Resonance unbuckling method and system for casing-coupling subsystem

Abstract

The invention relates to the technical field of tools, in particular to a resonance unbuckling method and system for a sleeve-coupling subsystem. The method comprises the steps that the make-up torque of a casing-coupling subsystem is obtained, and the maximum release torque is determined according to the make-up torque; basic parameters of the casing-coupling are determined, a finite element model is established according to the basic parameters, modal simulation analysis and experimental testing are carried out according to the finite element model, and the inherent frequency, the position of an excitation point and the excitation acceleration of the casing-coupling subsystem are determined; according to the excitation point and the excitation acceleration, a medium / high frequency excitation device is adopted to apply vibration excitation under the inherent frequency to the sleeve-coupling subsystem, and large resonance amplitude and resonance acceleration are excited in the sleeve-coupling subsystem, so that violent transverse or longitudinal swing is generated at the coupling position, the unfastening effect is generated, and the coupling is prevented from being loosened. And the unbuckling torque of a sleeve-coupling subsystem is obviously reduced, and high-efficiency unbuckling is guaranteed.

Description

Background Art

[0002] In order to redevelop and utilize old wells or seal abandoned wells, one of the main steps is to remove the oil casing string that has been lowered. Usually, the casing length can reach hundreds of meters or even thousands of meters, and the traditional milling operation uses a casing milling barrel to mill from the wellhead step by step downward, which is extremely inefficient, and the oil casing is milled into waste, losing its secondary use value, resulting in a considerable degree of resource waste. At present, the casing string lowered into the well is composed of multiple casings connected in the form of threads. If a torque machine is used at the wellhead to reversely twist the shackle, and then assisted by a pulling tool, the casing can be directly pulled out; but because the casing has been in service underground for a long time and the service environment is complex, there must be rust and adhesion at the threaded connection coupling, which greatly increases the shackle torque, and even makes the shackle torque greater than the maximum load of the torque machine, resulting in the inability to shackle. Summary of the invention

[0003] The technical problem to be solved by the present invention is to solve the shortcomings of the prior art, specifically to solve the problem of being unable to loosen the buckle, and specifically provide a resonant loosening method and system for a casing-coupling subsystem, which are as follows:

[0004] 1) In the first aspect, the present invention provides a resonance loosening method for a casing-coupling subsystem, and the specific technical scheme is as follows:

[0005] Obtain the maximum breakout torque of the casing-coupling system;

[0006] Determine basic parameters of the casing-coupling subsystem, establish a finite element model based on the basic parameters, and preliminarily determine the position of the excitation point and the excitation acceleration of the casing-coupling subsystem based on the finite element model;

[0007] The natural frequency of the casing-coupling system is measured by using an instrument, and the position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results to obtain the calibrated position of the excitation point and the calibrated excitation acceleration;

[0008] The casing-coupling subsystem is subjected to a resonance loosening process according to the calibrated position of the excitation point and the calibrated excitation acceleration.

[0009] The beneficial effects of the resonance loosening method of a casing-coupling subsystem provided by the present invention are as follows:

[0010] Through a series of simulation and test methods, the excitation acceleration and excitation point position of the casing-coupling subsystem are determined, and medium / high frequency excitation equipment is used to excite a larger resonance amplitude and acceleration in the casing-coupling subsystem, so that the coupling produces violent lateral or longitudinal swings, resulting in a loosening effect, thereby significantly reducing the casing-coupling subsystem's shackle torque and ensuring efficient shackle.

[0011] Based on the above solution, the present invention can also be improved as follows.

[0012] Further, the method for obtaining the maximum breakout torque of the casing-coupling subsystem is:

[0013] The maximum breakout torque of the casing-coupling subsystem is determined by the make-up torque of the casing-coupling subsystem.

[0014] Further, the basic parameters include: the steel grade of the casing of the casing-coupling subsystem, the buckle type at the coupling of the casing-coupling subsystem, the inner diameter of the casing of the casing-coupling subsystem, and the outer diameter of the casing of the casing-coupling subsystem.

[0015] Furthermore, the natural frequency of the casing-coupling subsystem is measured by an instrument, and the position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results, and the calibrated position of the excitation point and the calibrated excitation acceleration are obtained, which specifically include:

[0016] The casing-coupling subsystem is tested by an excitation hammer to obtain multi-order natural frequencies of the casing-coupling subsystem, and the multi-order natural frequencies are input into the finite element model to calibrate and determine the position of the precise excitation point and the precise excitation acceleration of the casing-coupling subsystem, and the position of the precise excitation point obtained after calibration is used as the position of the excitation point, and the precise excitation acceleration obtained after calibration is used as the excitation acceleration for resonant loosening processing.

