Downhole spatial positioning device and method based on magnetic field full tensor gradient measurement

Abstract

The present application relates to oil and gas drilling technology field, it is a kind of downhole space positioning device and method based on magnetic field full tensor gradient measurement, the former includes drill string, magnetic dipole magnetic source short section, communication cable, magnetic field gradient measurement probe tube, ground data receiving device, computer and power supply;The latter preparation process, data acquisition transmission process and data processing process.The present application is reasonable and compact in structure, convenient to use, it is measured by multiple triaxial fluxgate sensor to alternating magnetic field for full tensor magnetic field gradient between the normal drilling and target well, can effectively reduce the measurement error caused by the larger external environment interference of magnetic field gradient measurement probe tube;By tubing down magnetic field gradient measurement probe tube can keep magnetic field gradient measurement probe tube and magnetic dipole magnetic source short section in predetermined range all the time, tracking measurement is carried out, avoid repeatedly lifting and lowering drill string in the process of drilling, can effectively improve drilling efficiency, shorten operation cycle, reduce operation cost.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling technology, and is a downhole spatial positioning device and method based on magnetic field full tensor gradient measurement. Background Technology

[0002] In the oil and gas drilling field of the petroleum industry, the construction of certain special well types (such as dual horizontal wells, connecting wells, and horizontal well clusters) requires ensuring a high degree of consistency in the trajectories between the two wells. This necessitates both achieving a fixed spatial distance and controlling the overall extension of the horizontal section within the reservoir. This places high demands on the precise measurement of the wellbore trajectory and the accurate calculation of inter-layer positions. In connecting wells, the horizontal wellhead is typically located hundreds of meters away from the vertical wellhead, making the horizontal wellbore trajectory more complex and increasing the uncertainty of connecting the horizontal and vertical wells. Therefore, during the construction of these special well types, downhole spatial positioning devices and methods are required to ensure that the wellbore trajectory meets the design requirements.

[0003] Currently, most existing downhole spatial positioning devices use a single triaxial fluxgate sensor for measurement, and the measurement method is mostly magnetic field vector measurement. When the downhole spatial positioning device is located inside a magnetic tubing or when measuring in iron-bearing formations, its anti-interference ability is poor, resulting in large errors in the final calculation results. The magnetic field vector measurement method can only measure one point at a time and requires continuous raising and lowering of the drilling tubing, resulting in low measurement efficiency and increased drilling cycle and cost.

[0004] Chinese patent document CN201095981Y discloses a permanent magnet sub for drilling, which mainly consists of a body, permanent magnet A, and permanent magnet B. Several embedding grooves are evenly distributed on the outer surface of the body, with permanent magnet A and permanent magnet B embedded alternately in these grooves. During connection operations, the sub is connected to the female end of the drill bit at the top and inserted into the main wellbore. When the drill bit enters the range of the measuring instruments in the borehole, the permanent magnet sub continuously releases a constant magnetic field, which is detected. The operators adjust the position of the drill bit and the wellbore trajectory based on the detected magnetic field strength, achieving the purpose of connecting the two wells.

[0005] Chinese patent document CN213775355U discloses a downhole alternating magnetic field positioning device, which includes a power supply connection section, a measurement sensor module, a data processing module, a first magnetic source beacon, a second magnetic source beacon, a non-magnetic outer cylinder, and a guide head. The power supply connection section mainly consists of a cable connector and a power module, with the cable connector connected to the downhole cable for power supply. The first and second magnetic source beacons mainly consist of a magnetic core, a frame, and a coil. The frame is made of epoxy resin and separates the first and second magnetic source beacons. The guide head mainly consists of a metal head, a hydraulic plug seat, and a hydraulic plug. The metal head is connected to the instrument housing, the hydraulic plug is mounted on the hydraulic plug seat, and the hydraulic plug seat is mounted on the non-magnetic outer cylinder. Positioning is assisted by pumping hydraulic force. It can provide a magnetic guidance tool with more positioning beacons, and has strong controllability, high positioning accuracy, simple structure, easy operation and multiple positioning beacons, meeting the technical requirements of high-precision downhole magnetic positioning guidance.

[0006] Therefore, existing downhole spatial positioning devices and measurement methods have the following shortcomings in actual use: when operating in magnetic tubing or iron-bearing formations, the anti-interference ability of downhole spatial positioning devices is poor, resulting in large errors in measurement and calculation results; existing magnetic field vector measurement methods can only measure one point at a time, and the drilling tubing needs to be continuously raised / lowered during the measurement process, resulting in low work efficiency, long drilling cycles, and high costs. Summary of the Invention

[0007] This invention provides a downhole spatial positioning device and method based on magnetic field full tensor gradient measurement, which overcomes the shortcomings of the prior art. It can effectively solve the problems of poor anti-interference ability and large measurement and calculation error of existing downhole spatial positioning devices when operating in magnetic tubing or iron-bearing formations; and the problems of existing magnetic field vector measurement methods that can only measure one point at a time, and need to continuously raise / lower the drilling tubing during the measurement process, resulting in low work efficiency, long drilling cycle and high cost.

[0008] One of the technical solutions of this invention is achieved through the following measures: a downhole spatial positioning device based on magnetic field full tensor gradient measurement, comprising a drill string, a drill bit, a magnetic dipole source sub, a communication cable, a magnetic field gradient measurement probe, a ground data receiving device, and a computer. A magnetic dipole source sub is provided between the drill string and the drill bit, capable of generating alternating magnetic field signals as the drill string rotates. One end of the communication cable is connected to a magnetic field gradient measurement probe capable of receiving and transmitting alternating magnetic field measurement data, and the other end of the communication cable is connected to a ground data receiving device. The ground data receiving device is connected to a computer capable of calculating the relative position of the magnetic dipole source sub and the magnetic field gradient measurement probe based on the measurement data.

