Pressurizing wall protection device for underground coal mine nearly-horizontal drilling annular channel

Abstract

The invention discloses an underground coal mine nearly-horizontal drilling annular channel pressurization wall protection device which is suitable for clear water drilling and formula flushing fluid drilling at the same time, when clear water drilling is used, the hole wall is supported by increasing annular pressure, hole wall collapse is reduced, and the underground coal mine nearly-horizontal drilling annular channel pressurization wall protection device is suitable for being used in stratums which do not collapse seriously. When the formula impact fluid is used for drilling into a broken stratum, on one hand, the stratum pressure is balanced, and on the other hand, an anti-sloughing wall protection layer can be formed in cooperation with the anti-sloughing formula flushing fluid, and hole wall collapse is further inhibited; the use of the formula flushing fluid can be promoted, and the drilling cutting carrying capacity of the flushing fluid is improved; in conclusion, when the hole shrinkage stratum is drilled, the annular pressure is controlled, the formula flushing fluid is properly filtered to enter a certain range in the hole wall, a filter cake is formed, drill jamming is effectively prevented, the drilling problem of the hole shrinkage stratum such as mud rock is solved, and the device is suitable for large-scale industrial use and popularization.

Description

Technical Field

[0001] The invention belongs to the field of drilling devices, and in particular relates to a pressurized wall protection device for a nearly horizontal borehole annulus channel in an underground coal mine. Background Art

[0002] At present, directional drilling construction in coal mines mainly adopts a near-horizontal method to arrange holes, and uses clean water provided by a high-pressure mud pump as a punching and slag removal medium and a power medium. In the existing technology, since the horizontal fluctuations of drilling holes in coal mines are generally relatively stable and the height difference is extremely small, it is impossible to form a static liquid column pressure of the flushing fluid and balance the formation pressure. It is an underbalanced drilling construction, which is not conducive to maintaining the stability of the hole wall. The formulated flushing fluid cannot be properly filtered out to form a protective wall layer, resulting in the collapse and instability of the hole wall in the broken formation. It is not suitable for broken coal and rock formations.

[0003] On the other hand, water-sensitive strata such as mudstone and carbonaceous mudstone are widely distributed, gas drilling speed is extremely slow, and clear water drilling is prone to shrinkage, leading to drilling accidents; the use of inhibitory mud for pressure maintenance and wall protection can avoid borehole shrinkage, but near-horizontal drilling cannot be pressurized to form a wall protection mud cake, and the technology of mining flushing fluid solid control system is not mature yet, mud preparation and recycling are difficult, and the construction cost is high.

[0004] In summary, due to the inability to use formulated flushing fluid, the flushing fluid currently used has a poor ability to carry drill cuttings, which makes the drill sticking problem more likely to occur during hole collapse. Summary of the invention

[0005] The purpose of the present invention is to provide a pressurized wall protection device for an annular passage of a nearly horizontal borehole in an underground coal mine, so as to solve the problem of hole collapse and drill jamming that are easy to occur during directional drilling construction in underground coal mines in the prior art.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0007] A pressurized wall protection device for an annulus passage of a nearly horizontal borehole in a coal mine, an orifice device; the orifice device comprises a rotary sealer, one end of the rotary sealer is connected to the output end of a mud pump through a water feeder, and the other end of the rotary sealer is connected to the first end of an orifice tee pipe; the input end of the mud pump is connected to the first liquid outlet of a flushing liquid pool; the second end of the orifice tee pipe is connected to a drill pipe, and the third end of the orifice tee pipe is connected to an annulus pressurized device;

[0008] The annulus pressurizing device comprises a first tee; the first end of the first tee is connected to the third end of the orifice tee, the second end of the first tee is connected to one end of the Y-type filter, and the third end of the first tee is connected to one end of the first gate valve;

[0009] The other end of the Y-type filter is connected to one end of the second gate valve, the other end of the second gate valve is connected to one end of the throttle valve, and the other end of the throttle valve is connected to the second liquid outlet of the flushing liquid pool;

[0010] The other end of the first gate valve is connected to one end of the booster pump, and the other end of the booster pump is connected to the liquid inlet of the flushing liquid pool.

