A method of accurately orienting a magnetic azimuth surveying probe while measuring its magnetic declination

Abstract

The present application relates to a kind of measuring magnetic azimuth measuring probe tube magnetic declination when accurate orientation device and method, belong to directional drilling field.The present application provides a kind of measuring magnetic azimuth measuring probe tube magnetic declination when accurate orientation device and method, adjusting ring, instrument sleeve, laser, laser position adjusting screw, instrument sleeve position adjusting screw and clamping block are assembled into magnetic azimuth measuring probe tube accurate orientation device and are fixed to true north direction, then set bar target in fixed point north direction, after magnetic azimuth measuring probe tube is placed into the rear cavity of instrument sleeve, the average of the measured value of magnetic azimuth measuring probe tube is obtained by subtracting the north direction value from the average of the measured value of magnetic azimuth measuring probe tube, and the magnetic declination in the north direction is obtained, and the magnetic declination in the east direction, the south direction and the west direction is obtained according to the same method, and the average of the four magnetic declination values is the magnetic declination of the magnetic azimuth measuring probe tube.The present application can make probe tube placement orientation error less than 0.1 °, greatly improve the accuracy of probe tube azimuth magnetic declination measurement.

Description

Technical Field

[0001] This invention relates to a device and method for accurately orienting a probe when measuring the magnetic declination of a magnetic azimuth, belonging to the field of directional drilling. Background Technology

[0002] Currently, drilling operations are primarily directional drilling, requiring the drilled trajectory to closely match the designed path and achieving a high degree of target accuracy. The borehole trajectory coordinates are mainly calculated from three parameters: borehole depth, azimuth, and dip angle. Currently, borehole trajectory design mainly uses geodetic coordinates, while the azimuth parameters of the borehole trajectory during actual drilling are primarily measured using magnetic sensors. There is a magnetic declination between the measured magnetic azimuth value and the true azimuth. To accurately drill along the designed borehole trajectory, the magnetic declination of the magnetic azimuth measuring probe needs to be obtained to correct the magnetic azimuth data to the true azimuth data. The magnetic declination of the magnetic azimuth measuring probe is equal to the local magnetic declination plus the probe's azimuth zero-position offset. To obtain this value, the magnetic azimuth measuring probe needs to be placed in a direction with a known true azimuth; the magnetic declination of the probe is obtained by subtracting the measured value from the known true azimuth value. The accuracy of the orientation of the magnetic orientation measurement probe directly affects the magnitude of the magnetic declination measurement error. Currently, the orientation of the magnetic orientation measurement probe is mainly determined by manual placement along the line. This method of placement along the line is greatly affected by human factors and often introduces an orientation error of about 0.4°, which directly affects the accuracy of the magnetic declination measurement. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a precise orientation device and method for measuring the magnetic declination of a probe. This invention enables the probe placement orientation error to be less than 0.1°, greatly improving the accuracy of probe magnetic declination measurement.

[0004] To achieve the above objectives, the technical solution provided by the present invention is: a device and method for accurately orienting a probe when measuring the magnetic declination of a magnetic azimuth.

[0005] A device for accurately orienting a magnetic orientation measuring probe when measuring magnetic declination includes an adjusting ring, an instrument sleeve, a laser, a laser position adjusting screw, an instrument sleeve position adjusting screw, and a locking block. The locking block is fixed on a horizontal surface. The laser is located in the front inner cavity of the instrument sleeve. The adjusting ring is fitted onto the instrument sleeve. The laser position adjusting screw on the instrument sleeve is used to make the laser axis parallel to the instrument sleeve axis. The instrument sleeve position adjusting screw on the adjusting ring is used to adjust the orientation of the instrument sleeve. The magnetic orientation measuring probe is located in the rear inner cavity of the instrument sleeve.

[0006] In the above-mentioned device, the adjusting ring, instrument sleeve, laser position adjusting screw, instrument sleeve position adjusting screw, and locking block are all made of non-magnetic materials.

[0007] The laser position should be at least 1.5 meters away from the magnetic orientation measuring probe; the instrument sleeve wall thickness should be greater than 7 mm, and the instrument sleeve inner diameter should be greater than 50 mm.

[0008] Two adjusting rings are respectively set at a distance of 10cm from both ends of the instrument sleeve. The inner diameter of the adjusting ring is 5mm larger than the outer diameter of the instrument sleeve. Each adjusting ring is equipped with 8 instrument sleeve position adjusting screws, which are evenly distributed along the circumference of the adjusting ring. The instrument sleeve is fixed on the center line of the two adjusting rings by the instrument sleeve position adjusting screws.

