A wear-resistant curved shell and a manufacturing method and application thereof

Abstract

The application discloses a wear-resistant bend outer shell and a manufacturing method and application thereof, and belongs to the technical field of oil and natural gas drilling. The wear-resistant bend outer shell comprises a wear-resistant bend outer shell shell body. The outer circle of the wear-resistant bend outer shell shell body is free of bend angles. The outer diameter of the outer circle of the wear-resistant bend outer shell shell body is increased, the wall thickness is thickened, the axis of the outer circle is the same as that of the outer circle free of bend angles at the left end, hard alloy teeth are arranged at the back bend of the outer circle of the inner bend, and the wear-resistant bend outer shell further comprises an adjustable bend shell body assembly. The adjustable bend shell body assembly comprises an upper joint, an inner bend, a sliding sleeve and a flat key. Meanwhile, the application further discloses a manufacturing method of the wear-resistant bend outer shell and application of the wear-resistant bend outer shell as a tool for guiding and building a slope. The wear-resistant bend outer shell has the characteristics of simple structure, easy processing and manufacturing, low cost, good wear-resistant effect, and the ability to improve the build-up rate and build-up force, and is suitable for popularization and application.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling technology, and more specifically, to a wear-resistant curved shell, its manufacturing method, and its application. Background Technology

[0002] Horizontal wells are a public technology that increases oil well production and improves oilfield development by expanding the drainage area of ​​the oil reservoir. Horizontal wells play a crucial role in accelerating oilfield exploration and development and enhancing reservoir recovery. With the rapid development of horizontal well technology, the number of horizontal wells drilled has increased significantly year by year, and they are now widely used in oilfields across the country. Screw drill strings are drilling tools that provide downhole power for directional wells, horizontal wells, and sidetracking horizontal wells, resulting in a very large usage of screw drill strings.

[0003] Directional wells, horizontal wells, sidetracked horizontal wells, and extended reach horizontal wells primarily rely on screw drill strings for directional drilling and orientation. The key component for directional drilling and orientation using screw drill strings is the curved housing. Due to the structural characteristics of the curved housing, during drilling, the back bend of the housing experiences intense friction with the wellbore, leading to wear at the back bend support. When the back bend is worn flat, it affects the build-up rate. When the build-up rate is very low, effective orientation is impossible, necessitating tripping and replacement. This not only increases drilling costs and prolongs the drilling cycle but also increases drilling risks. Ordinary curved housings typically require replacement after approximately 100 hours of use due to severe wear and reduced build-up rate. Therefore, the usage of curved housings is very high.

[0004] One measure to improve the wear resistance life of curved shells is to laser clad a wear-resistant layer on the curved shell. However, due to limitations in process conditions, the thickness of the laser clad wear-resistant layer cannot be too thick, otherwise the coating will peel off, and the cost is very high. The life of the curved shell can be increased to about 200 hours. After wear, a new weld layer needs to be added, which increases the cost significantly, and the wear resistance effect is not significant. Welding will also have an adverse effect on the mechanical properties of the curved shell body, and the wear resistance problem is not fundamentally solved.

[0005] Other measures to improve the wear resistance life of the bend casing include: hot-fitting wear-resistant sleeves at the bend point, or welding keyed wear-resistant sleeves at the bend point (to prevent slippage and rotation). Hot-fitting wear-resistant sleeves at the bend point are prone to slippage or upward movement during field use, detaching from the bend casing; welded keyed wear-resistant sleeves cannot withstand the severe downhole wear and will also detach from the bend casing. After slipping, the wear-resistant sleeve may move to other positions on the drill string assembly, easily bumping against the wellbore and causing stuck pipe. In some cases, it may even wear off, leaving an open wear-resistant sleeve that falls into the annular space or drill bit, easily causing severe stuck pipe, blockage, very slow drilling speed, or even no progress. In severe cases, it can cause serious drilling accidents such as rotary table shutdown.

[0006] Therefore, wear-resistant curved shells are a technology that urgently needs to be solved. Summary of the Invention

[0007] The purpose of this invention is to solve the wear resistance problem existing in the prior art, and to provide a wear-resistant curved shell with simple structure, easy processing and manufacturing, low cost, good wear resistance, and the ability to improve the tilting rate and tilting force, as well as its manufacturing method and application.

