An initial orientation method for a dense cluster well group

Abstract

The present invention relates to a directional method for dense cluster well groups. Mainly, the bend point mark of a single-bend positive displacement motor is projected onto the wellhead by means of mark annotation, and then the orientation of the bend angle of the positive displacement motor is determined according to the orientation of the offshore drilling platform / the orientation of the derrick door of the drilling rig / the ground compass method. Then, the bend angle of the single-bend positive displacement motor is rotated to the device angle required for orientation through the rotary table / top drive, and then the orientation starts until the magnetic interference of the measurement-while-drilling instrument disappears and the true and error-free magnetic device angle and azimuth angle can be measured. Finally, it switches to the normal directional mode to continue the operation. This method can effectively avoid the use of high-cost instruments such as wired / measurement-while-drilling gyroscopes, which increases the operation steps and operation costs. It has the characteristics of simple operation, low cost, and high success rate, and can effectively solve the problem of initial orientation of shallow layers in dense cluster well groups.

Description

Technical Field

[0001] The present invention relates to a well drilling orientation method in the technical field of oil well drilling, and particularly to an initial orientation method for a dense cluster well group. Background Art

[0002] With the development of drilling technology and the increasing maturity of orientation technology, cluster well groups have been increasingly applied due to their advantages of small land acquisition area, convenient management, and beneficial to reducing the number of relocations. Large-scale cluster well groups have become one of the mainstream directions of current drilling development.

[0003] Due to the increase in the number of wells involved in the cluster well group, the slot spacing has become smaller and smaller. The wellhead distance of onshore cluster wells has decreased from 10 m to 3 - 5 m, and the slot spacing of offshore platforms has been reduced from 2.5 m × 2.5 m to 1.6 m × 1.8 m, with the spacing getting smaller and smaller; and the slot layout has increased from 3×3 and 3×4 to 4×9, forming large dense clusters with dozens of slots, and the number of well groups is increasing.

[0004] For the need of anti-collision, large-scale cluster well groups usually require rapid separation between wellbores. Therefore, the kick-off point is getting shallower and shallower. Currently, the general measurement-while-drilling (MWD) instruments mainly measure the earth's magnetic field and gravitational acceleration. The measurement of magnetic field parameters generally requires no interference within 3 m. Due to the too small wellhead spacing, conventional measurement instruments will be interfered by the magnetic field of adjacent well casings, resulting in inaccurate measurement of the magnetic tool face and azimuth, bringing great trouble to the construction.

[0005] To solve this problem, researchers have developed gyro measurement tools, which can avoid the magnetic field interference of adjacent well casings. However, currently, domestic measurement-while-drilling gyro measurement instruments have not been successfully developed, and wired gyro measurement instruments have problems such as high-precision, high price, complex operation steps, and long construction period, and are rarely used in actual field applications. The problem of shallow layer orientation of dense cluster well groups has not been effectively solved by a simple and convenient method. Summary of the Invention

[0006] The purpose of the present invention is to provide an orientation method for a dense cluster well group in view of the deficiencies in the prior art. By means of a marking method, the bend mark of a single-bend positive displacement motor is projected onto the wellhead, and then the orientation of the bend angle of the screw is determined according to the orientation of the offshore drilling platform, the direction of the rig derrick door, and the ground compass method. Then, the bend angle of the single-bend screw is rotated to the required device angle through the rotary table / top drive and then orientation starts until the magnetic interference of the measurement-while-drilling instrument disappears. Finally, it switches to the conventional orientation mode to continue the operation.

[0007] It can effectively avoid the use of high-cost wired / measurement-while-drilling gyro instruments to increase operation steps and operation costs, and can effectively solve the problem of shallow initial orientation of dense cluster well groups.

[0008] Its technical solution is as follows:

[0009] Step 1: Assemble the conventional directional drilling tool string. Check the bending angle marking orientation of the single-bend positive displacement motor (PDM), and project the bending angle marking of the single-bend PDM vertically upward to the uppermost part of the bottom hole assembly. Lock the rotary table or the top drive lifting ring to prevent rotation.

[0010] Step 2: Connect the drill pipe (drill collar, heavy weight drill pipe, drill pipe) and lower it into the well. During the lowering process, project the bending angle pointing orientation of the positive displacement motor vertically upward to the male thread at the uppermost part of each joint / stand of the drill pipe, and make a mark at the uppermost joint of the drill pipe with paint or other marking coatings or tools with marking ability.

[0011] Step 3: Repeat Step 2 until reaching the bottom of the well or the kick-off point, and then project the mark to the drill floor, and make corresponding marks on the rotary table, top drive joint or corresponding positions.

[0012] Step 4: Determine the rotary table orientation according to the orientation of the drilling platform / ship in place, the orientation of the drilling derrick gate, and the compass reference orientation, and make a mark for the due north direction (magnetic north direction).

[0013] Step 5: Based on the rotary table orientation, rotate the bending angle of the single-bend positive displacement motor to the directional orientation, and appropriately consider a certain anti-torque angle. Lock the rotary table / top drive, and start pumping for directional drilling.

