A method, device, equipment and medium for selecting premium threaded oil casing

Abstract

The application discloses a special thread oil sleeve selection method, device, equipment and medium, including the following steps: obtaining special thread oil sleeve specification parameters; obtaining the CEE curve of the special thread oil sleeve according to the equivalent yield model; obtaining the high anti-extrusion level, and obtaining the extrusion curve according to the high anti-extrusion level and the pipe body extrusion model; obtaining the VME curve and the distribution curve diagram of the sealing surface contact pressure on the sealing width at different load points according to the CEE curve and the extrusion curve; then obtaining the sealing contact strength value at different load points in combination with the sealing contact strength calculation model; grading the sealing contact strength; determining the sealing performance grade; and selecting the special thread oil sleeve of the corresponding grade according to the downhole service temperature and pressure to make the material selection plate. The special thread oil sleeve of the similar grade is selected in combination according to the downhole service temperature and pressure, and the best economic special thread oil sleeve is selected according to different well depths, so that the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of natural gas extraction technology, specifically relating to a method, apparatus, equipment, and medium for selecting special threaded oil casing. Background Technology

[0002] With the continuous development of natural gas exploration, the proportion of deep wells (depth > 3000 meters) and ultra-deep wells (depth > 6000 meters) in gas field development is constantly increasing. Deep and ultra-deep wells operate in complex downhole environments, facing the "three highs" of high temperature (bottom hole temperature up to 180℃), high pressure (downhole pressure > 80MPa), and highly corrosive media. Traditional API tubing can no longer meet the downhole operating requirements, and non-API special thread tubing with higher gas-tightness is increasingly widely used in the exploitation of high-temperature and high-pressure oil and gas fields.

[0003] The excellent sealing performance of special threaded tubing for the fluid medium inside the tubing is the main reason why it can be widely used in oil and gas wells under harsh conditions. Besides the sealing structure, the sealing performance of special threaded tubing is also greatly affected by parameters such as material properties, outer diameter, and wall thickness. Currently, there are approximately 70 specifications of special threaded tubing from nearly 20 manufacturers widely used in unconventional oil and gas fields such as high-temperature, high-pressure oil and gas fields and shale oil and gas fields. The sealing performance of special threaded tubing from different manufacturers and with different sealing structures varies greatly, resulting in significant price differences. This leads to numerous problems during the use of special threaded tubing, mainly including: (1) The actual sealing performance of the special threaded oil casing does not match the well conditions, resulting in severe annular pressure in oil and gas wells; (2) Although they are natural gas wells, some wells have low production and low medium pressure, while others have high production and high medium pressure. When oil and gas fields select special threaded oil casings, they do not select special threaded oil casings with different sealing capabilities according to different wells. Instead, they unilaterally pursue high sealing and select oil casings with good sealing performance and high price. This results in the tubing cost of wells with low production being large, which is not conducive to reducing costs and increasing efficiency and improving profits in oil fields.

[0004] (3) In the same well, the sealing performance requirements of the casing and tubing are different for different well depths. However, in actual selection, the casing and tubing are often selected according to the highest sealing requirements, rather than selecting different tubing materials according to different sealing requirements. This is not conducive to reducing the cost of well construction and production operation. Summary of the Invention

[0005] The purpose of this invention is to provide a special threaded oil casing selection method, device, equipment and medium, so as to minimize the use cost of oil and gas well tubing while ensuring the sealing of oil and gas wells.

[0006] To achieve the above objectives, the present invention employs the following technical solution: Firstly, a method for selecting a special threaded oil casing includes the following steps: Obtain the specifications of all special threaded tubing and casing in the oil and gas field's material warehouse; An equivalent yield model is established based on the specifications of special threaded oil casing, and the CEE curves of special threaded oil casing with different specifications are obtained based on the equivalent yield model. To obtain the high crush resistance level of the special threaded oil casing, and based on the high crush resistance level and the pipe body crush model under tensile load, the crush curve of the special threaded oil casing under tensile load is obtained: Based on the CEE curve and the bursting curve under tensile load, the VME curve of the special threaded oil casing under combined load is obtained. Based on the VME curve, simulated loading was performed to obtain the distribution curve of the sealing surface contact pressure on the sealing width of the special threaded oil casing at different load points. Based on the distribution curve of the sealing surface contact pressure of the special threaded oil casing at different load points on the sealing width and the calculation model of sealing contact strength, the sealing contact strength value of the special threaded oil casing at different load points is obtained. Based on the sealing contact strength, the sealing performance of special threads in oil casing is divided into several grades. The sealing performance level of the special threaded oil casing is determined based on the sealing contact strength value at different load points. Material selection charts are made based on downhole service temperature and pressure, and special threaded tubing of corresponding grades is selected according to different service temperature and pressure ranges.

