Auxiliary screwing device for oil casing coupling

Abstract

The invention belongs to the technical field of oil exploitation equipment, in particular to an auxiliary screwing device for an oil casing coupling, and provides the following scheme that the auxiliary screwing device specifically comprises a supporting frame, a main adjusting mechanism capable of floating up and down for adjustment is mounted at the top of the supporting frame, and two parallel vertical shaft rods are rotatably mounted at the front end of the main adjusting mechanism; two main supports are fixedly installed in the middle of each of the two vertical shaft rods, and a fixing ring of a semicircular structure is installed in the middle of each main support. The coupling fixing sleeve and the casing pipe guiding assembly are both installed on the vertical shaft rod, the vertical shaft rod is installed on the main adjusting mechanism capable of being adjusted in an up-and-down floating mode, and the coupling fixing sleeve and the casing pipe guiding assembly can move along with the change of the screwing depth between the coupling and the pipe opening of the petroleum casing pipe. And compression damage to a threaded groove between the oil casing and the coupling is avoided, and the connection stability of the oil casing and the coupling is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil production equipment, in particular to an auxiliary screwing device for an oil casing coupling. Background Art

[0002] Oil casing is a steel pipe used to support the wall of oil and gas wells to ensure the normal operation of the entire oil well during the drilling process and after completion. The casing is inserted into the wellbore and fixed with cement to help the wellbore separate the rock layer and prevent the wellbore from collapsing, while ensuring the circulation of drilling mud for drilling and mining. Each well uses several layers of casing according to different drilling depths and geological conditions. Due to different geological conditions, the stress state downhole is complex, and the combined effects of tension, compression, bending and torsion stress act on the pipe body, which puts higher requirements on the quality of the casing itself. Once the casing itself is damaged for some reason, it may lead to a reduction in production of the entire well or even scrapping.

[0003] After the casing is lowered into the well, cement is used for cementing. Unlike oil pipes and drill pipes, it cannot be reused and is a disposable consumable material. Oil casing is the lifeline for maintaining the operation of oil wells. Casing and pipelines are connected together by couplings to prevent water and gas leakage in the pipeline and ensure the normal operation of the pipeline. Compared with the traditional welding connection method, the connection of casing couplings is tighter and more stable, and can be disassembled and replaced according to actual needs. The internal threads of oil casing couplings are densely distributed. When tightening the couplings, the casing needs to be pulled from both ends to the middle, causing the couplings to move as they are tightened. The position between the couplings and the casing is prone to offset, affecting the tightness of the coupling screw connection.

[0004] In view of this, the present invention provides an auxiliary screwing device for a petroleum casing coupling to solve the technical problems existing in the above-mentioned prior art. Summary of the invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes an auxiliary screwing device for a petroleum casing coupling.

[0006] The invention provides an auxiliary screwing device for a petroleum casing coupling, comprising a support frame, a main adjustment mechanism that can be adjusted up and down and is installed on the top of the support frame, and two parallel vertical shafts are rotatably installed at the front end of the main adjustment mechanism, two main brackets are fixedly installed in the middle of the two vertical shafts, and a semicircular fixed ring is installed in the middle of each main bracket, a locking plate with a wedge structure is installed between the fixed ring and the end of the retaining frame, and a locking sleeve is provided on the outer end of the locking plate, two fixed rings at the same height are assembled to form a fixed hoop, and a coupling fixing sleeve that drives the coupling to rotate is rotatably installed between the two fixed hoops The coupling fixing sleeve is composed of two pieces, and semicircular retaining frames are installed at both ends of the two vertical shafts. A casing guide assembly with an annular structure is formed between the two retaining frames at the same height. The casing guide assembly is coaxially arranged with the coupling fixing sleeve. A driving gear is rotatably installed between the two main brackets located on the same side, and the driving gear is meshed and connected with the coupling fixing sleeve. Stepper motors are installed on the tops of the two main brackets at the upper ends, and the output shafts of the stepper motors are transmission-connected with the driving gears. A grease coating mechanism is clamped on the coupling fixing sleeve and the casing guide assembly, and the grease coating mechanism is distributed outside the connection seam between the petroleum casing and the coupling.

