An eccentric cutter for cutting inner casing and cement ring of a borehole

Abstract

The present invention belongs to an eccentric cutter, and specifically relates to an eccentric cutter for cutting borehole inner casing and cement ring. An eccentric cutter for cutting borehole inner casing and cement ring, wherein the cutter includes a tool holder, which is a cylinder with a conical lower end, and a square groove for accommodating a knife in the middle upper position of the cylinder, and a square hole is milled transversely through the lower end of the square groove, and an eccentric circular hole for installing a knife rod and allowing the knife rod to move up and down is provided from the top to the middle lower part of the tool holder, and the upper end of the tool holder has an external thread. The significant effects of the present invention are: by adopting a single knife, the thickness of the knife is increased; by eccentricity of the push rod, the width of the knife is increased; by moving the pin shaft hole inward, the diameter of the pin shaft is increased, so as to achieve the effect of overcoming the breakage of the knife and the deformation and damage of the pin shaft and the pin shaft hole.

Description

Technical Field

[0001] The invention belongs to an eccentric cutter, in particular to an eccentric cutter for cutting a casing and a cement ring in a borehole. Background Art

[0002] In the existing technology of cutting well pipe and cement ring in the borehole of the in-situ leaching process, a cylindrical cutter is installed at the lower end of the drill pipe, and three blades are evenly distributed radially in the cylindrical cutter. A piston is installed at the center position of the cutter, and a push rod is connected to the lower end of the piston. The triangular prism rack at the lower end of the push rod is meshed with the round teeth on the three blades. During operation, the high-pressure water descending from the drill pipe pushes the piston and the push rod to move downward, and the triangular prism rack on the push rod pushes the round teeth on the blade to rotate, thereby pushing the blade out of the cylindrical blade holder. After the blade extends out of the blade holder, the drilling rig is started to rotate the drill pipe, and the drill pipe drives the cutter to rotate, thereby achieving the cutting of the well pipe and cement ring. At present, the problems of this cutter in practical application are frequent failures, the blade and the pin shaft are easy to break, and the pin shaft hole is easy to deform and break. Summary of the invention

[0003] The present invention aims at solving the defects of the prior art and provides an eccentric cutter for cutting the inner casing and cement ring of a borehole.

[0004] The present invention is implemented as follows: an eccentric cutter for cutting the inner casing and cement ring of a borehole, which includes a tool holder, which is a cylinder with a conical lower end, a square groove for accommodating the installation of a tool at the upper middle position of the cylinder, a square hole milled transversely through the lower end of the square groove, an eccentric circular hole for installing a tool rod and allowing the tool rod to move up and down from the top to the middle and lower part of the tool holder, and an external thread is provided at the upper end of the tool holder.

[0005] An eccentric cutter for cutting inner casing and cement ring of a borehole as described above, wherein the eccentric joint is an eccentric reducer, the lower end of which is cylindrical and the upper end is an inclined frustum, both ends of the eccentric joint have internal threads, the lower end internal thread is connected to the external thread on the tool holder, the upper end internal thread is connected to the lower end external thread on the cylinder, the upper end screw hole and the lower end screw hole of the eccentric joint are not concentric, and the center line of the upper end screw hole is biased to the right in the figure.

[0006] As described above, an eccentric cutter for cutting inner casing and cement ring of a borehole, wherein the cylinder is a round tube with threads at both ends, the upper end of the cylinder is internally threaded and connected to the external thread at the lower end of the upper joint, and the lower end of the cylinder is externally threaded and connected to the internal thread at the upper end of the eccentric joint.

[0007] As described above, an eccentric cutter for cutting casing and cement ring in a borehole, wherein the piston is a cylinder with an eccentric circular hole, the eccentric circular hole in the piston is a variable diameter circular hole, the diameter of the circular hole at the upper end is small, the diameter of the circular hole at the lower end is large, the circular hole at the lower end is provided with an internal thread, and is connected with the external thread at the upper end of the cutter rod. A circular shoulder is provided at the lower part of the circular hole at the upper end of the piston, and a circular square groove is provided at the upper part, and a throttling nozzle is installed in the circular hole at the upper end of the piston.

[0008] The eccentric cutter for cutting the inner casing and cement ring of a borehole as described above, wherein the cutter bar is a cylinder with an eccentric circular hole inside, with an external thread at the upper end connected to the internal thread at the lower end of the piston. A rack is milled on one side of the outer side of the lower end of the cutter bar, and the rack meshes with the teeth on the cutter.

[0009] The eccentric cutter for cutting inner casing and cement ring of a borehole as described above, wherein the return spring is sleeved on the cutter rod, the lower end of the return spring is supported on the upper end surface of the cutter holder, and the upper end is supported on the lower end surface of the piston.

