Downhole inclined drilling local grouting device and grouting method

Abstract

The present invention discloses a local grouting device and grouting method for an underground inclined borehole. The local grouting device includes an upper joint, a connecting pipe, an external component of a packer, a central pipe body, a piston I, a piston II, a one-way valve, a lower joint, etc., and is provided with a grouting channel, a packing channel, a pressure relief channel, a pressure relief groove, and other channels. The grouting process adopts a two-ball pitching method. The entire process can realize a series of process flows such as cyclic hole washing, cyclic slurry replacement, high-pressure sealing, pressure relief and drainage, high-pressure grouting, and cyclic cleaning. The grouting device and method of the present invention can ensure that a sufficient amount of grouting is injected into the broken area of ​​the inclined borehole in the coal mine, effectively avoid the dilution effect of the cement slurry by clear water in the hole and the drill pipe, greatly improve the grouting effect, and realize reliable local reinforcement of the stratum. In addition, timely cyclic cleaning after grouting can avoid the cement slurry in the drill pipe from solidifying and clogging the drill pipe and causing losses.

Description

Technical Field

[0001] The invention belongs to the field of underground coal mine drilling grouting, and relates to a grouting device and a grouting method for grouting and reinforcing a local broken area of ​​an underground inclined borehole. Background Art

[0002] At present, during the underground drilling construction process in coal mines, various unstable strata such as stratum structures or water collapse are always encountered, which makes it impossible to construct the drilling normally. For this reason, grouting reinforcement is often used to deal with it, including full-hole grouting or local grouting. The whole hole section grouting is to seal the hole mouth directly and inject the grouting material. For deep holes, the whole hole grouting not only consumes a large amount of slurry, but also has a poor slurry diffusion effect due to the long grouting distance, making it difficult to achieve the expected effect. The local grouting is to use a packer to isolate the hole in the hole and then grout the hole section that needs to be treated. For local grouting, when grouting in the downward inclined hole, the clear water accumulated in the hole bottom and drill pipe due to drilling or drilling punching causes the cement slurry to be severely diluted during grouting, affecting the effect. In addition, the broken or cracked conditions in the hole are unknown, and the actual amount of grouting slurry required cannot be guaranteed. The grouting process is only judged based on the pressure. Often, after a small amount of slurry is injected, the pressure begins to build up, resulting in a very small amount of effective slurry entering the formation. Or after the designed volume of slurry is injected and clear water is used to replace the slurry, it is found that the pressure cannot be established, indicating that the grouting amount is insufficient. This conventional local grouting method cannot guarantee or control the actual required slurry volume and cannot achieve the purpose of effective reinforcement. Summary of the Invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a local grouting device and grouting method for downhole inclined drilling, so as to ensure that sufficient grouting volume is injected into the broken area of ​​the downhole inclined hole, greatly improve the local grouting reinforcement effect, and timely circulate and clean to avoid losses caused by cement solidification in the drill pipe.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A downhole local grouting device for inclined drilling comprises an upper joint, a connecting pipe, a packer external component, and a lower joint, which are coaxially arranged in sequence. The central passage of the upper joint, the connecting pipe, and the packer external component is a central flow passage, and a central tube body is provided therein. A piston I is provided in the central passage of the central tube body, and a piston II is provided in the central passage of the piston I and the central passage of the central tube body. The central passage of the piston II is connected to the central flow passage and the central passage of the piston I. A grouting one-way valve is provided between the lower end of the central tube body and the lower joint.

[0006] The upper end of the upper joint can be connected to the drill pipe, and the lower end can be connected to the central pipe body; the upper and lower ends of the outer assembly of the packer are respectively connected to the connecting pipe and the lower joint; the lower end of the lower joint can be connected to the drill bit;

[0007] The central tube body can move axially relative to the connecting tube, and a positioning pin is provided on the connecting tube and cooperates with the positioning step on the outer wall of the central tube body to realize axial positioning; the annular gap between the upper part of the central tube body and the connecting tube and between the upper part of the external component of the packer is the setting seal flow annular gap, and a one-way valve is provided on the side wall of the central tube body. The one-way valve can be connected with the setting seal flow annular gap and the one-way valve is located above piston I and piston II; a grouting channel is provided in the wall of the central tube body, and the two ends of the grouting channel are connected to the central channel of the central tube body through the grouting connecting hole I and the grouting connecting hole II respectively; the inner wall of the central tube body is respectively provided with a piston blocking step I and a piston blocking step II, the piston blocking step I is provided below the piston I and is located between the grouting connecting hole I and the grouting connecting hole II, and the piston blocking step II is provided below the piston II and is located below the grouting connecting hole II;

[0008] The upper ends of the pistons I and II are provided with ball seats to correspond to the steel balls I and II respectively, and a shear pin for axial limitation is provided between the piston II and the central tube body; the side wall of the piston II is provided with a grouting flow hole;

[0009] The external components of the packer include a packer tube, a packer one-way valve and an expansion capsule on the outer wall of the packer tube; the packer one-way valve can connect the setting seal flow annulus gap and the expansion capsule.