[0017] 2) In the second aspect, the present invention also provides a resonance loosening system for a casing-coupling subsystem, and the specific technical solution is as follows:

[0018] The acquisition module is used to: obtain the maximum breakout torque of the casing-coupling subsystem;

[0019] The determination module is used to: determine basic parameters of the casing-coupling subsystem, establish a finite element model according to the basic parameters, and preliminarily determine the position of the excitation point and the excitation acceleration of the casing-coupling subsystem according to the finite element model;

[0020] The calibration module is used to: measure the natural frequency of the casing-coupling subsystem using an instrument, calibrate the position of the initially determined excitation point and the initially determined excitation acceleration according to the measurement results, and obtain the calibrated position of the excitation point and the calibrated excitation acceleration;

[0021] The processing module is used for performing resonance loosening processing on the casing-coupling subsystem according to the calibrated position of the excitation point and the calibrated excitation acceleration.

[0022] Based on the above solution, the present invention can also be improved as follows.

[0023] Further, the method for obtaining the maximum breakout torque of the casing-coupling subsystem is:

[0024] The maximum breakout torque of the casing-coupling subsystem is determined by the make-up torque of the casing-coupling subsystem.

[0025] Further, the basic parameters include: the steel grade of the casing of the casing-coupling subsystem, the buckle type at the coupling of the casing-coupling subsystem, the inner diameter of the casing of the casing-coupling subsystem, and the outer diameter of the casing of the casing-coupling subsystem.

[0026] Furthermore, the natural frequency of the casing-coupling subsystem is measured by an instrument, and the position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results, and the calibrated position of the excitation point and the calibrated excitation acceleration are obtained, which specifically include:

[0027] The casing-coupling subsystem is tested by an excitation hammer to obtain multi-order natural frequencies of the casing-coupling subsystem, and the multi-order natural frequencies are input into the finite element model to calibrate and determine the position of the precise excitation point and the precise excitation acceleration of the casing-coupling subsystem, and the position of the precise excitation point obtained after calibration is used as the position of the excitation point, and the precise excitation acceleration obtained after calibration is used as the excitation acceleration for resonant loosening processing.

[0028] It should be noted that the beneficial effects achieved by the technical solution of the second aspect of the present invention and the corresponding possible implementation methods can be found in the above-mentioned technical effects of the first aspect and its corresponding possible implementation methods, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0030] Figure 1 A schematic flow chart of a resonance loosening method for a casing-coupling subsystem according to an embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of the architecture of a resonance loosening system of a casing-coupling subsystem according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of the cross section of the casing string. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] like Figure 1 As shown, a resonance loosening method of a casing-coupling subsystem according to an embodiment of the present invention comprises the following steps:

[0035] S1, obtain the maximum breakout torque of the casing-coupling system;

[0036] S2, determining basic parameters of the casing-coupling subsystem, and establishing a finite element model according to the basic parameters, and preliminarily determining the position of the excitation point and the excitation acceleration of the casing-coupling subsystem according to the finite element model;

[0037] S3, using an instrument to measure the natural frequency of the casing-coupling subsystem, and calibrating the initially determined position of the excitation point and the initially determined excitation acceleration according to the measurement result to obtain the calibrated position of the excitation point and the calibrated excitation acceleration;

[0038] S4, performing resonance loosening processing on the casing-coupling subsystem according to the calibrated position of the excitation point and the calibrated excitation acceleration.

[0039] The beneficial effects of the resonance loosening method of a casing-coupling subsystem provided by the present invention are as follows:

[0040] Through a series of simulation and test methods, a larger resonance amplitude and acceleration are excited in the casing-coupling subsystem, causing violent lateral or longitudinal swings at the coupling, resulting in a loosening effect, thereby significantly reducing the loosening torque of the casing-coupling subsystem and ensuring efficient shackle.

[0041] The process of obtaining the make-up torque of the casing-coupling subsystem and determining the maximum make-up torque according to the make-up torque is as follows:

[0042] like Figure 3 As shown, the x direction is the length direction of the tube, and the y direction and z direction are two directions perpendicular to each other in the tube cross section. 1, 2, 3, and 4 are nodes taken at the 1 / 4 arc of the cross section, d0 and d i are the inner and outer diameters of the tube respectively.