[0009] A method for accurately orienting a probe when measuring magnetic declination, the specific steps of which are as follows:

[0010] Step 1: Observe the influence of the geomagnetic environment of the selected test site on the measurement values ​​of the magnetic azimuth measurement probe. Rotate the magnetic azimuth measurement probe one revolution in the four directions of north, east, south and west and observe the change in magnetic field strength measured by the probe. If the change in magnetic field strength is less than 0.5 μT, the selected test site is qualified.

[0011] Step 2: Determine the true north direction at the test site using a gyro total station;

[0012] Step 3: Draw a line along the measured true direction, fix the two positioning blocks on the line, with the interval being the distance between the two adjustment rings. At the same time, place the orientation device on the positioning blocks in the measured true direction. Then, set the bar target along the line in the measured true direction, at a distance of not less than 200 meters from the fixed point of the orientation device.

[0013] Step 4: Turn on the laser switch and observe the laser projection point. If the laser projection point is not on the strip target, first adjust the orientation of the instrument sleeve by adjusting the position screw on the instrument sleeve on the adjustment ring so that the laser projection point is on the strip target.

[0014] Step 5: Fine-tune the orientation of the instrument sleeve by adjusting the position screw on the instrument sleeve on the adjustment ring so that the laser projection point is located within the center strip of the strip target;

[0015] Step 6: Insert the magnetic azimuth measuring probe into the inner cavity at the rear of the instrument sleeve, and then rotate the magnetic azimuth measuring probe by different angles θ1, θ2, ..., θ n For n≥2, take the measured values ​​at each rotation position, sum them up and divide by n to get the average value. Subtract this average value from the measured true direction azimuth value to get the magnetic declination of the magnetic azimuth measuring probe in the measured true direction.

[0016] Step 7: At the test site, use a gyro total station to measure the true east, south, and west directions. Repeat steps 3 to 6 above to obtain the true magnetic declination in the east, south, and west directions. Add up the magnetic declination values ​​obtained in the four directions of north, east, south, and west, and then divide by 4. The average value obtained is the magnetic declination of the magnetic azimuth measurement probe.

[0017] According to the above technical solution, the present invention provides a precise orientation device and method for measuring the magnetic declination of a magnetic azimuth measuring probe. The device assembles an adjusting ring, an instrument sleeve, a laser, a laser position adjusting screw, an instrument sleeve position adjusting screw, and a locking block. The true north direction is measured using a gyro total station. The orientation device is then fixed towards the true north direction, and a strip target is set in the true north direction. The laser projection point is positioned within the center strip of the strip target using the laser and the sleeve position adjusting screw. The magnetic azimuth measuring probe is then placed into the rear cavity of the instrument sleeve. The magnetic declination of the probe in the true north direction is obtained by subtracting the average value of the measured values ​​of different rotation angles of the magnetic azimuth measuring probe from the true north direction value. The same method is used to obtain the magnetic declination values ​​in the east, south, and west directions. The average value of the magnetic declination values ​​obtained in the four directions is then used to obtain the magnetic declination of the magnetic azimuth measuring probe. Compared with the existing technology of manually placing and positioning the probe along the line to measure the magnetic orientation, the present invention can make the probe placement orientation error less than 0.1°, which greatly improves the accuracy of the probe orientation magnetic declination measurement. Attached Figure Description

[0018] Figure 1 A schematic diagram illustrating the method of using a precise orientation device when measuring the magnetic declination of a magnetic azimuth probe.

[0019] Figure 2 A cross-sectional view of a device for accurately orienting a probe when measuring magnetic declination;

[0020] Figure 3 A cross-sectional view of the device for precisely oriented when the magnetic declination of the magnetic orientation measuring probe is inserted.

[0021] In the diagram: 1. Bar target; 2. Adjustment ring; 3. Positioning block; 4. Laser charging port; 5. Laser switch; 6. Instrument sleeve; 7. Magnetic orientation measuring probe; 8. Laser position adjustment screw; 9. Instrument sleeve position adjustment screw; 10. Laser; 11. Laser lamp head; 12. Laptop computer. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0023] A device for accurately orienting a magnetic orientation measuring probe when measuring magnetic declination includes an adjusting ring, an instrument sleeve, a laser, a laser position adjusting screw, an instrument sleeve position adjusting screw, and a locking block. The locking block is fixed on a horizontal surface. The laser is located in the front inner cavity of the instrument sleeve. The adjusting ring is fitted onto the instrument sleeve. The laser position adjusting screw on the instrument sleeve is used to make the laser axis parallel to the instrument sleeve axis. The instrument sleeve position adjusting screw on the adjusting ring is used to adjust the orientation of the instrument sleeve. The magnetic orientation measuring probe is located in the rear inner cavity of the instrument sleeve.