[0010] The present invention also includes the following technical features:

[0011] Specifically, the side wall of the piston 1 is provided with a pressure balance channel and a pressure relief hole; the pressure balance channel can connect the central channel of the piston 1 with the space below the piston 1; the piston 1 can block the grouting communication hole 1 and can be pushed to the piston blocking step 1 to open the grouting communication hole 1;

[0012] The steel ball II cooperates with the piston II to block the central flow channel, and the fluid pressure can push the piston II to move axially to cut off the shear pin. After the piston II moves to the piston blocking step II, the grouting flow hole on the side wall of the piston II can connect the grouting connecting hole II with the central flow channel; after the piston II moves to the piston blocking step II, the pressure relief hole of the piston I penetrates the side wall of the central tube body and the side wall of the external component to connect the central channel of the piston I with the outside.

[0013] Specifically, a leakage hole is provided on the side wall of the central tube body, which passes through the side wall of the external component to be connected with the outside, and a leakage plug is provided at the leakage hole; after the piston II moves to the piston blocking step II, the grouting flow hole on the side wall of the piston II can be connected with the leakage hole.

[0014] Specifically, the lower side wall of the packer tube body is provided with an expansion cavity pressure relief hole, and the expansion cavity pressure relief hole is communicated with the expansion capsule.

[0015] Specifically, a pressure relief groove is provided on the outer wall of the lower part of the central tube body. When the central tube moves upward axially relative to the connecting tube, the pressure relief groove can be connected with the pressure relief hole of the expansion chamber, the high-pressure water in the expansion chamber of the expansion capsule is depressurized, and the expansion capsule contracts to realize the unsealing of the packer.

[0016] Specifically, an axial seal is formed between the lower portion of the central tube body and the external components of the packer; and an axial seal is formed between the piston I, the piston II and the central tube body.

[0017] Specifically, the upper end of the upper joint is provided with a female buckle to connect with the drill pipe, and the lower end is provided with a female buckle to be threadedly connected with the upper end of the central pipe body; the upper end of the packer pipe body of the external component of the packer is connected with the connecting pipe through a thread, and the lower end of the packer pipe body is threadedly connected with the lower joint.

[0018] Specifically, a limiting platform is provided on the inner wall of the upper end of the connecting pipe. The limiting platform is located above the positioning step on the outer wall of the central tube body so as to cooperate with the positioning step to achieve axial limitation.

[0019] Specifically, the grouting one-way valve is connected to the lower joint, and a grouting flow channel is provided in the lower joint.

[0020] A method for local grouting using the downhole inclined drilling local grouting device comprises the following steps:

[0021] Step 1: Lower the grouting device and sweep the hole: According to the local grouting design requirements for the downhole inclined drilling, the lower joint is connected to the drill bit, the upper joint is connected to the drill pipe, and then it is lowered to the broken area in the hole. During the drilling process, water is passed through the hole at intervals, and the hole is swept down to the broken area at the bottom of the hole. During the drilling process, the entire central flow channel is in a conductive state. The water in the drill pipe flows through the upper joint, the central flow channel, the top-open grouting one-way valve, the grouting flow channel, and then through the lower joint to enter the bottom of the hole, playing the role of normal drilling and punching and the role of sweeping the hole after reaching the broken zone.

[0022] Step 2: Inject cement slurry and replace slurry: Place the drill bit in the broken hole section to be grouting, connect the grouting pump outlet to the drill pipe through a pipeline, and estimate the amount of cement slurry required for slurry replacement in the hole according to the length of the broken hole section, the hole diameter and the expected grouting length, and 2-4 times. Start the grouting pump and inject cement slurry into the hole along the drill pipe. Replace the clean water at the bottom of the hole with cement slurry to fill the broken hole section with cement slurry. Then lift the drill bit 10-20m away from the hole section to be grouting, and start the pump to inject clean water into the drill pipe. After sufficient circulation to flush the cement slurry in the drill pipe, lower the grouting device to the designed isolation position.

