A method for drilling wells based on grouting holes in overburden separation layers of horizontal wells

Abstract

The present application relates to a method for drilling overburden stratum grouting holes based on horizontal wells, which belongs to the field of overburden stratum grouting. It includes data measurement and three-stage drilling. The grouting pipes inserted after the first and second stage drillings are basically located in stable strata where no settlement occurs, reducing the probability of grouting pipe damage due to settlement of gradual rock strata.

Description

Technical Field

[0001] The present application relates to the field of overburden rock separation grouting, and in particular to a method for forming overburden rock separation grouting holes based on horizontal wells. Background Art

[0002] In recent years, with the large-scale exploitation of coal resources, a large number of goafs have been formed. The exploitation of underground coal seams will inevitably cause the settlement and migration of overlying rock strata. The changes in the strata have further developed into negative problems such as water inrush, sand burst, and surface subsidence. Among them, the problem of surface subsidence is particularly obvious, which not only causes the destruction of fertile fields and cultivated land and damage to buildings, but also easily causes environmental problems such as soil erosion and land desertification. At present, for the problem of surface subsidence, delamination grouting and subsidence reduction technology has become a technology of greater concern because it does not affect normal underground mining.

[0003] However, the commonly used construction methods currently have the following problems: the grouting pipe is located directly above the coal mining face and goes deep downward. As the coal mining face advances, the continuous movement of the overlying rock strata on the working face and the formation of shallow delamination cause the shallow casing to break, connecting the delamination space with the shallow aquifer, causing groundwater pollution and loss. Summary of the invention

[0004] In order to improve the above problems, the present application provides a method for drilling overburden separation grouting holes based on horizontal wells.

[0005] The present application provides a method for drilling a well in a horizontal well by grouting a stratum separation overburden, which adopts the following technical solution:

[0006] A method for forming a well by grouting holes in overburden separation layers based on a horizontal well, comprising:

[0007] S1: Data calculation: determine the positions of the soft rock layer and the key layer to be protected, the soft rock layer is located below the key layer, the key layer includes a main key layer and multiple sub-key layers, determine the positions of the main key layer and multiple sub-key layers, the boundary angle influence points of each layer, all boundary angle influence points are connected to form a boundary angle influence surface, determine the boundary of the ground influence zone, and select the ground drilling position, the ground drilling position is located outside the ground influence zone, the main key layer is located above all sub-key layers, and the grouting position is located between the key layer and the soft rock layer;

[0008] S2: First drilling: Drilling vertically downwards on the ground and inserting surface casing, cementing the well to form a vertical well section;

[0009] S3: Secondary drilling: Continue drilling at the bottom of the vertical well section and insert the technical casing, cement the well, and form a deflection section, the lower end of which is inclined close to the grouting position;

[0010] S4: three-hole drilling, drilling at the bottom end of the deflection section and inserting a flower pipe to form a grouting section, the length direction of the grouting section is parallel to the stratum, and the grouting section is located at the grouting position.

[0011] By adopting the above technical solution, the surface casing and the technical casing are basically located in a stable stratum where no settlement occurs, thereby reducing the probability of the grouting pipe being damaged due to the settlement of the gradual rock strata.

[0012] Preferably, the first subcritical layer from bottom to top is the first subcritical layer, the second subcritical layer is the second subcritical layer, and the intersection of the trajectory of the deflection section and the boundary angle influencing surface is located below the second subcritical layer.

[0013] Preferably, a plurality of water filtering holes are provided on the side wall of the flower tube, and a section of the flower tube inserted into the grouting position is fixedly connected with a cone head.

[0014] By adopting the above technical solution, the grouting slurry enters the abscission stratum through the water filter hole, and the diffusion range is more uniform. The presence of the cone head enables the flower pipe to be inserted into the stratum at the grouting position more smoothly.

[0015] Preferably, a float shoe is fixedly connected to the end of the technical casing, and a horn joint is fixedly connected to the end of the flower tube away from the cone head, and a large-diameter end of the horn joint is located on the side away from the flower tube.