[0007] Preferably in the present invention, the main adjustment mechanism includes a vertically distributed rectangular bracket, and a floating platform is slidably installed inside the rectangular bracket, a threaded screw is rotatably installed inside the rectangular bracket, and the threaded screw and the floating platform are threadedly matched, and an adjustment motor for driving the threaded screw to rotate is installed on the top of the rectangular bracket.

[0008] Preferably in the present invention, a rectangular rod is provided in the middle of the floating platform, and a floating block is slidably installed on the outer side of the rectangular rod, the vertical shaft rod is installed on the floating block, and push springs are installed above and below the floating block, and a pressure sensor is installed between the push spring and the floating platform.

[0009] Preferably in the present invention, the locking sleeve includes an outer shell, and the side of the outer shell is provided with a trapezoidal groove for engaging two locking plates, multiple electric push rods are installed on both sides of the outer shell, and the ends of the electric push rods are installed with locking blocks that are engaged with the locking plate steps.

[0010] Preferably in the present invention, the retaining frame includes a connecting arm and a semicircular ring arranged at the end of the connecting arm, a wheel seat with a V-shaped structure is arranged inside the semicircular ring, two rollers distributed up and down are installed at the front end position of the wheel seat, and a plurality of annular teeth are arranged on the surface of the roller.

[0011] Preferably in the present invention, the coupling fixing sleeve includes a ring rotatably installed between two fixing hoops, and two annular grooves are provided in the middle of the ring, and a plurality of locking blocks cooperating with the outer wall of the coupling are installed inside the two annular grooves, and a driven mechanism for driving the locking blocks to move is rotatably installed inside the ring, and a gear ring is provided on the outside of the driven mechanism.

[0012] Preferably in the present invention, the driven mechanism is composed of two layers of ring sheets, and annularly distributed wedge-shaped transmission blocks are provided at the inner side of the driven mechanism, and a plurality of transmission grooves of fan-shaped structures are provided on the surface of the driven mechanism.

[0013] Preferably in the present invention, a transmission block with a fan-shaped structure is arranged inside the annular groove of the collar, and the transmission block passes through the interior of the transmission groove. The rotation angle between the collar and the driven mechanism is 0-15°, and limit rings are installed at both ends of the collar to rotate with the fixed ring.

[0014] Preferably in the present invention, the locking block is rotatably installed inside the mounting groove of the collar, and the outer side surface of the locking block is provided with a locking groove that slides with the wedge-shaped transmission block, and the inner side surface of the locking block is provided with anti-slip teeth that contact the surface of the coupling.

[0015] Preferably in the present invention, the grease coating mechanism includes an oil storage shell and a pressure plate with two semicircular structures, the ends of the oil storage shell and the pressure plate are provided with snap locks for fixing, the outer side of the pressure plate is threaded with a plurality of fastening bolts fixed to the oil casing, and the bottom of the oil storage shell is provided with an extrusion groove facing the coupling connection seam, a sealing cover is installed on the top of the oil storage shell, and the middle part of the sealing cover is slidably connected with the extrusion plate.