[0007] A further improvement of the present invention is that, when obtaining the VME curve of the special threaded oil casing under combined load based on the CEE curve and the bursting curve under tensile load, the VME curve of the special threaded oil casing under combined load is obtained by coupling 95% of the CEE curve with the bursting curve under tensile load.

[0008] A further improvement of the present invention is that, when simulating loading based on the VME curve to obtain the distribution curve of the sealing surface contact pressure on the sealing width of the special threaded oil casing at different load points, the simulation software is first used to select the internal and external thread mating mode as the worst sealing performance mode before simulating loading based on the VME curve.

[0009] A further improvement of the present invention is that: when obtaining the sealing contact strength value of the special threaded oil casing at different load points based on the distribution curve of the sealing surface contact pressure on the sealing width and the sealing contact strength calculation model, the sealing contact strength value of the special threaded oil casing at different load points is obtained by integrating the contact pressure on the sealing surface on the sealing surface contact width according to the sealing contact strength calculation model.

[0010] A further improvement of the present invention is that the special thread sealing performance of the oil casing is divided into 5 levels.

[0011] A further improvement of the present invention is that the simulation software is ABAQUS software.

[0012] A further improvement of the present invention is that the sealing contact strength is classified as Grade 1 in the range of 20 N / mm to 260 N / mm, Grade 2 in the range of 260 N / mm to 780 N / mm, Grade 3 in the range of 780 N / mm to 1630 N / mm, Grade 4 in the range of 1630 N / mm to 2020 N / mm, and Grade 5 for strength greater than 2020 N / mm.

[0013] Secondly, a special threaded oil casing selection device includes: Specification Parameter Acquisition Module: Used to acquire the specification parameters of all special threaded oil casings in the oil and gas field material warehouse; CEE curve acquisition module: used to establish an equivalent yield model based on the specifications of special threaded oil casing, and to obtain the CEE curves of special threaded oil casing with different specifications based on the equivalent yield model; The bursting curve acquisition module is used to obtain the high bursting resistance level of special threaded oil casing. Based on the high bursting resistance level and the pipe body bursting model under tensile load, the bursting curve of the special threaded oil casing under tensile load is obtained. VME curve acquisition module: used to obtain the VME curve of special threaded oil casing under combined load based on the CEE curve and the bursting curve under tensile load; Distribution curve acquisition module: used to simulate loading based on VME curve, and obtain the distribution curve of the sealing surface contact pressure of the special threaded oil casing at different load points on the sealing width; Sealing contact strength calculation module: This module is used to obtain the sealing contact strength value of the special threaded oil casing at different load points based on the distribution curve of the sealing surface contact pressure on the sealing width and the sealing contact strength calculation model of the special threaded oil casing at different load points. Grading module: used to classify the sealing performance of special threads of oil casing into several grades according to the sealing contact strength; Grade determination module: used to determine the sealing performance grade of special threaded oil casing based on the sealing contact strength value at different load points; Selection Module: Used to create material selection charts based on downhole service temperature and pressure, and to select the corresponding grade of special threaded tubing according to different service temperature and pressure ranges.

[0014] Thirdly, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement the above-described method for selecting a special threaded oil casing.

[0015] Fourthly, a computer-readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, implements the above-described method for selecting a special threaded oil casing.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention classifies special threaded oil casing based on sealing contact strength, and selects special threaded oil casings of similar grades in combination with downhole service temperature and pressure. The most economical special threaded oil casings can be selected and combined according to different well depths, which reduces the cost of natural gas well construction and operation. 2. This invention proposes a reasonable grading range by dividing special threaded oil casing into 5 levels, thereby improving work efficiency.