[0023] Step three, packer sealing: throw steel ball II into the hole, steel ball II enters the ball seat of piston II and plays a blocking role. At this time, the fluid can no longer enter the bottom of the hole through the central flow channel, and then pump clean water. The clean water enters the flow annulus of the setting seal through the one-way valve, and then enters the expansion capsule through the one-way valve of the setting seal. The expansion capsule expands to achieve reliable setting. When the pressure continues to be held to 8-10MPa, the piston II is pushed downward to shear the shear pin, and the central channel of the piston I is connected to the pressure relief hole. The high-pressure clean water is depressurized through the pressure relief hole and flows into the annular space channel between the grouting device and the borehole, and then flows out of the hole. Due to the limiting effect of the piston blocking step II, the grouting flow hole and the grouting connecting hole of the piston II are connected, and the grouting flow hole is also connected with the discharge hole.

[0024] Step 4: grouting at the bottom of the hole: connect the grouting pump and the drill pipe, estimate the volume inside the drill pipe according to the length and inner diameter of the drill pipe, and estimate the volume of slurry required for grouting and reinforcement in the hole, throw the steel ball 1 into the hole, and then continue grouting. The slurry pushes the piston 1 to move downward, and the center flow channel of the piston 1 and the pressure relief hole are blocked. The grouting channel is opened, and the cement slurry flows along the grouting channel and the lower center flow channel through the grouting one-way valve and the lower joint into the grouting reinforcement hole section; when the grouting pressure reaches 5-7MPa, the discharge plug is opened due to the pressure of the cement slurry, and the excess cement slurry flows out of the device along the discharge channel at the discharge plug; the injected cement slurry will not be depressurized and reflux after entering the formation due to the action of the grouting one-way valve;

[0025] Step 5: Circulation cleaning: After the cement slurry is injected, the grouting pressure gradually increases. When the grouting pressure reaches 5-7 MPa, the cement slurry pressure will open the discharge plug. At this time, the pressure is released. Due to the presence of the grouting one-way valve, the slurry injected into the bottom of the hole will not flow back. At this time, the pumped cement slurry no longer enters the broken hole section, but enters the annular space between the packer and the borehole along the pressure relief channel. At this time, the mud pump is used to pump clean water to flush the drill pipe. The residual cement slurry in the drill pipe enters the annular space between the packer and the borehole through the pressure relief channel.

[0026] Step 6: Unsealing the packer: When the cement slurry initially sets, pull the drill pipe outward to drive the upper joint and the shear pin of the central tube to move axially upward. The positioning step shears the positioning pin, and the pressure relief hole on the outer component of the packer is connected to the pressure relief groove of the central tube. The expansion capsule is depressurized and shrinks, and the packer is unsealed.

[0027] Step 7: Lift the drill: After the packer is unsealed, pull out all the drill rods in the hole, remove the local packer, and complete the local grouting work.

[0028] Compared with the prior art, the present invention has the following technical effects:

[0029] The present invention aims to address the problems of water accumulation and dilution of clean water in the drill pipe during the current grouting of inclined holes. By replacing the slurry, the volume of the grouting cement slurry injected into the crushing section and the quality of the injected slurry are always guaranteed and controlled throughout the entire process, ensuring that all injected cement slurry is high-quality, greatly improving the grouting effect, and achieving reliable local reinforcement of the formation.

[0030] The present invention can promptly use clean water to circulate and clean the inside of the drill rod after grouting, thereby avoiding the problem that the cement slurry in the drill rod is not cleaned in time and solidifies, thereby causing blockage and loss of the drill rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the local grouting device for the inclined hole in the well.

[0032] Figure 2 It is a schematic diagram of the circulating slurry replacement of the local grouting device.

[0033] Figure 3 Schematic diagram of isolation grouting of local grouting device.

[0034] Figure 4 Flow chart of the isolation grouting process of the underground local grouting device.

