inspect the appearance of the product according to the specifications.

[0017] Preferably, in step S1, the concentration of the slurry is 20-30%.

[0018] Preferably, in step S1, the weight content of HNBR glue in the slurry is 20-30%.

[0019] Preferably, in step S2, the rubber content of the rubber-coated cloth is 3-6%.

[0020] Preferably, the weight content of HNBR glue in the rubberized cloth is 3-6%.

[0021] Preferably, in step S2, the coating is aramid cloth, nylon cloth or polyester cloth.

[0022] Preferably, in step S3, in order to avoid concentrated joints, the coated cloth should be cut into a parallelogram, the width of the cloth is equal to the cross-sectional perimeter of the product plus the overlap width, and the length of the cloth is equal to the outer perimeter of the product plus the overlap length.

[0023] Preferably, in step S4, the blank is in a cylindrical shape and has a weight deviation of ±3 grams.

[0024] Preferably, in step S5, the texture of the rubberized cloth forms an angle of 45 degrees with the circumferential direction of the rubber blank.

[0025] The beneficial effects achieved by the present invention are:

[0026] 1. Without changing the original fracturing packing structure, a protective layer is added to the surface of the rubber packing in the fracturing packing assembly to improve the wear resistance, tear resistance and corrosion resistance of the fracturing packing and extend its service life;

[0027] 2. The aramid cloth used has high wear resistance, tear resistance and corrosion resistance, which can effectively improve the tear strength of rubber packing, reduce friction coefficient and reduce leakage;

[0028] 3. After being coated with glue, the aramid cloth used can have good adhesion with the rubber packing compound without delamination or peeling;

[0029] 4. Make full use of the characteristic of aramid cloth that it has a small amount of elastic deformation at the bevel angle;

[0030] 5. It is suitable for various types and specifications of fracturing packings, easy to operate, and does not require special equipment and process conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a flow chart of the present invention;

[0032] Figure 2 is a schematic diagram of a rubberized cloth;

[0033] Figure 3 is a schematic diagram of rubber packing;

[0034] In the figure: 1. Rubberized cloth; 11. Warp; 12. Weft; 2. Rubber packing. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] The HNBR described in the present invention refers to hydrogenated nitrile rubber.

[0037] As shown in Figures 1-3, the present invention provides a method for processing cloth-wrapped fracturing packing, comprising the following steps:

[0038] S1. Pulping: Soaking HNBR slurry with a solvent to achieve a fully dissolved state. The present invention has no particular limitation on the type of solvent, as long as it can dissolve HNBR. Those skilled in the art can select a solvent based on known solvents in the art. The present invention will not go into details herein, and those skilled in the art should not interpret this as a limitation to the present invention.

[0039] S2. Sizing: Evenly scrape the HNBR slurry soaked in step S1 onto the aramid cloth, cool and dry it (this operation can be done in batches for standby use) to make a standby rubberized cloth;

[0040] S3. Cutting the cloth: Use an electric cutting machine to cut the prepared coated cloth to the required size. Preferably, to avoid concentrated joints, the cloth is cut into a parallelogram. The width of the cloth is equal to the cross-sectional perimeter of the product plus the overlap width, and the length of the cloth is equal to the outer perimeter of the product plus the overlap length. The direction of cutting the cloth and the direction of the warp and weft are shown in Figure 2. The inventors have found that under this preferred condition, the wear resistance, tear resistance and corrosion resistance of the fracturing packing can be further improved, resulting in a fracturing packing assembly with a longer service life.

[0041] S4. Rubber blank molding: Use a rubber extruder to extrude the rubber packing into a barrel-shaped blank according to its shape and weight. The weight should be accurate and the weight deviation should be ±3 grams.

[0042] S5. Blank forming: Wrap the rubberized cloth cut in step S3 around the surface of the rubber blank formed in step S4 (the cloth grain should be at a 45-degree angle to the circumferential direction of the rubber blank), and use a forming tool to cold-press and shape it to form a rubber packing blank. The inventors have found that by maintaining the cloth grain and the circumferential direction of the rubber blank at this preferred angle, a fracturing packing assembly with improved wear resistance, tear resistance, and corrosion resistance can be obtained.

[0043] S6. Vulcanization: Put the formed rubber packing blank into the mold, push it into the flat vulcanizer according to the process requirements, and vulcanize the rubber packing blank under pressure and temperature;

[0044] S7, trimming: trimming the burrs of the product;

[0045] S8. Inspection: Inspect the appearance of the product according to the specifications.

[0046] The present invention has no particular limitation on the specific operations of vulcanization, trimming and inspection. Those skilled in the art can select the specific operations according to existing operating means in the art. The present invention will not be described in detail here, and those skilled in the art should not understand it as limiting the present invention.

[0047] Take a certain type of rubber packing as an example. Its outer diameter is 154mm, inner diameter is 126mm and thickness is 18mm. Follow the steps below to handle it:

[0048] S1. Pulping: Soak HNBR mortar with solvent until it is fully dissolved and the mortar concentration is 20-30%;

[0049] S2. Sizing: Evenly scrape the glue soaked in step S1 onto the aramid cloth, with a glue content of 3-6%. Let it dry and make the rubberized cloth for use.