[0009] The following are further optimizations and / or improvements to the above-mentioned technical solution: The aforementioned magnetic dipole source sub may include a sub body with an axial channel, a magnetic dipole rod, and a retaining ring. The outer side of the middle part of the sub body has several magnetic source mounting holes with outward openings. A magnetic dipole rod is installed in each magnetic source mounting hole. A retaining ring groove is provided in the magnetic source mounting hole corresponding to the outer end of each magnetic dipole rod, and a retaining ring is provided in each retaining ring groove. A drill bit connection outer ring groove is provided on the outer side of the left end of the sub body.

[0010] The aforementioned magnetic field gradient measurement probe may include an outer cylinder, a left end cap, a right end cap, a main support, a sensor assembly, a power management unit, a data acquisition unit, a data transmission unit, and a cable plug. The inner left and right ends of the outer cylinder are respectively equipped with a left end cap and a right end cap. A main support, located to the right of the left end cap, is installed on the middle left side of the right end cap. The main support is equipped with a sensor assembly capable of measuring alternating magnetic field signals, a power management unit, a data acquisition unit, and a data transmission unit. The outer left side of the left end cap has an outer annular groove for connecting an oil pipe. The middle right side of the left end cap has a blind hole opening to the right. The middle left side of the left end cap also has a plug mounting hole communicating with the blind hole, and a cable plug is installed inside the plug mounting hole. The cable plug is connected to the data transmission unit and the power management unit. The power management unit is connected to the sensor assembly, the data acquisition unit, and the data transmission unit. The sensor assembly is connected to the data acquisition unit, and the data acquisition unit is connected to the data transmission unit.

[0011] The aforementioned sensor assembly may include a first three-axis fluxgate sensor, a second three-axis fluxgate sensor, a third three-axis fluxgate sensor, a fourth three-axis fluxgate sensor, a fifth three-axis fluxgate sensor, a sixth three-axis fluxgate sensor, a seventh three-axis fluxgate sensor, an accelerometer, and a coin-shaped bracket. The main bracket is an upward-opening U-shaped bracket. From left to right, the inner side of the lower end of the U-shaped bracket is sequentially equipped with the second three-axis fluxgate sensor, a data transmission unit, the first three-axis fluxgate sensor, a data acquisition unit, an accelerometer, a power management unit, and the third three-axis fluxgate sensor; corresponding to the first three-axis fluxgate sensor... A copper coin-shaped bracket is fixedly installed on the outside of the U-shaped bracket on the left side of the door sensor. The fourth, fifth, sixth, and seventh three-axis fluxgate sensors are fixedly installed on the front right, rear right, upper right, and lower right sides of the copper coin-shaped bracket, respectively. The first, second, third, fourth, fifth, sixth, and seventh three-axis fluxgate sensors and the acceleration sensor are connected to the data acquisition unit and the power management unit, respectively.

[0012] The aforementioned magnetic field gradient measurement probe may also include a data storage unit. The data storage unit is installed on the main support between the data transmission unit and the sensor assembly. The data storage unit is connected to the power management unit and the data acquisition unit, respectively.

[0013] The aforementioned magnetic field gradient measuring probe may also include sealing rings, with sealing rings provided between the left end of the outer cylinder and the left end cap, and between the right end of the outer cylinder and the right end cap.

[0014] The second technical solution of the present invention is achieved through the following measures: a positioning method for a downhole spatial positioning device based on magnetic field full tensor gradient measurement, including a preparation process, a data acquisition and transmission process, and a data processing process; The preparation process is as follows: First, install the magnetic dipole source short section between the drill string and the drill bit and run it into the predetermined position P of the drilling. Then, connect one end of the communication cable to the cable plug on the magnetic field gradient measurement probe. Next, connect the connector at the end of the tubing to the outer side of the left end of the magnetic field gradient measurement probe. Then, connect the other end of the communication cable to the ground data receiving device. Next, connect the data receiving device to the computer. Finally, run the magnetic field gradient measurement probe into point Q in the target well through the communication cable. The data acquisition and transmission process is as follows: First, when the drill string rotates, the magnetic dipole source section located at point P in the drilling well generates an alternating magnetic field signal as the drill string rotates. Second, the sensor assembly on the magnetic field gradient measurement probe located at point Q in the target well measures the magnetic field gradient of the alternating magnetic field. Then, the data acquisition unit collects the measurement data and sends it to the data transmission unit. The data transmission unit sends the measurement data to the ground data receiving device through the communication cable. Finally, the ground receiving device sends the received measurement data to the computer, and the computer receives and stores the above measurement data. The data processing involves the computer calculating the relative positions of point P in the drilling well and point Q in the target well based on the received magnetic field gradient measurement data. It then uses formulas 1, 2, 3, and 4 to calculate the lateral, vertical, and longitudinal distances of point Q in the target well relative to point P in the drilling well. Formula 1 is... in, and These represent the magnetic field components along the X-axis of the second and third triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Y-axis of the second and third triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Z-axis of the second and third triaxial fluxgate sensors, respectively. The distance between the second and third three-axis fluxgate sensors; Formula 2 is in, and These represent the magnetic field components along the X-axis of the fourth and fifth triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Y-axis of the fourth and fifth triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Z-axis of the fourth and fifth triaxial fluxgate sensors, respectively. The distance between the fourth and fifth three-axis fluxgate sensors; Formula 3 is in, and These represent the magnetic field components along the X-axis of the sixth and seventh three-axis fluxgate sensors, respectively. and These represent the magnetic field components along the Y-axis of the sixth and seventh three-axis fluxgate sensors, respectively. and These represent the magnetic field components along the Z-axis of the sixth and seventh three-axis fluxgate sensors, respectively. The distance between the sixth and seventh three-axis fluxgate sensors; Formula 4 is in, The results for the second and third triaxial fluxgate sensors, respectively, are calculated using Formula 1. The results for the fourth and fifth three-axis fluxgate sensors, respectively, are calculated using Formula 2. The results for the sixth and seventh three-axis fluxgate sensors, respectively, are calculated using Formula 3. The first three-axis fluxgate sensor has magnetic field components on the X, Y, and Z axes, where x, y, and z are the lateral, vertical, and longitudinal distances of point Q in the target well relative to point P in the drilling well, respectively.