[0014] Step 6: After drilling each joint / stand of the drill pipe, conduct well inclination measurement through the measurement-while-drilling (MWD) instrument, and record relevant parameters (well inclination, azimuth, magnetic field strength, magnetic field dip angle). At the same time, compare with the normal geomagnetic parameters in the construction area to judge the magnetic interference intensity.

[0015] Step 7: After drilling each joint / stand of the drill pipe and completing the well inclination measurement, connect a single joint / stand, and then continue to project the bending angle mark of the single-bend positive displacement motor vertically to the corresponding position of the connected drill pipe and make a mark.

[0016] Step 8: Repeat Steps 5, 6, and 7 until the magnetic parameters measured by the MWD instrument are normal; then switch to the MWD instrument parameters for directional construction operations.

[0017] The beneficial effects of the present invention are as follows:

[0018] (1) Effectively avoids the high cost of using wired / MWD gyro high-cost instruments and increases the operation steps and operation costs.

[0019] (2) Has the characteristics of simple operation, low cost, and high success rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the bending angle orientation marking and projection method of the positive displacement motor for the initial orientation method of the dense cluster well group of the present invention.

[0021] Figure 2 Schematic diagram of the turntable surface orientation marking method for the initial orientation method of the dense cluster well group of the present invention.

[0022] Markings in the figure: 1. Marking, 2. Bending angle of the screw, 3. Drill bit, 4. Casing of adjacent well, 5. Casing. Detailed implementation manners

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0024] Refer to Figure 1 and 2 For an initial orientation method of a dense cluster well group, assemble the bottom hole assembly including a single-bend screw 2 and a drill bit 3, lower the drill string to the bottom of the well or the kick-off point, rotate the bottom hole assembly to the required azimuth, start the pump for directional drilling, make bending angle markings 1 on the reference object and the drill string respectively according to the bending angle azimuth of the single-bend screw 2, determine the drilling direction according to the bending angle marking 1, measure the inclination with a measurement-while-drilling instrument after drilling each stand or joint of drill string, record relevant parameters, and at the same time compare with the normal geomagnetic parameters in the construction area to judge the magnetic interference intensity. If there is magnetic interference, it means that the magnetic interference range of the adjacent well casing has not been escaped. If the magnetic interference disappears, switch to the conventional directional drilling operation.

[0025] The bending angle marking 1 is the vertical projection of the bending angle azimuth on the reference object.

[0026] The reference object includes but is not limited to the turntable, top drive, drill string, drill pipe, etc. During the process of lowering the drill string to the bottom of the well or the kick-off point, first make the bending angle marking 1 on the turntable or top drive, then make the bending angle marking 1 on the drill string, and at the same time make the bending angle marking 1 at the uppermost end of the drill pipe before connecting each new drill pipe. The bending angle markings 1 on the turntable or top drive, drill string, and drill pipe always maintain the same azimuth, that is, they are aligned; after drilling from the bottom of the well or the kick-off point, when rotating to the required azimuth, there is a certain included angle between the azimuth of the aforementioned bending angle marking 1 and the reference azimuth, the marking of the true north direction, etc. Before the magnetic interference of the adjacent well casing disappears, use this included angle as the direction reference, and use a measurement-while-drilling logging instrument for conventional directional drilling after the magnetic interference disappears.

[0027] Specifically, it includes the following steps:

[0028] Step 1, assemble the bottom hole assembly including the screw and the drill bit 3, and project the bending angle azimuth of the screw 2 to the male thread position at the uppermost end of the bottom hole assembly in the way of vertical projection, lock the turntable or top drive sling to prevent rotation;

[0029] Step 2: Connect the drill pipe on the drill floor and lower the drill string. Lower the bottom hole assembly into the casing 5. Project the bend angle of the screw bent sub 2 in the vertically upward direction onto the top joint of each stand / column of drill pipe, and make a mark 1 at the top joint of the drill pipe with paint or other marking coatings or tools with marking ability.

[0030] Step 3: Repeat Step 2 until reaching the bottom of the well or the kick-off point. Then project the screw drill tool bend angle mark onto the drill floor and make corresponding marks 1 on the rotary table, top drive joint or corresponding positions.

[0031] Step 4: Determine the azimuth of the rotary table surface according to the positioning azimuth of the drilling platform / ship, the orientation of the drilling derrick door, and the reference azimuth of the compass, and make a mark for the true north direction (magnetic north direction) on the rotary table surface.

[0032] Step 5: Based on the azimuth of the rotary table surface, rotate the bend angle of the single-bend screw drill tool to the directional azimuth, and appropriately consider a certain anti-torque angle. Lock the rotary table / top drive and start pumping for directional drilling.

[0033] Step 6: After each stand or column (one column consists of two, three or four drill pipes) of the drill string is drilled, perform well inclination measurement through the measurement-while-drilling instrument, and record relevant parameters (well inclination, azimuth, magnetic field strength, magnetic field dip angle). At the same time, compare with the normal geomagnetic parameters in the construction area to judge the magnetic interference intensity.