[0043] Estimate the make-up torque (≥ make-up torque) at the coupling based on the make-up torque data of the casing-coupling subsystem, and determine the maximum achievable make-up torque based on the maximum load of the on-site torque machine;

[0044] The casing-coupling subsystem consists of two parts: casing and cylindrical coupling, wherein the casing joint part is externally threaded, the coupling tube is internally threaded, and the two casings are connected together by the coupling;

[0045] The estimation process is as follows: The connection process between the casing and the coupling is generally called make-up, which is achieved using a torque machine. At the same time, the make-up torque can be read through the torque machine indication.

[0046] The maximum achievable loosening torque is determined as follows: According to the maximum load of the on-site torque machine during make-up, the maximum loosening torque can be obtained, that is, make-up torque ≤ maximum loosening torque ≤ maximum load of the torque machine.

[0047] The process of determining basic parameters of the casing-coupling subsystem, establishing a finite element model based on the basic parameters, and preliminarily determining the position of the excitation point of the casing-coupling subsystem and the excitation acceleration based on the finite element model is as follows:

[0048] Determine the steel grade of the casing, the buckle type at the coupling, the length of the casing string, the inner and outer diameters of the casing (i.e. Figure 3 d0 and d1 in );

[0049] Steel grade: the strength grade of steel pipes. The general unit in the oil field is ksi, 1ksi≈6.895MPa;

[0050] Steel grades may include: 80ksi, 105ksi, 110ksi.

[0051] The buckle type refers to the threaded connection between the casing and the coupling. Generally, the casing end is connected to the inner wall of the coupling body with a tapered thread, and the end of the coupling body is connected to the casing with a flat thread with the same thread and pitch. It has the characteristics of alleviating the stress concentration at the root of the external thread of the oil pipe when connecting with a single tapered thread, is not prone to fatigue fracture, and has a good connection effect.

[0052] Buckle types include: stepped buckle, long round buckle, short round buckle, etc.

[0053] The casing string is a long string formed by the circulation of casing-coupling subsystem-casing-coupling subsystem.

[0054] The finite element model of the casing string-coupling system is established. According to the symmetry, a node is selected for every 1 / 4 arc, that is, Figure 3 The positions of points 1, 2, 3, and 4 in the model are analyzed and the multi-order natural frequencies (1 to 10) of the casing-coupling subsystem are obtained by modal analysis. The resonance amplitude and resonance acceleration under different modal orders are calculated based on the results of the multi-order modes, and the position of the excitation point and the excitation acceleration (a0) are analyzed and determined.

[0055] Multiple modes refer to multiple natural frequencies.

[0056] The calculation in the case of calculating different modal orders refers to: using the finite element modal analysis method to calculate the resonant amplitude and resonant acceleration at different orders of natural frequencies.

[0057] The process of analysis and determination is:

[0058] By using the finite element analysis method, the external exciter placement position (i.e., excitation point) that can excite the casing-coupling subsystem to produce the maximum resonant amplitude and the external exciter acceleration (i.e., excitation acceleration) that can excite the casing-coupling subsystem to produce the maximum resonant acceleration are obtained.

[0059] The process of resonantly loosening the casing-coupling subsystem according to the position and the excitation acceleration is as follows:

[0060] Use instruments such as excitation hammers to measure the multi-order natural frequencies of the casing string-coupling system, and calibrate the results of finite element modal analysis (including but not limited to the magnitude of excitation acceleration and the location of excitation points, etc.);

[0061] Among them, the excitation hammer refers to: also called an impact hammer, which is a device for testing the multi-order natural frequencies of an object. By installing a sensor on the surface of the object to be tested, after knocking the surface of the object to be tested, the multi-order natural frequencies of the object to be tested are calculated through the response data of the object to be tested displayed by the sensor.

[0062] The calibration process is: using the multi-order natural frequency data results measured by the excitation hammer to update the data results of the finite element modal analysis.

[0063] Based on the results of finite element modal analysis, the magnitude of the excitation acceleration and the excitation position are preliminarily obtained. Subsequently, experimental tests are carried out using test methods such as excitation hammers to determine the multi-order natural frequencies of the casing-coupling subsystem. The multi-order natural frequencies measured in the test are then input into the finite element modal analysis software for a second finite element analysis to calibrate and determine the precise excitation acceleration and excitation point position.

[0064] According to the results of the calibration modal analysis, determine the location of the excitation point in the casing-coupling subsystem (p1, p2, p3...), use the medium frequency / high frequency excitation equipment to load, and realize the resonance of the casing-coupling subsystem. In this process, the number of excitation equipment can be selected according to the actual working conditions. For example, select a single excitation equipment for loading, or place multiple excitation equipment at multiple positions such as p1, p2, p3 for simultaneous loading;

[0065] The proposed loading acceleration is the excitation acceleration a0, and a0 is adjusted so that it can be freely selected in the range of 0.5g to 10g to excite the bushing string to resonate.

