Back reaming tool for coal bed gas

Abstract

The invention belongs to the technical field of drilling machinery, and relates to a back reaming tool for coal bed gas, which comprises an outer square sleeve, an inner square sleeve and a drill rod clamping mechanism, the outer square sleeve is of a square cylindrical structure and is formed by buckling two half outer square sleeves; the inner square sleeve is of a square cylindrical structure and is formed by buckling two half inner square sleeves, and the inner square sleeve is arranged in the outer square sleeve in a sliding mode. The drill rod clamping mechanism is detachably installed at the top end of the inner square sleeve and used for clamping and fixing a drill rod. The outer square sleeve and the inner square sleeve of the back reaming tool are both of a split structure, are convenient and rapid to install at a wellhead, can be rapidly installed and used without lifting and lowering, can avoid drill jamming accidents caused by lifting and lowering of a drilling tool when the back reaming tool is installed, and are not influenced by hanging load of the drilling tool and height of a drilling rod at the wellhead; the inner square sleeve can slide in the outer square sleeve in the vertical direction relative to the outer square sleeve, so that the inner square sleeve has a certain length of movement range, the drilling tool can be lifted and put down while being moved, and back reaming operation is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling machinery and relates to a back-marking tool for coal bed methane. Background Art

[0002] With the continuous increase in the number of wells drilled by the company recently, the coal seams encountered in the drilling process are becoming more and more complex, and there are more and more drilling complexities such as drill bit sticking. In the process of rotary table driven drilling, when the drill bit is stuck, the conventional technology uses slips to back-ream to unblock the stuck hole, but the slip back-ream technology has the following defects:

[0003] (1) When the weight of the slip is small, it is easy to slip, and when the weight is large, it is easy to lift the drilling tool;

[0004] (2) When the rotary table power is transmitted by slips to rotate the drilling tool, the change of the suspended weight cannot be seen, and it is difficult to distinguish the underground situation;

[0005] (3) When reaching the drill pipe joint, it is difficult to install the slips and it is difficult to use the slips to ream the holes;

[0006] (4) The risk of slips reversing and drilling is high: when installing slips, lifting and lowering the drill bit can easily cause the drill to get stuck; reversing the turntable can cause the slips to fly out of the turntable and injure people. Summary of the invention

[0007] The purpose of the present invention is to provide a back-marking tool for coalbed methane to solve the problems raised in the above-mentioned background technology.

[0008] The present invention is achieved through the following technical solutions:

[0009] A back-marking tool for coalbed methane, comprising an outer square sleeve, an inner square sleeve and a drill rod clamping mechanism;

[0010] The outer square sleeve is a square cylindrical structure, which is formed by buckling two half pieces of outer square sleeves. The outer square sleeve can sit stably in the square bushing of the turntable and can rotate with the turntable.

[0011] The inner square sleeve is a square cylindrical structure, which is formed by buckling two half-piece inner square sleeves. The inner square sleeve is slidably arranged inside the outer square sleeve. The inner square sleeve can slide in the vertical direction inside the outer square sleeve. When the outer square sleeve rotates with the turntable, it can drive the inner square sleeve to rotate to transmit torque. When installed at the wellhead, the two half-piece inner square sleeves can be respectively attached to the inner side walls of the two half-piece outer square sleeves, and can be buckled with the two half-piece outer square sleeves and sleeved on the wellhead drill pipe body. The buckled outer square sleeve can clamp and straighten the inner square sleeve. The inner square sleeve can slide in the vertical direction inside the outer square sleeve. When the outer square sleeve rotates with the turntable, it can drive the inner square sleeve to rotate. The buckling method of two pieces is convenient for installation at the wellhead and quick disassembly and assembly.

