A method and apparatus for monitoring the uplift of a natural gas wellhead

Abstract

The application provides a natural gas well wellhead uplift monitoring method and device. The natural gas well wellhead uplift monitoring method comprises the following steps: S1, obtaining relative displacement data between the natural gas well wellhead and the ground through a natural gas well wellhead uplift monitoring device; S2, obtaining ground subsidence displacement data; and S3, calculating the uplift height of the natural gas well wellhead according to the relative displacement data between the natural gas well wellhead and the ground and the ground subsidence displacement data. The automatic real-time monitoring of the wellhead uplift is realized. The relative displacement monitoring between the wellhead and the ground is deployed in a single well, and the ground subsidence monitoring is deployed in a well site, so that the automatic real-time monitoring of the wellhead uplift height considering the ground subsidence is realized, the labor intensity of users is reduced, the wellhead uplift in two forms of string elongation and ground subsidence can be accurately distinguished, and the monitoring precision and the automation level are improved. The application meets the needs of real-time early warning, informatization and intelligentization development of well operation safety.

Description

Technical Field

[0001] This invention relates to the field of risk monitoring technology for natural gas wells and gas storage wells, and particularly to a method and device for monitoring wellhead rise in natural gas wells. Background Technology

[0002] Wellhead lift is a common phenomenon in natural gas wells and gas storage wells during injection and production operations, affecting the safe operation of gas wells. This phenomenon is particularly pronounced in gas storage facilities. Therefore, the industry standard for gas storage facilities, "SY / T 7651 Gas Storage Well Operation Management Specification," explicitly requires that "wellhead lift should be monitored regularly every year." Oil and gas production practice shows that wellhead lift manifests as relative displacement between the wellhead and the ground, possibly caused by two factors: firstly, the wellbore elongates under thermal stress; and secondly, ground subsidence. With the increasing importance of wellbore safety monitoring and early warning in high-pressure gas wells and gas storage wells, real-time monitoring of wellhead lift has become a hot topic in oil and gas production. Currently, the common method in the field is manual reading using steel rulers, which is insufficient to distinguish between wellhead lift caused by tubing elongation and ground subsidence. This method cannot achieve automatic real-time monitoring and is ill-suited to the needs of real-time early warning for well operation safety and the development of information technology and intelligent systems. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and device for monitoring wellhead rise in natural gas wells, addressing the shortcomings of the prior art.

[0004] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for monitoring wellhead rise in natural gas wells, comprising:

[0005] S1. Obtain relative displacement data between the natural gas wellhead and the ground through a natural gas wellhead lift monitoring device;

[0006] S2. Obtain foundation settlement and displacement data;

[0007] S3. Calculate the wellhead lift height of the natural gas well based on the relative displacement data between the wellhead and the ground and the foundation settlement displacement data.

[0008] The beneficial effects of adopting the technical solution of this invention are: It enables automatic real-time monitoring of wellhead lift. By deploying wellhead-to-surface relative displacement monitoring in single wells and surface settlement monitoring at the well site, it achieves automatic real-time monitoring of wellhead lift height considering surface settlement. This reduces user workload, accurately distinguishes between wellhead lift caused by tubing elongation and surface settlement, and solves the problems of indistinguishable wellhead lift and surface settlement at natural gas well and gas storage well production sites, as well as insufficient automation and real-time monitoring of wellhead lift. This improves monitoring accuracy and automation levels, meeting the needs of real-time early warning for well operation safety and the development of informatization and intelligentization.

[0009] Further, step S1 includes: S11, fixing the outer cylinder of the natural gas wellhead lifting monitoring device to the data collection tree, and burying the bottom of the inner cylinder of the natural gas wellhead lifting monitoring device in the ground;

[0010] S12. Obtain relative displacement data between the natural gas wellhead and the ground through a natural gas wellhead lift monitoring device.