[0066] 10 per resonance 3 ~10 5After one vibration cycle, stop the vibration and use the torque machine to set the torque to one-half to two-thirds of the make-up torque, and try to unfasten the buckle; if the buckle still cannot be unfastened, continue to resonate for 10 3 ~10 5 Try again after a vibration cycle.

[0067] Further, the method for obtaining the maximum breakout torque of the casing-coupling subsystem is:

[0068] The maximum breakout torque of the casing-coupling subsystem is determined by the make-up torque of the casing-coupling subsystem.

[0069] Further, the basic parameters include: the steel grade of the casing of the casing-coupling subsystem, the buckle type at the coupling of the casing-coupling subsystem, the inner diameter of the casing of the casing-coupling subsystem, and the outer diameter of the casing of the casing-coupling subsystem.

[0070] Furthermore, the natural frequency of the casing-coupling subsystem is measured by an instrument, and the position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results, and the calibrated position of the excitation point and the calibrated excitation acceleration are obtained, which specifically include:

[0071] The casing-coupling subsystem is tested by an excitation hammer to obtain multi-order natural frequencies of the casing-coupling subsystem, and the multi-order natural frequencies are input into the finite element model to calibrate and determine the position of the precise excitation point and the precise excitation acceleration of the casing-coupling subsystem, and the position of the precise excitation point obtained after calibration is used as the position of the excitation point, and the precise excitation acceleration obtained after calibration is used as the excitation acceleration for resonant loosening processing.

[0072] like Figure 2 As shown, the present invention also provides a resonance loosening system 200 of a casing-coupling subsystem, and the specific technical solution is as follows:

[0073] The acquisition module 210 is used to: acquire the maximum breakout torque of the casing-coupling subsystem;

[0074] The determination module 220 is used to: determine basic parameters of the casing-coupling subsystem, establish a finite element model according to the basic parameters, and preliminarily determine the position of the excitation point and the excitation acceleration of the casing-coupling subsystem according to the finite element model;

[0075] The calibration module 230 is used to: measure the natural frequency of the casing-coupling subsystem using an instrument, calibrate the position of the initially determined excitation point and the initially determined excitation acceleration according to the measurement result, and obtain the calibrated position of the excitation point and the calibrated excitation acceleration;

[0076] The processing module 240 is used to perform a resonance loosening process on the casing-coupling subsystem according to the calibrated position of the excitation point and the calibrated excitation acceleration.

[0077] Further, the method for obtaining the maximum breakout torque of the casing-coupling subsystem is:

[0078] The maximum breakout torque of the casing-coupling subsystem is determined by the make-up torque of the casing-coupling subsystem.

[0079] Further, the basic parameters include: the steel grade of the casing of the casing-coupling subsystem, the buckle type at the coupling of the casing-coupling subsystem, the inner diameter of the casing of the casing-coupling subsystem, and the outer diameter of the casing of the casing-coupling subsystem.

[0080] Furthermore, the natural frequency of the casing-coupling subsystem is measured by an instrument, and the position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results, and the calibrated position of the excitation point and the calibrated excitation acceleration are obtained, which specifically include:

[0081] The casing-coupling subsystem is tested by an excitation hammer to obtain multi-order natural frequencies of the casing-coupling subsystem, and the multi-order natural frequencies are input into the finite element model to calibrate and determine the position of the precise excitation point and the precise excitation acceleration of the casing-coupling subsystem, and the position of the precise excitation point obtained after calibration is used as the position of the excitation point, and the precise excitation acceleration obtained after calibration is used as the excitation acceleration for resonant loosening processing.

[0082] It should be noted that the beneficial effects of the resonance loosening system 200 of a casing-coupling subsystem provided in the above-mentioned embodiment are the same as the beneficial effects of the resonance loosening method of the above-mentioned casing-coupling subsystem, which will not be repeated here. In addition, when the system provided in the above-mentioned embodiment realizes its functions, it is only illustrated by the division of the above-mentioned functional modules. In practical applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the system can be divided into different functional modules according to actual conditions to complete all or part of the functions described above. In addition, the system and method embodiments provided in the above-mentioned embodiment belong to the same conception, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0083] In an exemplary embodiment, a computer program product or a computer program is also provided, the computer program product or the computer program comprising computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device performs any of the above methods.

[0084] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects and represent the definition of a specific order or sequence. The order of use of similar objects can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than the order shown or described.