[0012] The drill rod clamping mechanism is detachably mounted on the top of the inner square sleeve and is used to clamp and fix the drill rod;

[0013] The outer square sleeve and the inner square sleeve of the back-sliding eye tool are both split structures, which are convenient and quick to install at the wellhead. They can be quickly installed and used without lifting and lowering, and can avoid drill sticking accidents caused by lifting and lowering the drill tool when installing the back-sliding eye tool. They are not affected by the hanging weight of the drill tool and the height of the drill pipe at the wellhead. When lifting and lowering the drill tool, the inner square sleeve can slide in the outer square sleeve relative to the outer square sleeve in the vertical direction, so that it has a certain range of movement, and the drill tool can be lifted and lowered while moving the drill tool to achieve the back-sliding eye operation.

[0014] According to further definition, the right side walls of the two half-piece outer square sleeves are hinged by setting a hinge link, the left side outer walls of the two half-piece outer square sleeves are welded with fixing hole seats, and the fixing hole seats on the two half-piece outer square sleeves are connected by bolts; when the outer square sleeve is installed at the wellhead, the two half-piece outer square sleeves can be opened and stuck outside the wellhead drill pipe body, and after the half-piece outer square sleeves are buckled, the outer square sleeves can sit stably in the turntable square bushing, which is convenient for disassembly and assembly.

[0015] According to further definition, a support plate is provided at the inner bottom of each half-piece outer square sleeve. When the half-piece inner square sleeve is attached to the inner wall of the half-piece outer square sleeve, its bottom end is placed on the support plate. The support plate can support the half-piece inner square sleeve. A semicircular groove is provided on the inner wall of each support plate. When the two half-piece outer square sleeves are buckled together, the two semicircular grooves enclose a circular hole to allow the drill rod to move.

[0016] According to further limitations, a hook is welded on the outer side wall of each half-piece of the outer square sleeve, and the outer square sleeve can be lifted to the drill pipe position at the wellhead by hooking the hook with the help of a small winch on the drilling platform. When lifting the outer square sleeve, the two half-pieces of the inner square sleeve are respectively attached to the inner side walls of the two half-pieces of the outer square sleeve, and can be lifted together with the outer square sleeve.

[0017] According to further definition, steps are provided at the buckling edges between the two half-pieces of the inner square sleeves, so that the buckling edges between the two half-pieces of the inner square sleeves are overlapped concavely and convexly, and the concave and convex overlapping parts are fastened by installing multiple bolts at intervals in the vertical direction. This structure can strengthen the transmission of the torque of the turntable by the inner square sleeve, and ensure that the body of the inner square sleeve does not deform when the torque is transmitted. While transmitting the torque, under the action of the drilling rig lifting system, the inner square sleeve is lifted and lowered synchronously with the drilling tool, and the inner square sleeve can slide up and down along the inner wall of the outer square sleeve relative to the outer square sleeve to perform back-marking.

[0018] According to further limitations, a lifting ring is welded on the outer side wall of each half-piece inner square sleeve. After the outer square sleeve and the inner square sleeve are buckled together at the wellhead turntable, the outer square sleeve sits in the turntable square bushing, and the two half-piece inner square sleeves can be lifted by hooking the lifting ring with the help of a small winch on the drilling platform, so that screws can be installed and locked at the concave and convex overlapping parts of the two half-piece inner square sleeves. After the inner square sleeve is lowered, bolts are installed and locked between the fixing hole seats on the two half-piece outer square sleeves; the two half-piece inner square sleeves and the two half-piece outer square sleeves of the back-marking tool are locked and connected, so it is not easy for components to fly off during the back-marking operation, and the safety performance is high.

[0019] According to further definition, the top inner wall of each half-piece outer square sleeve is provided with a limiting flange, and the bottom outer wall of each half-piece inner square sleeve is provided with a limiting boss. The inner wall of the limiting flange is in gap contact with the outer wall of the half-piece inner square sleeve, and the outer wall of the limiting boss is in gap contact with the inner wall of the half-piece outer square sleeve. After the two half-piece outer square sleeves and the two half-piece inner square sleeves are buckled together, the outer square sleeve can clamp and straighten the inner square sleeve, thereby achieving the unification of the internal and external torque bearing capacity and improving the torque transmission effect. When the inner square sleeve is lifted, the inner square sleeve can be prevented from detaching from the top of the outer square sleeve under the limiting action of the limiting flange.