[0011] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the outer cylinder is fixed to the gas production tree, while the inner cylinder and part of the waveguide are inserted underground. Wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor with the waveguide, and an integrated automatic data acquisition and control system enables real-time monitoring of wellhead lift. This facilitates accurate measurement of the relative displacement data between the natural gas wellhead and the ground by the natural gas wellhead lift monitoring device.

[0012] Further, step S11 includes: S111, digging a tunnel based on the ground surface;

[0013] S112. The bottom of the natural gas wellhead lifting monitoring device is vertically buried in the underground cavity;

[0014] S113. Lift the outer cylinder of the natural gas wellhead lifting monitoring device so that the bottom cover of the outer cylinder is flush with the zero mark of the inner cylinder;

[0015] S114. Fix the outer cylinder of the natural gas wellhead lifting monitoring device to the flange of the data acquisition tree;

[0016] S115, connects to power supply and automatic control equipment.

[0017] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the outer cylinder is fixed to the gas production tree, and the inner cylinder and part of the waveguide are inserted underground. The wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor and the waveguide, and the integrated automatic acquisition and control system realizes real-time monitoring of the wellhead lift.

[0018] Further, step S2 includes:

[0019] S21. Obtain strain data of the natural gas pipeline by using strain gauges installed on the natural gas pipeline;

[0020] S22. Based on the strain data of the natural gas pipeline, calculate the foundation settlement displacement data corresponding to the strain of the natural gas pipeline using a mechanical model.

[0021] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: Ground settlement monitoring is carried out using methods such as strain monitoring of natural gas pipelines within the well site and static leveling sensors for foundation settlement. A ground settlement monitoring system is deployed at the well site, and ground settlement monitoring is conducted using strain monitoring of natural gas pipelines within the well site. Strain gauges are attached to the monitoring points, and the foundation settlement displacement corresponding to the strain changes generated by the pipeline is calculated through a mechanical model.

[0022] Furthermore, in step S21, the strain gauge is located at the bend of the natural gas pipeline, away from the wellhead and close to the outlet.

[0023] The beneficial effects of adopting the above-mentioned further technical solution are as follows: First, locations with large strain in the ground pipeline are selected as monitoring points. These points are typically located at pipe bends or similar locations, and monitoring points should be as far away from the manhole as possible and closer to the outlet to avoid the impact of manhole uplift on the pipeline's stress state. Then, the ground settlement displacement corresponding to the pipeline strain is calculated using strain gauges and a mechanical model.

[0024] Further, step S3 includes: calculating the wellhead lift height of the natural gas well based on the relative displacement data between the wellhead and the ground and the average value of multiple foundation settlement displacement data.

[0025] The beneficial effects of adopting the above-mentioned further technical solutions are: averaging multiple foundation settlement displacement data, improving data accuracy, and enhancing monitoring reliability.

[0026] Further, in step S3, the wellhead lift height of the natural gas well is calculated using the following formula:

[0027] h = S1 - (D1 + D2 + ... + Dn) / n, where h is the wellhead lift height of the natural gas well, S1 is the relative displacement between the wellhead of the natural gas well and the ground, and D1, D2, ... Dn are multiple foundation settlement displacement data.

[0028] The beneficial effects of adopting the above-mentioned further technical solutions are: averaging multiple foundation settlement displacement data, improving data accuracy, and enhancing monitoring reliability.

[0029] Furthermore, the present invention also provides a natural gas wellhead lift monitoring device for performing a natural gas wellhead lift monitoring method as described in any of the above claims. The natural gas wellhead lift monitoring device includes: an inner cylinder, an outer cylinder, a magnetostrictive sensor, a power supply, and an automatic control device. The outer cylinder is fixed to a data acquisition tree. The top of the inner cylinder is slidably installed on the inner side of the bottom of the outer cylinder. The top of the magnetostrictive sensor is located in the outer cylinder, and the bottom of the magnetostrictive sensor is located in the inner cylinder. The power supply and the automatic control device are both connected to the magnetostrictive sensor.