[0011] The present invention also has the following features:

[0012] Furthermore, a flushing liquid filter is provided at the second liquid outlet of the flushing liquid pool;

[0013] The other end of the throttle valve is connected to the second liquid outlet through a flushing liquid filter.

[0014] Furthermore, it also includes a controller;

[0015] The first gate valve and the second gate valve are both electric gate valves, and the throttle valve is an electric throttle valve;

[0016] The controller is connected to the first gate valve, the second gate valve, the throttle valve and the booster pump respectively.

[0017] Furthermore, a first flow meter is provided between the throttle valve and the second liquid outlet of the flushing liquid pool;

[0018] The other end of the first gate valve is connected to the first end of the second three-way pipe, the second end of the second three-way pipe is connected to one end of the booster pump, and the other end of the booster pump is connected to the first end of the third three-way pipe;

[0019] The third end of the second three-way pipe is connected to one end of the overflow valve, the other end of the overflow valve is connected to the second end of the third three-way pipe, and the overflow valve is provided with a second pressure sensor;

[0020] The third end of the third three-way pipe is connected to the liquid inlet of the flushing liquid pool, and a second flow meter is arranged between the third end of the third three-way pipe and the liquid inlet of the flushing liquid pool;

[0021] The controller is also connected to the first pressure sensor, the first flow meter, the second pressure sensor and the second flow meter respectively.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] The coal mine underground near-horizontal borehole annulus channel pressurization wall protection device of the present invention is suitable for both clean water drilling and formulated flushing fluid drilling. When using clean water drilling, the hole wall is supported by increasing the annulus pressure to reduce hole wall collapse, and is suitable for use in strata where collapse is not serious.

[0024] When drilling into a broken formation using a formulated impact fluid, on the one hand, the formation pressure is balanced, and on the other hand, in combination with an anti-collapse formulated flushing fluid, an anti-collapse wall protection layer can be formed to further inhibit the collapse of the hole wall; it can promote the use of the formulated flushing fluid and increase the flushing fluid's ability to carry drill cuttings;

[0025] In summary, when drilling into reduced-diameter formations, the annular pressure is controlled so that the formulated flushing fluid is appropriately filtered out and enters a certain range within the hole wall to form a filter cake, which effectively prevents drill sticking and solves the drilling problem in reduced-diameter formations such as mudstone. This method is suitable for large-scale use and promotion in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the pressurized wall protection device for the annular passage of a nearly horizontal borehole in a coal mine underground according to the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the annular space pressurizing device in the present invention;

[0028] Figure 3 It is a schematic diagram of the structure of the orifice device in the present invention.

[0029] The meaning of the symbols in the figure is:

[0030] 1. Orifice device; 2. Rotary sealer; 3. Mud pump; 4. Orifice tee; 5. Flushing liquid pool; 6. Drill pipe; 7. Annulus booster device; 8. First tee; 9. Y-type filter; 10. First gate valve; 11. Second gate valve; 12. Throttle valve; 13. Overflow valve; 14. Booster pump; 15. Flushing liquid filter; 16. Controller; 17. First pressure sensor; 18. First flow meter; 19. Second tee; 20. Second pressure sensor; 21. Third tee; 21. Third tee; 22. Second flow meter. DETAILED DESCRIPTION

[0031] It should be noted that, unless otherwise specified, all components in the present invention are components known in the prior art, such as the rotary sealer, the Y-type filter and the controller.

[0032] All methods in the present invention, unless otherwise specified, all adopt methods known in the prior art, such as the control of the sensor by the controller adopts methods known in the prior art.

[0033] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0034] like Figures 1 to 3As shown, a pressurized wall protection device for an annulus passage of a nearly horizontal borehole in an underground coal mine is characterized in that the orifice device 1 comprises a rotary sealer 2, one end of the rotary sealer 2 is connected to the output end of a mud pump 3 through a water feeder, and the other end is connected to the first end of an orifice tee pipe 4; the input end of the mud pump 3 is connected to the first liquid outlet of a flushing liquid pool 5 through a pipeline; the second end of the orifice tee pipe 4 is connected to a drill pipe 6, and the third end of the orifice tee pipe 4 is connected to an annulus pressurizing device 7;

[0035] The annular space pressurizing device 7 comprises a first tee pipe 8; a first end of the first tee pipe 8 is connected to a third end of the orifice tee pipe 4, a second end of the first tee pipe 8 is connected to one end of a Y-type filter 9, and a third end of the first tee pipe 8 is connected to one end of a first gate valve 10;

[0036] The other end of the Y-type filter 9 is connected to one end of the second gate valve 11, the other end of the second gate valve 11 is connected to one end of the throttle valve 12, and the other end of the throttle valve 12 is connected to the second liquid outlet of the flushing liquid pool 5;

[0037] The other end of the first gate valve 10 is connected to one end of the booster pump 14 , and the other end of the booster pump 14 is connected to the liquid inlet of the flushing liquid pool 5 .