[0024] In the above-mentioned device, the adjusting ring, instrument sleeve, laser position adjusting screw, instrument sleeve position adjusting screw, and locking block are all made of non-magnetic materials.

[0025] The laser position should be at least 1.5 meters away from the magnetic orientation measuring probe to prevent interference from the laser. The instrument sleeve wall thickness should be greater than 7 mm, and the instrument sleeve inner diameter should be greater than 50 mm.

[0026] Two adjusting rings are respectively set at a distance of 10cm from both ends of the instrument sleeve. The inner diameter of the adjusting ring is 5mm larger than the outer diameter of the instrument sleeve. Each adjusting ring is equipped with 8 instrument sleeve position adjusting screws, which are evenly distributed along the circumference of the adjusting ring. The instrument sleeve is fixed on the center line of the two adjusting rings by the instrument sleeve position adjusting screws.

[0027] A method for accurately orienting a probe when measuring magnetic declination, the specific steps of which are as follows:

[0028] Step 1: Observe the influence of the geomagnetic environment of the selected test site on the measurement values ​​of the magnetic azimuth measurement probe. Rotate the magnetic azimuth measurement probe one revolution in the four directions of north, east, south and west and observe the change in magnetic field strength measured by the probe. If the change in magnetic field strength is less than 0.5 μT, the selected test site is qualified.

[0029] Step 2: Determine the true north direction at the test site using a gyro total station;

[0030] Step 3: Draw a line along the measured true direction, fix the two positioning blocks on the line, with the interval being the distance between the two adjustment rings. At the same time, place the orientation device on the positioning blocks in the measured true direction. Then, set the bar target along the line in the measured true direction, at a distance of not less than 200 meters from the fixed point of the orientation device.

[0031] Step 4: Turn on the laser switch and observe the laser projection point. If the laser projection point is not on the strip target, first adjust the orientation of the instrument sleeve by adjusting the position screw on the instrument sleeve on the adjustment ring so that the laser projection point is on the strip target.

[0032] Step 5: Fine-tune the orientation of the instrument sleeve by adjusting the position screw on the instrument sleeve on the adjustment ring so that the laser projection point is located within the center strip of the strip target;

[0033] Step 6: Insert the magnetic azimuth measuring probe into the inner cavity at the rear of the instrument sleeve, and then rotate the magnetic azimuth measuring probe by different angles θ1, θ2, ..., θ n For n≥2, take the measured values ​​at each rotation position, sum them up and divide by n to get the average value. Subtract this average value from the measured true direction azimuth value to get the magnetic declination of the magnetic azimuth measuring probe in the measured true direction.

[0034] Step 7: At the test site, use a gyro total station to measure the true east, south, and west directions. Repeat steps 3 to 6 above to obtain the true magnetic declination in the east, south, and west directions. Add up the magnetic declination values ​​obtained in the four directions of north, east, south, and west, and then divide by 4. The average value obtained is the magnetic declination of the magnetic azimuth measurement probe.

[0035] Example: Reference Figure 1 , Figure 2 and Figure 3The adjusting ring 2, instrument sleeve 6, laser position adjusting screw 8, instrument sleeve position adjusting screw 9, and locking block 3 are all made of non-magnetic brass or aluminum alloy. The laser 10 is positioned at least 1.5 meters away from the magnetic orientation probe 7 behind it to prevent interference from the laser with the magnetic orientation measurement probe. The instrument sleeve 6 has a wall thickness greater than 7mm and an inner diameter greater than 50mm. During assembly, the laser 10 axis is aligned with the instrument sleeve 6 axis using the laser position adjusting screw 8 on the instrument sleeve 6. Then, potting compound is used to fill the gap between the laser and the instrument sleeve wall to prevent the laser from becoming loose during use. When using a magnetic declination measuring probe to accurately orient the device, the true north direction is determined using a gyro total station. A line is drawn along this true direction, and two positioning blocks 3 are fixed to the line, with the spacing between them equal to the distance between the two adjusting rings 2. The orienting device is then placed on the positioning blocks 3 facing the true direction. Next, a strip target 1 is set along the line in the true direction, at least 200 meters from the fixing point of the orienting device. The laser 10 is switched on, and the laser projection point is observed. If the laser projection point is not on the strip target 1, the orientation of the instrument sleeve 6 is first adjusted using the instrument sleeve position adjusting screw 9 on the adjusting ring until the laser projection point is on the strip target 1. Then, the orientation of the instrument sleeve 6 is finely adjusted using the instrument sleeve position adjusting screw 9 on the adjusting ring. Position the laser projection point within the central strip of the strip target 1; place the magnetic azimuth measuring probe 7 into the rear cavity of the instrument sleeve 6, then rotate the magnetic azimuth measuring probe at 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°, and take the measurement value at each rotation position. Sum the values ​​and divide by 8 to obtain the average value. Subtract this average value from the true north value to obtain the magnetic declination of the magnetic azimuth measuring probe in the true north direction; measure the true east, south, and west directions at the test site using a gyro total station, and repeat the above operation to obtain the magnetic declination in the east, south, and west directions. Sum the magnetic declination values ​​obtained in the four directions of north, east, south, and west and divide by 4 to obtain the average value, which is the azimuth magnetic declination of the magnetic azimuth measuring probe.