[0008] The embodiments of the present invention are implemented as follows:

[0009] On one hand, embodiments of the present invention provide a wear-resistant bending housing, including a wear-resistant bending housing shell. The outer circle of the wear-resistant bending housing shell is without bends. The outer diameter of the inner bend of the wear-resistant bending housing shell is increased, the wall thickness is increased, and the axis of its outer circle is the same axis as the outer circle without bends on the left end. Carbide teeth are provided at the back bend of the outer circle of the inner bend. It also includes an adjustable bending housing assembly, which includes an upper connector, an inner bend, a sliding sleeve, a flat key, an angle mark, and an angle alignment mark. The upper connector and the inner bend are connected by threads. The flat key and the inner bend are interference-fitted. The sliding sleeve has square grooves inside, and the number of square grooves is equal to the number of flat keys. The sliding sleeve is installed outside the inner bend by insertion. The inner bend and the wear-resistant bending housing shell are connected by threads. The angle mark and the angle alignment mark are both located on the wear-resistant bending housing shell.

[0010] Preferably, the length of the cemented carbide tooth is 100-200 mm.

[0011] Preferably, the cemented carbide teeth are arranged circumferentially at an angle of 120°.

[0012] Preferably, the wear-resistant bending shell is made of high-strength alloy steel.

[0013] Preferably, the minimum diameter of the chamfer at the lower end of the curved outer shell is the same as the outer diameter of the drill assembly connected to it. This chamfer forms a bend point, which is then lowered. A chamfer angle of 70° to 80° is selected.

[0014] Furthermore, the drill assembly is a drive shaft housing.

[0015] On the other hand, embodiments of the present invention provide a method for manufacturing a wear-resistant bending shell, comprising the following steps:

[0016] Step 1: Based on the mechanical properties of the material, heat treatment is generally required to achieve higher strength and hardness, with a yield strength of not less than 785MPa, a tensile strength of not less than 980MPa, and a hardness of not less than 300HB. Before heat treatment, non-destructive testing is required to prevent defects in the material itself from affecting product quality, such as ultrasonic testing.

[0017] Step 2: Using turning, complete the machining of all outer diameters and transition chamfers. The bends of the wear-resistant curved shell are selected according to the engineering requirements. The clamping parameters are chosen based on the lathe (generally a tubular lathe; this patent uses a tubular lathe as an example). The dimensions of the four jaws and aluminum pads are adjusted, and the clamping accuracy is checked with a dial indicator, generally within 0.05. Then, the internal threads with bends are machined. After completing the turning process, non-destructive testing is performed to check for cracks and defects in the material after heat treatment.

[0018] Step 3: After non-destructive testing confirms the part is free of defects, proceed with drilling or milling the carbide tooth holes. Use interference fit for the carbide teeth, typically columnar teeth, but can also be serrated or other shapes. The depth of the carbide tooth hole should be 0.5–0.85 mm greater than the length of the carbide tooth, and the interference fit between the columnar carbide tooth and the insert hole should be 0.06–0.12 mm. The carbide teeth should be assembled using a press, and should be substantially flush with the outer cylindrical surface without cracking.

[0019] On the other hand, embodiments of the present invention also provide an application of the wear-resistant curved housing as a tool in the guidance and directional drilling process. When used in conjunction with a near-bit drilling instrument, the wear-resistant curved housing provides guidance. directional drilling is the process of forcibly deviating the drill bit from the vertical direction to increase the drilling angle starting from the directional drilling point.