[0016] By adopting the above technical solution, the shrinkage structure of the float shoe limits the trumpet joint, and the flower pipe is not easy to slip off the technical casing during grouting.

[0017] Preferably, the tube wall of the flower tube is divided into a spraying area and a non-porous area, all the water filter holes are located in the spraying area, and a guide structure is provided in the technical casing. The guide structure is used to control the circumferential angle of the flower tube after passing through the float shoe. During grouting, the non-porous area is located at the top, and the orifices of the water filter holes are oriented horizontally or vertically downward.

[0018] By adopting the above technical solution, during grouting, the slurry is mainly directed sideways or downwards, with less impact on the upper strata, thereby improving the structural stability of the upper strata.

[0019] Preferably, the guide structure includes a plurality of guide ridges, wherein the guide ridges are fixedly connected to the inner wall of the float shoe, and guide channels or alignment channels are formed between adjacent guide ridges. The trajectory of the guide channel is staggered with the axial direction of the float shoe, and the length direction of the alignment channel is parallel to the axial direction of the float shoe and is located on the upper inner wall of the float shoe. All the guide channels are connected to the alignment channel, and a section of the flower tube close to the cone head is fixedly connected with an alignment protrusion. When the cone head passes through the float shoe, the alignment protrusion enters the alignment channel or guide channel, and a stop-rotation ridge is fixedly connected to the side wall of the flower tube. The stop-rotation ridge is located on the side of the alignment protrusion away from the cone head, and the length direction of the stop-rotation ridge is consistent with the length direction of the flower tube.

[0020] By adopting the above technical solution, the guiding structure corrects the angle of the flower tube so that the opening direction of the water filter hole meets the design requirements.

[0021] Preferably, there is an overlap section between the technical sleeve and the floral tube, the length of the overlap section is 20%-40% of the total length of the floral tube, and a buffer mechanism is provided in the technical sleeve, and the buffer mechanism is used to apply resistance to the floral tube when the horn joint is located in the overlap section and moves close to the float shoe.

[0022] By adopting the above technical solution, the flower tube has a sliding margin relative to the technical sleeve. When the stratum delaminates and moves, a push-pull force will be generated on the flower tube. The flower tube can slide to remove this force, thereby protecting the flower tube structure.

[0023] Preferably, the buffer mechanism includes a stress ring, which is located in the technical sleeve and the two are coaxial. The stress ring and the technical sleeve slide relative to each other, and the sliding direction is consistent with the length direction of the technical sleeve. The sliding stroke range is located in the overlapping section of the technical sleeve. The stress ring abuts against the outer wall of the horn joint. The buffer mechanism also includes a damping member, which is used to apply movement resistance to the stress ring.

[0024] Preferably, the damping member includes a mounting block, a buffer roller and a buffer spring. The inner wall of the overlapping section of the technical sleeve is gradually reduced in radial dimension along the grouting direction. The mounting block is slidably mounted on the force ring, and the sliding direction is the radial direction of the force ring. The buffer roller is rotatably connected to the mounting block, and the wheel surface of the buffer roller abuts against the inner wall of the overlapping section of the technical sleeve. One end of the buffer spring is connected to the force ring, and the other end is connected to the mounting block.

[0025] By adopting the above technical solution, when the force ring moves close to the floating shoe, the buffer roller is continuously squeezed, the buffer spring contracts, the movement resistance of the force ring increases, the grouting pressure generates a propulsion force on the flower pipe through the horn joint, and the buffer mechanism generates a reaction force on the flower pipe through the horn joint. The two work together to improve the stability of the overlap section while ensuring that the flower pipe has enough space to move.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. The main body of the vertical well section and the deflection section is located outside the boundary angle influence surface, and the surface casing and the technical casing are basically located in the stable stratum where no settlement occurs, which reduces the probability of grouting pipe damage caused by the settlement of the gradual rock strata;

[0028] 2. Through the setting of the overlapping section, the flower pipe has a sliding margin relative to the technical casing. When the stratum delamination moves, it will produce a push-pull force on the flower pipe. The flower pipe can slide to remove this force, thereby protecting the flower pipe structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram used to reflect the formation structure and step-by-step drilling trajectory in Example 1 of the present application.