[0017] 3. The special threaded oil casing selected by this invention is matched with the well conditions, thus avoiding annular pressure in oil and gas wells. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of a special threaded oil casing selection method according to the present invention; Figure 2 This is the CEE curve diagram in Embodiment 2 of the present invention; Figure 3 This is the anti-crushing curve diagram in Embodiment 2 of the present invention; Figure 4 This is the VME curve diagram in Embodiment 2 of the present invention; Figure 5 This is a distribution curve of the sealing surface contact pressure over the sealing width at different load points in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the selection board in Embodiment 2 of the present invention; Figure 7 This is a system block diagram of a special threaded oil casing selection device according to the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0020] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0021] Example 1 A special method for selecting threaded oil casing, such as Figure 1 As shown, it includes the following steps: Obtain the specifications of all special threaded tubing and casing in the oil and gas field's material warehouse; An equivalent yield model is established based on the specifications of special threaded oil casing, and the CEE curves of special threaded oil casing with different specifications are obtained based on the equivalent yield model. To obtain the high crush resistance level of the special threaded oil casing, and based on the high crush resistance level and the pipe body crush model under tensile load, the crush curve of the special threaded oil casing under tensile load is obtained: Based on the CEE curve and the bursting curve under tensile load, the VME curve of the special threaded oil casing under combined load is obtained. Based on the VME curve, simulated loading was performed to obtain the distribution curve of the sealing surface contact pressure on the sealing width of the special threaded oil casing at different load points. Based on the distribution curve of the sealing surface contact pressure of the special threaded oil casing at different load points on the sealing width and the calculation model of sealing contact strength, the sealing contact strength value of the special threaded oil casing at different load points is obtained. Based on the sealing contact strength, the sealing performance of special threads in oil casing is divided into several grades. Based on the sealing contact strength values ​​at different load points, the average value of the sealing contact strength is calculated, and the average value of the sealing contact strength is taken as the nominal value of the sealing contact strength of the special threaded oil casing of this specification. The sealing performance level of the special threaded oil casing of this specification is determined based on the nominal value of the sealing contact strength. Material selection charts are made based on downhole service temperature and pressure, and special threaded tubing of corresponding grades is selected according to different service temperature and pressure ranges.

[0022] When establishing an equivalent yield model based on the specifications of special threaded oil casing, the equivalent yield model is as follows: ; ; ; ; In the formula, D－ outer diameter, d wall － inner diameter, P i － Internal pressure, P O － External pressure, r－ polar coordinates F a － Axial load, Ap – cross-sectional area of ​​the tube. σ a － Axial stress, σ r - Radial stress, σ h - Circumferential stress, σ e - Equivalent stress; D－ outer diameter, d wall － inner diameter, P i － Internal pressure, P O － External pressure, r－ polar coordinates F a － Axial load and Ap – cross-sectional area of ​​the tube are both known parameters.

[0023] When obtaining high extrusion resistance levels for special threaded oil casing, obtain them from the product quality certificate provided by the special threaded oil casing manufacturer.

[0024] Pipe body collapse model: ; ; In the formula, f ymn － Minimum yield strength specified for special threaded oil casing materials f yax－ Equivalent yield strength σ a － Axial stress, t－ Pipe wall thickness.

[0025] When obtaining the VME curve of the special threaded oil casing under combined load based on the CEE curve and the bursting curve under tensile load, the VME curve of the special threaded oil casing under combined load is obtained by coupling 95% of the CEE curve with the bursting curve under tensile load.

[0026] When simulating loading based on the VME curve to obtain the distribution curve of the sealing surface contact pressure on the sealing width of the special threaded oil casing at different load points, the specific steps include: Based on the special thread design drawings, the special threaded oil casing was simulated and loaded according to the VME load curve using ABAQUS software to obtain the distribution curve of the sealing surface contact pressure on the sealing width at different load points. When the ABAQUS software simulates loading according to the VME load curve, the worst sealing performance mode is selected for the internal and external thread fit mode, namely the minimum sealing interference fit, the tapered fit of the outer ring and the inner ring, and the minimum top torque.

[0027] Based on the distribution curve of the sealing surface contact pressure on the sealing width at different load points of the special threaded oil casing, when establishing the sealing contact strength calculation model, the contact pressure on the sealing surface is integrated on the sealing surface contact width according to the sealing contact strength calculation model to obtain the sealing contact strength value of special threaded oil casing of different specifications at room temperature.

[0028] Calculation model for sealing contact strength: ; In the formula, S C For sealing contact strength, σ- Contact stress on the sealing surface l－ The contact width of the sealing surface.

[0029] The sealing contact strength values ​​of the special threaded oil casing at different load points were obtained based on the sealing contact strength calculation model.

[0030] When classifying the sealing performance of special threads of oil casing pipes according to sealing contact strength, the classification is carried out according to actual needs. In this embodiment, it is divided into 5 levels: Level 1 is when the sealing contact strength is in the range of (20~260) N / mm, Level 2 is in the range of (260~780) N / mm, Level 3 is in the range of (780~1630) N / mm, Level 4 is in the range of (1630~2020) N / mm, and Level 5 is when the sealing contact strength exceeds 2020 N / mm.