[0015] This invention features a reasonable and compact structure, and is easy to use. It generates an alternating magnetic field by rotating a magnetic dipole source section with the drill string. A magnetic field gradient measurement probe measures the magnetic field gradient signal and transmits the data to a ground receiving device. A computer runs relevant programs based on the measurement data to calculate the relative position between the magnetic dipole source section and the magnetic field gradient measurement probe. The wellbore trajectory of the current drilling operation is compared with that of the target well, allowing for timely adjustments to the drill bit position during drilling to ensure the wellbore trajectory meets design requirements. Furthermore, multiple [mechanical parameters] are used between the current drilling operation and the target well. A three-axis fluxgate sensor performs full-tensor magnetic field gradient measurement of alternating magnetic fields, effectively preventing large errors in measurement results caused by interference when the magnetic field gradient measurement probe is used in magnetic tubing or iron-bearing formations. The magnetic field gradient measurement probe, lowered into the target well via tubing, can maintain the magnetic field gradient measurement probe and the magnetic dipole source section within a predetermined range for tracking measurement by continuing to lower the tubing. This avoids repeated drilling string raising and lowering during drilling, effectively improving drilling efficiency, shortening the operation cycle, and reducing operating costs. Attached Figure Description

[0016] Appendix Figure 1 This is a schematic diagram of the usage state of Embodiments 1-6 of the present invention.

[0017] Appendix Figure 2 For the appendix Figure 1 A magnified front view cross-sectional diagram of the probe for measuring the magnetic field gradient.

[0018] Appendix Figure 3 For the appendix Figure 2 A magnified AA cross-sectional diagram of the probe for measuring the magnetic field gradient.

[0019] Appendix Figure 4 For the appendix Figure 1 A magnified front half-section diagram of the short section of the medium magnetic dipole source.

[0020] Appendix Figure 5 This is a schematic diagram of the calculation model for calculating the relative position of the magnetic dipole source section and the magnetic field gradient measurement probe in Embodiment 7 of the present invention.

[0021] The codes in the attached diagram are as follows: 1 for drill string, 2 for drill bit, 3 for communication cable, 4 for ground data receiving device, 5 for computer, 6 for power supply, 7 for axial channel, 8 for short section body, 9 for magnetic dipole rod, 10 for retaining ring, 11 for magnetic source mounting hole, 12 for drill string connection outer annular groove, 13 for outer cylinder, 14 for left end cap, 15 for right end cap, 16 for power management unit, 17 for data acquisition unit, 18 for data transmission unit, 19 for cable plug, and 20 for tubing connection outer annular groove. Slot, 21 is a blind hole, 22 is the first three-axis fluxgate sensor, 23 is the second three-axis fluxgate sensor, 24 is the third three-axis fluxgate sensor, 25 is the fourth three-axis fluxgate sensor, 26 is the fifth three-axis fluxgate sensor, 27 is the sixth three-axis fluxgate sensor, 28 is the seventh three-axis fluxgate sensor, 29 is an accelerometer, 30 is a coin-shaped bracket, 31 is a U-shaped bracket, 32 is a data storage unit, 33 is a sealing ring, 34 is for drilling, and 35 is for the target well. Detailed Implementation

[0022] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0023] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0024] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figure 1 , 2 As shown in Figures 3 and 4, the downhole spatial positioning device based on magnetic field full tensor gradient measurement includes a drill string 1, a drill bit 2, a magnetic dipole source sub, a communication cable 3, a magnetic field gradient measurement probe, a ground data receiving device, and a computer 5. A magnetic dipole source sub is provided between the drill string 1 and the drill bit 2, which can generate alternating magnetic field signals as the drill string 1 rotates. One end of the communication cable 3 is connected to a magnetic field gradient measurement probe that can receive and transmit alternating magnetic field measurement data, and the other end of the communication cable 3 is connected to a ground data receiving device. The ground data receiving device is connected to a computer 5 that can calculate the relative position of the magnetic dipole source sub and the magnetic field gradient measurement probe based on the measurement data.

[0025] With this setup, the magnetic dipole source sub, installed between the drill string 1 and the drill bit 2, generates an alternating magnetic field as the drill string 1 rotates, which is used to locate the position of the drill bit 2 in the drilling well 34. The magnetic field gradient measurement probe connected to the end of the tubing is used to measure the magnetic field gradient of the alternating magnetic field signal emitted by the magnetic dipole source sub and send the measurement data to the ground data receiving device. After the computer 5 runs the relevant program, it can calculate the relative position between the magnetic dipole source sub and the magnetic field gradient measurement probe, thereby comparing the wellbore trajectory of the drilling well 34 with the wellbore trajectory of the target well 35, and adjusting the position of the drill bit 2 in the drilling well 34 in a timely manner so that the wellbore trajectory of the drilling well 34 meets the design requirements. During use, the magnetic dipole source submersible initially lowered into the drilling well 34 and the magnetic field gradient measurement probe lowered into the target well 35 are typically 30 to 50 meters apart. Then, as the drill bit 2 advances 30 to 50 meters, the tubing can be lowered the same distance again (the tubing can be lowered via a small repair vehicle), ensuring that the magnetic dipole source submersible and the magnetic field gradient measurement probe remain within the predetermined range. This allows for tracking and measurement of multiple points, eliminating the need to repeatedly raise and lower the drill string 1 during the measurement process. This effectively improves drilling efficiency, shortens the operation cycle, and reduces operating costs.