[0020] Further definition, the drill rod holding mechanism includes two cava seats, the rear ends of the two cava seats are hinged, and the front ends of the two cava seats are connected by locking bolts. The inner side wall of each cava seat is provided with an installation groove, and a pressure plate seat for clamping and fixing the drill rod is installed in the installation groove. After removing the locking bolts and opening the two cava seats, they can be clamped outside the drill rod at the wellhead. After the two cava seats are fastened, the two pressure plate seats clamp the drill rod, and after installing the locking bolts and locking, the drill rod can be clamped and fixed; a clamping plate is fixed to the bottom end of each cava seat, and a clamping groove is provided on the outer side wall of the top end of each half-piece inner square sleeve. When the two cava seats are fastened, the two clamping plates are clamped in the clamping groove to fix the drill rod holding mechanism to the top end of the inner square sleeve, which can facilitate the disassembly and assembly of the drill rod holding mechanism, and the torque is transmitted through the two clamping plates so that the drill rod holding mechanism can rotate with the inner square sleeve to move the drilling tool.

[0021] According to further limitations, a pin extending in the vertical direction is installed at the front end of one of the cava seats, one end of the locking bolt is mounted on the pin, the locking bolt can rotate around the pin, the other end of the locking bolt is threadedly connected with a locking nut, and the front ends of the two cava seats are provided with U-shaped grooves for the locking bolts to be inserted into. When the two cava seats are buckled together, the locking nuts are inserted into the U-shaped grooves and locked. The locking nuts can lock and connect the front ends of the two cava seats to prevent the two cava seats from opening.

[0022] According to further limitations, the mounting groove on the inner wall of the cava seat is a square groove, and each pressure plate seat is a square block structure. The cava seat and the pressure plate seat are fastened by bolts, and the inner wall of each pressure plate seat is provided with a semicircular jaw, and the inner wall of the semicircular jaw is provided with jaw teeth. When the two cava seats are buckled, the two semicircular jaws are combined to form a circular jaw to clamp and fix the drill rod; the mounting structure between the pressure plate seat and the cava seat can disassemble and assemble the pressure plate seat, improve the stability of the pressure plate seat, prevent the pressure plate seat from falling off, enhance the torque transmission effect between the pressure plate seat and the cava seat, and avoid slipping.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The outer square sleeve, inner square sleeve and drill pipe clamping mechanism of the back-sliding eye tool are all split structures, which are convenient and quick to install at the wellhead. They can be quickly installed and used without lifting and lowering, which can avoid the accident of drilling tools being stuck by lifting and lowering when installing the back-sliding eye tool, and are not affected by the hanging weight of drilling tools and the height of the drill pipe at the wellhead. After installation, the turntable can be quickly started to rotate the drilling tools with the help of the rotating table linkage power, and the drilling tools can be lifted and lowered while the movable turntable is rotated. The inner square sleeve can slide in the outer square sleeve relative to the outer square sleeve in the vertical direction, so that it has a certain length of range of movement.

[0025] 2. The drill pipe clamping mechanism of the back-reaming tool is easy to loosen, and the drill tool can be lifted and lowered at will after the locking nut is loosened. The back-reaming tool meets the requirements of the explosive loosening process, and the changes in the suspended weight can be observed at any time, and the active drill tool can send the reverse torque to the loosening well depth;

[0026] 3. The inner square sleeve of the back-ream tool can be lifted and lowered in the vertical direction inside the outer square sleeve, which increases its effective working length. When installed and used, it is not affected by the drill pipe joint at the wellhead. It can be used in the position where the drilling tool encounters obstacles in the well, easily avoiding the connection and confinement of the drilling tool joint. When the current obstacle is safely removed, the drilling tool can be lifted and lowered while the turntable is moved;