Claims

1. A method for accurately orienting a probe when measuring magnetic declination, wherein a device for accurately orienting a probe when measuring magnetic declination is used, characterized in that: The precise orientation device for measuring the magnetic declination of the magnetic orientation measuring probe includes an adjusting ring, an instrument sleeve, a laser, a laser position adjusting screw, an instrument sleeve position adjusting screw, and a locking block. The locking block is fixed on a horizontal surface. The laser is located in the front inner cavity of the instrument sleeve. The adjusting ring is fitted onto the instrument sleeve. The laser position adjusting screw on the instrument sleeve is used to make the laser axis parallel to the instrument sleeve axis. The instrument sleeve position adjusting screw on the adjusting ring is used to adjust the orientation of the instrument sleeve. The magnetic orientation measuring probe is located in the rear inner cavity of the instrument sleeve. The precise orientation method for measuring the magnetic declination of a probe when measuring magnetic azimuth is as follows: Step 1: Observe the influence of the geomagnetic environment of the selected test site on the measurement values ​​of the magnetic azimuth measurement probe. Rotate the magnetic azimuth measurement probe one revolution in the four directions of north, east, south and west and observe the change in magnetic field strength measured by the probe. If the change in magnetic field strength is less than 0.5 μT, the selected test site is qualified. Step 2: Determine the true north direction at the test site using a gyro total station; Step 3: Draw a line along the measured true direction, fix the two positioning blocks on the line, with the interval being the distance between the two adjustment rings. At the same time, place the orientation device on the positioning blocks in the measured true direction. Then, set the bar target along the line in the measured true direction, at a distance of not less than 200 meters from the fixed point of the orientation device. Step 4: Turn on the laser switch and observe the laser projection point. If the laser projection point is not on the strip target, first adjust the orientation of the instrument sleeve by adjusting the position screw on the instrument sleeve on the adjustment ring so that the laser projection point is on the strip target. Step 5: Fine-tune the orientation of the instrument sleeve by adjusting the position screw on the instrument sleeve on the adjustment ring so that the laser projection point is located within the center strip of the strip target; Step 6: Insert the magnetic azimuth measuring probe into the inner cavity at the rear of the instrument sleeve, and then rotate the magnetic azimuth measuring probe by different angles θ1, θ2, ..., θ n For n≥2, take the measured values ​​at each rotation position, sum them up and divide by n to get the average value. Subtract this average value from the measured true direction azimuth value to get the magnetic declination of the magnetic azimuth measuring probe in the measured true direction. Step 7: At the test site, use a gyro total station to measure the true east, south, and west directions. Repeat steps 3 to 6 above to obtain the true magnetic declination in the east, south, and west directions. Add up the magnetic declination values ​​obtained in the four directions of north, east, south, and west, and then divide by 4. The average value obtained is the magnetic declination of the magnetic azimuth measurement probe.

2. The method for accurately orienting a probe when measuring magnetic declination according to claim 1, characterized in that: The adjusting ring, instrument sleeve, laser position adjusting screw, instrument sleeve position adjusting screw, and locking block are all made of non-magnetic materials.

3. The method for accurately orienting a probe when measuring magnetic declination according to claim 1, characterized in that: The laser position should be at least 1.5 meters away from the magnetic orientation measuring probe; the instrument sleeve wall thickness should be greater than 7 mm, and the instrument sleeve inner diameter should be greater than 50 mm.

4. The method for accurately orienting a probe when measuring magnetic declination according to claim 1, characterized in that: Two adjusting rings are respectively set at a distance of 10cm from both ends of the instrument sleeve. The inner diameter of the adjusting ring is 5mm larger than the outer diameter of the instrument sleeve. Each adjusting ring is equipped with 8 instrument sleeve position adjusting screws, which are evenly distributed along the circumference of the adjusting ring. The instrument sleeve is fixed on the center line of the two adjusting rings by the instrument sleeve position adjusting screws.

Images