[0030] The beneficial effects of adopting the technical solution of this invention are: It enables automatic real-time monitoring of wellhead lift. By deploying wellhead-to-surface relative displacement monitoring in single wells and surface settlement monitoring at the well site, it achieves automatic real-time monitoring of wellhead lift height considering surface settlement. This reduces user workload, accurately distinguishes between wellhead lift caused by tubing elongation and surface settlement, and solves the problems of indistinguishable wellhead lift and surface settlement at natural gas well and gas storage well production sites, as well as insufficient automation and real-time monitoring of wellhead lift. This improves monitoring accuracy and automation levels, meeting the needs of real-time early warning for well operation safety and the development of informatization and intelligentization.

[0031] Furthermore, both the inner cylinder and the outer cylinder are provided with bottom covers with central holes. The inner cylinder is slidably mounted on the bottom cover of the outer cylinder. The outer wall of the inner cylinder is provided with scale values. The top of the inner cylinder is provided with a flange extending radially outward along the inner cylinder. The flange is engaged with the top of the bottom cover of the outer cylinder. The outer cylinder is fixed to the collection tree by a fixing plate.

[0032] The beneficial effects of adopting the above-mentioned further technical solution are: the inner cylinder top includes a flange to prevent the inner cylinder from detaching from the outer cylinder. The scale value setting facilitates users' intuitive observation of the relative displacement data between the natural gas wellhead and the ground, facilitates the detection of errors in the natural gas wellhead lift monitoring device and automatic control equipment, and facilitates timely adjustment of the natural gas wellhead lift monitoring device and automatic control equipment. The outer cylinder is fixed to the gas production tree, and the inner cylinder and part of the waveguide are inserted underground. Wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor and the waveguide, and an integrated automatic acquisition and control system enables real-time monitoring of wellhead lift.

[0033] Furthermore, the magnetostrictive sensor includes: an electronic chamber, a measurement blind end, a waveguide, and an annular permanent magnet. The top of the outer cylinder is provided with a support base with a partition, and the top of the support base is provided with an end cap. The electronic chamber is mounted on the partition of the support base. The power supply and the automatic control device are both connected to the electronic chamber. The top of the waveguide is connected to the electronic chamber, and the bottom of the waveguide penetrates the inner cylinder and is exposed on the outside. The measurement blind end and the annular permanent magnet are sleeved on the waveguide. The measurement blind end is located above the annular permanent magnet, and the annular permanent magnet abuts against the bottom of the inner cylinder.

[0034] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the outer cylinder is fixed to the gas production tree, and the inner cylinder and part of the waveguide are inserted underground. The wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor and the waveguide, and the integrated automatic acquisition and control system realizes real-time monitoring of the wellhead lift.

[0035] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart illustrating the natural gas wellhead lift monitoring method provided in an embodiment of the present invention.

[0037] Figure 2 This is one of the structural schematic diagrams of a natural gas wellhead lift monitoring device provided in an embodiment of the present invention.

[0038] Figure 3 This is the second schematic diagram of the structure of the natural gas wellhead lift monitoring device provided in an embodiment of the present invention.

[0039] Figure 4 The third schematic diagram of the structure of the natural gas wellhead lift monitoring device provided in the embodiment of the present invention.

[0040] Reference numerals: 1. End cap; 2. Support base; 3. Inner cylinder; 4. Outer cylinder; 41. Variable diameter surface; 5. Magnetostrictive sensor; 51. Electronic compartment; 52. Measurement blind end; 53. Waveguide; 54. Ring permanent magnet; 6. Fixing plate; 7. Power supply; 8. Automatic control equipment; 9. Reference surface; 10. Ground cavity; 11. Data collection tree; 12. Scale value; 13. Single well; 14. Natural gas wellhead lift monitoring device; 15. Surface pipeline; 16. Monitoring point; 17. Large cross-junction; 18. Casing head. Detailed Implementation

[0041] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0042] like Figure 1 As shown, this embodiment of the invention provides a method for monitoring wellhead uplift in natural gas wells, including:

[0043] S1. Obtain relative displacement data between the natural gas wellhead and the ground through a natural gas wellhead lift monitoring device;

[0044] S2. Obtain foundation settlement and displacement data;

[0045] S3. Calculate the wellhead lift height of the natural gas well based on the relative displacement data between the wellhead and the ground and the foundation settlement displacement data.