[0027] 4. When the back-marking tool is used to release stuck drill bits, it can be quickly installed and used without lifting or lowering when the downhole drill bits are blocked. It can remove the risk of stuck drill bits within an effective range. When the drill bits in the well are stuck, using the slips to release the stuck bits is prone to slipping, and the turntable can reverse the slips and fly out of the turntable to injure people. However, the various components of the back-marking tool are connected and locked, and are not easy to fly off. It has high safety performance and can completely use the power of the turntable to resolve the risk of downhole drill bits being blocked, thereby ensuring the safety of the well crew and the equipment and property. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0029] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0030] Figure 2 It is a schematic diagram of the main structure of the present invention;

[0031] Figure 3 It is a schematic diagram of the top view of the structure of the present invention;

[0032] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure in the AA direction;

[0033] Figure 5 for Figure 3 Schematic diagram of the cross-sectional structure in the middle BB direction;

[0034] Figure 6 It is a schematic diagram of the explosion structure of the present invention;

[0035] Figure 7 It is a schematic diagram of the installation structure of the outer sleeve and the inner sleeve in the present invention.

[0036] The names of the components in the figure are: 1. External square sleeve; 1.1. Half external square sleeve; 1.2. Limit flange; 1.3. Support plate; 2. Internal square sleeve; 2.1. Half internal square sleeve; 2.2. Limit boss; 2.3. First connecting hole; 2.4. Slot; 3. Drill rod holding mechanism; 3.1. Slip seat; 3.2. Pressure plate seat; 3.3. Captive nut; 3.4. Captive bolt; 3.5. Card plate; 3.6. Pin; 3.7. Second connecting hole; 4. Slot hole; 5. Lifting ring; 6. Hook; 7. Hinge link; 8. Fixing hole seat. DETAILED DESCRIPTION

[0037] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0038] In the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inside", "outside", "front", "back", "left", "right", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0039] A back-marking tool for coalbed methane, such as Figure 1 and Figure 2 As shown, it is mainly composed of an outer square sleeve 1, an inner square sleeve 2 and a drill rod clamping mechanism 3.

[0040] like Figure 1 and Figure 6 As shown, the outer square sleeve 1 is a square cylindrical structure, which is formed by buckling two half-piece outer square sleeves 1.1. The right side walls of the two half-piece outer square sleeves 1.1 are hinged by setting a hinge link 7. The left side outer walls of the two half-piece outer square sleeves 1.1 are welded with fixing holes 8. The fixing holes 8 on the two half-piece outer square sleeves 1.1 are connected by bolts. When the outer square sleeve 1 is installed at the wellhead, the two half-piece outer square sleeves 1.1 can be opened and stuck outside the wellhead drill pipe body. After buckling the half-piece outer square sleeve 1.1, the outer square sleeve 1 can be stably seated in the turntable square bushing, which is convenient for disassembly and assembly, and the outer square sleeve 1 can rotate with the turntable.

[0041] Specifically, Figure 1 , Figure 2 , Figure 5 , Figure 6 As shown, two hinge links 7 are provided and spaced apart in the vertical direction, which can ensure the stability between the two half-piece outer square sleeves 1.1. Each hinge link 7 is composed of four stacked iron plates and pins installed between the four iron plates, two of which are welded to the right outer wall of one half-piece outer square sleeve 1.1, and the other two are welded to the right outer wall of the other half-piece outer square sleeve 1.1; two fixing holes 8 are welded to the left outer wall of each half-piece outer square sleeve 1.1, which can improve the locking strength between the two half-piece outer square sleeves 1.1, and the bolts are high-strength bolts.