[0026] According to requirements, the magnetic dipole source short section can be implemented using the permanent magnet short section for drilling disclosed in Chinese patent document CN201095981Y, or it can be implemented using a permanent magnet that can be installed on the drill string 1 or other permanent magnet short sections. Furthermore, the two ends of the magnetic dipole source short section can be equipped with corresponding connecting threads according to the drill string 1 and drill bit 2 they are connected to. Additionally, an axial flow channel can be provided in the middle of the magnetic dipole source short section for drilling fluid circulation. Considering that magnetic field measurement operations are subject to significant interference during construction in magnetic tubing or iron-bearing formations, and that magnetic field gradient measurement has good anti-interference capabilities, multiple fluxgate sensors (or other types of sensors capable of measuring alternating magnetic fields) can be spaced apart on the magnetic field gradient measurement probe to achieve magnetic field gradient measurement. Fluxgate sensors are used primarily because they have high resolution, a wide range for measuring weak magnetic fields, reliability, the ability to directly measure magnetic field components, and suitability for use in high-speed motion systems. In this embodiment, to achieve horizontal axial (x-axis) measurement... The device measures the magnetic field gradient in all directions (horizontal and vertical, y-axis and z-axis). Two fluxgate sensors are simultaneously installed at intervals in the horizontal axis, horizontal and vertical axes, respectively. Furthermore, in this embodiment, the magnetic field gradient measurement probe can be lowered into the target well 35 via tubing. To avoid tangling and wear of the communication cable 3, the communication cable 3 can be placed inside the tubing. Therefore, the end of the magnetic field gradient measurement probe connected to the communication cable 3 has a connecting thread that matches the tubing connector. The communication cable 3 includes a signal transmission cable and a power cable for supplying power to the magnetic field gradient measurement probe. A power supply 6 can also be provided to power this device, which can be powered by a battery, lithium battery pack, generator, solar panel, small wind power generator, or mains power, as is available in existing technologies. The computer 5 can be implemented using a desktop computer, laptop computer, computer workstation, or other intelligent computing device capable of running a predetermined program and performing calculations / storage according to the predetermined program. In addition, this embodiment includes... Figure 1 The device described is used in dual horizontal wells, but it can also be used to determine the relative position between the target well and the well being drilled in drilling processes such as connecting wells or horizontal well clusters.

[0027] This invention features a reasonable and compact structure, and is easy to use. It generates an alternating magnetic field by rotating a magnetic dipole source section with the drill string 1. A magnetic field gradient measurement probe measures the magnetic field gradient signal of the alternating magnetic field and sends the measurement data to a ground receiving device. Computer 5 calculates the relative position between the magnetic dipole source section and the magnetic field gradient measurement probe based on the measurement data and runs relevant programs. It then compares the wellbore trajectory of the main drilling well 34 with the wellbore trajectory of the target well 35, and adjusts the position of the drill bit 2 in the main drilling well 34 in a timely manner to ensure that the wellbore trajectory of the main drilling well 34 meets the design requirements. The alternating magnetic field between well 34 and target well 35 is measured by magnetic field gradient measurement, which can effectively prevent large errors in the measurement calculation results caused by the magnetic field gradient measurement probe when conducting magnetic field measurement operations in magnetic tubing or iron-bearing formations. The magnetic field gradient measurement probe, which is lowered into target well 35 by tubing, can keep the magnetic field gradient measurement probe and the magnetic dipole source sub within a predetermined range by continuing to lower the tubing, so as to carry out tracking measurement. This avoids repeated raising and lowering of drill string 1 during drilling, which can effectively improve drilling efficiency, shorten the operation cycle, and reduce operation costs.

[0028] The above-mentioned downhole spatial positioning device based on magnetic field full tensor gradient measurement can be further optimized and / or improved according to actual needs: Example 2: As shown in the attached document Figure 1 , 4 As shown, the magnetic dipole source sub includes a sub body 8 with an axial channel 7, a magnetic dipole rod 9, and a retaining ring 10. The outer side of the middle part of the sub body 8 has several outward-facing magnetic source mounting holes 11. A magnetic dipole rod 9 is installed in each magnetic source mounting hole 11. A retaining ring groove is provided in the magnetic source mounting hole 11 corresponding to the outer end position of each magnetic dipole rod 9. A retaining ring 10 is provided in each retaining ring groove. A drill tool connecting outer ring groove 12 is provided on the outer side of the left end of the sub body 8. According to requirements, the short section body 8 is used to connect with the drill string 1 and the drill bit 2. Therefore, the two ends of the short section body 8 can be equipped with matching connecting threads according to the connection thread type of the drill string 1 and the drill bit 2. The axial channel 7 in the middle of the short section body 8 is used for the flow of drilling fluid. In this embodiment, the bottom of the drill string connecting outer annular groove 12 is tapered and inclined with a smaller left side and a larger right side, and is provided with an external connecting pipe thread. The inner side of the right end of the short section body 8 is tapered and inclined with a smaller left side and a larger right side, and is provided with an internal connecting pipe thread. According to the design requirements of the alternating magnetic field, several sets of magnetic dipole rods 9 of equal number can be arranged at intervals along the circumference of the short section body 8, or two sets of magnetic dipole rods 9 of unequal number can be alternately arranged at intervals along the circumference of the short section body 8. In this embodiment, two sets of magnetic dipole rods 9 of unequal number are alternately arranged at intervals along the circumference of the short section body 8, and one set has three distributed at intervals along the axial direction of the short section body 8, and the other set has two distributed at intervals along the axial direction of the short section body 8.