[0046] The beneficial effects of adopting the technical solution of this invention are: It enables automatic real-time monitoring of wellhead lift. By deploying wellhead-to-surface relative displacement monitoring in single wells and surface settlement monitoring at the well site, it achieves automatic real-time monitoring of wellhead lift height considering surface settlement. This reduces user workload, accurately distinguishes between wellhead lift caused by tubing elongation and surface settlement, and solves the problems of indistinguishable wellhead lift and surface settlement at natural gas well and gas storage well production sites, as well as insufficient automation and real-time monitoring of wellhead lift. This improves monitoring accuracy and automation levels, meeting the needs of real-time early warning for well operation safety and the development of informatization and intelligentization.

[0047] The system measures the relative displacement between the wellhead and the ground, as well as the ground settlement within the well site, to achieve accurate monitoring of the wellhead lift considering ground settlement. Automatic real-time measurement of the relative displacement between the wellhead and the ground is achieved through a magnetostrictive displacement sensor and an automatic data acquisition and control system.

[0048] Further, step S1 includes: S11, fixing the outer cylinder of the natural gas wellhead lifting monitoring device to the data collection tree, and burying the bottom of the inner cylinder of the natural gas wellhead lifting monitoring device in the ground;

[0049] S12. Obtain relative displacement data between the natural gas wellhead and the ground through a natural gas wellhead lift monitoring device.

[0050] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the outer cylinder is fixed to the gas production tree, while the inner cylinder and part of the waveguide are inserted underground. Wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor with the waveguide, and an integrated automatic data acquisition and control system enables real-time monitoring of wellhead lift. This facilitates accurate measurement of the relative displacement data between the natural gas wellhead and the ground by the natural gas wellhead lift monitoring device.

[0051] Further, step S11 includes: S111, digging a tunnel based on the ground surface;

[0052] S112. The bottom of the natural gas wellhead lifting monitoring device is vertically buried in the underground cavity;

[0053] S113. Lift the outer cylinder of the natural gas wellhead lifting monitoring device so that the bottom cover of the outer cylinder is flush with the zero mark of the inner cylinder;

[0054] S114. Fix the outer cylinder of the natural gas wellhead lifting monitoring device to the flange of the data acquisition tree;

[0055] S115, connects to power supply and automatic control equipment.

[0056] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the outer cylinder is fixed to the gas production tree, and the inner cylinder and part of the waveguide are inserted underground. The wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor and the waveguide, and the integrated automatic acquisition and control system realizes real-time monitoring of the wellhead lift.

[0057] Further, step S2 includes:

[0058] S21. Obtain strain data of the natural gas pipeline by using strain gauges installed on the natural gas pipeline;

[0059] S22. Based on the strain data of the natural gas pipeline, calculate the foundation settlement displacement data corresponding to the strain of the natural gas pipeline using a mechanical model.

[0060] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: Ground settlement monitoring is carried out using methods such as strain monitoring of natural gas pipelines within the well site and static leveling sensors for foundation settlement. A ground settlement monitoring system is deployed at the well site, and ground settlement monitoring is conducted using strain monitoring of natural gas pipelines within the well site. Strain gauges are attached to the monitoring points, and the foundation settlement displacement corresponding to the strain changes generated by the pipeline is calculated through a mechanical model.

[0061] Furthermore, in step S21, the strain gauge is located at the bend of the natural gas pipeline, away from the wellhead and close to the outlet.

[0062] The beneficial effects of adopting the above-mentioned further technical solution are as follows: First, locations with large strain in the ground pipeline are selected as monitoring points. These points are typically located at pipe bends or similar locations, and monitoring points should be as far away from the manhole as possible and closer to the outlet to avoid the impact of manhole uplift on the pipeline's stress state. Then, the ground settlement displacement corresponding to the pipeline strain is calculated using strain gauges and a mechanical model.