[0042] like Figure 1 and Figure 6 As shown, the inner square sleeve 2 is a square cylindrical structure, which is formed by buckling two half-piece inner square sleeves 2.1. The inner square sleeve 2 is slidably arranged inside the outer square sleeve 1. The inner square sleeve 2 can slide in the vertical direction inside the outer square sleeve 1. When the outer square sleeve 1 rotates with the turntable, it can drive the inner square sleeve 2 to rotate to transmit torque;

[0043] When installing at the wellhead, the two half-pieces of the inner square sleeve 2.1 can be respectively attached to the inner side walls of the two half-pieces of the outer square sleeve 1.1, and can be put on the outside of the wellhead drill pipe body after being buckled with the two half-pieces of the outer square sleeve 1.1. The buckled outer square sleeve 1 can clamp and straighten the inner square sleeve 2, and the inner square sleeve 2 can slide in the vertical direction inside the outer square sleeve 1. When the outer square sleeve 1 rotates with the turntable, it can drive the inner square sleeve 2 to rotate. The buckled method of the two pieces is convenient for installation at the wellhead and quick disassembly and assembly.

[0044] like Figure 4 and Figure 5 As shown, the inner bottom of each half-piece outer square sleeve 1.1 is integrally formed with a support plate 1.3. When the half-piece inner square sleeve 2.1 is attached to the inner side wall of the half-piece outer square sleeve 1.1, its bottom end is placed on the support plate 1.3. The support plate 1.3 can support the half-piece inner square sleeve 2.1. The inner side wall of each support plate 1.3 is provided with a semicircular groove. When the two half-piece outer square sleeves 1.1 are buckled together, the two semicircular grooves enclose a circular hole to allow the drill rod to move.

[0045] like Figure 1 and Figure 7 As shown, the outer side wall of each half piece of the outer square sleeve 1.1 is welded with a hook 6, and the outer square sleeve 1 can be lifted to the wellhead drill pipe position by hooking the hook 6 with the help of the drilling platform small winch. When lifting the outer square sleeve 1, the two half pieces of the inner square sleeve 2.1 are respectively attached to the inner side walls of the two half pieces of the outer square sleeve 1.1, and can be lifted together with the outer square sleeve 1;

[0046] like Figures 4 to 7 As shown, steps are provided at the buckling edges between the two half-piece inner square sleeves 2.1, so that the buckling edges between the two half-piece inner square sleeves 2.1 are overlapped concavely and convexly, and the concave-convex overlap portion is locked by installing a plurality of bolts at intervals in the vertical direction. Specifically, a plurality of first linking holes 2.3 distributed at intervals in the vertical direction are provided at the concave-convex overlap portion of each half-piece inner square sleeve 2.1, and the bolts are hexagonal bolts. The first linking holes 2.3 on the outer side of the concave-convex overlap portion of the two half-piece inner square sleeves 2.1 are countersunk holes to accommodate the bolt heads, and the first linking holes 2.3 on the inner side are threaded holes connected with the bolts by threads; this structure can strengthen the transmission of the torque of the turntable by the inner square sleeve 2, and ensure that the body of the inner square sleeve 2 does not deform when transmitting the torque. While transmitting the torque, under the action of the drilling rig lifting system, the inner square sleeve 2 is lifted and lowered synchronously with the drilling tool, and the inner square sleeve 2 can slide up and down along the inner wall of the outer square sleeve 1 relative to the outer square sleeve 1 to perform back-marking;

[0047] like Figure 1 and Figure 4As shown, each half-piece inner square sleeve 2.1 is welded with a lifting ring 5 on the outer side wall. After the outer square sleeve 1 and the inner square sleeve 2 are buckled at the wellhead rotary table, the outer square sleeve 1 sits in the rotary table square bushing, and the two half-piece inner square sleeves 2.1 can be lifted by hooking the lifting ring 5 with the help of the drilling platform small winch, so that screws are installed and locked at the concave and convex overlapping parts of the two half-piece inner square sleeves 2.1. After the inner square sleeve 2 is lowered, bolts are installed and locked between the fixing hole seats 8 on the two half-piece outer square sleeves 1.1; the two half-piece inner square sleeves 2.1 and the two half-piece outer square sleeves 1.1 of the back-marking tool are locked and connected, and it is not easy to throw away parts during the back-marking operation, and the safety performance is high;