[0030] Figure 2 It is a top view structural schematic diagram used to reflect the drilling position and grouting diffusion in Example 1 of the present application.

[0031] Figure 3 It is a structural schematic diagram used to reflect the overlapping state of the technical sleeve and the flower tube in Example 1 of the present application.

[0032] Figure 4 It is a structural schematic diagram used to reflect the overlapping state of the technical sleeve and the flower tube in the second embodiment of the present application.

[0033] Figure 5 It is a structural schematic diagram used to reflect the guiding structure in the embodiment of the present application.

[0034] Explanation of the reference numerals in the accompanying drawings: 1. soft rock layer; 11. grouting position; 12. boundary angle influencing surface; 13. main key layer; 14. first sub-key layer; 15. second sub-key layer; 2. vertical well section; 21. surface casing; 3. deflection section; 31. technical casing; 32. floating shoe; 33. guide structure; 331. guide edge; 332. guide channel; 333. alignment channel; 34. overlap section; 4. flower pipe; 41. grouting area; 411. water filter hole; 42. horn joint; 43. cone head; 44. alignment protrusion; 45. anti-rotation edge; 46. non-hole area; 5. buffer mechanism; 51. force ring; 52. damping member; 521. mounting block; 522. buffer roller; 523. buffer spring. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1-5 This application is described in further detail.

[0036] Embodiment 1:

[0037] The present application embodiment discloses a method for forming a well by grouting holes in a horizontal well. Figure 1 As shown, the following steps are included in sequence:

[0038] S1: Data calculation: determine the positions of the soft rock layer 1 and the key layer to be protected, the soft rock layer 1 is located below the key layer, the key layer includes a main key layer 13 and multiple sub-key layers, determine the positions of the main key layer 13 and multiple sub-key layers, the boundary angle influence points of each layer, all boundary angle influence points are connected to form a boundary angle influence surface 12, determine the boundary of the ground influence zone, and select the ground drilling position, the ground drilling position is located outside the ground influence zone, the main key layer 13 is located above all sub-key layers, the grouting position 11 is located between the key layer and the soft rock layer 1, the first sub-key layer from bottom to top is the first sub-key layer 14, and the second sub-key layer is the second sub-key layer 15;

[0039] S2: First drilling: Drill vertically downward at the selected drilling position on the ground, use a φ346mm drill bit to drill to 10-20m below the bedrock, and insert the surface casing 21, which is a φ273mm, 8.00mm thick, D20 grade steel pipe, and cement for 48 hours to form a vertical well section 2;

[0040] S3: Secondary drilling: Continue drilling at the bottom of the vertical well section 2, use a φ244.5mm drill bit to drill to the secondary drilling target point according to the designed trajectory, the secondary drilling target point is located at the edge of the grouting position 11, insert the technical casing 31, the technical casing 31 is φ177.8mm, the wall thickness is 8.05mm, and the N80 grade steel pipe is cemented for 72 hours to form the deflection section 3, so that the lower end of the deflection section 3 is inclined close to the grouting position 11, and the intersection of the trajectory of the deflection section 3 and the boundary angle influence surface 12 is located below the second sub-critical layer 15;

[0041] S4: Three holes are drilled at the bottom of the inclined section 3. A φ152mm drill bit is used to drill 50 meters and a flower pipe 4 is inserted to form a grouting section. The flower pipe 4 is a φ114.3mm, 6.35mm thick, N80 grade steel pipe. The length direction of the grouting section is parallel to the local stratum, not horizontal. The grouting section is located at grouting position 11.