[0063] Further, step S3 includes: calculating the wellhead lift height of the natural gas well based on the relative displacement data between the wellhead and the ground and the average value of multiple foundation settlement displacement data.

[0064] The beneficial effects of adopting the above-mentioned further technical solutions are: averaging multiple foundation settlement displacement data, improving data accuracy, and enhancing monitoring reliability.

[0065] Further, in step S3, the wellhead lift height of the natural gas well is calculated using the following formula:

[0066] h = S1 - (D1 + D2 + ... + Dn) / n, where h is the wellhead lift height of the natural gas well, S1 is the relative displacement between the wellhead of the natural gas well and the ground, and D1, D2, ... Dn are multiple foundation settlement displacement data.

[0067] The beneficial effects of adopting the above-mentioned further technical solutions are: averaging multiple foundation settlement displacement data, improving data accuracy, and enhancing monitoring reliability.

[0068] The system automatically measures wellhead lift in real time, enabling automatic monitoring and early warning of wellhead lift. It distinguishes between ground subsidence and precise measurement of wellhead lift height, employing magnetostrictive sensors to monitor the relative displacement between the wellhead (natural gas wellhead) and the ground. By deploying wellhead-to-ground relative displacement monitoring in single wells, ground subsidence monitoring at the well site, and wellhead-to-ground relative displacement measurement with built-in magnetostrictive sensors, the system achieves automatic real-time monitoring of wellhead lift height, taking ground subsidence into account.

[0069] Automatic real-time monitoring of the relative displacement between the wellhead and the ground is achieved using a relative displacement measuring device (natural gas wellhead lift monitoring device). The outer cylinder and the gas production tree are fixed, and the inner cylinder is partially buried underground.

[0070] 1. Select a reference surface 9 as a flat ground and excavate a certain depth of pit 10. The depth of pit 10 should exceed the measurement range of the automatic displacement measuring device (natural gas wellhead lift monitoring device) between the wellhead (natural gas wellhead) and the ground. The surface of the pit and the pithead should be hardened with cement.

[0071] 2. Place the wellhead relative displacement measuring device (natural gas wellhead lift monitoring device) vertically, with the inner cylinder bottom diameter change surface 41 coinciding with the reference surface 9, and the protruding part of the waveguide 53 placed inside the tunnel 10. Raise the outer cylinder 4 to a certain height until the bottom cover of the outer cylinder is flush with the zero mark of the inner cylinder, and keep the length of the reserved waveguide 53 inside the tunnel 10 not less than the measuring range.

[0072] 3. Fix the fixing plate 6 to a flange of the gas extraction tree by welding.

[0073] 4. Connect the power supply 7 and the automatic control device 8, calibrate the reference, and set the monitoring parameters, such as the sampling time interval and unit.

[0074] like Figure 2 The diagram shows the overall schematic of the wellhead lift monitoring method.

[0075] 1. Deploy an automatic real-time monitoring device for the relative displacement between the wellhead and the ground (natural gas wellhead lift monitoring device 14) in single well 13 to realize automatic real-time measurement of the relative displacement between the wellhead and the ground; and carry out ground settlement monitoring by means of natural gas pipeline strain monitoring in the well site and static leveling sensor for foundation settlement.

[0076] 2. Deploy a ground settlement monitoring system at the well site and conduct ground settlement monitoring using the method of natural gas pipeline strain monitoring within the well site;

[0077] (1) For pipeline strain monitoring, the location of the ground pipeline 15 with large strain should be selected as monitoring point 16. This can be done through ground settlement, pipeline stress and strain numerical simulation, etc. Generally, it is the pipeline bend and other parts. In order to avoid the impact of wellhead rise on the pipeline stress state, monitoring point 16 should be as far away from the wellhead as possible and close to the outlet.

[0078] (2) Strain gauges were attached to monitoring point 16, and the ground settlement displacement corresponding to the strain change generated by the pipeline was calculated by mechanical model.