[0029] Example 3: As shown in the attached document Figure 1 ,2 As shown in Figure 3, the magnetic field gradient measurement probe includes an outer cylinder 13, a left end cap 14, a right end cap 15, a main support, a sensor assembly, a power management unit 16, a data acquisition unit 17, a data transmission unit 18, and a cable plug 19. The left end cap 14 and the right end cap 15 are respectively located on the inner left and right sides of the outer cylinder 13. A main support with its left end to the right of the left end cap 14 is installed in the middle left side of the right end cap 15. The main support is equipped with a sensor assembly capable of measuring alternating magnetic field signals, a power management unit 16, a data acquisition unit 17, and a data transmission unit. 18; The left end cover 14 has an outer annular groove 20 for connecting oil pipes on its left outer side, a blind hole 21 with an opening to the right in the middle of the right side of the left end cover 14, and a plug mounting hole communicating with the blind hole 21 in the middle of the left side of the left end cover 14. A cable plug 19 is installed in the plug mounting hole. The cable plug 19 is connected to the data transmission unit 18 and the power management unit 16 respectively. The power management unit 16 is connected to the sensor assembly, the data acquisition unit 17 and the data transmission unit 18 respectively. The sensor assembly is connected to the data acquisition unit 17 and the data acquisition unit 17 is connected to the data transmission unit.

[0030] With this configuration, the left end cap 14 is connected to the connector at the end of the oil pipe via the outer annular groove 20 of the oil pipe connection. The structure of this part can also be configured according to the type of oil pipe connector. In this embodiment, to facilitate the insertion and removal of the cable plug, an external connection thread is provided within the outer annular groove 20 of the oil pipe connection. Depending on the requirements, to achieve magnetic field gradient measurement, the main support can be a cross-shaped support. Sensors capable of measuring alternating magnetic fields (commonly fluxgate sensors) in the sensor assembly can be arranged in pairs at intervals in the left-right, front-back, and up-down directions of the cross-shaped support to achieve omnidirectional magnetic field gradient measurement in the horizontal axis (x-axis), horizontal vertical (y-axis), and longitudinal (z-axis), improving measurement accuracy and reducing interference from the external environment. The power management unit 16 manages and distributes the power supply to each circuit unit within the magnetic field gradient measurement probe, and the data acquisition unit 17 collects sensor data. The magnetic field gradient data measured by the instrument component is transmitted by the data transmission unit 18 to the ground receiving device. The ground receiving device uploads the received measurement data to the computer 5 for calculation and comparison. The left end cover 14 and the right end cover 15 can be connected to the outer cylinder 13 by riveting, welding, interference fit, threaded connection or bonding in the prior art. In this embodiment, a threaded connection is used. To facilitate installation and disassembly, a wrench groove can be provided on the outer side of the middle part of the outer cylinder 13 and the outer side of the right end cover 15. A wrench table can be provided on the outer side of the left end cover 14 corresponding to the left end position of the outer cylinder 13.

[0031] Example 4: As shown in the appendix Figure 2 , 3As shown, the sensor assembly includes a first three-axis fluxgate sensor 22, a second three-axis fluxgate sensor 23, a third three-axis fluxgate sensor 24, a fourth three-axis fluxgate sensor 25, a fifth three-axis fluxgate sensor 26, a sixth three-axis fluxgate sensor 27, a seventh three-axis fluxgate sensor 28, an accelerometer 29, and a coin-shaped bracket 30. The main bracket is an U-shaped bracket 31 with its opening facing upwards. From left to right, the inner side of the lower end of the U-shaped bracket 31 is sequentially equipped with the second three-axis fluxgate sensor 23, a data transmission unit 18, the first three-axis fluxgate sensor 22, a data acquisition unit 17, an accelerometer 29, a power management unit 16, and the third three-axis fluxgate sensor 24; corresponding to the first three-axis fluxgate sensor... A copper coin-shaped bracket 30 is fixedly installed on the outside of the U-shaped bracket 31 on the left side of the door sensor 22. A fourth three-axis fluxgate sensor 25, a fifth three-axis fluxgate sensor 26, a sixth three-axis fluxgate sensor 27, and a seventh three-axis fluxgate sensor 28 are fixedly installed on the front right, rear right, upper right, and lower right sides of the copper coin-shaped bracket 30, respectively. The first three-axis fluxgate sensor 22, the second three-axis fluxgate sensor 23, the third three-axis fluxgate sensor 24, the fourth three-axis fluxgate sensor 25, the fifth three-axis fluxgate sensor 26, the sixth three-axis fluxgate sensor 27, the seventh three-axis fluxgate sensor 28, and the acceleration sensor 29 are connected to the data acquisition unit 17 and the power management unit 16, respectively.