[0016] Compared with the prior art, the present invention provides an auxiliary screwing device for a petroleum casing coupling, which has the following beneficial effects: In the present invention, an assembleable retaining frame, a fixing ring and a coupling fixing sleeve are provided, a casing guide assembly of an annular structure is formed between two retaining frames at the same height, the pipe mouth of the oil casing is fixed in the casing guide assembly, and the coupling located between the oil casing is fixed in the coupling fixing sleeve, and the two sides of the coupling fixing sleeve rotate under the action of the driving gear and the stepping motor, driving the coupling to rotate around the pipe mouth of the oil casing, gradually tightening the oil casing at both ends and screwing them into the coupling synchronously, the casing guide assembly and the coupling fixing sleeve are coaxially arranged, and the pipe mouth axis of the oil casing is maintained by relying on the action of the casing guide assembly The stability of the vertical movement can prevent the oil casing from following the rotation and deflection, and provide stability in the process of tightening the coupling. The oil casing squeezes the grease coating mechanism when it is synchronously tightened, and the grease inside the grease coating mechanism is squeezed out and smeared on the threads at the pipe mouth of the oil casing. At the same time, the coupling fixing sleeve and the casing guide assembly are both installed on the vertical shaft rod, and the vertical shaft rod is installed on the main adjustment mechanism that can be adjusted up and down. The coupling fixing sleeve and the casing guide assembly can move with the change of the screwing depth between the coupling and the pipe mouth of the oil casing, avoiding compression damage to the thread groove between the oil casing and the coupling, and further providing the stability of the oil casing coupling connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural schematic diagram of an auxiliary screwing device for a petroleum casing coupling proposed by the present invention; Figure 2 A schematic diagram of the partial structure of an auxiliary screwing device for a petroleum casing coupling proposed by the present invention; Figure 3 This is a schematic diagram of the distribution structure of the grease coating mechanism of the petroleum casing coupling auxiliary screwing device proposed by the present invention; Figure 4 This is a schematic diagram of the grease coating mechanism of the petroleum casing coupling auxiliary screwing device proposed by the present invention; Figure 5 This is a schematic diagram of the locking sleeve structure of a petroleum casing coupling auxiliary screwing device proposed by the present invention; Figure 6 A schematic diagram of the transmission structure of a coupling fixing sleeve of a petroleum casing coupling auxiliary screwing device proposed by the present invention; Figure 7 A schematic diagram of the distribution structure of a coupling fixing sleeve of a petroleum casing coupling auxiliary screwing device proposed by the present invention; Figure 8 A schematic diagram of the collar structure of a petroleum casing coupling auxiliary screwing device proposed by the present invention; Fig. 9 A schematic diagram of the structure of a driven mechanism of an auxiliary screwing device for a petroleum casing coupling proposed by the present invention; Fig.10The present invention provides a schematic diagram of the locking groove structure of an auxiliary screwing device for a petroleum casing coupling.

[0018] In the figure: 1 support frame, 2 locking plate, 3 locking sleeve, 31 outer shell, 32 electric push rod, 33 locking block, 34 trapezoidal groove, 4 grease coating mechanism, 41 oil storage shell, 42 extrusion groove, 43 fastening bolt, 44 pressure plate, 45 cover, 46 extrusion plate, 5 stepper motor, 6 retaining frame, 61 connecting arm, 62 semicircular ring, 63 roller, 7 main bracket, 8 driving gear, 9 main adjustment mechanism, 91 rectangular bracket, 92 threaded screw, 93 adjustment motor, 94 floating platform, 95 floating block, 96 push spring, 10 fixing ring, 11 vertical shaft, 12 coupling fixing sleeve, 121 collar, 122 driven mechanism, 123 limit ring, 124 gear ring, 125 transmission block, 126 wedge-shaped transmission block, 127 locking block, 128 transmission groove, 129 locking groove. DETAILED DESCRIPTION

[0019] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0020] Reference Figure 1-10 A petroleum casing coupling auxiliary screwing device includes a support frame 1, a main adjustment mechanism 9 that can be adjusted up and down is installed on the top of the support frame 1, and two parallel vertical shafts 11 are rotatably installed at the front end of the main adjustment mechanism 9, two main brackets 7 are fixedly installed in the middle of the two vertical shafts 11, and a semicircular fixing ring 10 is installed in the middle of each main bracket 7, a locking plate 2 with a wedge structure is installed between the fixing ring 10 and the end of the retaining frame 6, and a locking sleeve 3 is sleeved on the outer end of the locking plate 2, two fixing rings 10 at the same height are assembled to form a fixing hoop, and a coupling fixing sleeve 12 that drives the coupling to rotate is rotatably installed between the two fixing hoops, and the coupling The fixing sleeve 12 is composed of two pieces, and semicircular retaining frames 6 are installed at both ends of the two vertical shafts 11. A casing guide assembly with an annular structure is formed between the two retaining frames 6 at the same height. The casing guide assembly is coaxially arranged with the coupling fixing sleeve 12. A driving gear 8 is rotatably installed between the two main brackets 7 located on the same side, and the driving gear 8 is meshed and connected with the coupling fixing sleeve 12. Stepper motors 5 are installed on the tops of the two main brackets 7 located at the upper ends, and the output shafts of the stepper motors 5 are transmission-connected with the driving gear 8. The coupling fixing sleeve 12 and the casing guide assembly are clamped with a grease coating mechanism 4, and the grease coating mechanism 4 is distributed outside the connecting seam between the oil casing and the coupling.