[0042] like Figure 1 and 2 As shown, the coal seam depth is H, the mining width at the coal seam is L, the boundary angle is α, and the extension width of the ground influence zone is calculated to be L1=Htanα; there are multiple grouting points, and the spacing between two adjacent vertical well sections 2 is equal to L, and the slurry diffusion radius is r,

[0043] like Figure 3As shown, the side wall of the flower tube 4 is provided with a plurality of water filtering holes 411, and a section of the flower tube 4 inserted into the grouting position 11 is fixedly connected with a cone head 43, and the existence of the cone head 43 enables the flower tube 4 to be inserted into the stratum of the grouting position 11 more smoothly. The end of the technical casing 31 away from the surface casing 21 is fixedly connected with a floating shoe 32, and the end of the flower tube 4 away from the cone head 43 is fixedly connected with a horn joint 42, and the large-diameter end of the horn joint 42 is located on the side away from the flower tube 4; the slurry passes through the surface casing 21, the technical casing 31 in sequence, and then enters the flower tube 4 through the horn joint 42, and finally enters the abscission stratum through the water filtering holes 411.

[0044] Embodiment 2:

[0045] like Figure 4 and 5 As shown, the wall of the flower tube 4 is divided into a grouting area 41 and a non-porous area 46, and all the water filter holes 411 are located in the grouting area 41. In the axial projection of the flower tube 4, the non-porous area 46 and the grouting area 41 are located in different angle intervals. A guide structure 33 is provided in the technical casing 31, and the guide structure 33 is used to control the circumferential angle of the flower tube 4 after passing through the float shoe 32, so that during grouting, the non-porous area 46 is located above the flower tube 4, and the opening of the water filter hole 411 is oriented horizontally or vertically downward. The guide structure 33 includes a plurality of guide ridges 331, and the guide ridges 331 are fixedly connected to the inner wall of the float shoe 32. A positive channel 333 or a plurality of guide channels 332 are formed between adjacent guide ridges 331. The trajectory of the guide channel 332 is staggered with the axial direction of the float shoe 32. The length direction of the positive channel 333 is parallel to the axial direction of the float shoe 32 and is located on the upper inner wall of the float shoe 32. One end of all guide channels 332 along the grouting direction is connected to the positive channel 333. A section of the flower tube 4 close to the cone head 43 is fixedly connected with a positive projection 44. When the cone head 43 passes through the float shoe 32, the positive projection 44 enters the positive channel 333 or selects one to enter the guide channel 332. If it enters the guide channel 332, it can finally enter the positive channel 333 under the abutment of the guide ridges 331, that is, when the positive projection 44 passes through the float shoe 32, the positive projection 44 and the non-porous area 46 are both located on the upper side of the flower tube 4. A stop edge 45 is fixedly connected to the side wall of the flower tube 4. The stop edge 45 is located on the side of the alignment block 44 away from the cone head 43. The length direction of the stop edge 45 is consistent with the length direction of the flower tube 4. When the alignment block 44 moves out of the alignment channel 333, the stop edge 45 enters the alignment channel 333. The guide edges 331 on both sides of the alignment channel 333 form two-side limit stops for the stop edge 45. The flower tube 4 cannot rotate easily, and the positions of the non-porous area 46 and the spraying area 41 can remain relatively stable.

[0046] like Figure 4 and 5As shown, when the floral tube 4 is installed in place, there is an overlap section 34 between the technical sleeve 31 and the floral tube 4, and the length of the overlap section 34 is 20%-40% of the total length of the floral tube 4. Through the overlap section 34, the floral tube 4 has a sliding margin relative to the technical sleeve 31. When the stratum delamination moves, it will generate a push-pull force on the floral tube 4. The floral tube 4 can slide to remove this force, thereby protecting the structure of the floral tube 4. A buffer mechanism 5 is provided in the technical sleeve 31. The buffer mechanism 5 is used to apply resistance to the floral tube 4 when the horn joint 42 is located in the overlap section 34 and moves close to the float shoe 32, thereby ensuring the existence of the overlap section 34 and reducing the probability of direct contact between the horn joint 42 and the float shoe 32.