[0032] During use, the second and third triaxial fluxgate sensors 23 and 24 can measure the magnetic field gradients of the magnetic field components in the X, Y, and Z directions along the horizontal axis (i.e., horizontal transverse direction). The fourth and fifth triaxial fluxgate sensors 25 and 26 can measure the magnetic field gradients of the magnetic field components in the X, Y, and Z directions along the horizontal vertical direction. The sixth and seventh triaxial fluxgate sensors 27 and 28 can measure the magnetic field gradients of the magnetic field components in the X, Y, and Z directions along the longitudinal direction. By combining the distances between the second and third three-axis fluxgate sensors 23 and 24, the fourth and fifth three-axis fluxgate sensors 25 and 26, and the sixth and seventh three-axis fluxgate sensors 27 and 28, the spatial distance between the magnetic field gradient measurement probe and the magnetic dipole source section can be determined by calculating the magnetic field gradient measurement probe with the sensor distance data and the magnetic field component data in the X-axis, Y-axis and Z-axis directions measured by the first three-axis fluxgate sensor 22 according to the relevant formula.

[0033] With this configuration, the triaxial fluxgate sensor can further measure the magnetic field gradient in each of the horizontal axis (x-axis), horizontal vertical axis (y-axis), and longitudinal axis (z-axis) directions (i.e., realize the full tensor magnetic field gradient measurement of alternating magnetic field signals), thereby improving measurement accuracy and reducing measurement error, and minimizing or avoiding the influence and interference of the external environment on the magnetic field gradient measurement probe. The acceleration sensor 29 can be used to monitor the attitude of the magnetic field gradient measurement probe (such as ensuring that the left and right directions of the magnetic field gradient measurement probe are always on the same horizontal line), and can also upload acceleration data to the computer 5 for calculation during operation according to predetermined requirements. According to the requirements, the first three-axis fluxgate sensor 22, the second three-axis fluxgate sensor 23 and the third three-axis fluxgate sensor 24, the first three-axis fluxgate sensor 22, the fourth three-axis fluxgate sensor 25 and the fifth three-axis fluxgate sensor 26, the first three-axis fluxgate sensor 22, the sixth three-axis fluxgate sensor 27 and the seventh three-axis fluxgate sensor 28 are all set on a straight line. The right end of the main bracket and the right end cover 15, and the main bracket and the coin-shaped bracket 30 can be connected or installed together by bonding, welding or threaded fasteners or hot melt welding or riveting in the existing known technology.

[0034] Example 5: As shown in the attached document Figure 2 The magnetic field gradient measurement probe also includes a data storage unit 32. This data storage unit 32 is mounted on the main support between the data transmission unit 18 and the sensor assembly. The data storage unit 32 is connected to the power management unit 16 and the data acquisition unit 17. This configuration allows the data storage unit 32 to back up measurement data, facilitating review and preventing data loss in case of accidents involving the data transmission unit 18, communication cable 3, or ground data receiving device.

[0035] Example 6: As shown in the appendix Figure 2 The magnetic field gradient measurement probe also includes sealing rings 33. Sealing rings 33 are provided between the left end of the outer cylinder 13 and the left end cap 14, and between the right end of the outer cylinder 13 and the right end cap 15. This arrangement can prevent water vapor in the target well 35 from entering the gradient measurement probe and damaging the circuit units inside.

[0036] Example 7: As attached Figure 5 The positioning method of the downhole spatial positioning device based on magnetic field full tensor gradient measurement includes a preparation process, a data acquisition and transmission process, and a data processing process. The preparation process is as follows: First, install the magnetic dipole magnetic source short section between the drill string 1 and the drill bit 2 and lower it into the predetermined position P of the drilling well 34. Then, connect one end of the communication cable 3 to the cable plug 19 on the magnetic field gradient measurement probe. Next, connect the connector at the end of the tubing to the outer side of the left end of the magnetic field gradient measurement probe. Then, connect the other end of the communication cable 3 to the ground data receiving device. Next, connect the data receiving device to the computer 5. Finally, lower the magnetic field gradient measurement probe into point Q in the target well 35 through the communication cable 3. The data acquisition and transmission process is as follows: First, when the drill string 1 rotates, the magnetic dipole magnetic source sub at point P in the main drilling well 34 generates an alternating magnetic field signal as the drill string 1 rotates. Second, the sensor assembly on the magnetic field gradient measurement probe at point Q in the target well 35 measures the magnetic field gradient of the alternating magnetic field. Then, the data acquisition unit 17 collects the measurement data and sends it to the data transmission unit 18. The data transmission unit 18 sends the measurement data to the ground data receiving device through the communication cable 3. Finally, the ground receiving device sends the received measurement data to the computer 5. The computer 5 receives and stores the above measurement data. The data processing procedure involves computer 5 calculating the relative positions of point P within the drilling well 34 and point Q within the target well 35 based on the received magnetic field gradient measurement data. It then calculates the lateral, vertical, and longitudinal distances of point Q within the target well 35 relative to point P within the drilling well 34 using formulas 1, 2, 3, and 4. Formula 1 is... and These represent the magnetic field components along the X-axis of the second triaxial fluxgate sensor 23 and the third triaxial fluxgate sensor 24, respectively. and These represent the magnetic field components on the Y-axis of the second triaxial fluxgate sensor 23 and the third triaxial fluxgate sensor 24, respectively. and These represent the magnetic field components along the Z-axis of the second triaxial fluxgate sensor 23 and the third triaxial fluxgate sensor 24, respectively. The distance between the second three-axis fluxgate sensor 23 and the third three-axis fluxgate sensor 24; Formula 2 is in, and These represent the magnetic field components along the X-axis of the fourth triaxial fluxgate sensor 25 and the fifth triaxial fluxgate sensor 26, respectively. and These represent the magnetic field components on the Y-axis of the fourth triaxial fluxgate sensor 25 and the fifth triaxial fluxgate sensor 26, respectively. and These represent the magnetic field components along the Z-axis of the fourth triaxial fluxgate sensor 25 and the fifth triaxial fluxgate sensor 26, respectively. The distance between the fourth three-axis fluxgate sensor 25 and the fifth three-axis fluxgate sensor 26; Formula 3 is in, and These represent the magnetic field components along the X-axis of the sixth three-axis fluxgate sensor 27 and the seventh three-axis fluxgate sensor 28, respectively. and These are the magnetic field components on the Y-axis of the sixth three-axis fluxgate sensor 27 and the seventh three-axis fluxgate sensor 28, respectively. and These are the magnetic field components along the Z-axis of the sixth three-axis fluxgate sensor 27 and the seventh three-axis fluxgate sensor 28, respectively. The distance between the sixth three-axis fluxgate sensor 27 and the seventh three-axis fluxgate sensor 28; Formula 4 is in, The results are calculated using Formula 1 for the second triaxial fluxgate sensor 23 and the third triaxial fluxgate sensor 24, respectively. The results for the fourth triaxial fluxgate sensor 25 and the fifth triaxial fluxgate sensor 26, respectively, are calculated using Formula 2. The results for the sixth three-axis fluxgate sensor 27 and the seventh three-axis fluxgate sensor 28, respectively, are calculated using Formula 3. The first three-axis fluxgate sensor 22 has magnetic field components on the X, Y, and Z axes, where x, y, and z are the lateral, vertical, and longitudinal distances of point Q in the target well 35 relative to point P in the drilling well 34, respectively.