[0034] Step 7: After each stand / column of the drill string is drilled and the well inclination measurement is completed, connect a single joint / stand, and then continue to project the bend angle mark of the single-bend screw drill tool vertically upward to the corresponding position of the connected drill string and make a mark 1.

[0035] Step 8: Then continue drilling, repeat Steps 5, 6, and 7 until the magnetic field interference of the adjacent well casing 4 disappears and the magnetic parameters measured by the measurement-while-drilling instrument are normal. Then switch to the conventional measurement-while-drilling instrument directional mode and perform directional construction operations relying on the parameters of the measurement-while-drilling instrument.

[0036] The true north direction (i.e., magnetic north azimuth) correction method of the present invention is calculated by using the positioning azimuth of the drilling platform or ship, the orientation of the drilling derrick door, the compass and other reference azimuths. For example, if the orientation of the derrick door is 100°, then rotate counterclockwise by 100° to get the true north direction, that is, the magnetic north azimuth 0° position. If the required initial azimuth for directional drilling is 200°, then start from 0° for the screw bent angle mark previously projected onto the rotary table surface and rotate clockwise by 200° (while considering the anti-torque angle and azimuth correction angle), and the bend angle of the screw can be oriented to the required azimuth.

[0037] The present invention can avoid the magnetic field interference of adjacent well casings and is a simple and convenient solution for preventing collision and achieving fast directional separation between wellbores in large cluster well groups.

[0038] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims.

Claims

1. An initial orientation method for a dense cluster well group, assembling a bottom hole assembly including a single bend screw drill (2) and a drill bit (3), running the drill string to the bottom of the well or the kick-off point, rotating the bottom hole assembly to the required azimuth, and starting the pump for directional drilling, characterized in that, Before the magnetic interference of the casing of the adjacent well disappears, the drilling direction is determined by a marking method, and after the magnetic interference disappears, a conventional directional drilling construction method is used; the method also includes making a bend mark (1) on a reference object and a drilling tool according to the bend angle orientation of the single-bend screw (2), determining the drilling direction according to the bend mark (1), the bend mark (1) being a vertical projection of the bend angle orientation on the reference object, and measuring the inclination through a downhole measurement instrument after drilling each drill bit or column of drill bits, and recording relevant parameters, and comparing them with normal geomagnetic parameters in the construction area to determine the intensity of magnetic interference. If magnetic interference exists, then It indicates that the drilling has not escaped the magnetic interference range of the casing of the adjacent well. If the magnetic interference disappears, switch to conventional directional construction operation. The following steps are used to perform the initial directional construction operation: Step 1, check the bending angle of the single-bend screw (2), determine the bending angle orientation, and make a first bending angle mark (1) at the uppermost end of the drilling tool assembly at the bottom. The bending angle mark (1) is the vertical projection of the bending angle orientation of the single-bend screw (2). Lock the turntable or top drive lifting ring to prevent rotation; Step 2, connect the drilling tool and drill down. During the drilling process, make a bending angle mark (1) at the uppermost joint of each drill bit or column drilling tool; Step 3, repeat step 2 until Drill down to the bottom of the well or the inclination point, and then make another bend mark (1) on the drill floor, turntable or top drive joint or other corresponding position according to the bend mark (1) at the uppermost joint of the drilling tool in step 2. During the drilling process, keep the bend mark (1) on the drill floor, turntable or top drive joint or other corresponding position aligned; step 4, determine the turntable surface orientation according to the positioning orientation of the drilling platform or ship, the direction of the drilling derrick gate, and the compass reference orientation, and mark the true north direction; step 5, based on the turntable surface orientation, rotate the bend angle of the single-bend screw (2) to the required directional orientation, and lock it. Hold the rotary table or top drive, start the pump for directional drilling; step 6, after drilling each drill bit or column, measure the inclination through the drilling instrument, and record the relevant parameters, and compare them with the normal geomagnetic parameters of the construction area to determine the intensity of magnetic interference. If magnetic interference exists, proceed to the next step; step 7, after drilling each drill bit or column and measuring the inclination, connect a new single drill bit or column, and then continue to make corner marks (1) for the connected drill bit; step 8, repeat steps 5, 6, and 7 until the magnetic parameters measured by the drilling instrument are normal; then switch to the drilling instrument for directional construction.

2. The initial orientation method for a dense cluster well group according to claim 1, wherein In the step five, when the bending angle of the single-bend screw (2) is rotated to a directional position, a certain reverse twist angle is added.

3. The initial orientation method for a dense cluster well group according to claim 1, characterized in that, In the second step, a bend mark (1) is made at the uppermost joint of the drilling tool using paint or other coatings or tools with marking capabilities.

4. The initial orientation method for a dense cluster well group according to claim 1, characterized in that, The true north direction marked on the turntable surface in step 4 is the magnetic north direction.

5. A method for initial orientation of a dense cluster well group according to claim 1, characterized in that: The inclination measurement parameters of the while-drilling measurement instrument in step six include well inclination, azimuth, magnetic field intensity, and magnetic field inclination.

6. The initial orientation method for a dense cluster well group according to claim 1, characterized in that: One column of the drilling tool is composed of two, three or four drill rods.

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