[0047] like Figure 4 and 5 As shown, the buffer mechanism 5 includes a stress ring 51 and a damping member 52. The stress ring 51 is located in the technical sleeve 31 and the two are coaxial. The stress ring 51 slides relatively to the technical sleeve 31, and the sliding direction is consistent with the length direction of the technical sleeve 31. The sliding stroke range is located in the overlap section 34 of the technical sleeve 31. The inner diameter of the stress ring 51 is smaller than the major diameter of the horn joint 42 and larger than the outer diameter of the flower tube 4. The outer side walls of the stress ring 51 and the horn joint 42 are in contact, and the damping member 52 is used to apply movement resistance to the stress ring 51 moving close to the floating shoe 32. The damping member 52 includes a mounting block 521, a buffer roller 522 and a buffer spring 523. The mounting block 521 is slidably mounted on the stress ring 51, and the sliding direction is the radial direction of the stress ring 51. The buffer roller 522 is rotatably connected to the mounting block 521. The wheel surface of the buffer roller 522 rolls against the inner wall of the overlap section 34 of the technical casing 31. One end of the buffer spring 523 is connected to the stress ring 51, and the other end is connected to the mounting block 521. The inner wall of the overlap section 34 of the technical casing 31 is gradually reduced in radial dimension along the grouting direction. When the stress ring 51 moves close to the floating shoe 32, the buffer roller 522 is continuously squeezed, the buffer spring 523 contracts, and the movement resistance of the stress ring 51 increases. The grouting pressure generates a propulsion force on the flower tube 4 through the horn joint 42, and the buffer mechanism 5 generates a reaction force on the flower tube 4 through the horn joint 42. The two work together to improve the stability of the overlap section 34 while ensuring that the flower tube 4 has a certain amount of moving space.

[0048] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for drilling a well by grouting holes in overburden separation layers based on a horizontal well, characterized in that: Including: S1: Data calculation: determining the positions of the soft rock layer (1) and the key layer to be protected, wherein the soft rock layer (1) is located below the key layer, and the key layer includes a main key layer (13) and a plurality of sub-key layers, determining the positions of the main key layer (13) and the plurality of sub-key layers, and the boundary angle influence points of each layer, and connecting all the boundary angle influence points to form a boundary angle influence surface (12), determining the boundary of the ground influence zone, and selecting the ground drilling position, wherein the ground drilling position is located outside the ground influence zone, the main key layer (13) is located above all the sub-key layers, and the grouting position (11) is located between the key layer and the soft rock layer (1); S2: First drilling: Drilling a hole vertically downward on the ground and inserting a surface casing (21), cementing the well, and forming a vertical well section (2); S3: Secondary drilling: Continue drilling at the bottom of the vertical well section (2) and insert a technical casing (31), cement the well, and form a deflection section (3), wherein the lower end of the deflection section (3) is inclined close to the grouting position (11); S4: Drilling three holes, drilling a hole at the bottom end of the deflection section (3) and inserting a flower pipe (4) to form a grouting section, the length direction of the grouting section is parallel to the stratum, and the grouting section is located at the grouting position (11).

2. A method for drilling a horizontal well by grouting holes in overburden separation layers according to claim 1, characterized in that: The first sub-critical layer from bottom to top is the first sub-critical layer (14), the second sub-critical layer is the second sub-critical layer (15), and the intersection of the trajectory of the deflection section (3) and the boundary angle influence surface (12) is located below the second sub-critical layer (15).

3. A method for drilling a well by grouting holes in overburden separation layers based on a horizontal well according to claim 1 or 2, characterized in that: The side wall of the flower tube (4) is provided with a plurality of water filtering holes (411), and a section of the flower tube (4) inserted into the grouting position (11) is fixedly connected with a cone head (43).