[0037] In use, Formula 1 can be used to calculate the horizontal (i.e., wellbore axial) magnetic field gradient measurement data in the X, Y, and Z axes measured at point Q within the target well 35. Formula 2 can be used to calculate the horizontal vertical (front-back direction) magnetic field gradient measurement data in the X, Y, and Z axes measured at point Q within the target well 35. Formula 3 can be used to calculate the longitudinal (up-down direction) magnetic field gradient measurement data in the X, Y, and Z axes measured at point Q within the target well 35. Based on the magnetic field component data in the X, Y, and Z axes measured by the first triaxial fluxgate sensor 22 located at point Q, and Formula 4, the horizontal distance x, vertical distance y, and longitudinal distance z between point Q within the target well 35 and point P within the drilling well 34 can be calculated. Using the above measurement and calculation methods, real-time measurement and calculation can be performed during the drilling process of drill bit 2. The wellbore trajectory of the main drilling well 34 can be compared with the wellbore trajectory of the target well 35 based on the calculation results, and the drilling direction of drill bit 2 can be adjusted in a timely manner to ensure that the wellbore trajectory of the main drilling well 34 meets the relevant requirements. Alternatively, measurements and calculations can be performed periodically to compare the wellbore trajectory of the main drilling well 34 with that of the target well 35. In addition, this system can be linked with the control system of drill string 1 of the main drilling well 34 through relevant programs to automatically compare the two wellbore trajectories and adjust the drilling direction of drill bit 2 based on the calculation results.

[0038] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A downhole spatial positioning device based on magnetic field full tensor gradient measurement, characterized in that... The system includes a drill string, drill bit, magnetic dipole source section, communication cable, magnetic field gradient measurement probe, ground data receiving device, and computer. A magnetic dipole source section is installed between the drill string and the drill bit, which generates alternating magnetic field signals as the drill string rotates. One end of the communication cable is connected to a magnetic field gradient measurement probe that can receive and transmit alternating magnetic field measurement data, and the other end of the communication cable is connected to a ground data receiving device. The ground data receiving device is connected to a computer that can calculate the relative position of the magnetic dipole source section and the magnetic field gradient measurement probe based on the measurement data. The magnetic field gradient measurement probe includes an outer cylinder, a left end cap, a right end cap, a main support, a sensor assembly, a power management unit, a data acquisition unit, a data transmission unit, and a cable plug. The inner left and right ends of the outer cylinder are respectively equipped with a left end cap and a right end cap. A main support is installed on the middle left side of the right end cap, with its left end located to the right of the left end cap. The main support is equipped with a sensor assembly capable of measuring alternating magnetic field signals, a power management unit, a data acquisition unit, and a data transmission unit. The outer left side of the left end cap has an outer annular groove for connecting to an oil pipe. The middle right side of the left end cap has a blind hole opening to the right, and the middle left side of the left end cap has a plug mounting hole communicating with the blind hole. A cable plug is installed in the plug mounting hole. The cable plug connects to the data transmission unit and the power management unit. The power management unit connects to the sensor assembly, the data acquisition unit, and the data transmission unit. The sensor assembly connects to the data acquisition unit, and the data acquisition unit connects to the data transmission unit. The sensor assembly includes a first three-axis fluxgate sensor, a second three-axis fluxgate sensor, a third three-axis fluxgate sensor, a fourth three-axis fluxgate sensor, a fifth three-axis fluxgate sensor, a sixth three-axis fluxgate sensor, a seventh three-axis fluxgate sensor, an accelerometer, and a coin-shaped bracket. The main bracket is an upward-opening U-shaped bracket. From left to right, the inner side of the lower end of the U-shaped bracket is sequentially equipped with the second three-axis fluxgate sensor, a data transmission unit, the first three-axis fluxgate sensor, a data acquisition unit, an accelerometer, a power management unit, and the third three-axis fluxgate sensor. Corresponding to the first three-axis fluxgate sensor... A copper coin-shaped bracket is fixedly installed on the outside of the U-shaped bracket on the left side of the sensor. The fourth, fifth, sixth, and seventh three-axis fluxgate sensors are fixedly installed on the front right, rear right, upper right, and lower right sides of the copper coin-shaped bracket, respectively. The first, second, third, fourth, fifth, sixth, and seventh three-axis fluxgate sensors and the accelerometer are connected to the data acquisition unit and the power management unit, respectively.