[0020] The beneficial effects of the embodiments of the present invention are:

[0021] This invention provides a wear-resistant curved shell, its manufacturing method, and its application. The outer diameter of the inner curved corner is increased, and the axis of this circle is the same as the outer circle without a curved corner on the left. Increasing the outer diameter increases the wear allowance of the curved shell, thus extending its lifespan. It also increases the overall drill rod rigidity, leading to a greater directional drilling force. Furthermore, it facilitates machining, reduces machining work, decreases worker workload, improves efficiency, and lowers costs. The invention also incorporates carbide teeth or sintered carbide blocks at the back bend of the inner curved corner, along with a matching assembly. These carbide teeth or blocks, along with the wear-resistant sleeve, are not only cost-effective (compared to laser cladding costs) but also offer other wear-resistant benefits, thereby improving the wear resistance and service life of the curved shell. Since the outer circle of the inner curved corner has no bend point, the bend point is moved down to the chamfer position, which becomes the bend point location. Therefore, the bend point location is shifted downwards by a certain distance, thus increasing the directional drilling rate and force. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a diagram of the wear-resistant adjustable bendable outer shell in the embodiment of the present invention;

[0024] Figure 2 The external view of the wear-resistant bending shell in the embodiment of the present invention, wherein, Figure 2 B in the text is Figure 2 A sectional view of A along BB. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Reference Figures 1-2 This invention provides a wear-resistant curved housing that can be used independently, i.e., as a wear-resistant curved housing with a fixed bending angle; it can also be used with a general adjustable bending assembly, replacing the lower connector of the adjustable bending assembly. When used independently, it is connected to the upper and lower drill tool connectors via threads. When used with a general adjustable bending assembly, it replaces its lower connector, and both connections to the upper and lower parts are via threads. The wear-resistant curved housing is characterized by a shell 1 without any bends on its outer circumference. The outer diameter of the inner curved outer circumference is increased, the wall thickness is thickened, and the axis of the outer circumference is the same as the axis of the outer circumference without bends on the left. Carbide teeth 2 are located at the back bend of the inner curved outer circumference, with a suitable length of approximately 100-200 mm arranged at the back bend according to actual conditions. To save costs, the carbide teeth are arranged circumferentially with a central angle of approximately 120°. The wear-resistant curved housing is made of high-quality high-strength alloy steel. The assembly also includes an adjustable bend housing assembly, which comprises an upper connector 4, an inner bend 5, a sliding sleeve 6, a flat key 7, an angle mark 8, and an angle alignment mark 9. The upper connector 4 is threadedly connected to the inner bend 5, and the flat key 7 is interference-fitted to the inner bend 5. The sliding sleeve 6 has square grooves inside, and the number of square grooves is equal to the number of flat keys 7. The sliding sleeve 6 is installed outside the inner bend 5 by insertion. The inner bend 5 is threadedly connected to the wear-resistant bend housing 1. The angle mark 8 and the angle alignment mark 9 are both located on the wear-resistant bend housing 1. The angle adjustment method for the adjustable bend housing assembly is as follows: Loosen the thread of the upper connector 4, rotate the sliding sleeve 6 and the wear-resistant bend housing 1 to select the desired angle, and screw the upper connector 4 in according to the torque requirement through the angle mark 8 and the angle alignment mark 9.

[0027] The minimum diameter of the chamfer at the lower end of the curved housing is the same as the outer diameter of the part it is connected to. The minimum diameter of the chamfer at the lower end of the curved housing is the same as the outer diameter of the drill assembly (usually the drive shaft housing) it is connected to. This chamfer forms the bend point 3, so the bend point 3 moves down. A relatively large chamfer angle is selected. In order to prevent collision with the well wall, a chamfer of 70° to 80° is generally selected.

[0028] On the other hand, embodiments of the present invention provide a method for manufacturing a wear-resistant bending shell, comprising the following steps:

[0029] Step 1: Based on the mechanical properties of the material, heat treatment is generally required to achieve higher strength and hardness, with a yield strength of not less than 785MPa, a tensile strength of not less than 980MPa, and a hardness of not less than 300HB. Before heat treatment, non-destructive testing is required to prevent defects in the material itself from affecting product quality, such as ultrasonic testing.

[0030] Step 2: Using turning, complete the machining of all outer diameters and transition chamfers. The bends of the wear-resistant curved shell are selected according to the engineering requirements. The clamping parameters are chosen based on the lathe (generally a tubular lathe; this patent uses a tubular lathe as an example). The dimensions of the four jaws and aluminum pads are adjusted, and the clamping accuracy is checked with a dial indicator, generally within 0.05. Then, the internal threads with bends are machined. After completing the turning process, non-destructive testing is performed to check for cracks and defects in the material after heat treatment.