[0035] The meaning of each number in the figure is:

[0036] 1-Upper connector; 2-Connecting pipe; 3-Locate pin; 4-Center pipe; 5-Packer external components; 6-Setting annulus gap; 7-Grouting check valve; 8-Lower connector; 9-Drain plug; 10-Piston II; 11-Pressure relief channel; 12-Steel ball II; 13-Piston I; 14-Steel ball I; 15-Drill bit; 16-Drill pipe; 17-Water accumulation in the hole;

[0037] 41 - positioning step; 42 - one-way valve; 43 - grouting channel; 44 - piston blocking step I; 45 - shear pin; 46 - grouting communication hole II; 47 - piston blocking step II; 48 - central flow channel; 49 - pressure relief groove; 410 - discharge hole;

[0038] 51-packer one-way valve; 53-expansion capsule; 54-expansion chamber pressure relief hole;

[0039] 81- grouting flow channel; 101- grouting flow hole; 131- pressure balance channel; 132- pressure relief hole. DETAILED DESCRIPTION

[0040] The present invention provides a local grouting device and a grouting method for an underground inclined borehole. The method can ensure that a sufficient amount of grouting is injected into the broken area of ​​the underground inclined borehole, greatly improving the local grouting reinforcement effect, and timely circulating cleaning to avoid losses caused by cement solidification in the drill pipe.

[0041] 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 modifications made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0042] Example 1:

[0043] like Figure 1 As shown, this embodiment provides a local grouting device for downhole inclined drilling, which is provided with grouting channels, isolation channels, pressure relief channels, flow relief channels, pressure relief grooves and other channels. The grouting process adopts a two-ball method. The entire process can achieve the purpose of a series of process functions such as cyclic hole washing, cyclic slurry replacement, high-pressure setting, pressure relief and drainage, high-pressure grouting, and cyclic cleaning. The local grouting device includes an upper joint 1, a connecting pipe 2, an external assembly of the isolation device 5 and a lower joint 8 arranged coaxially in sequence; the central channel of the upper joint 1, the connecting pipe 2 and the external assembly of the isolation device 5 is a central flow channel 48 and a central tube body 4 is provided therein, a piston I13 is provided in the central channel of the central tube body 4, and a piston II10 is provided in the piston I13 and the central channel of the central tube body 4. The central channel of the piston II10 is connected to the central flow channel 48 and the central channel of the piston I13; a grouting check valve 7 is provided between the lower end of the central tube body 4 and the lower joint 8.

[0044] The upper end of the upper joint 1 can be connected to the drill pipe 16, and the lower end can be connected to the central pipe body 4; the upper and lower ends of the outer component 5 of the packer are respectively connected to the connecting pipe 2 and the lower joint 8; the lower end of the lower joint 8 can be connected to the drill bit 15.

[0045] The central tube body 4 can move axially relative to the connecting pipe 2. The connecting pipe 2 is provided with a positioning pin 3 which cooperates with the positioning step 41 on the outer wall of the central tube body 4 to achieve axial positioning. The annular gap between the upper part of the central tube body 4 and the connecting pipe 2 and between the upper part of the external component 5 of the packer is the sealing annular gap 6. The side wall of the central tube body 4 is provided with a one-way valve 42. The one-way valve 42 can be connected with the sealing annular gap 6 and the one-way valve 42 is located above the piston I13 and the piston II10. A grouting channel 43 is provided in the wall of the central tube body 4. The two ends of the grouting channel 43 are connected to the central channel of the central tube body 4 through the grouting connecting hole I and the grouting connecting hole II46 respectively. The inner wall of the central tube body 4 is provided with a piston blocking step I44 and a piston blocking step II47 respectively. The piston blocking step I44 is provided below the piston I13 and between the grouting connecting hole I and the grouting connecting hole II46. The piston blocking step II47 is provided below the piston II10 and below the grouting connecting hole II46.

[0046] The upper ends of piston I13 and piston II10 are both provided with ball seats to correspond to steel ball I14 and steel ball II12 respectively, and an axially limited shear pin 45 is provided between piston II10 and the central tube body 4; the steel ball II12 cooperates with piston II10 to block the central flow channel 48, and the fluid pressure can further push the piston II10 to move axially to shear off the shear pin 45 and after the piston II10 moves to the piston blocking step II47, the grouting flow hole 101 on the side wall of the piston II10 can connect the grouting connecting hole II46 with the central flow channel 48; the piston I13 can block the grouting connecting hole I and can be pushed to the piston blocking step I44 to open the grouting connecting hole I.

[0047] The external component 5 of the packer includes a packer tube body, a packer one-way valve 51 and an expansion capsule 53 on the outer wall of the packer tube body; the packer one-way valve 51 can connect the setting seal flow annulus gap 6 and the expansion capsule 53, and high-pressure water enters the expansion capsule 53 through the one-way valve 42, the setting seal flow annulus gap 6 and the packer one-way valve 51 in sequence, causing the expansion capsule 53 to expand and deform to achieve the purpose of setting.