[0021] In the present invention, an assembleable retainer 6, a fixing ring 10 and a coupling fixing sleeve 12 are provided. A casing guide assembly of an annular structure is formed between two retainers 6 at the same height. The pipe mouth of the oil casing is fixed in the casing guide assembly, and the coupling located between the oil casing is fixed in the coupling fixing sleeve 12. The two sides of the coupling fixing sleeve 12 rotate under the action of the driving gear 8 and the stepping motor 5, driving the coupling to rotate around the pipe mouth of the oil casing, gradually tightening the oil casing at both ends and screwing them into the coupling synchronously. The casing guide assembly is coaxially arranged with the coupling fixing sleeve 12, and the oil casing is kept in a fixed position by relying on the action of the casing guide assembly. The axial movement of the mouth is stable, which prevents the oil casing from following the rotation and deviation, and provides stability during the tightening process of the coupling. The oil casing squeezes the grease coating mechanism 4 when it is synchronously tightened, and the grease inside the grease coating mechanism 4 is squeezed out and applied to the threads at the mouth of the oil casing. At the same time, the coupling fixing sleeve 12 and the casing guide assembly are both installed on the vertical shaft rod 11, and the vertical shaft rod 11 is installed on the main adjustment mechanism 9 that can be adjusted up and down. The coupling fixing sleeve 12 and the casing guide assembly can move with the change of the screwing depth between the coupling and the oil casing mouth, avoiding compression damage to the thread groove between the oil casing and the coupling, and further providing stability of the oil casing coupling connection.

[0022] As a further solution in the present invention, the main adjustment mechanism 9 includes a vertically distributed rectangular bracket 91, and a floating platform 94 is slidably installed inside the rectangular bracket 91, a threaded screw 92 is rotatably installed inside the rectangular bracket 91, and the threaded screw 92 and the floating platform 94 are threadedly matched, and an adjustment motor 93 for driving the threaded screw 92 to rotate is installed on the top of the rectangular bracket 91. In the present invention, the retaining frame 6, the fixing ring 10 and the coupling fixing sleeve 12 are all fixed on the floating platform 94. When used, the floating platform 94 is driven to adjust to the working position by adjusting the motor 93 and the threaded screw 92. During the auxiliary screwing process of the coupling, the floating platform 94 is driven to move downward according to the signal feedback of the floating platform 94 to compensate for the displacement spacing of the floating platform 94 and protect the thread between the coupling and the oil casing.

[0023] As a further solution in the present invention, a rectangular rod is provided in the middle of the floating platform 94, and a floating block 95 is slidably installed on the outer side of the rectangular rod, a vertical shaft rod 11 is installed on the floating block 95, and push springs 96 are installed on the upper and lower sides of the floating block 95, and a pressure sensor is installed between the push spring 96 and the floating platform 94. In the present invention, when the retaining frame 6, the fixing ring 10 and the coupling fixing sleeve 12 follow the movement of the coupling, they first push the upper and lower elastically supported push springs 96 to deform, and elastically compensate for the displacement change during the screwing process of the coupling. At the same time, the regulating motor 93 moves according to the feedback information of the pressure sensor, drives the floating platform 94 to descend, compensates for the deformation of the push spring 96, keeps the tension between the oil casing and the coupling within a controllable range, protects the internal screw thread from damage, and provides stability for the coupling installation.

[0024] As a further solution in the present invention, the locking sleeve 3 includes an outer shell 31, and the side of the outer shell 31 is provided with a trapezoidal groove 34 for engaging the two locking plates 2. A plurality of electric push rods 32 are installed on both sides of the outer shell 31, and the ends of the electric push rods 32 are installed with locking blocks 33 that are step-engaged with the locking plates 2. In the present invention, when the retaining frame 6, the fixing ring 10 and the coupling fixing sleeve 12 are assembled, the locking sleeve 3 is inserted into the ends of the two locking plates 2, and the locking sleeve 3 is pulled to move by the electric push rod 32, and the two locking plates 2 are gradually tightened and approached in the trapezoidal groove 34, completing the stability of the assembly and fixation of the retaining frame 6, the fixing ring 10 and the coupling fixing sleeve 12.