[0031] Example 2 A graded selection method for a special threaded tubing (Φ114.3mm×9.65mm 13Cr-110) used in a natural gas well is described in Example 1. The nominal outer diameter of the tubing is 114.3 mm, the nominal wall thickness is 9.65 mm, and the minimum yield strength is 758 MPa. The CEE curve of the tubing is calculated based on the equivalent yield model, as follows: Figure 2 As shown; Based on the high resistance to crushing of the tubing and the crushing model of the tubing body, the crushing resistance curves of the tubing body under axial compression and tensile loads are calculated, such as... Figure 3 As shown; By coupling 95% of the CEE curve with the burst curve under external pressure, the VME curve of the tubing under combined load is obtained, as shown below. Figure 4 As shown; The internal and external thread fit mode is selected as the worst sealing performance mode, that is, the minimum sealing interference fit (the sealing diameter tolerance is reduced by -0.04mm), the outer ring and inner ring taper fit (both internal and external thread tapers are 59.0mm / m), and the minimum top torque (corresponding to the shoulder interference set to 0.02~0.03 turns increment). Based on the design drawings for the special thread, after inputting the above settings into the ABAQUS software, follow... Figure 4 After simulating loading at the 14 load points shown, the distribution curves of the sealing surface contact pressure of this special threaded oil pipe across the sealing width at different load points were obtained, as shown in the figure. Figure 5 As shown; The contact pressure on the sealing surface is integrated over the contact width of the sealing surface according to the sealing contact strength calculation model to obtain the sealing contact strength value of the special threaded oil sleeve at room temperature, as shown in Table 1. Table 1

[0032] The maximum value (1813 N / mm) and minimum value (724 N / mm) of the actual calculated results of the sealing surface contact strength of the special threaded oil pipe were selected and the average value was obtained to obtain the nominal value of the sealing contact strength of the special threaded oil pipe as 1268 N / mm. Based on the sealing contact strength, the sealing performance of special threads in oil casing is divided into 5 levels, and this special thread oil pipe is level 3. Selection charts are created based on the requirements for the contact strength of special thread seals under different temperatures and pressures, such as... Figure 6 As shown, the pressure and temperature ranges used for this special threaded tubing are determined.

[0033] Example 3 A special threaded oil casing selection device, such as Figure 7 As shown, it includes: Specification Parameter Acquisition Module: Used to acquire the specification parameters of all special threaded oil casings in the oil and gas field material warehouse; CEE curve acquisition module: used to establish an equivalent yield model based on the specifications of special threaded oil casing, and to obtain the CEE curves of special threaded oil casing with different specifications based on the equivalent yield model; The burst curve acquisition module is used to obtain the high burst resistance level of special threaded oil casing. Based on the high burst resistance level and the pipe burst model under tensile load, the burst curve of the special threaded oil casing under tensile load is obtained. VME curve acquisition module: used to obtain the VME curve of special threaded oil casing under combined load based on the CEE curve and the bursting curve under tensile load; Distribution curve acquisition module: used to simulate loading based on VME curve, and obtain the distribution curve of the sealing surface contact pressure of the special threaded oil casing at different load points on the sealing width; Sealing contact strength calculation module: This module is used to establish a sealing contact strength calculation model based on the distribution curve of the sealing surface contact pressure across the sealing width at different load points for special threaded oil casing, and to obtain the sealing contact strength values ​​of the special threaded oil casing at different load points based on the sealing contact strength calculation model. Grading module: used to classify the sealing performance of special threads of oil casing into several grades according to the sealing contact strength; Grade determination module: Calculate the average value of the sealing contact strength based on the sealing contact strength values ​​at different load points, and use the average value of the sealing contact strength as the nominal value of the sealing contact strength of the special threaded oil casing of this specification. Determine the sealing performance grade of the special threaded oil casing of this specification based on the nominal value of the sealing contact strength of the special threaded oil casing of this specification. Selection Module: Used to create material selection charts based on downhole service temperature and pressure, and to select the corresponding grade of special threaded tubing according to different service temperature and pressure ranges.

[0034] Example 4 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a special threaded oil casing selection method according to Embodiment 1.

[0035] Example 5 A computer-readable storage medium storing a computer program that, when executed by a processor, implements a special threaded oil casing selection method as described in Embodiment 1.

[0036] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.