[0085] Those skilled in the art know that the present invention can be implemented as a system, method or computer program product. Therefore, the present disclosure can be specifically implemented in the following forms, namely: it can be complete hardware, it can be complete software (including firmware, resident software, microcode, etc.), or it can be a combination of hardware and software, which is generally referred to as "circuit", "module" or "system" herein. In addition, in some embodiments, the present invention can also be implemented in the form of a computer program product in one or more computer-readable media, and the computer-readable medium contains computer-readable program code.

[0086] Any combination of one or more computer-readable media may be used. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, device, or device.

[0087] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A resonance loosening method for a casing-coupling system, characterized in that: include: Obtain the maximum breakout torque of the casing-coupling system; Determine basic parameters of the casing-coupling subsystem, establish a finite element model based on the basic parameters, and preliminarily determine the position of the excitation point and the excitation acceleration of the casing-coupling subsystem based on the finite element model; The natural frequency of the casing-coupling system is measured by using an instrument, and the position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results to obtain the calibrated position of the excitation point and the calibrated excitation acceleration; The casing-coupling subsystem is subjected to a resonance loosening process according to the calibrated position of the excitation point and the calibrated excitation acceleration.

2. A resonance loosening method for a casing-coupling subsystem according to claim 1, characterized in that: The method for obtaining the maximum breakout torque of the casing-coupling subsystem is: The maximum breakout torque of the casing-coupling subsystem is determined by the make-up torque of the casing-coupling subsystem.

3. A resonance loosening method for a casing-coupling subsystem according to claim 1, characterized in that: The basic parameters include: the steel grade of the casing of the casing-coupling subsystem, the buckle type at the coupling of the casing-coupling subsystem, the inner diameter of the casing of the casing-coupling subsystem, and the outer diameter of the casing of the casing-coupling subsystem.

4. A resonance loosening method for a casing-coupling system according to any one of claims 1 to 3, characterized in that: The natural frequency of the casing-coupling system is measured by an instrument. The position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results. The calibrated position of the excitation point and the calibrated excitation acceleration are obtained, which specifically include: The casing-coupling subsystem is tested by an excitation hammer to obtain multi-order natural frequencies of the casing-coupling subsystem, and the multi-order natural frequencies are input into the finite element model to calibrate and determine the position of the precise excitation point and the precise excitation acceleration of the casing-coupling subsystem, and the position of the precise excitation point obtained after calibration is used as the position of the excitation point, and the precise excitation acceleration obtained after calibration is used as the excitation acceleration for resonant loosening processing.

5. A resonance loosening system for a casing-coupling system, characterized in that: include: The acquisition module is used to: obtain the maximum breakout torque of the casing-coupling subsystem; The determination module is used to: determine basic parameters of the casing-coupling subsystem, establish a finite element model according to the basic parameters, and preliminarily determine the position of the excitation point and the excitation acceleration of the casing-coupling subsystem according to the finite element model; The calibration module is used to: measure the natural frequency of the casing-coupling subsystem using an instrument, calibrate the position of the initially determined excitation point and the initially determined excitation acceleration according to the measurement results, and obtain the calibrated position of the excitation point and the calibrated excitation acceleration; The processing module is used for performing resonance loosening processing on the casing-coupling subsystem according to the calibrated position of the excitation point and the calibrated excitation acceleration.

6. A resonance loosening system for a casing-coupling subsystem according to claim 5, characterized in that: The method for obtaining the maximum breakout torque of the casing-coupling subsystem is: The maximum breakout torque of the casing-coupling subsystem is determined by the make-up torque of the casing-coupling subsystem.

7. A resonance loosening system for a casing-coupling subsystem according to claim 5, characterized in that: The basic parameters include: the steel grade of the casing of the casing-coupling subsystem, the buckle type at the coupling of the casing-coupling subsystem, the inner diameter of the casing of the casing-coupling subsystem, and the outer diameter of the casing of the casing-coupling subsystem.

8. A resonance loosening system for a casing-coupling subsystem according to any one of claims 5 to 7, characterized in that: The natural frequency of the casing-coupling system is measured by an instrument. The position of the initially determined excitation point and the initially determined excitation acceleration are calibrated according to the measurement results. The calibrated position of the excitation point and the calibrated excitation acceleration are obtained, which specifically include: The casing-coupling subsystem is tested by an excitation hammer to obtain multi-order natural frequencies of the casing-coupling subsystem, and the multi-order natural frequencies are input into the finite element model to calibrate and determine the position of the precise excitation point and the precise excitation acceleration of the casing-coupling subsystem, and the position of the precise excitation point obtained after calibration is used as the position of the excitation point, and the precise excitation acceleration obtained after calibration is used as the excitation acceleration for resonant loosening processing.

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