An on-line detection and calibration method for downhole safety valve

Abstract

A kind of well safety valve on-line detection and calibration method, comprising the following steps: (1) deployment downhole television, obtains safety valve image;(2) given the ground pressure needing calibration, record the image of safety valve;(3) utilize three-dimensional modeling and calibration software to draw model;(4), adjust model parameters to make model image consistent with actual camera parameters, obtain the image of safety valve in well, and record model safety valve opening degree;The present application utilizes downhole camera to detect safety valve gate position, measures the opening degree of safety valve by three-dimensional model imaging and parameter matching, calibrates the relationship between ground hydraulic system pressure and downhole safety valve opening degree, to realize the detection and calibration of downhole safety valve.

Description

Technical Field

[0001] This invention relates to the field of safety testing technology in the oil and gas industry, and in particular to a method for online testing and calibration of downhole safety valves. Background Technology

[0002] A subsurface safety valve (SSSV) is a downhole tool installed inside an oil and gas well. It is designed to shut off in emergency situations such as fires in production facilities, pipeline ruptures, or unforeseen natural disasters (e.g., earthquakes, ice storms, strong typhoons) to prevent blowouts and ensure the safety of oil and gas well operations and production. In offshore operations, it is also known as a subsea safety valve.

[0003] Downhole safety valves are classified into two categories based on their control method: surface-controlled and automatic downhole fluid control. Surface-controlled valves are further divided into wireline recovery type and tubing-carried annulus safety valves. Currently, the most commonly used type is the tubing-carried safety valve (TRSV). (See reference...) Figure 1 The working principle of the downhole safety valve is as follows: Hydraulic oil is pressurized through the ground control pipeline and passes through the pressure transmission hole to the piston, pushing the piston downward and compressing the spring to open the baffle. If the control sleeve is held, the safety valve is in the open position. Hydraulic pressure is released, releasing the pressure in the control sleeve, and the spring tension pushes the piston upward to close the safety valve.

[0004] Downhole safety valves are installed on the production tubing of oil and gas wells, referring to... Figure 2 The downhole safety valve is lowered into the well along with the tubing string, typically to a depth of about 100 meters. It is a purely hydraulic mechanical device without any electronic measuring units. After being lowered into the well, its operation is controlled by surface pressure, and the valve gate position cannot be monitored in real time. The downhole opening pressure and the surface opening pressure of the downhole safety valve usually differ significantly, with the downhole opening pressure being higher than the surface opening pressure. Actual surface operating pressure relies heavily on empirical data, which can easily lead to insufficient pressure for incomplete opening or excessive pressure affecting the lifespan of the downhole safety valve or even causing damage.

[0005] In recent years, newly developed advanced visual detection devices for oil and gas wells can monitor the working status of safety valves through live logging methods using cable pressurized operations. However, they can only acquire video images of the safety valves and cannot obtain quantitative information on the opening degree of the safety valves. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention aims to provide an online detection and calibration method for downhole safety valves. This method utilizes a downhole camera to detect the position of the safety valve gate, measures the opening degree of the safety valve through three-dimensional model imaging and parameter matching, and calibrates the relationship between the surface hydraulic system pressure and the opening degree of the downhole safety valve, thereby achieving the detection and calibration of the downhole safety valve.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A method for online testing and calibration of downhole safety valves includes the following steps:

[0009] (1) Deploy downhole television to acquire images of safety valves;

[0010] By operating the well logging truck winch, the well logging tool string is lowered into the wellbore to the safety valve position. The downhole well logging tool string completes video acquisition, compression encoding, and high-speed remote transmission to transmit the video images to the surface system in real time, thereby obtaining the downhole safety valve image.

[0011] (2) Given the ground pressure to be calibrated, record the image of the safety valve;

[0012] (3) Use 3D modeling and calibration software to draw the model;

[0013] The three-dimensional calibration model is simplified into three parts: well shaft, safety valve gate, and gate shaft. The input parameters include pipe diameter, shaft center, length, shaft origin, shaft direction, and gate opening.

[0014] Wellbore: Draw a cylindrical surface with radius r, length l, axis parallel to the z-axis, and intersection point (xo, yo) with the xy plane;

[0015] Safety valve gate: A filled circle with radius R is drawn on the bottom surface of the cylinder; it can rotate around the axis within the range of 0° to 90°;

[0016] Gate pivot: Z = O, X = C, where C is the distance from the pivot to the center of the sleeve.