[0048] like Figure 4 and Figure 5 As shown, the top inner wall of each half-piece outer square sleeve 1.1 is provided with a limiting flange 1.2, and the bottom outer wall of each half-piece inner square sleeve 2.1 is provided with a limiting boss 2.2. The inner wall of the limiting flange 1.2 is in gap contact with the outer wall of the half-piece inner square sleeve 2.1, and the outer wall of the limiting boss 2.2 is in gap contact with the inner wall of the half-piece outer square sleeve 1.1; after the two half-piece outer square sleeves 1.1 and the two half-piece inner square sleeves 2.1 are buckled together, the outer square sleeve 1 can clamp and straighten the inner square sleeve 2, thereby achieving the unification of the internal and external torque bearing capacity and improving the torque transmission effect. When the inner square sleeve 2 is lifted, the inner square sleeve 2 can be prevented from detaching from the top of the outer square sleeve 1 under the limiting action of the limiting flange 1.2.

[0049] like Figures 1 to 5 As shown, the drill rod clamping mechanism 3 can be detachably mounted on the top of the inner square sleeve 2 for clamping and fixing the drill rod, and comprises two slip seats 3.1, the rear ends of the two slip seats 3.1 are hinged, and the front ends of the two slip seats 3.1 are clamped and connected by locking bolts 3.4. The inner side wall of each slip seat 3.1 is provided with a mounting groove, and a pressure plate seat 3.2 for clamping and fixing the drill rod is installed in the mounting groove. After removing the locking bolts 3.4 and opening the two slip seats 3.1, they can be clamped outside the wellhead drill rod. After buckling the two slip seats 3.1, the two The pressure plate seat 3.2 clamps the drill rod, and after the locking bolt 3.4 is installed and locked, the drill rod can be clamped and fixed; a clamping plate 3.5 is fixed to the bottom end of each slip seat 3.1, and a clamping groove 2.4 is opened on the outer wall of the top end of each half inner square sleeve 2.1. When the two slip seats 3.1 are buckled, the two clamping plates 3.5 are clamped in the clamping groove 2.4 to fix the drill rod clamping mechanism 3 to the top end of the inner square sleeve 2, which can facilitate the disassembly and assembly of the drill rod clamping mechanism 3, and the torque is transmitted through the two clamping plates 3.5, so that the drill rod clamping mechanism 3 can rotate with the inner square sleeve 2 to move the drilling tool;

[0050] like Figure 1 and Figure 2As shown, a pin shaft 3.6 extending in the vertical direction is installed at the front end of one of the slip seats 3.1, one end of the locking bolt 3.4 is sleeved on the pin shaft 3.6, the locking bolt 3.4 can rotate around the pin shaft 3.6, and the other end of the locking bolt 3.4 is threadedly connected with a locking nut 3.3. The front ends of the two slip seats 3.1 are provided with U-shaped grooves for the locking bolts 3.4 to be inserted into. When the two slip seats 3.1 are buckled together, the locking nut 3.3 is inserted into the U-shaped groove and the locking nut 3.3 is locked to lock the front ends of the two slip seats 3.1 and prevent the two slip seats 3.1 from opening;

[0051] like Figures 1 to 5 As shown, the installation groove of the inner side wall of the slip seat 3.1 is a square groove, and each pressure plate seat 3.2 is a square block structure. The slip seat 3.1 and the pressure plate seat 3.2 are locked by bolts. Specifically, the slip seat 3.1 and the pressure plate seat 3.2 are provided with a second connecting hole 3.7 for installing bolts, and the inner side wall of each pressure plate seat 3.2 is provided with a semicircular jaw, and the inner side wall of the semicircular jaw is provided with jaw teeth. When the two slip seats 3.1 are buckled, the two semicircular jaws are combined to form a circular jaw to clamp and fix the drill rod; the installation structure between the pressure plate seat 3.2 and the slip seat 3.1 can disassemble and assemble the pressure plate seat 3.2, improve the stability of the pressure plate seat 3.2, prevent the pressure plate seat 3.2 from falling off, and enhance the torque transmission effect between the pressure plate seat 3.2 and the slip seat 3.1 to avoid slipping;

[0052] like Figure 1 As shown, each slip seat 3.1 is provided with a slot 4, so that a handle for easy operation is formed on the slip seat 3.1.