[0050] S3. Cutting the fabric: Use an electric cutting machine to cut the prepared coated fabric to the required size. The length and width of the fabric are calculated as follows: length = 3.14*154+5≈488MM; width = (154-126)+18*2+10+6≈80MM. The fabric size can be adjusted according to the actual product size and overlap width.

[0051] S4. Rubber blank molding: Use a rubber extruder to extrude the blank (the blank is in a barrel shape) according to the shape and weight of the rubber packing. The weight must be accurate and the deviation must be controlled within ±3 grams;

[0052] S5, Blank Forming: Wrap the aramid cloth cut in S3 on the surface of the rubber blank formed in S4 (the cloth grain should be at a 45-degree angle to the circumference of the rubber blank), and use a forming tool to cold-press and shape it to form the rubber packing blank;

[0053] S6. Vulcanization: Place the formed rubber packing blank into the mold and vulcanize the rubber packing blank according to the process requirements;

[0054] S7, trimming: trimming the burrs of the product;

[0055] S8. Inspection: Inspect the appearance of the product according to the inspection specifications.

[0056] The rubber packing after protective treatment (see Figure 3) has the following advantages:

[0057] 1) The surface is smooth, without defects, bubbles or cracks;

[0058] 2) The size meets the requirements and there is no deformation or delamination;

[0059] 3) The bonding strength reaches more than 12MPa and is not easy to peel or slip;

[0060] 4) The friction coefficient is reduced, and the tear strength and corrosion resistance are improved.

[0061] In addition to the rubber packing in the fracturing packing assembly, other similar dynamic sealing rubber parts can also be treated with a protective layer, such as the first ring packing in the cementing packing assembly, V-type oil seals, etc.; in addition to aramid cloth, the protective layer can also be replaced by other flexible materials with high wear resistance, high tear resistance and corrosion resistance, such as nylon cloth, polyester cloth, etc.

[0062] It should be noted that the description of the above technical solutions is exemplary, and this specification may be embodied in various forms and should not be construed as limiting the technical solutions set forth herein. Rather, these descriptions are provided to make the disclosure of the present invention thorough and complete, and to fully convey the scope of the disclosure of this specification to those skilled in the art. Furthermore, the technical solutions of the present invention are limited only by the scope of the claims.

[0063] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments and is susceptible to numerous variations. Any simple modifications, equivalent variations, and modifications to the above embodiments based on the technical essence of the present invention shall be deemed to fall within the scope of protection of the present invention.

Claims

1. A processing method for a wrapped packing used in hydraulic fracturing, characterized in that: The following steps are involved: S1. Pulping: Soak HNBR slurry with solvent to achieve full dissolution; S2, coating: evenly scrape the HNBR adhesive soaked in step S1 onto the coating, cool and dry, and make a standby coated cloth; S3. Cutting cloth: using an electric cutting machine to cut the prepared rubberized cloth into required sizes; S4, rubber blank molding: use a rubber extruder to extrude the blank according to the shape and weight of the rubber packing; S5, blank forming: Wrap the rubber-coated cloth cut in step S3 on the surface of the rubber blank formed in step S4, and use a forming tool to cold-mold and shape it to form a rubber packing blank; S6, Vulcanization: Put the formed rubber packing blank into the mold, push it into the flat vulcanizer according to the process requirements, and vulcanize the rubber packing blank under pressure and temperature; S7, trimming: trimming the burrs of the product; S8. Inspection: Inspect the appearance of the product according to the specifications.

2. The treatment method of the wrapped packing for hydraulic fracturing according to claim 1, wherein: In step S1, the concentration of the glue is 20-30%.

3. The treatment method of the wrapped packing for hydraulic fracturing according to claim 1, characterized in that: In step S2, the rubber content of the rubber-coated cloth is 3-6%.

4. The treatment method of the wrapped packing for hydraulic fracturing according to claim 1, wherein: In step S2, the coating is aramid cloth, nylon cloth or polyester cloth.

5. The treatment method of the packing for wireline fracturing according to claim 1, wherein: In step S3, the rubber-coated cloth is cut into a parallelogram, the width of the cloth is equal to the cross-sectional perimeter of the product plus the overlap width, and the length of the cloth is equal to the outer perimeter of the product plus the overlap length.

6. The processing method of the wrapped packing for hydraulic fracturing according to claim 1, characterized in that: In step S4, the blank is in a cylindrical shape with a weight deviation of ±3 grams.

7. The treatment method of the wrapped packing for hydraulic fracturing according to claim 1, wherein: In step S5, the texture of the rubber-coated cloth forms an angle of 45 degrees with the circumferential direction of the rubber blank.

8. The treatment method of the wrapped packing for hydraulic fracturing according to claim 2, characterized in that: In step S1, the weight content of HNBR glue in the glue slurry is 20-30%.

9. The treatment method of the wrapped packing for hydraulic fracturing according to claim 3, characterized in that: In step S2, the weight content of HNBR glue in the rubber-coated cloth is 3-6%.

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