2. The downhole spatial positioning device based on magnetic field full tensor gradient measurement according to claim 1, characterized in that... The magnetic dipole source sub includes a sub body with an axial channel, a magnetic dipole rod, and a retaining ring. The outer side of the middle part of the sub body has several outward-facing magnetic source mounting holes. A magnetic dipole rod is installed in each magnetic source mounting hole. A retaining ring groove is provided in the magnetic source mounting hole corresponding to the outer end of each magnetic dipole rod, and a retaining ring is provided in each retaining ring groove. A drill bit connection outer ring groove is provided on the outer side of the left end of the sub body.

3. The downhole spatial positioning device based on magnetic field full tensor gradient measurement according to claim 1 or 2, characterized in that... The magnetic field gradient measurement probe also includes a data storage unit. The data storage unit is installed on the main support between the data transmission unit and the sensor assembly. The data storage unit is connected to the power management unit and the data acquisition unit respectively.

4. The downhole spatial positioning device based on magnetic field full tensor gradient measurement according to claim 1 or 2, characterized in that... The magnetic field gradient measurement probe also includes a data storage unit. The data storage unit is installed on the main support between the data transmission unit and the sensor assembly. The data storage unit is connected to the power management unit and the data acquisition unit respectively.

5. The downhole spatial positioning device based on magnetic field full tensor gradient measurement according to claim 3, characterized in that... The magnetic field gradient measurement probe also includes a data storage unit. The data storage unit is installed on the main support between the data transmission unit and the sensor assembly. The data storage unit is connected to the power management unit and the data acquisition unit respectively.

6. The downhole spatial positioning device based on magnetic field full tensor gradient measurement according to claim 1, 2, or 5, characterized in that... The magnetic field gradient measurement probe also includes sealing rings, with sealing rings provided between the left end of the outer cylinder and the left end cap, and between the right end of the outer cylinder and the right end cap.

7. The downhole spatial positioning device based on magnetic field full tensor gradient measurement according to claim 3, characterized in that... The magnetic field gradient measurement probe also includes sealing rings, with sealing rings provided between the left end of the outer cylinder and the left end cap, and between the right end of the outer cylinder and the right end cap.

8. The downhole spatial positioning device based on magnetic field full tensor gradient measurement according to claim 4, characterized in that... The magnetic field gradient measurement probe also includes sealing rings, with sealing rings provided between the left end of the outer cylinder and the left end cap, and between the right end of the outer cylinder and the right end cap.

9. The positioning method of the downhole spatial positioning device based on magnetic field full tensor gradient measurement according to any one of claims 1 to 8, characterized in that... This includes the preparation process, the data acquisition and transmission process, and the data processing process; The preparation process is as follows: First, install the magnetic dipole source short section between the drill string and the drill bit and run it into the predetermined position P of the drilling. Then, connect one end of the communication cable to the cable plug on the magnetic field gradient measurement probe. Next, connect the connector at the end of the tubing to the outer side of the left end of the magnetic field gradient measurement probe. Then, connect the other end of the communication cable to the ground data receiving device. Next, connect the data receiving device to the computer. Finally, run the magnetic field gradient measurement probe into point Q in the target well through the communication cable. The data acquisition and transmission process is as follows: First, when the drill string rotates, the magnetic dipole source section located at point P in the drilling well generates an alternating magnetic field signal as the drill string rotates. Second, the sensor assembly on the magnetic field gradient measurement probe located at point Q in the target well measures the magnetic field gradient of the alternating magnetic field. Then, the data acquisition unit collects the measurement data and sends it to the data transmission unit. The data transmission unit sends the measurement data to the ground data receiving device through the communication cable. Finally, the ground receiving device sends the received measurement data to the computer, and the computer receives and stores the above measurement data. The data processing involves the computer calculating the relative positions of point P in the drilling well and point Q in the target well based on the received magnetic field gradient measurement data. It then uses formulas 1, 2, 3, and 4 to calculate the lateral, vertical, and longitudinal distances of point Q in the target well relative to point P in the drilling well. Formula 1 is... in, and These represent the magnetic field components along the X-axis of the second and third triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Y-axis of the second and third triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Z-axis of the second and third triaxial fluxgate sensors, respectively. The distance between the second and third three-axis fluxgate sensors; Formula 2 is in, and These represent the magnetic field components along the X-axis of the fourth and fifth triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Y-axis of the fourth and fifth triaxial fluxgate sensors, respectively. and These represent the magnetic field components along the Z-axis of the fourth and fifth triaxial fluxgate sensors, respectively. The distance between the fourth and fifth three-axis fluxgate sensors; Formula 3 is in, and These represent the magnetic field components along the X-axis of the sixth and seventh three-axis fluxgate sensors, respectively. and These represent the magnetic field components along the Y-axis of the sixth and seventh three-axis fluxgate sensors, respectively. and These represent the magnetic field components along the Z-axis of the sixth and seventh three-axis fluxgate sensors, respectively. The distance between the sixth and seventh three-axis fluxgate sensors; Formula 4 is in, The results for the second and third triaxial fluxgate sensors, respectively, are calculated using Formula 1. The results for the fourth and fifth three-axis fluxgate sensors, respectively, are calculated using Formula 2. The results for the sixth and seventh three-axis fluxgate sensors, respectively, are calculated using Formula 3. The first three-axis fluxgate sensor has magnetic field components on the X, Y, and Z axes, where x, y, and z are the lateral, vertical, and longitudinal distances of point Q in the target well relative to point P in the drilling well, respectively.

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