[0048] The side wall of piston I13 is provided with a pressure-balancing channel 131 and a pressure relief hole 132; the pressure-balancing channel 131 connects the central channel of piston I13 with the space below piston I13; when steel ball II12 enters the ball seat, water flows through pressure-balancing channel 131 into the lower portion of piston I13, balancing the pressures front and back of piston I13 and preventing axial movement of piston I13. When steel ball I14 enters the ball seat, the fluid pressure pushes piston I13 to move axially. After piston II10 moves to piston blocking step II47, the pressure relief hole 132 of piston I13 penetrates the side wall of central tube body 4 and the pressure relief channel 11 on the side wall of the external component to connect the central channel of piston I13 with the outside.

[0049] A leakage hole 410 is provided on the side wall of the central tube body 4, and the leakage hole 410 passes through the side wall of the external component to be connected with the outside. A leakage plug 9 is provided at the leakage hole 410; after the piston II10 moves to the piston blocking step II47, the grouting flow hole 101 on the side wall of the piston II10 can be connected with the leakage hole 410.

[0050] An expansion cavity pressure relief hole 54 is provided on the lower side wall of the packer tube body, and the expansion cavity pressure relief hole 54 is communicated with the expansion capsule 53 .

[0051] A pressure relief groove 49 is provided on the lower outer wall of the central tube body 4. When the central tube moves axially upward relative to the connecting tube 2, the pressure relief groove 49 can be connected with the pressure relief hole 54 of the expansion chamber, and the high-pressure water in the expansion chamber of the expansion capsule 53 is depressurized, and the expansion capsule 53 contracts to realize the unsealing of the packer.

[0052] The lower part of the central tube body 4 and the outer assembly 5 of the packer are axially sealed; the piston I13, the piston II10 and the central tube body 4 are axially sealed.

[0053] The upper end of the upper joint 1 is provided with a female buckle to connect with the drill pipe 16, and the lower end is provided with a female buckle to be threadedly connected with the upper end of the central pipe body 4; the upper end of the packer pipe body of the packer external component 5 is connected with the connecting pipe 2 through a thread, and the lower end of the packer pipe body is threadedly connected with the lower joint 8.

[0054] A limiting platform is provided on the inner wall of the upper end of the connecting pipe 2 . The limiting platform is located above the positioning step 41 on the outer wall of the central tube body 4 so as to cooperate with the positioning step 41 to achieve axial limitation.

[0055] The grouting one-way valve 7 is connected to the lower joint 8 , and a grouting flow passage 81 is provided in the lower joint 8 .

[0056] Example 2:

[0057] This embodiment provides a method for local grouting using the downhole inclined drilling local grouting device of embodiment 1, such as Figure 2-4 As shown, the following steps are included:

[0058] Step 1: Lower the grouting device and sweep the hole: According to the local grouting design requirements for the downhole inclined drilling, the lower joint is connected to the drill bit, the upper joint is connected to the drill pipe, and then it is lowered to the broken area in the hole. During the drilling process, water is passed through the hole at intervals, and the hole is swept down to the broken area at the bottom of the hole. During the drilling process, the entire central flow channel is in a conductive state. The water in the drill pipe flows through the upper joint, the central flow channel, the top-open grouting one-way valve, the grouting flow channel, and then through the lower joint to enter the bottom of the hole, playing the role of normal drilling and punching and the role of sweeping the hole after reaching the broken zone.

[0059] Step 2: Inject cement slurry and replace slurry: Position the drill bit in the broken hole section to be grouting, connect the grouting pump outlet to the drill pipe through a pipeline, estimate the amount of cement slurry required for slurry replacement in the hole according to the length of the broken hole section, the hole diameter and the expected grouting length, and 2-4 times, start the grouting pump, and inject the prepared cement slurry into the hole along the drill pipe. Replace the clean water at the bottom of the hole with the cement slurry, so that the broken hole section is filled with the prepared cement slurry. Then, lift the drill bit 10-20m away from the hole section to be grouting, and start the pump to inject clean water into the drill pipe. After sufficient circulation to flush the cement slurry in the drill pipe, lower the grouting device to the designed isolation position of the packer;