[0025] As a further solution in the present invention, the retainer 6 includes a connecting arm 61 and a semicircular ring 62 arranged at the end of the connecting arm 61. A wheel seat with a V-shaped structure is arranged inside the semicircular ring 62. Two rollers 63 distributed up and down are installed at the front end of the wheel seat. A plurality of annular teeth are arranged on the surface of the roller 63. In the present invention, the two semicircular rings 62 are assembled to form an annular structure distributed on the outside of the oil casing, and two layers of rollers 63 distributed in an annular array are arranged on the outside of the oil casing. The rollers 63 are in axial rolling contact with the oil casing, providing guidance and limiting effect for the oil casing to approach the coupling, and the setting of the teeth effectively prevents the oil casing from rotating with the coupling, thereby increasing the speed at which the oil casing is rotated and screwed into the two ends of the coupling.

[0026] As a further solution of the present invention, the coupling fixing sleeve 12 includes a collar 121 rotatably mounted between the two fixing hoops, and two annular grooves are provided in the middle of the collar 121, and a plurality of locking blocks 127 cooperating with the outer wall of the coupling are installed inside the two annular grooves, and a driven mechanism 122 for driving the locking blocks 127 to move is rotatably installed inside the collar 121, and a gear ring 124 is provided on the outer side of the driven mechanism 122. In the present invention, when the stepping motor 5 drives the driven mechanism 122 to rotate through the driving gear 8, the driven mechanism 122 drives the collar 121 rotates synchronously, and the driven mechanism 122 rotates clockwise to squeeze the locking block 127 located inside the collar 121. The locking block 127 gathers toward the outer wall of the coupling and firmly locks the coupling, driving the coupling to rotate synchronously and pulling the oil casing at both ends toward the middle. When the driven mechanism 122 rotates counterclockwise, the locking block 127 located inside the collar 121 is driven away from the coupling, and the coupling surface is loosened in time, cooperating with the internal floating structure of the main adjusting mechanism 9, and adjusting the axial tension of the coupling fixing sleeve 12 on the coupling in time to protect the coupling thread from damage.

[0027] As a further solution in the present invention, the driven mechanism 122 is composed of two layers of ring plates, and a ring-shaped wedge-shaped transmission block 126 is arranged on the inner side of the driven mechanism 122, and a plurality of fan-shaped transmission grooves 128 are arranged on the surface of the driven mechanism 122. In the present invention, the driven mechanism 122 limits the range of coaxial rotation of the collar 121 by the constraint of the transmission groove 128. At the same time, when the driven mechanism 122 rotates clockwise, the wedge-shaped transmission block 126 pushes the locking block 127 close to the coupling and realizes the transmission between the collar 121. When the driven mechanism 122 rotates counterclockwise, the wedge-shaped transmission block 126 pushes the locking block 127 away from the coupling in the opposite direction.

[0028] As a further solution in the present invention, a transmission block 125 with a fan-shaped structure is arranged inside the annular groove of the collar 121, and the transmission block 125 passes through the interior of the transmission groove 128. The rotation angle between the collar 121 and the driven mechanism 122 is 0-15°, and limit rings 123 that rotate with the fixing ring 10 are installed at both ends of the collar 121. In the present invention, the collar 121 constitutes the skeleton structure of the coupling fixing sleeve 12, and relies on the sliding cooperation between the transmission block 126 and the transmission groove 128 to limit and guide the coaxial rotation movement of the driven mechanism 122.

[0029] As a further solution in the present invention, the locking block 127 is rotatably installed inside the installation groove of the ring 121, and the outer side surface of the locking block 127 is provided with a locking groove 129 that slides with the wedge-shaped transmission block 126, and the inner side surface of the locking block 127 is provided with anti-slip teeth that contact the surface of the coupling. In the present invention, the locking block 127 is acted upon by the transmission block 126, and the outer end of the transmission block 125 gathers toward the center of the coupling to achieve locking of the coupling. With the clockwise transmission of the driven mechanism 122, self-locking fixation is completed, thereby improving the stability of the coupling screwing process.