[0053] The outer half square sleeve 1.1 and the inner half square sleeve 2.1 are both made of carbon steel or cast iron.

[0054] The working principle of the back reaming tool is:

[0055] During the back-marking operation, remove the bolts between the fixing holes 8 on the outer square sleeve 1, and stand the two halves of the outer square sleeve 1.1 apart until the opening is greater than 45°;

[0056] Remove the bolts at the concave-convex overlapped parts of the two half inner square sleeves 2.1 on the inner square sleeve 2, and install the two half inner square sleeves 2.1 into the inner sides of the two half outer square sleeves 1.1 respectively, so that the support plate 1.3 can support the half inner square sleeves 2.1;

[0057] Keep the opening of the outer square sleeve 1, and use the two hooks 6 of the drilling platform small winch to lift the outer square sleeve 1 to the wellhead drill pipe position, and the inner square sleeve 2 is lifted together with the outer square sleeve 1. After the wellhead drill pipe is inserted into the opening of the two halves of the outer square sleeve 1.1, buckle the two halves of the outer square sleeve 1.1 to make the outer square sleeve 1 sit stably in the turntable square bushing, and install the bolts between the fixing holes 8 on the outer square sleeve 1;

[0058] After removing the wire rope of the drilling platform winch from the hook 6, hang it on the two lifting rings 5 ​​on the inner square sleeve 2. With the help of the drilling platform winch, lift the two halves of the inner square sleeve 2.1 to the maximum extension height, buckle the two halves of the inner square sleeve 2.1, and install the hexagonal bolts at the concave and convex overlap parts and tighten them;

[0059] Lower the inner square sleeve 2 and lock the bolts between the fixing holes 8 on the outer square sleeve 1;

[0060] Align the slot 2.4 at the top of the inner square sleeve 2 to install the drill rod clamping mechanism 3, so that the clamping plate 3.5 is clamped into the slot 2.4, and the two pressure plate seats 3.2 clamp the drill rod after the two slip seats 3.1 are buckled, and the locking bolts 3.4 are installed and the locking nuts 3.3 are locked, so that the drill rod can be clamped and fixed;

[0061] When the turntable rotates, the outer square sleeve 1, the inner square sleeve 2 and the drill rod holding mechanism 3 can transmit torque to rotate the drill rod, thereby moving the drill tool. At the same time, the drill tool can be lifted and lowered with the help of the drilling rig lifting system. The drill rod holding mechanism 3 and the inner square sleeve 2 can be lifted and lowered synchronously with the drill tool. At this time, the lifting and lowering operation space is the height difference between the top surface of the limiting boss 2.2 and the bottom surface of the limiting flange 1.2. The change of the suspended weight can be observed at any time. After loosening the locking nut 3.3, the clamping of the pressure plate seat 3.2 on the drill rod can be loosened, so that the drill tool can be lifted and lowered at will.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A back-marking tool for coalbed methane, characterized in that: include: An outer square sleeve (1), the outer square sleeve (1) is a square cylindrical structure, which is formed by buckling two half pieces of the outer square sleeve (1.1); The inner square sleeve (2) is a square cylindrical structure, which is formed by buckling two half-pieces of the inner square sleeve (2.1). The inner square sleeve (2) is slidably arranged inside the outer square sleeve (1), and the inner square sleeve (2) can slide in the vertical direction inside the outer square sleeve (1); A drill rod clamping mechanism (3) is detachably mounted on the top end of the inner square sleeve (2) and is used to clamp and fix the drill rod.