[0031] Step 3: After non-destructive testing confirms the part is free of defects, proceed with drilling or milling the carbide tooth holes. Use interference fit for the carbide teeth, typically columnar teeth, but can also be serrated or other shapes. The depth of the carbide tooth hole should be 0.5–0.85 mm greater than the length of the carbide tooth, and the interference fit between the columnar carbide tooth and the insert hole should be 0.06–0.12 mm. The carbide teeth should be assembled using a press, and should be substantially flush with the outer cylindrical surface without cracking.

[0032] On the other hand, embodiments of the present invention also provide an application of the wear-resistant curved housing as a tool in the guidance and directional drilling process. When used in conjunction with a near-bit drilling instrument, the wear-resistant curved housing provides guidance. directional drilling is the process of forcibly deviating the drill bit from the vertical direction to increase the drilling angle starting from the directional drilling point.

[0033] Furthermore, when the wear-resistant curved housing is used as an independent curved housing, it has a fixed bending angle. Commonly used structural bending angle specifications are generally 1°, 1.25°, 1.5°, 1.75°, and 2°. In the drill bit assembly, the wear-resistant curved housing is connected to the drive shaft housing to form a curved housing screw drill bit for directional drilling. This drill bit assembly has advantages such as high directional drilling rate, small drill bit deviation, and easy drilling down. Currently, the most commonly used method is the "curved housing screw drill bit assembly" for directional drilling, and the commonly used bending angle of the curved housing screw drill bit is generally around 1.5°. During directional drilling, the wear-resistant curved shell of this invention has hard alloy teeth embedded at the back bend, close to the lower well wall. During the directional drilling stage, the back bend of the wear-resistant curved shell slides and rubs against the well wall. During the composite drilling process, the radius of motion at the apex of the wear-resistant curved shell is greater than the distance from the central axis of the stabilizer to the lower well wall. After a long period of composite drilling, the part of the screw drill with the large radius of motion suffers severe friction and wear against the well wall. Because the outer diameter of the wear-resistant curved shell of this patent is larger and it has hard alloy teeth for protection, the directional drilling process is stable, the bend point moves down, and the directional drilling rate is improved. Due to its "wear resistance," the directional drilling section maintains a long, uniform, and gentle arc-shaped section, which can withstand long-term wear and tear, and can complete the directional drilling construction efficiently and safely.

[0034] When the wear-resistant curved shell of the present invention replaces the lower connector of the adjustable curved shell assembly, the adjustable curved shell is connected, the internal elbow is connected, and the skewing process is the same as that of the wear-resistant curved shell with a fixed angle.

[0035] The ordinary curved shell and the wear-resistant curved shell were compared through experiments, as shown in Tables 1 and 2.

[0036] Table 1

[0037]

[0038] Table 2

[0039]

[0040] This invention implements wear-resistant measures on the curved back of the outer shell, such as inlaying carbide teeth for interference fit assembly. Other wear-resistant measures, such as sintered carbide teeth, can also be used. It should be noted that the minimum diameter of the chamfer at the lower end of the curved shell is the same as the outer diameter of the connected part.

[0041] It is widely used in oilfields as a tool for guidance and directional drilling in near-bit geological steering systems. Each wear-resistant curved shell can accumulate more than 1,000 hours of use, which not only improves the directional drilling rate but also the directional drilling force, and the effect is good.

[0042] Furthermore, this invention features an innovative design for the curved shell's external structure, achieving an improved slope without altering the bending angle. The proof is as follows:

[0043] The build-up rate K of a single-bend drill string is:

[0044]

[0045] Where: λ=L T (KK δ ) / 60μ,L T =L1+L2+L3, μ=L3 / L S L S =L2+L3.

[0046] Where: K is the build-up rate, (°) / 30m; λ is the structural bend angle of the directional drilling tool, (°); L1 is the first span length, m; L2 is the second span length, m; L3 is the third span length, m; K δ The build-up rate caused by the gap is (°) / 30m; when the build-up rate caused by the gap between the lower stabilizer and the wellbore is not considered, i.e., K δ =0.