[0060] Step three, packer sealing: throw steel ball II into the hole, steel ball II enters the ball seat of piston II and plays a blocking role. At this time, the fluid can no longer enter the bottom of the hole through the central flow channel, and then pump clean water. The clean water enters the flow annulus of the setting seal through the one-way valve, and then enters the expansion capsule through the one-way valve of the setting seal. The expansion capsule expands to achieve reliable setting. When the pressure continues to be held to 8-10MPa, the piston II is pushed downward to shear the shear pin, and the central channel of the piston I is connected to the pressure relief hole. The high-pressure clean water is depressurized through the pressure relief hole and flows into the annular space channel between the grouting device and the borehole, and then flows out of the hole. Due to the limiting effect of the piston blocking step II, the grouting flow hole and the grouting connecting hole of the piston II are connected, and the grouting flow hole is also connected with the discharge hole.

[0061] After the grouting is completed, the grouting hole is put into the well and the pressure relief hole is increased, and the pressure relief hole is increased, and the pressure relief hole is increased. When the grouting pressure reaches 5-7 MPa, the grouting pump is connected to the drill pipe, and the volume of the drill pipe is estimated according to the length and inner diameter of the drill pipe, and the volume of slurry required for grouting and reinforcement in the hole is estimated. When the drill pipe is full of cement slurry according to the amount of slurry pumped, the steel ball 1 is thrown into the hole, and then the grouting is continued. The slurry pushes the piston 1 to move downward, and the center flow channel of the piston 1 and the pressure relief hole are blocked. The grouting channel is opened, and the cement slurry flows along the grouting channel and the lower center flow channel through the grouting one-way valve and the lower joint into the grouting reinforcement hole section; when the grouting pressure reaches 5-7 MPa, the discharge plug is opened due to the pressure of the cement slurry, and the excess cement slurry flows out of the device along the discharge channel at the discharge plug; the injected cement slurry will not be depressurized and reflux after entering the formation due to the action of the grouting one-way valve;

[0062] Step 5: Circulation cleaning: After a certain amount of cement slurry is injected, the grouting pressure gradually increases. When the grouting pressure reaches 5-7 MPa, the cement slurry pressure will open the discharge plug. At this time, the pressure is released. Due to the presence of the grouting one-way valve, the slurry injected into the bottom of the hole will not flow back. At this time, the pumped cement slurry no longer enters the broken hole section, but enters the annular space between the packer and the borehole along the pressure relief channel. At this time, the mud pump is used to pump clean water to flush the drill pipe. The residual cement slurry in the drill pipe enters the annular space between the packer and the borehole through the pressure relief channel.

[0063] Step 6: Unsealing the packer: When the cement slurry initially sets, pull the drill pipe outward to drive the upper joint and the shear pin of the central tube body to move axially upward. The positioning step shears the positioning pin, and the plastic hole at the pressure relief hole and the pressure relief channel is also destroyed. The pressure relief hole on the external component of the packer is connected to the pressure relief groove of the central tube body. The high-pressure water in the expansion capsule is depressurized and shrinks, separating from the hole wall, and the packer is unsealed.

[0064] Step 7: Lift the drill: After the packer is unsealed, pull out all the drill rods in the hole, remove the local packer, and complete the local grouting work.