[0038] As a preferred solution, a flushing liquid filter 15 is provided at the second liquid outlet of the flushing liquid pool 5;

[0039] The other end of the throttle valve 12 is connected to the second liquid outlet through the flushing liquid filter 15 .

[0040] As a preferred solution, it also includes a controller 16;

[0041] The first gate valve 10 and the second gate valve 11 are both electric gate valves, and the throttle valve 12 is an electric throttle valve;

[0042] The controller 16 is connected to the first gate valve 10 , the second gate valve 11 , the throttle valve 12 and the boost pump 14 , respectively.

[0043] Further preferably, a first flow meter 18 is provided between the throttle valve 12 and the second liquid outlet of the flushing liquid pool 5;

[0044] The other end of the first gate valve 10 is connected to the first end of the second three-way pipe 19, the second end of the second three-way pipe 19 is connected to one end of the booster pump 14, and the other end of the booster pump 14 is connected to the first end of the third three-way pipe 21;

[0045] The third end of the second three-way pipe 19 is connected to one end of the relief valve 13, and the other end of the relief valve 13 is connected to the second end of the third three-way pipe 21. The relief valve 13 is provided with a second pressure sensor 20;

[0046] The third end of the third three-way pipe 21 is connected to the liquid inlet of the flushing liquid pool 5, and a second flow meter 22 is provided between the third end of the third three-way pipe 21 and the liquid inlet of the flushing liquid pool 5;

[0047] The controller 16 is also connected to the first pressure sensor 17 , the first flow meter 18 , the second pressure sensor 20 , and the second flow meter 22 , respectively.

[0048] The above settings can increase the automation level of the device and can be adjusted according to the real-time detected data, making it more suitable for downhole drilling operations.

[0049] When the mud pump 3 stops during the process of drilling and adding a single drill pipe, the booster pump 14 cooperates with the one-way valve at the bottom of the borehole to draw flushing fluid from the flushing fluid pool and inject flushing fluid into the annular channel to maintain the pressure set by the relief valve 13. The relief valve 13 allows excess flushing fluid to flow back to the flushing fluid pool when the pipeline pressure exceeds the set pressure.

[0050] The control logic of control system 3 is:

[0051] Determine the pressure range of the boost pressure according to the formation pressure and the properties of the formulated mud, and input the pressure value into the control system 3;

[0052] During normal drilling, the control system 3 controls the first gate valve 10 to open and the second gate valve 11 to close. The first pressure sensor 203 feeds back the pressure of the return channel to the control system 3. When the pressure is higher than the upper limit of the set pressure, the control system 3 controls the opening of the throttle valve 12 to increase until the pressure value drops to within the set range; when the pressure is lower than the lower limit of the set pressure, the control system 3 controls the opening of the throttle valve 12 to decrease until the pressure value rises to within the set range.

[0053] During the drilling process, the control system 3 controls the first gate valve 10 to close, the second gate valve 11 to open, and the booster pump 14 to start, so as to draw the flushing fluid from the flushing fluid pool 5 and re-inject it into the annular channel to maintain the middle value of the set pressure range of the annular channel. The control system 3 sets the overflow pressure of the overflow valve 13 to the middle value, and the excess flushing fluid flows back to the flushing fluid pool through the overflow valve 13.

[0054] A specific working process of the device is given below:

[0055] During normal drilling, the mud pump 3 draws the flushing fluid from the flushing fluid pool 5 and injects it into the internal through hole of the drill pipe 6, and the drilling is carried out by driving the bottom hole drilling tool externally;

[0056] At this time, the controller 16 issues a command to open the first gate valve 10 of the annular space booster device 2 and close the second gate valve 11 of the return annular space booster device 2. After the flushing fluid returns from the annular space channel, it enters the annular space booster device 2.