[0037] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0038] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0039] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0040] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for selecting a special threaded oil casing, characterized in that, Includes the following steps: Obtain the specifications of all special threaded tubing and casing in the oil and gas field's material warehouse; An equivalent yield model is established based on the specifications of special threaded oil casing, and the CEE curves of special threaded oil casing with different specifications are obtained based on the equivalent yield model. To obtain the high crush resistance level of the special threaded oil casing, and based on the high crush resistance level and the pipe body crush model under tensile load, the crush curve of the special threaded oil casing under tensile load is obtained: Based on the CEE curve and the bursting curve under tensile load, the VME curve of the special threaded oil casing under combined load is obtained. Based on the VME curve, simulated loading was performed to obtain the distribution curve of the sealing surface contact pressure on the sealing width of the special threaded oil casing at different load points. Based on the distribution curve of the sealing surface contact pressure of the special threaded oil casing at different load points on the sealing width and the calculation model of sealing contact strength, the sealing contact strength value of the special threaded oil casing at different load points is obtained. Based on the sealing contact strength, the sealing performance of special threads in oil casing is divided into several grades. The sealing performance level of the special threaded oil casing is determined based on the sealing contact strength value at different load points. Material selection charts are made based on downhole service temperature and pressure, and special threaded tubing of corresponding grades is selected according to different service temperature and pressure ranges. When obtaining the VME curve of the special threaded oil casing under combined load based on the CEE curve and the bursting curve under tensile load, the VME curve of the special threaded oil casing under combined load is obtained by coupling 95% of the CEE curve with the bursting curve under tensile load. When simulating loading based on the VME curve to obtain the distribution curve of the sealing surface contact pressure on the sealing width of the special threaded oil casing at different load points, the simulation software is first used to select the worst sealing performance mode for the internal and external thread mating mode, and then the simulation loading is performed based on the VME curve. Based on the distribution curve of the sealing surface contact pressure on the sealing width at different load points and the sealing contact strength calculation model, the sealing contact strength value of the special threaded oil casing at different load points is obtained. Then, the contact pressure on the sealing surface is integrated on the sealing surface contact width according to the sealing contact strength calculation model to obtain the sealing contact strength value of the special threaded oil casing of different specifications at room temperature. The special thread sealing performance of the oil casing is divided into 5 levels; The sealing contact strength is classified as follows: Grade 1 for 20 N / mm to 260 N / mm, Grade 2 for 260 N / mm to 780 N / mm, Grade 3 for 780 N / mm to 1630 N / mm, Grade 4 for 1630 N / mm to 2020 N / mm, and Grade 5 for greater than 2020 N / mm.

2. The method for selecting a special threaded oil casing according to claim 1, characterized in that, The simulation software is ABAQUS.

3. A special threaded oil casing selection device, used to implement the special threaded oil casing selection method described in claim 1 or 2, characterized in that, include: Specification Parameter Acquisition Module: Used to acquire the specification parameters of all special threaded oil casings in the oil and gas field material warehouse; CEE curve acquisition module: used to establish an equivalent yield model based on the specifications of special threaded oil casing, and to obtain the CEE curves of special threaded oil casing with different specifications based on the equivalent yield model; The bursting curve acquisition module is used to obtain the high bursting resistance level of special threaded oil casing. Based on the high bursting resistance level and the pipe body bursting model under tensile load, the bursting curve of the special threaded oil casing under tensile load is obtained. VME curve acquisition module: used to obtain the VME curve of special threaded oil casing under combined load based on the CEE curve and the bursting curve under tensile load; Distribution curve acquisition module: used to simulate loading based on VME curve, and obtain the distribution curve of the sealing surface contact pressure of the special threaded oil casing at different load points on the sealing width; Sealing contact strength calculation module: This module is used to obtain the sealing contact strength value of the special threaded oil casing at different load points based on the distribution curve of the sealing surface contact pressure on the sealing width and the sealing contact strength calculation model of the special threaded oil casing at different load points. Grading module: used to classify the sealing performance of special threads of oil casing into several grades according to the sealing contact strength; Grade determination module: used to determine the sealing performance grade of special threaded oil casing based on the sealing contact strength value at different load points; Selection Module: Used to create material selection charts based on downhole service temperature and pressure, and to select the corresponding grade of special threaded tubing according to different service temperature and pressure ranges.

4. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the special threaded oil casing selection method as described in claim 1 or 2.

5. A computer-readable storage medium storing a computer program, characterized in that, When a computer program is executed by a processor, it implements the special threaded oil casing selection method described in claim 1 or 2.

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