Claims

1. A local grouting device for downhole inclined drilling, characterized in that: The invention comprises an upper joint (1), a connecting pipe (2), an external component of a packer (5) and a lower joint (8) which are coaxially arranged in sequence; the central channel of the upper joint (1), the connecting pipe (2) and the external component of the packer (5) is a central flow channel (48) and a central tube body (4) is provided therein; a piston I (13) is provided in the central channel of the central tube body (4); a piston II (10) is provided in the central channel of the piston I (13) and the central channel of the central tube body (4); the central channel of the piston II (10) is communicated with the central flow channel (48) and the central channel of the piston I (13); a grouting one-way valve (7) is provided between the lower end of the central tube body (4) and the lower joint (8); The upper end of the upper joint (1) can be connected to the drill pipe (16), and the lower end can be connected to the central pipe body (4); the upper and lower ends of the packer external component (5) are connected to the connecting pipe (2) and the lower joint (8) respectively; the lower end of the lower joint (8) can be connected to the drill bit (15); The central tube body (4) can move axially relative to the connecting tube (2). The connecting tube (2) is provided with a positioning pin (3) which cooperates with the positioning step (41) on the outer wall of the central tube body (4) to achieve axial positioning. The annular gap between the upper part of the central tube body (4) and the connecting tube (2) and the upper part of the outer component (5) of the packer is a sealing annular gap (6). The side wall of the central tube body (4) is provided with a one-way valve (42). The one-way valve (42) can be connected to the sealing annular gap (6). A grouting channel is provided in the wall of the central tube body (4). (43), the two ends of the grouting channel (43) are connected to the central channel of the central tube body (4) through the grouting connecting hole I and the grouting connecting hole II (46) respectively; the inner wall of the central tube body (4) is provided with a piston blocking step I (44) and a piston blocking step II (47), the piston blocking step I (44) is provided below the piston I (13) and is located between the grouting connecting hole I and the grouting connecting hole II (46), and the piston blocking step II (47) is provided below the piston II (10) and is located below the grouting connecting hole II (46); The upper ends of the pistons I (13) and II (10) are provided with ball seats to correspond to the steel balls I (14) and II (12), respectively. A shear pin (45) for axial limiting is provided between the piston II (10) and the central tube (4). The side wall of the piston II (10) is provided with a grouting flow hole (101). The packer external component (5) comprises a packer tube body, a packer one-way valve (51) and an expansion capsule (53) on the outer wall of the packer tube body; the packer one-way valve (51) can connect the setting flow annulus gap (6) with the expansion capsule (53).

2. The downhole inclined drilling local grouting device according to claim 1, characterized in that: The side wall of the piston I (13) is provided with a pressure balancing channel (131) and a pressure relief hole (132); the pressure balancing channel (131) can connect the central channel of the piston I (13) with the space below the piston I (13); the piston I (13) can block the grouting communication hole I and can open the grouting communication hole I after being pushed to the piston blocking step I (44); The steel ball II (12) cooperates with the piston II (10) to block the central flow channel (48), and the fluid pressure can push the piston II (10) to move axially to cut the shear pin (45). After the piston II (10) moves to the piston blocking step II (47), the grouting flow hole (101) on the side wall of the piston II (10) can connect the grouting connecting hole II (46) with the central flow channel (48); after the piston II (10) moves to the piston blocking step II (47), the pressure relief hole (132) of the piston I (13) penetrates the side wall of the central tube body (4) and the side wall of the outer assembly (5) of the packer to connect the central channel of the piston I (13) with the outside.

3. The downhole local grouting device for inclined drilling according to claim 2, characterized in that: The side wall of the central tube body (4) is provided with a leakage hole (410), which penetrates the side wall of the outer component (5) of the packer so as to be in communication with the outside, and a leakage plug (9) is provided at the leakage hole (410); after the piston II (10) moves to the piston blocking step II (47), the grouting flow hole (101) on the side wall of the piston II (10) can be in communication with the leakage hole (410).

4. The downhole inclined drilling local grouting device according to claim 3, characterized in that: An expansion cavity pressure relief hole (54) is provided on the lower side wall of the packer tube body, and the expansion cavity pressure relief hole (54) is communicated with the expansion capsule (53).

5. The downhole local grouting device for inclined drilling according to claim 4, characterized in that: A pressure relief groove (49) is provided on the outer wall of the lower portion of the central tube body (4). When the central tube body (4) moves upward axially relative to the connecting tube (2), the pressure relief groove (49) can communicate with the pressure relief hole (54) of the expansion cavity, and the high-pressure water in the expansion cavity of the expansion capsule (53) is depressurized, and the expansion capsule (53) contracts to realize unsealing of the packer.

6. The downhole local grouting device for inclined drilling according to claim 5, characterized in that: An axial seal is formed between the lower portion of the central tube body (4) and the outer assembly (5) of the packer; and an axial seal is formed between the piston I (13), the piston II (10) and the central tube body (4).

7. The downhole local grouting device for inclined drilling according to claim 6, characterized in that: The upper end of the upper joint (1) is provided with a female buckle for connecting to the drill pipe (16), and the lower end is provided with a female buckle for threaded connection to the upper end of the central pipe body (4); the upper end of the packer pipe body of the packer external component (5) is connected to the connecting pipe (2) through a thread, and the lower end of the packer pipe body is threadedly connected to the lower joint (8).

8. The downhole local grouting device for inclined drilling according to claim 7, characterized in that: A limiting platform is provided on the inner wall of the upper end of the connecting pipe (2). The limiting platform is located above the positioning step (41) on the outer wall of the central tube body (4) so ​​as to cooperate with the positioning step (41) to achieve axial limiting.