[0079] 3. The relative displacement between the wellhead of well 13 and the ground (relative displacement data between the natural gas wellhead and the ground) is S1. The ground settlement (foundation settlement and displacement data) measured at each monitoring point in the well site is D1, D2, ..., Dn. The wellhead lift height h of the natural gas well can be determined by the following formula:

[0080] h = S1 - (D1 + D2 + ... + Dn) / n, where h is the wellhead lift height of the natural gas well.

[0081] like Figures 2 to 4 As shown, the present invention also provides a natural gas wellhead lift monitoring device for performing a natural gas wellhead lift monitoring method as described in any of the above-mentioned methods. The natural gas wellhead lift monitoring device includes: an inner cylinder 3, an outer cylinder 4, a magnetostrictive sensor 5, a power supply 7, and an automatic control device 8. The outer cylinder 4 is fixed to the data acquisition tree 11. The top of the inner cylinder 3 is slidably installed on the inner side of the bottom of the outer cylinder 4. The top of the magnetostrictive sensor 5 is located in the outer cylinder 4, and the bottom of the magnetostrictive sensor 5 is located in the inner cylinder 3. The power supply 7 and the automatic control device 8 are both connected to the magnetostrictive sensor 5.

[0082] The beneficial effects of adopting the technical solution of this invention are: It enables automatic real-time monitoring of wellhead lift. By deploying wellhead-to-surface relative displacement monitoring in single wells and surface settlement monitoring at the well site, it achieves automatic real-time monitoring of wellhead lift height considering surface settlement. This reduces user workload, accurately distinguishes between wellhead lift caused by tubing elongation and surface settlement, and solves the problems of indistinguishable wellhead lift and surface settlement at natural gas well and gas storage well production sites, as well as insufficient automation and real-time monitoring of wellhead lift. This improves monitoring accuracy and automation levels, meeting the needs of real-time early warning for well operation safety and the development of informatization and intelligentization.

[0083] The acquisition tree 11 may include a large cross 17 and a casing head 18. The large cross 17 is installed above the casing head 18. The support base 2 of the natural gas wellhead lift monitoring device 14 can be fixedly connected to the flange of the casing head 18 through the fixing plate 6.

[0084] like Figures 2 to 4As shown, both the inner cylinder 3 and the outer cylinder 4 are provided with bottom covers with central holes. The inner cylinder 3 is slidably mounted on the bottom cover of the outer cylinder 4. The outer wall of the inner cylinder 3 is provided with a scale value 12. The top of the inner cylinder 3 is provided with a flange extending radially outward along the inner cylinder 3. The flange is engaged with the top of the bottom cover of the outer cylinder 4. The outer cylinder 4 is fixed to the collection tree 11 by a fixing plate 6.

[0085] The beneficial effects of adopting the above-mentioned further technical solution are: the inner cylinder top includes a flange to prevent the inner cylinder from detaching from the outer cylinder. The scale value setting facilitates users' intuitive observation of the relative displacement data between the natural gas wellhead and the ground, facilitates the detection of errors in the natural gas wellhead lift monitoring device and automatic control equipment, and facilitates timely adjustment of the natural gas wellhead lift monitoring device and automatic control equipment. The outer cylinder is fixed to the gas production tree, and the inner cylinder and part of the waveguide are inserted underground. Wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor and the waveguide, and an integrated automatic acquisition and control system enables real-time monitoring of wellhead lift.

[0086] like Figures 2 to 4 As shown, the magnetostrictive sensor 5 further includes: an electronic chamber 51, a measurement blind end 52, a waveguide 53, and an annular permanent magnet 54. The top of the outer cylinder 4 is provided with a support base 2 with a partition, and the top of the support base 2 is provided with an end cap 1. The electronic chamber 51 is mounted on the partition of the support base 2. The power supply 7 and the automatic control device 8 are both connected to the electronic chamber 51. The top of the waveguide 53 is connected to the electronic chamber 51, and the bottom of the waveguide 53 penetrates the inner cylinder 3 and is exposed on the outside. The measurement blind end 52 and the annular permanent magnet 54 are sleeved on the waveguide 53. The measurement blind end 52 is located above the annular permanent magnet 54, and the annular permanent magnet 54 abuts against the bottom of the inner cylinder 3.