[0017] (4) Adjust the model parameters to match the actual image. Deploy the camera on the central axis of the tubing string, and adjust the distance, field of view, and azimuth. Calibrate the camera parameters, including camera position, field of view, viewing angle, and azimuth. Adjust the model parameters to match the actual camera parameters to obtain the image of the safety valve in the well and record the opening degree of the safety valve in the model. Specifically:

[0018] (4.1) Adjust the distance between the model and the camera so that the end face of the model image is the same size as the end face of the column image;

[0019] (4.2) Adjust the model center coordinates by translating in the horizontal and vertical directions to make the end face of the model image coincide with the end face of the column image;

[0020] (4.3) Adjust the orientation by rotating the model gate so that its rotation direction is consistent with that of the actual gate.

[0021] (4.4) Adjust the opening of the model gate so that the model gate coincides with the actual gate image. At this time, the opening of the model safety valve is the same as the opening of the actual safety valve.

[0022] (5) Calibrate all the points that need to be calibrated one by one, record the values ​​of control pressure and opening in a table, and draw their relationship curve to complete the calibration.

[0023] Advantages of this invention:

[0024] By using a downhole camera to detect the position of the safety valve gate, a virtual 3D model is created using 3D modeling and calibration software. The model and camera parameters are adjusted to match the model image with the actual image, thus achieving the purpose of measuring and calibrating the safety valve opening. Combined with visualization technology, the safety valve opening is calibrated under actual operating conditions, resulting in more intuitive, accurate, and efficient results. Attached Figure Description

[0025] Figure 1 This describes the structure and working principle of a safety valve.

[0026] Figure 2 It is a completion string with a downhole safety valve.

[0027] Figure 3 This is a downhole instrument for visually detecting oil and gas wells and its main parameters.

[0028] Figure 4 A downhole visualization toolkit for acquiring video images of downhole safety valves.

[0029] Figure 5 Video capture of construction scenes for downhole safety valves.

[0030] Figure 6 This is an image of a downhole safety valve opening.

[0031] Figure 7 This is a side view of the 3D calibration model.

[0032] Figure 8 This is a perspective view of the 3D calibration model.

[0033] Figure 9 This is a perspective view of the 3D calibration model.

[0034] Figure 10 This is the original image of the downhole safety valve.

[0035] Figure 11 Matching images to the downhole safety valve model.

[0036] Figure 12 Image for calibrating the opening degree of downhole safety valves. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings.

[0038] A method for online testing and calibration of downhole safety valves includes the following steps:

[0039] (1) Deploy downhole television to acquire images of safety valves;

[0040] Figure 5 This section describes the video acquisition process for downhole safety valve installations. Most oil and gas wells with downhole safety valves have wellhead pressures of tens of megapascals, placing certain pressure resistance requirements on the video acquisition equipment. Oil and gas well logging operations utilize single-core or multi-core armored logging cables lowered into the testing equipment. These cables are typically 4000m-8000m long. Transmitting video signals over such long cables demands high transmission rates from the video acquisition equipment. Figure 3 This invention relates to a downhole instrument for visual monitoring of oil and gas wells and its key parameters. The video acquisition device in this patent application utilizes high-speed remote transmission technology and a lens pressure-bearing structure design based on patent application number CN201710708245.3, and is designed with reference to... Figure 4 The logging tool string consists of: cable logging adapter + 54 universal spring centralizer + battery sub + remote transmission sub + imaging sub.

[0041] During on-site construction, the downhole television ground system and the downhole video acquisition device are connected via a 7-core armored logging cable. The logging tool string is lowered into the wellbore to the safety valve position using the logging truck winch. The downhole logging tool string acquires, compresses, and encodes the video, then transmits the video images in real-time to the ground system via high-speed remote transmission, thereby obtaining the downhole safety valve image. For example... Figure 6 The image shown is of a downhole safety valve in operation.

[0042] (2) Given the ground pressure that needs to be calibrated, record the image of the safety valve.

[0043] (3) Use 3D modeling and calibration software to draw the model;

[0044] The three-dimensional calibration model is simplified into three parts: well shaft, safety valve gate, and gate shaft. Input parameters include pipe diameter, shaft center, length, shaft origin, shaft direction, and gate opening.

[0045] like Figure 7 This is a side view of the model. Figure 8 This is a perspective view of the model.