9. The downhole local grouting device for inclined drilling according to claim 8, characterized in that: The grouting one-way valve (7) is connected to the lower joint (8), and a grouting flow passage (81) is provided in the lower joint (8).

10. A method for local grouting using the downhole inclined drilling local grouting device according to claim 9, characterized in that: The following steps are involved: Step 1: Lower the grouting device and sweep the hole: According to the local grouting design requirements for the downhole inclined drilling, the lower joint is connected to the drill bit, the upper joint is connected to the drill pipe, and then it is lowered to the broken area in the hole. During the drilling process, water is passed through the hole at intervals, and the hole is swept down to the broken area at the bottom of the hole. During the drilling process, the entire central flow channel is in a conductive state. The water in the drill pipe flows through the upper joint, the central flow channel, the top-open grouting one-way valve, the grouting flow channel, and then through the lower joint to enter the bottom of the hole, playing the role of normal drilling and punching and the role of sweeping the hole after reaching the broken zone. Step 2: Inject cement slurry and replace slurry: Place the drill bit in the broken hole section to be grouting, connect the grouting pump outlet to the drill pipe through a pipeline, and estimate the amount of cement slurry required for slurry replacement in the hole according to the length of the broken hole section, the hole diameter and the expected grouting length, and 2-4 times. Start the grouting pump and inject cement slurry into the hole along the drill pipe. Replace the clean water at the bottom of the hole with cement slurry to fill the broken hole section with cement slurry. Then lift the drill bit 10-20m away from the hole section to be grouting, and start the pump to inject clean water into the drill pipe. After sufficient circulation to flush the cement slurry in the drill pipe, lower the grouting device to the designed isolation position. Step three, packer sealing: throw steel ball II into the hole, steel ball II enters the ball seat of piston II and plays a blocking role. At this time, the fluid can no longer enter the bottom of the hole through the central flow channel, and then pump clean water. The clean water enters the sealing flow annulus through the one-way valve and then enters the expansion capsule through the packer one-way valve. The expansion capsule expands to achieve reliable sealing. When the pressure continues to be held to 8-10MPa, push piston II downward to shear the shear pin, and the central channel of piston I is connected to the pressure relief hole. High-pressure clean water is depressurized through the pressure relief hole and flows into the annular channel between the grouting device and the borehole, and then flows out of the hole. Due to the limiting effect of piston blocking step II, piston II's grouting flow hole and grouting connecting hole II are connected, and the grouting flow hole is also connected to the discharge hole. Step 4: grouting at the bottom of the hole: connect the grouting pump and the drill pipe, estimate the volume inside the drill pipe according to the length and inner diameter of the drill pipe, and estimate the volume of slurry required for grouting and reinforcement in the hole, throw the steel ball 1 into the hole, and then continue grouting. The slurry pushes the piston 1 to move downward, and the center flow channel of the piston 1 and the pressure relief hole are blocked. The grouting channel is opened, and the cement slurry flows along the grouting channel and the lower center flow channel through the grouting one-way valve and the lower joint into the grouting reinforcement hole section; when the grouting pressure reaches 5-7MPa, the discharge plug is opened due to the pressure of the cement slurry, and the excess cement slurry flows out of the device along the discharge channel at the discharge plug; the injected cement slurry will not be depressurized and reflux after entering the formation due to the action of the grouting one-way valve; Step 5: Circulation cleaning: After the cement slurry is injected, the grouting pressure gradually increases. When the grouting pressure reaches 5-7 MPa, the cement slurry pressure will open the discharge plug. At this time, the pressure is released. Due to the presence of the grouting one-way valve, the slurry injected into the bottom of the hole will not flow back. At this time, the pumped cement slurry no longer enters the broken hole section, but enters the annular space between the packer and the borehole along the pressure relief channel. At this time, the mud pump is used to pump clean water to flush the drill pipe. The residual cement slurry in the drill pipe enters the annular space between the packer and the borehole through the pressure relief channel. Step 6: Unsealing the packer: When the cement slurry initially sets, pull the drill pipe outward to drive the upper joint and the central tube, causing the shear pin to move axially upward. The positioning step shears the positioning pin, and the pressure relief hole on the outer component of the packer is connected to the pressure relief groove of the central tube. The expansion capsule is depressurized and shrinks, and the packer is unsealed. Step 7: Lift the drill: After the packer is unsealed, pull out all the drill rods in the hole, remove the local packer, and complete the local grouting work.

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