[0010] As described above, an eccentric cutter for cutting inner casing and cement ring of a borehole, wherein the throttling nozzle is a cylinder with a funnel-shaped circular hole inside, the lower end of the throttling nozzle sits on the annular shoulder inside the piston, and the upper end of the throttling nozzle is blocked by a retaining spring embedded in the groove at the upper end of the circular hole in the piston.

[0011] As described above, an eccentric cutter for cutting inner casing and cement ring of a borehole, wherein the upper joint is a cylinder with a circular hole inside, the lower end has an external thread connected to the internal thread of the upper end of the cylinder, and the upper end circular hole has an internal thread connected to the drill rod.

[0012] As described above, an eccentric cutter for cutting inner casing and cement ring of a borehole, wherein the cutter is a thick plate-like component with a semicircular lower portion and an oblique lower portion, a circular hole is provided at the center of the semicircular end for inserting a pin shaft, and the outer edge of the lower end of the cutter is inlaid with a cutting alloy.

[0013] The eccentric cutter for cutting the inner casing and cement ring of a borehole as described above, wherein the pin shaft is a cylinder.

[0014] The remarkable effects of the present invention are: increasing the thickness of the knife by adopting a single knife, increasing the width of the knife by eccentricity of the push rod, and increasing the diameter of the pin shaft by inward movement of the pin shaft hole, so as to achieve the effect of overcoming the breakage of the knife and the deformation and damage of the pin shaft and the pin shaft hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Eccentric cutter

[0016] Figure 2 Schematic diagram of eccentric cutter cutting construction

[0017] In the figure: 1. tool holder, 2. eccentric joint, 3. cylinder, 4. piston, 5. tool rod, 6. return spring, 7. throttling nozzle, 8 upper joint, 9 tool, 10. pin, 11. eccentric cutter, 12 drill rod, 13 borehole, 14. well pipe, 15. cement ring, 16 high-pressure water pump, 17 high-pressure pipeline. DETAILED DESCRIPTION

[0018] An eccentric cutter for cutting inner casing and cement ring of a borehole, wherein the tool holder 1 is a cylinder with a conical lower end, a square groove for accommodating a mounting tool 9 is provided at the middle upper position of the cylinder, a square hole is milled transversely through the lower end of the square groove, an eccentric circular hole for mounting a tool rod 5 and allowing the tool rod 5 to move up and down is provided from the top to the middle lower part of the tool holder 1, and an external thread is provided at the upper end of the tool holder 1.

[0019] The eccentric joint 2 is an eccentric reducing joint, the lower end of which is cylindrical and the upper end is an oblique frustum. Both ends of the eccentric joint 2 have internal threads. The lower end internal thread is connected to the external thread on the tool holder 1, and the upper end internal thread is connected to the lower end external thread on the cylinder 3. The upper end screw hole and the lower end screw hole of the eccentric joint 2 are not concentric, and the center line of the upper end screw hole is biased to the right in the figure.

[0020] The cylinder 3 is a round tube with threads at both ends. The upper end of the cylinder 3 is internally threaded and connected to the external thread at the lower end of the upper joint 8. The lower end of the cylinder 3 is externally threaded and connected to the internal thread at the upper end of the eccentric joint 2.

[0021] The piston 4 is a cylinder with an eccentric circular hole. The eccentric circular hole in the piston 4 is a variable diameter circular hole with a small diameter at the upper end and a large diameter at the lower end. The lower end circular hole has an internal thread connected to the external thread at the upper end of the arbor 5. The inner circular hole at the upper end of the piston 4 has an annular shoulder at the lower end and an annular square groove at the upper end. A throttling nozzle 7 is installed in the inner circular hole at the upper end of the piston 4.

[0022] The knife bar 5 is a cylinder with an eccentric circular hole, and the upper end is provided with an external thread, which is connected with the internal thread of the lower end of the piston 4. The lower end of the knife bar 5 is milled with a rack on one side, and the rack is meshed with the teeth on the knife 9.

[0023] The return spring 6 is sleeved on the tool rod 5 , the lower end of the return spring 6 is supported on the upper end surface of the tool holder 1 , and the upper end is supported on the lower end surface of the piston 4 .

[0024] The throttling nozzle 7 is a cylinder with a funnel-shaped circular hole. The lower end of the throttling nozzle 7 sits on the annular shoulder in the piston 4, and the upper end of the throttling nozzle 7 is blocked by a retaining spring embedded in the groove at the upper end of the circular hole in the piston 4.

[0025] The upper joint 8 is a cylinder with a circular hole inside, with an external thread at the lower end connected to the internal thread at the upper end of the cylinder 3, and an internal thread in the circular hole at the upper end connected to the drill rod.

[0026] The knife 9 is a thick plate-like component with a semicircular lower portion and an oblique angle at the lower portion. A circular hole is provided at the center of the semicircular end for inserting the pin 10. The outer edge of the lower end of the knife 9 is inlaid with a cutting alloy.