[0087] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the outer cylinder is fixed to the gas production tree, and the inner cylinder and part of the waveguide are inserted underground. The wellhead lift is measured by measuring the relative position of the permanent magnet of the displacement sensor and the waveguide, and the integrated automatic acquisition and control system realizes real-time monitoring of the wellhead lift.

[0088] This invention provides a natural gas wellhead lift monitoring device, which can be used to monitor wellhead lift in natural gas wells and gas storage wells, enabling automatic real-time monitoring of wellhead lift. By deploying wellhead-to-surface relative displacement monitoring in single wells and surface settlement monitoring at the well site, automatic real-time monitoring of wellhead lift height considering surface settlement is achieved. Simultaneously, an inner and outer sleeve structure, a magnetostrictive displacement sensor, and an automatic acquisition and control system (automatic control equipment) are used to automatically measure the relative displacement between the wellhead and the surface. This solves the current problems of indistinguishability between wellhead lift and surface settlement in natural gas wells and gas storage wells, and the insufficient level of automation and real-time monitoring of wellhead lift, thus improving monitoring accuracy and automation. The outer sleeve is fixed to the gas production tree, while the inner sleeve and part of the waveguide are inserted underground. Wellhead lift is measured by measuring the relative position of the permanent magnet (ring permanent magnet) of the displacement sensor with the waveguide, and the integrated automatic acquisition and control system forms real-time monitoring of wellhead lift. It can be used for real-time quantitative monitoring and early warning of wellhead lift and settlement in high-pressure gas wells and gas storage wells.

[0089] The natural gas wellhead lift monitoring device includes an end cap 1, a support base 2, an inner cylinder 3, an outer cylinder 4, a magnetostrictive sensor 5, a fixing plate 6, a power supply 7, and an automatic control device 8. The magnetostrictive sensor 5 includes an electronic compartment 51, a measurement blind end 52, a waveguide 53, and a ring-shaped permanent magnet 54.

[0090] The natural gas wellhead lift monitoring device is a nested structure of inner cylinder 3 and outer cylinder 4. Both inner and outer cylinders are tubular structures with bottom covers. The bottom cover has a central hole. The inner cylinder 3 is nested inside the outer cylinder 4. The inner cylinder 3 passes through the central hole of the bottom cover of the outer cylinder 4 and can move freely inside the outer cylinder 4.

[0091] The inner cylinder 3 has a flange at its top to prevent it from detaching from the outer cylinder. An annular permanent magnet 54 is placed at the bottom of the inner cylinder 3. The bottom cover of the inner cylinder contains an externally connected tapered tubular structure. The inner cylinder is marked with a scale value of 12 on its outer surface, with the smallest scale unit being millimeters. The recommended range is -10cm to +25cm, with the zero point near the bottom of the inner cylinder.

[0092] The automatic control device 8 includes a control circuit, a wireless transmitter terminal, and data acquisition and control software. The automatic control device 8 can utilize wireless transmission and, with the accompanying computer control software, achieve remote real-time measurement and data acquisition.

[0093] The support base 2 is a tubular structure with a partition in the middle. The electronic compartment 51 of the magnetostrictive sensor 5 is placed on the partition, and the lower part of the electronic compartment 51 passes through the central hole of the partition. The upper part of the support base 2 is threaded to the end cap 1, and the power supply 7 and the automatic control device 8 are connected to the electronic compartment 51 through the central hole at the top of the end cap 1. The lower part of the support base 2 is threaded to the top of the outer cylinder 3. A fixing plate 6 is connected to the outer side of the support base 2.

[0094] The waveguide 53 of the magnetostrictive sensor 5 passes through the bottom cover of the outer cylinder 4, the annular permanent magnet 54 and the bottom cover of the inner cylinder 3 in sequence, and the waveguide 53 extends out of the inner cylinder 3 by a certain length.