[0030] As a further solution in the present invention, the grease coating mechanism 4 includes two semicircular oil storage shells 41 and a pressure plate 44, the ends of the oil storage shell 41 and the pressure plate 44 are provided with a buckle lock for fixing, the outer side of the pressure plate 44 is screwed with a plurality of fastening bolts 43 fixed to the oil casing, and the bottom of the oil storage shell 41 is provided with an extrusion groove 42 facing the coupling connection seam, the top of the oil storage shell 41 is installed with a cover 45, and the middle of the cover 45 is slidably connected with an extrusion plate 46. In the present invention, the sealing grease is injected into the oil storage shell In the body 41, one end of the oil storage shell 41 is contacted with the end of the coupling so that the extrusion groove 42 faces the connecting seam between the oil casing and the coupling, and the pressure plate 44 is fixed on the oil casing. When the oil casing is pulled toward the coupling, the pressure plate 44 drives the extrusion plate 46 to squeeze the sealing grease inside the oil storage shell 41. The sealing grease overflows from the extrusion groove 42 and is smeared on the screw groove at the end of the oil casing, and the grease is dispersed when the coupling rotates. The grease application amount is automatically controlled as the oil casing is screwed into the depth, effectively avoiding the occurrence of uneven sealing grease application.

[0031] When in use, the nozzle of the oil casing is fixed in the casing guide assembly, and the coupling located between the oil casing is fixed in the coupling fixing sleeve 12. The two sides of the coupling fixing sleeve 12 rotate under the action of the driving gear 8 and the stepping motor 5, driving the coupling to rotate around the nozzle of the oil casing, gradually tightening the oil casing at both ends and screwing them into the coupling synchronously. The casing guide assembly is coaxially arranged with the coupling fixing sleeve 12. Relying on the action of the casing guide assembly, the axial movement of the nozzle of the oil casing is kept stable to prevent the oil casing from rotating with it. and deviation occurs, providing stability during the tightening process of the coupling. The oil casing squeezes the grease coating mechanism 4 when it is synchronously tightened, and the grease inside the grease coating mechanism 4 is squeezed out and applied to the threads at the pipe mouth of the oil casing. At the same time, the coupling fixing sleeve 12 and the casing guide assembly are both installed on the vertical shaft rod 11, and the vertical shaft rod 11 is installed on the main adjustment mechanism 9 which can be adjusted up and down. The coupling fixing sleeve 12 and the casing guide assembly can move with the change of the screwing depth between the coupling and the pipe mouth of the oil casing, avoiding compression damage to the thread groove between the oil casing and the coupling.

[0032] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A petroleum casing coupling auxiliary screwing device, comprising a support frame (1), characterized in that: A main adjustment mechanism (9) capable of floating and adjusting up and down is installed on the top of the support frame (1), and two parallel vertical shafts (11) are rotatably installed at the front end of the main adjustment mechanism (9), and two main brackets (7) are fixedly installed in the middle of the two vertical shafts (11), and a semicircular fixing ring (10) is installed in the middle of each main bracket (7), a locking plate (2) with a wedge structure is installed between the fixing ring (10) and the end of the retaining frame (6), and a locking sleeve (3) is sleeved on the outer end of the locking plate (2), and two fixing rings (10) located at the same height are assembled to form a fixing hoop, and a coupling fixing sleeve (12) for driving the coupling to rotate is rotatably installed between the two fixing hoop, and the coupling fixing sleeve (12) is composed of two pieces. The invention relates to an assembly structure, wherein a semicircular retaining frame (6) is installed at both ends of the two vertical shafts (11), a casing guide assembly of an annular structure is formed between the two retaining frames (6) at the same height, the casing guide assembly is coaxially arranged with a coupling fixing sleeve (12), a driving gear (8) is rotatably installed between two main brackets (7) located on the same side, and the driving gear (8) is meshingly connected with the coupling fixing sleeve (12), a stepping motor (5) is installed on the top of the two main brackets (7) at the upper end, and the output shaft of the stepping motor (5) is drivingly connected with the driving gear (8), and a grease coating mechanism (4) is clamped with the coupling fixing sleeve (12) and the casing guide assembly, and the grease coating mechanism (4) is distributed at the outer side of the connection seam between the oil casing and the coupling.