4. A method for drilling a grouting hole in a horizontal well based on overburden separation layer according to claim 3, characterized in that: The end of the technical sleeve (31) is fixedly connected to a float shoe (32), and the end of the flower tube (4) away from the cone head (43) is fixedly connected to a horn joint (42), and the large-diameter end of the horn joint (42) is located on the side away from the flower tube (4).

5. A method for forming a well by grouting holes in overburden separation layers based on a horizontal well according to claim 4, characterized in that: The tube wall of the flower tube (4) is divided into a grouting area (41) and a non-porous area (46), and all the water filter holes (411) are located in the grouting area (41). A guide structure (33) is provided in the technical casing (31), and the guide structure (33) is used to control the circumferential angle of the flower tube (4) after passing through the floating shoe (32). During grouting, the non-porous area (46) is located at the top, and the openings of the water filter holes (411) are oriented horizontally or vertically downward.

6. A method for drilling a well by grouting holes in overburden separation layers based on a horizontal well according to claim 5, characterized in that: The guide structure (33) comprises a plurality of guide ribs (331), wherein the guide ribs (331) are fixedly connected to the inner wall of the float shoe (32), and guide channels (332) or aligning channels (333) are formed between adjacent guide ribs (331). The trajectory of the guide channel (332) is staggered with the axial direction of the float shoe (32), and the length direction of the aligning channel (333) is parallel to the axial direction of the float shoe (32) and is located on the upper inner wall of the float shoe (32). All the guide channels (332) are aligned with the aligning channels (333). (333) is connected, a section of the flower tube (4) close to the cone head (43) is fixedly connected with a positive position protrusion (44), when the cone head (43) passes through the floating shoe (32), the positive position protrusion (44) enters the positive position channel (333) or the guide channel (332), and a stop edge (45) is fixedly connected to the side wall of the flower tube (4), the stop edge (45) is located on the side of the positive position protrusion (44) away from the cone head (43), and the length direction of the stop edge (45) is consistent with the length direction of the flower tube (4).

7. A method for forming a well by grouting holes in overburden separation layers based on a horizontal well according to claim 5, characterized in that: An overlap section (34) is provided between the technical sleeve (31) and the flower tube (4), the length of the overlap section (34) being 20% ​​to 40% of the total length of the flower tube (4), and a buffer mechanism (5) is provided inside the technical sleeve (31), the buffer mechanism (5) being used to apply resistance to the flower tube (4) when the horn joint (42) is located inside the overlap section (34) and moves close to the float shoe (32).

8. A method for drilling a grouting hole in a horizontal well based on overburden separation layer according to claim 7, characterized in that: The buffer mechanism (5) comprises a stress ring (51), the stress ring (51) is located in the technical sleeve (31) and the two are coaxial, the stress ring (51) and the technical sleeve (31) slide relative to each other, the sliding direction is consistent with the length direction of the technical sleeve (31), the sliding stroke range is located in the overlapping section (34) of the technical sleeve (31), the stress ring (51) and the outer side wall of the horn joint (42) are in abutment, and the buffer mechanism (5) also comprises a damping member (52), and the damping member (52) is used to apply movement resistance to the stress ring (51).

9. A method for forming a well by grouting holes in overburden separation layers based on a horizontal well according to claim 8, characterized in that: The damping member (52) comprises a mounting block (521), a buffer roller (522) and a buffer spring (523); the inner wall of the overlapping section (34) of the technical sleeve (31) is gradually reduced in radial dimension along the grouting direction; the mounting block (521) is slidably mounted on the force ring (51), and the sliding direction is the radial direction of the force ring (51); the buffer roller (522) is rotatably connected to the mounting block (521); the wheel surface of the buffer roller (522) abuts against the inner wall of the overlapping section (34) of the technical sleeve (31); one end of the buffer spring (523) is connected to the force ring (51), and the other end is connected to the mounting block (521).

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