[0095] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for monitoring wellhead uplift in natural gas wells, characterized in that, include: S1. Obtain relative displacement data between the natural gas wellhead and the ground through a natural gas wellhead lift monitoring device; S2. Obtain foundation settlement and displacement data; S3. Calculate the wellhead lift height of the natural gas well based on the relative displacement data between the wellhead and the ground and the foundation settlement displacement data; Step S1 includes: S11, fixing the outer cylinder of the natural gas wellhead lifting monitoring device to the data collection tree, and burying the bottom of the inner cylinder of the natural gas wellhead lifting monitoring device in the ground; S12. Obtain relative displacement data between the natural gas wellhead and the ground through a natural gas wellhead lift monitoring device; Step S11 includes: S111, digging a tunnel based on the ground surface; S112. The bottom of the natural gas wellhead lifting monitoring device is vertically buried in the underground cavity; S113. Lift the outer cylinder of the natural gas wellhead lifting monitoring device so that the bottom cover of the outer cylinder is flush with the zero mark of the inner cylinder; S114. Fix the outer cylinder of the natural gas wellhead lifting monitoring device to the flange of the data acquisition tree; S115, Connect to power supply and automatic control equipment; Step S2 includes: S21. Obtain strain data of the natural gas pipeline by using strain gauges installed on the natural gas pipeline; S22. Based on the strain data of the natural gas pipeline, calculate the foundation settlement displacement data corresponding to the strain of the natural gas pipeline using a mechanical model; In step S21, the strain gauge is located at the bend of the natural gas pipeline, away from the wellhead and close to the outlet.

2. The method for monitoring wellhead rise in natural gas wells according to claim 1, characterized in that, Step S3 includes: calculating the wellhead lift height of the natural gas well based on the relative displacement data between the wellhead and the ground and the average value of multiple foundation settlement displacement data.

3. The method for monitoring wellhead lift of a natural gas well according to claim 1, characterized in that, In step S3, the wellhead lift height of the natural gas well is calculated using the following formula: h = S1 - (D1 + D2 + ... + Dn) / n, where h is the wellhead lift height of the natural gas well, S1 is the relative displacement between the wellhead of the natural gas well and the ground, and D1, D2, ... Dn are multiple foundation settlement displacement data.

4. A natural gas wellhead lift monitoring device, characterized in that, A natural gas wellhead lift monitoring device for implementing any one of claims 1 to 3 includes: an inner cylinder, an outer cylinder, a magnetostrictive sensor, a power supply, and an automatic control device. The outer cylinder is fixed to a data acquisition tree. The top of the inner cylinder is slidably mounted on the inner side of the bottom of the outer cylinder. The top of the magnetostrictive sensor is located in the outer cylinder, and the bottom of the magnetostrictive sensor is located in the inner cylinder. The power supply and the automatic control device are both connected to the magnetostrictive sensor. The bottom of both the inner cylinder and the outer cylinder is provided with a bottom cover with a central hole. The inner cylinder is slidably mounted on the bottom cover of the outer cylinder. The outer wall of the inner cylinder is provided with a scale value. The top of the inner cylinder is provided with a flange extending radially outward along the inner cylinder. The flange is engaged with the top of the bottom cover of the outer cylinder. The outer cylinder is fixed to the data acquisition tree by a fixing plate.

5. A natural gas wellhead lift monitoring device according to claim 4, characterized in that, The magnetostrictive sensor includes an electronic chamber, a measurement blind end, a waveguide, and an annular permanent magnet. The top of the outer cylinder is provided with a support base with a partition, and the top of the support base is provided with an end cap. The electronic chamber is mounted on the partition of the support base. The power supply and the automatic control device are both connected to the electronic chamber. The top of the waveguide is connected to the electronic chamber, and the bottom of the waveguide penetrates the inner cylinder and is exposed on the outside. The measurement blind end and the annular permanent magnet are sleeved on the waveguide. The measurement blind end is located above the annular permanent magnet, and the annular permanent magnet abuts against the bottom of the inner cylinder.

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