[0047] μ is the coefficient and has no actual meaning.

[0048] Because the bend point shifts downwards, L3 increases, while the total length L1+L2+L3 remains unchanged. As it increases, the slope of the slope increases.

[0049] According to the theoretical knowledge of drilling tool build-up force, the build-up force will be significantly increased when the bend point is lowered.

[0050] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A wear-resistant bending shell, characterized in that, The system includes a wear-resistant curved outer shell housing, wherein the outer diameter of the wear-resistant curved outer shell housing is without any bends, and the outer diameter of the inner curved outer shell housing is increased, the wall thickness is increased, and the axis of the inner curved outer shell housing is the same as the axis of the outer curved outer shell housing on the left end without bends. Carbide teeth are provided at the back bend of the inner curved outer shell housing. The system also includes an adjustable curved shell housing assembly, wherein the adjustable curved shell housing assembly includes an upper connector, an inner elbow, a sliding sleeve, a flat key, an angle mark, and an angle alignment mark. The upper connector is threadedly connected to the inner elbow, and the flat key is interference-fitted to the inner elbow. The sliding sleeve has square grooves inside, and the number of square grooves is equal to the number of flat keys. The sliding sleeve is installed outside the inner elbow by insertion. The inner elbow is threadedly connected to the wear-resistant curved outer shell housing. The angle mark and the angle alignment mark are both located on the wear-resistant curved outer shell housing. The minimum diameter of the chamfer at the lower end of the curved outer shell is the same as the outer diameter of the drill bit assembly it is connected to. This chamfer forms a bend point, which is moved downwards. The chamfer angle is selected as 70° to 80°. When the wear-resistant curved outer shell is used independently, it is connected to the upper and lower drill bit joints by threads. When the wear-resistant curved outer shell is used with a general adjustable curved assembly, it replaces its lower joint. Both the upper and lower connections are made by threads.

2. The wear-resistant bending shell according to claim 1, characterized in that, The length of the cemented carbide teeth is 100-200 mm.

3. The wear-resistant bending shell according to claim 1, characterized in that, The cemented carbide teeth are arranged circumferentially at an angle of 120°.

4. The wear-resistant bending shell according to claim 1, characterized in that, The drill assembly is a drive shaft housing.

5. A method for manufacturing the wear-resistant bending shell according to claim 1, characterized in that, Includes the following steps: Step 1: Based on the mechanical properties of the material, perform heat treatment to achieve a yield strength of not less than 785MPa, a tensile strength of not less than 980MPa, and a hardness of not less than 300HB. Non-destructive testing is required before heat treatment to prevent defects in the material itself from affecting product quality. Step 2: Use turning to complete the machining of each outer circle and transition chamfer; the bend of the wear-resistant curved shell is selected according to the engineering requirements, and the clamping parameters are selected according to the lathe. The dimensions of the four jaws and aluminum pads are adjusted, and the clamping accuracy is checked with a dial indicator. The clamping accuracy is controlled within 0.

05. Then, the internal thread with bend is machined. After the turning process is completed, non-destructive testing is performed to check whether there are cracks and defects in the material after heat treatment. Step 3: After non-destructive testing, if the part is found to be without defects, proceed with drilling or milling the carbide tooth holes. Use interference fit for the carbide teeth. The depth of the carbide tooth hole should be 0.5 to 0.85 mm greater than the length of the carbide tooth. The interference between the columnar carbide tooth and the insert hole should be 0.06 to 0.12 mm. The carbide teeth should be assembled using a press. The carbide teeth should be basically flush with the outer cylindrical surface and should not break.

6. The method for manufacturing the wear-resistant bent shell according to claim 5, characterized in that, In step 1, the non-destructive testing employs ultrasonic testing.

7. The method for manufacturing the wear-resistant bent shell according to claim 5, characterized in that, In step 2, the lathe is a tube lathe.

8. The method for manufacturing the wear-resistant bent shell according to claim 5, characterized in that, In step 3, the cemented carbide teeth are columnar alloy teeth or flower-shaped teeth.

9. The application of the wear-resistant bending housing of claim 1 as a tool in guiding and skewing processes.

Images