2. The back-marking tool for coalbed methane according to claim 1, characterized in that: The right side walls of the two half-piece outer square sleeves (1.1) are hingedly connected by a hinge link (7), the left side outer walls of the two half-piece outer square sleeves (1.1) are welded with fixing hole seats (8), and the fixing hole seats (8) on the two half-piece outer square sleeves (1.1) are locked and connected by bolts.

3. The back-marking tool for coalbed methane according to claim 1, characterized in that: The inner bottom of each half-piece outer square sleeve (1.1) is provided with a support plate (1.3), and the inner side wall of each support plate (1.3) is provided with a semicircular groove, and when the two half-piece outer square sleeves (1.1) are buckled together, the two semicircular grooves surround and form a circular hole.

4. The back-marking tool for coalbed methane according to claim 3, characterized in that: The outer side wall of each half-piece outer square sleeve (1.1) is welded with a hook (6).

5. The back-marking tool for coalbed methane according to claim 4, characterized in that: Steps are provided at the buckling edges between the two half-piece inner square sleeves (2.1), so that the buckling edges between the two half-piece inner square sleeves (2.1) overlap concavely and convexly, and the concave and convex overlapping parts are locked by installing a plurality of bolts at intervals in the vertical direction.

6. The back-marking tool for coal bed methane according to claim 5, characterized in that: The outer side wall of each half-piece inner square sleeve (2.1) is welded with a lifting ring (5).

7. The back-marking tool for coalbed methane according to claim 6, characterized in that: The top inner side wall of each half-piece outer square sleeve (1.1) is provided with a limiting flange (1.2), and the bottom outer side wall of each half-piece inner square sleeve (2.1) is provided with a limiting boss (2.2); the inner side wall of the limiting flange (1.2) is in gap contact with the outer side wall of the half-piece inner square sleeve (2.1), and the outer side wall of the limiting boss (2.2) is in gap contact with the inner side wall of the half-piece outer square sleeve (1.1).

8. The back-marking tool for coalbed methane according to any one of claims 1 to 7, characterized in that: The drill rod clamping mechanism (3) comprises two slip seats (3.1), the rear ends of the two slip seats (3.1) are hinged, the front ends of the two slip seats (3.1) are locked and connected by locking bolts (3.4), the inner side wall of each slip seat (3.1) is provided with a mounting groove, and a pressure plate seat (3.2) for clamping and fixing the drill rod is installed in the mounting groove; a clamping plate (3.5) is fixed at the bottom end of each slip seat (3.1), and a clamping groove (2.4) is provided on the outer side wall of the top end of each half-piece inner square sleeve (2.1); when the two slip seats (3.1) are buckled, the two clamping plates (3.5) are clamped in the clamping groove (2.4), so that the drill rod clamping mechanism (3) is fixed to the top end of the inner square sleeve (2).

9. The back-marking tool for coal bed methane according to claim 8, characterized in that: A pin shaft (3.6) extending in the vertical direction is installed at the front end of one of the slip seats (3.1), one end of a locking bolt (3.4) is sleeved on the pin shaft (3.6), and the other end of the locking bolt (3.4) is threadedly connected with a locking nut (3.3). The front ends of the two slip seats (3.1) are each provided with a U-shaped groove for the locking bolt (3.4) to be inserted into. When the two slip seats (3.1) are buckled together, the locking nut (3.3) is inserted into the U-shaped groove and the locking nut (3.3) is locked, so that the front ends of the two slip seats (3.1) can be locked and connected.

10. The back-marking tool for coal bed methane according to claim 8, characterized in that: The mounting groove of the inner side wall of the slip seat (3.1) is a square groove, and each pressure plate seat (3.2) is a square block structure. The slip seat (3.1) and the pressure plate seat (3.2) are fastened by bolts, and the inner side wall of each pressure plate seat (3.2) is provided with a semicircular jaw, and the inner side wall of the semicircular jaw is provided with jaw teeth. When the two slip seats (3.1) are buckled together, the two semicircular jaws are combined to form a circular jaw to clamp and fix the drill rod.

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