[0046] Wellbore: Draw a cylindrical surface with radius r, length l, axis parallel to the z-axis, and intersection point (xo, yo) with the xy plane;

[0047] Safety valve gate: A filled circle with radius R is drawn on the bottom surface of the cylinder; it can rotate around the axis within the range of 0° to 90°;

[0048] Gate pivot: Z = O, X = C, where C is the distance from the pivot to the center of the sleeve.

[0049] Figure 9 To provide the viewing angle of the safety valve gate from above the central axis of the model column.

[0050] (4) Adjust the model parameters to match the actual image. Deploy the camera on the central axis of the tubing string, adjusting the distance, field of view, and azimuth. Calibrate the camera parameters, including camera position, field of view, viewing angle, and azimuth. Adjust the model parameters to match the actual camera parameters, obtaining the image of the safety valve in the well and recording the opening degree of the safety valve in the model. Specifically:

[0051] (4.1) Adjust the distance between the model and the camera so that the end face of the model image is the same size as the end face of the column image;

[0052] (4.2) Adjust the model center coordinates by translating horizontally and vertically to make the end face of the model image coincide with the end face of the column image, such as... Figure 11 As shown;

[0053] (4.3) Adjust the orientation by rotating the model gate so that its rotation direction is consistent with that of the actual gate.

[0054] (4.4) Adjust the opening of the model gate so that the model gate coincides with the actual gate image. At this point, the opening of the model safety valve is the same as the actual safety valve opening. Figure 12 As shown, the red part is where the gate plate and the safety valve in the video image below are completely overlapped, and the safety valve opening is 62°.

[0055] (5) Calibrate all the points that need to be calibrated one by one, record the values ​​of control pressure and opening in a table, and draw their relationship curve to complete the calibration.

[0056] This invention utilizes a downhole camera to detect the position of the safety valve gate, establishes a virtual 3D model using 3D modeling and calibration software, and adjusts the model and camera parameters to match the model image with the actual image. The opening degree of the safety valve is measured, and the opening degree of the safety valve is calibrated under the actual working state of the safety valve, thereby realizing the detection and calibration of the downhole safety valve. The results are more intuitive, accurate, and efficient.

Claims

1. A method for online detection and calibration of downhole safety valves, characterized in that, Includes the following steps: (1) Deploy downhole television to acquire images of safety valves. By operating the well logging truck winch, the well logging tool string is lowered into the wellbore to the safety valve position. The downhole well logging tool string completes video acquisition, compression encoding, and high-speed remote transmission to transmit the video images to the surface system in real time, thereby obtaining the downhole safety valve image. (2) Given the ground pressure to be calibrated, record the image of the safety valve; (3) Use 3D modeling and calibration software to draw the model. The three-dimensional calibration model is simplified into three parts: well shaft, safety valve gate, and gate shaft. The input parameters include pipe diameter, shaft center, length, shaft origin, shaft direction, and gate opening. (4) Adjust the model parameters to match the actual image. Deploy the camera in the model on the central axis of the well. The distance, field of view and azimuth can be adjusted. Calibrate the actual camera parameters, including the camera position, field of view and azimuth. Adjust the camera parameters in the model to be consistent with the actual camera parameters to obtain the image of the safety valve in the well and record the opening degree of the safety valve in the model. Step (4) is as follows: (4.1) Adjust the model so that the end face of the model image is the same size as the end face of the well shaft image; (4.2) Adjust the coordinates of the model center by translating it horizontally and vertically so that the end face of the model image coincides with the end face of the well shaft image; (4.3) Adjust the orientation by rotating the model gate so that its rotation direction is consistent with that of the actual gate. (4.4) Adjust the opening of the model gate so that the model gate coincides with the actual gate image. At this time, the opening of the model safety valve is the actual safety valve opening. (5) Calibrate all the points that need to be calibrated one by one, record the values ​​of control pressure and opening in a table, and draw their relationship curve to complete the calibration.

2. The method for online detection and calibration of downhole safety valves according to claim 1, characterized in that, The parameters of the three-dimensional calibration model of the well shaft, safety valve gate, and gate shaft are as follows: Wellbore: Draw a cylindrical surface with radius r, length l, axis parallel to the z-axis, and intersection point (xo, yo) with the xy plane; Safety valve gate: A filled circle with radius R is drawn on the bottom surface of the cylinder; it can rotate around the axis within the range of 0°~90°; Gate pivot: Z=0, X=C, C is the distance from the pivot to the center of the shaft.

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