[0057] The throttling pressure range is set by the controller 16:

[0058] If it is set to 0.8~1.2MPa (adjustment range 0-3MPa), the first pressure sensor 17 will feed back the pressure in the pipeline to the controller 16. When the pressure is less than 0.8MPa, the controller 16 will issue a command to reduce the opening of the throttle valve 12. When the pressure is greater than 1.2MPa, the controller 16 will issue a command to increase the opening of the throttle valve 12.

[0059] During the process of drilling and drilling, and adding a single root, the mud pump 8 is in the shut-down state, and the controller 16 issues a command to close the first gate valve 10 of the annular space booster device 2 and open the second gate valve 11 of the annular space booster device 2. The booster pump 14 starts to draw the flushing liquid from the flushing liquid pool 5 to set the pressure. In this embodiment, the set pressure is 1 MPa. After the controller 16 sets the overflow pressure of the overflow valve 13 to 1 MPa, the excess flushing liquid flows back to the flushing liquid pool through the overflow valve 13.

Claims

1. A pressurized wall protection device for a near-horizontal borehole annulus in a coal mine, characterized in that: An orifice device (1); the orifice device (1) comprises a rotary sealer (2), one end of the rotary sealer (2) is connected to the output end of a mud pump (3) through a water feeder, and the other end of the rotary sealer (2) is connected to the first end of an orifice tee pipe (4); the input end of the mud pump (3) is connected to the first liquid outlet of a flushing liquid pool (5); the second end of the orifice tee pipe (4) is connected to a drill pipe (6), and the third end of the orifice tee pipe (4) is connected to an annulus pressurizing device (7); The annular space pressurizing device (7) comprises a first tee (8); the first end of the first tee (8) is connected to the third end of the orifice tee (4), the second end of the first tee (8) is connected to one end of the Y-type filter (9), and the third end of the first tee (8) is connected to one end of the first gate valve (10); The other end of the Y-type filter (9) is connected to one end of the second gate valve (11), the other end of the second gate valve (11) is connected to one end of the throttle valve (12), and the other end of the throttle valve (12) is connected to the second liquid outlet of the flushing liquid pool (5); The other end of the first gate valve (10) is connected to one end of a booster pump (14), and the other end of the booster pump (14) is connected to the liquid inlet of the flushing liquid pool (5).

2. The pressurized wall protection device for the annular passage of a nearly horizontal borehole in an underground coal mine according to claim 1, characterized in that: A flushing liquid filter (15) is provided at the second liquid outlet of the flushing liquid pool (5); The other end of the throttle valve (12) is connected to the second liquid outlet through a flushing liquid filter (15) of the flushing liquid pool (5).

3. The pressurized wall protection device for the annular passage of a nearly horizontal borehole in an underground coal mine as claimed in claim 2, characterized in that: Also includes a controller (16); The first gate valve (10) and the second gate valve (11) are both electric gate valves, and the throttle valve (12) is an electric throttle valve; The controller (16) is connected to the first gate valve (10), the second gate valve (11), the throttle valve (12) and the booster pump (14) respectively.

4. The pressurized wall protection device for the annular passage of a nearly horizontal borehole in an underground coal mine as claimed in claims 1 to 3, characterized in that: A first flow meter (18) is provided between the throttle valve (12) and the second liquid outlet of the flushing liquid pool (5); The other end of the first gate valve (10) is connected to the first end of the second three-way pipe (19), the second end of the second three-way pipe (19) is connected to one end of the booster pump (14), and the other end of the booster pump (14) is connected to the first end of the third three-way pipe (21); The third end of the second three-way pipe (19) is connected to one end of the overflow valve (13), and the other end of the overflow valve (13) is connected to the second end of the third three-way pipe (21), and the overflow valve (13) is provided with a second pressure sensor (20); The third end of the third three-way pipe (21) is connected to the liquid inlet of the flushing liquid pool (5), and a second flow meter (22) is provided between the third end of the third three-way pipe (21) and the liquid inlet of the flushing liquid pool (5); The controller (16) is also connected to the first pressure sensor (17), the first flow meter (18), the second pressure sensor (20) and the second flow meter (22) respectively.

Images