[0027] The pin 10 is a cylinder.

[0028] As attached Figure 1 , Attachment Figure 2 As shown, the eccentric cutter 11 for cutting the casing and cement ring in the borehole is connected to the drill rod 12 and is lowered into the borehole 13 to the position where the well pipe 14 and cement ring 15 need to be cut. At this time, the high-pressure water pump 16 delivers high-pressure water to the drill rod 12 through the high-pressure pipeline 17. The high-pressure water flows down from the drill rod to the cavity above the piston 4 in the eccentric cutter 11 for cutting the casing and cement ring in the borehole. Because the water hole of the throttling nozzle 7 on the piston 4 is small, the water generates a downward thrust (pressure) on the piston 4, and the piston 4 overcomes the elastic force of the return spring 6 under the thrust of the water. The cutter bar 5 connected with the piston 4 by thread is pushed downward by the piston 4. The cutter bar 5 moving downward pushes the cutter 9 meshing with it to rotate clockwise with the pin 10 as a circle through the rack at its lower end, so that the cutter 9 extends outward and upward from the square groove of the cutter holder 1. At this time, the drilling rig is started to rotate the drill rod 12, so that the cutter 9 can rotate and cut the well pipe 14 and cement ring 15 in the borehole 13. The debris cut by the cutter 9 is carried to the ground by the high-pressure water flowing out of the water hole of the cutter bar 5 through the return air between the drill rod 11 and the inner wall of the borehole 13. The cutter 9 can be extended to the vertical position between the cutter 9 and the cutter holder 1 at most.

Claims

1. An eccentric cutter for cutting inner casing and cement ring of a borehole, characterized in that: The utility model comprises a tool holder (1), an eccentric joint (2), a cylinder (3), a piston (4), a tool rod (5), a reset spring (6), a throttling nozzle (7), an upper joint (8), a tool (9) and a pin shaft (10). The tool holder (1) is a cylinder with a conical lower end. A square groove for accommodating the installation of the tool (9) is provided at the middle upper position of the cylinder. A square hole is milled through the lower end of the square groove in a transverse direction. An eccentric circular hole for installing the tool rod (5) and allowing the tool rod (5) to move up and down is provided from the top to the middle lower part of the tool holder (1). The upper end of the tool holder (1) is provided with an external thread. The eccentric joint (2) is an eccentric reducer, the lower end of which is cylindrical and the upper end is an oblique truncated cone. Both ends of the eccentric joint (2) have internal threads, the lower internal threads are connected to the external threads on the tool holder (1), and the upper internal threads are connected to the lower external threads on the cylinder (3). The upper screw hole and the lower screw hole of the eccentric joint (2) are not concentric, and the center line of the upper screw hole is biased to the right. The cylinder (3) is a round tube with threads at both ends. The upper end of the cylinder (3) is internally threaded and connected to the externally threaded lower end of the upper joint (8). The lower end of the cylinder (3) is externally threaded and connected to the internally threaded upper end of the eccentric joint (2). The piston (4) is a cylinder with an eccentric circular hole. The eccentric circular hole in the piston (4) is a variable diameter circular hole. The diameter of the circular hole at the upper end is small, and the diameter of the circular hole at the lower end is large. The circular hole at the lower end is provided with an internal thread, which is connected with the external thread at the upper end of the knife rod (5). The inner circular hole at the upper end of the piston (4) is provided with a circular shoulder at the lower part and a circular square groove at the upper part. A throttling nozzle (7) is installed in the inner circular hole at the upper end of the piston (4); The knife rod (5) is a cylinder with an eccentric circular hole inside, with an external thread at the upper end connected to the internal thread at the lower end of the piston (4), and a rack is milled on one side of the outer side of the lower end of the knife rod (5), and the rack meshes with the teeth on the knife (9); The return spring (6) is sleeved on the knife rod (5), the lower end of the return spring (6) is supported on the upper end surface of the knife holder (1), and the upper end is supported on the lower end surface of the piston (4); The throttling nozzle (7) is a cylinder with a funnel-shaped circular hole inside. The lower end of the throttling nozzle (7) sits on a circular shoulder inside the piston (4), and the upper end of the throttling nozzle (7) is blocked by a retaining spring embedded in a groove at the upper end of the inner circular hole of the piston (4). The upper joint (8) is a cylinder with a circular hole inside, and has an external thread at the lower end, which is connected to the internal thread at the upper end of the cylinder (3). The circular hole at the upper end has an internal thread, which is connected to the drill rod; The knife (9) is a thick plate-like component with a semicircular upper portion and an oblique lower portion, and a circular hole is provided at the center of the semicircular end for inserting a pin shaft (10); The pin (10) is a cylinder.

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