2. The petroleum casing coupling auxiliary screwing device according to claim 1 is characterized in that: The main adjustment mechanism (9) comprises a vertically distributed rectangular bracket (91), wherein a floating platform (94) is slidably mounted inside the rectangular bracket (91), a threaded screw (92) is rotatably mounted inside the rectangular bracket (91), and the threaded screw (92) and the floating platform (94) are threadedly engaged, and an adjustment motor (93) for driving the threaded screw (92) to rotate is mounted on the top of the rectangular bracket (91).

3. The petroleum casing coupling auxiliary screwing device according to claim 2 is characterized in that: A rectangular rod is provided in the middle of the floating platform (94), and a floating block (95) is slidably mounted on the outer side of the rectangular rod. The vertical shaft (11) is mounted on the floating block (95), and push springs (96) are mounted above and below the floating block (95). A pressure sensor is mounted between the push spring (96) and the floating platform (94).

4. The petroleum casing coupling auxiliary screwing device according to claim 1, characterized in that: The locking sleeve (3) comprises an outer shell (31), and a trapezoidal groove (34) for engaging two locking plates (2) is provided on the side of the outer shell (31). A plurality of electric push rods (32) are installed at both sides of the outer shell (31), and locking blocks (33) are installed at the ends of the electric push rods (32) to be step-engaged with the locking plates (2).

5. The petroleum casing coupling auxiliary screwing device according to claim 1, characterized in that: The retaining frame (6) comprises a connecting arm (61) and a semicircular ring (62) arranged at the end of the connecting arm (61); a wheel seat with a V-shaped structure is arranged inside the semicircular ring (62); two rollers (63) distributed up and down are installed at the front end of the wheel seat; and a plurality of annular teeth are arranged on the surface of the rollers (63).

6. The petroleum casing coupling auxiliary screwing device according to claim 5, characterized in that: The coupling fixing sleeve (12) comprises a collar (121) rotatably mounted between two fixing hoops, wherein two annular grooves are arranged in the middle of the collar (121), and a plurality of locking blocks (127) cooperating with the outer wall of the coupling are arranged inside the two annular grooves, and a driven mechanism (122) is rotatably mounted inside the collar (121) for driving the locking blocks (127) to move, and a gear ring (124) is arranged outside the driven mechanism (122).

7. The petroleum casing coupling auxiliary screwing device according to claim 6, characterized in that: The driven mechanism (122) is composed of two layers of ring plates, and an annularly distributed wedge-shaped transmission block (126) is provided at the inner side of the driven mechanism (122), and a plurality of transmission grooves (128) in a fan-shaped structure are provided on the surface of the driven mechanism (122).

8. The petroleum casing coupling auxiliary screwing device according to claim 7, characterized in that: A transmission block (125) of a fan-shaped structure is arranged inside the annular groove of the collar (121), and the transmission block (125) passes through the interior of the transmission groove (128). The rotation angle between the collar (121) and the driven mechanism (122) is 0-15 degrees. Limiting rings (123) that are rotatably matched with the fixing ring (10) are installed at both ends of the collar (121).

9. The petroleum casing coupling auxiliary screwing device according to claim 8, characterized in that: The locking block (127) is rotatably mounted inside the mounting groove of the collar (121), and the outer side surface of the locking block (127) is provided with a locking groove (129) that slidably cooperates with the wedge-shaped transmission block (126), and the inner side surface of the locking block (127) is provided with anti-slip teeth that contact the surface of the coupling.

10. The petroleum casing coupling auxiliary screwing device according to claim 1, characterized in that: The grease coating mechanism (4) comprises two semicircular oil storage shells (41) and a pressure plate (44), the ends of the oil storage shell (41) and the pressure plate (44) are both provided with snap locks for fixing, the outer side of the pressure plate (44) is threaded with a plurality of fastening bolts (43) fixed to the oil casing, and the bottom of the oil storage shell (41) is provided with an extrusion groove (42) facing the coupling connection seam, and the top of the oil storage shell (41) is installed with a sealing cover (45), and the middle part of the sealing cover (45) is slidably connected with an extrusion plate (46).

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