A downhole safety joint for cuttable cable

Abstract

This invention discloses a downhole safety connector capable of cutting cables, comprising a core and a lower connector. One end of the core is inserted into the lower connector and secured with a shear pin. An outer shell is fitted over the core and the lower connector. An axially oriented cable groove is formed on the outer wall of both the core and the lower connector, and a cable is embedded within the groove. A guide cam is also connected to the core, and a circumferentially oriented arc-shaped cam groove is formed on the outer wall of the lower connector, with the guide cam embedded within the arc-shaped cam groove. This downhole safety connector is primarily used before well workover operations in cable monitoring wells. It enables the release of the downhole tubing and the cutting of the cable, reducing interference caused by the cable during retrieval operations, lowering the difficulty of the operation, and greatly facilitating the retrieval of working wells. This invention has a simple structure, high stability and reliability, and significant practical value.

Description

Technical Field

[0001] This invention relates to the field of intelligent oil production technology, and in particular to a tool for dropping downhole tubing and cutting cables before production tubing retrieval operations. Background Technology

[0002] Currently, in smart oilfield development, reservoir control is often achieved through cables, pressure lines, and hydraulic control pipelines. Cables, as the most commonly used monitoring and control method, can both control downhole tools and monitor downhole data. However, during well workover in cable-monitored wells, the complex downhole conditions, especially the difficulty in handling the sand control section tubing, necessitate a tool capable of cutting both the sand control section tubing and the production tubing above it. Conventional cutting tools can only cut tubing. Therefore, the inventors believe that developing a tool that can cut both tubing and cables, thereby reducing the difficulties in retrieval caused by pipelines, is of great significance. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a downhole safety connector capable of cutting cables. While fulfilling the functions of a conventional downhole safety connector, it also enables cable cutting, offering advantages such as a rational structural design, high safety and reliability, ease of operation, and convenient construction.

[0004] This application is achieved using the following technical solution.

[0005] A cuttable cable downhole safety connector includes a core and a lower connector. One end of the core is inserted into the lower connector and fixed by a shear pin. An outer shell is fitted over the core and the lower connector. An axially arranged cable groove is formed on the outer wall of both the core and the lower connector, and a cable is embedded in the cable groove. A guide cam is also connected to the core, and a circumferentially arranged arc-shaped cam groove is formed on the outer wall of the lower connector, and the guide cam is embedded in the arc-shaped cam groove.

[0006] Furthermore, both the shaft core and the lower connector are provided with multiple radial circular holes, and the shear pins pass through the corresponding circular holes in both the shaft core and the lower connector.

[0007] Furthermore, both the shaft core and the unused ends of the lower connector are equipped with oil pipe fasteners.

[0008] Furthermore, the shaft core and the outer casing are connected by threads.

[0009] Furthermore, a threaded hole is formed on the shaft core, and the bottom end of the guide cam is inserted into the threaded hole.

[0010] Furthermore, on the outer wall of the lower connector, the arc-shaped cam groove and the cable groove are arranged intersectingly.

[0011] This application has the following beneficial effects.

[0012] The downhole safety connector of this invention achieves tubing release via shear pins and cable shearing via a guide cam, thereby cutting the cable above the mandrel and reducing interference caused by the cable during retrieval operations. This invention features a simple tool structure, high stability and reliability, and can be used in cabled intelligent injection-production wells, solving the technical problem of difficult tubing retrieval operations caused by redundant cables after tubing cutting in intelligent injection-production wells. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention;

[0014] Figure 2 yes Figure 1 Cross-sectional view along line AA;

[0015] Figure 3 yes Figure 1 Cross-sectional view along line BB;

[0016] Figure 4 This is a schematic diagram of the connector structure of the present invention.

[0017] Among them, 1. mandrel; 2. cable; 3. housing; 4. lower connector; 5. shear pin; 6. guide cam; 7. arc-shaped cam groove; 8. round hole; 9. cable groove. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] like Figure 1-4 As shown, a downhole safety connector capable of cutting cables includes a mandrel 1, a cable 2, a housing 3, a lower connector 4, a shear pin 5, a guide cam 6, an arc-shaped cam groove 7, a round hole 8, and a cable groove 9.

[0020] One end of the mandrel 1 is inserted into the lower connector 4 and fixed by a shear pin 5. Specifically, multiple radial holes 8 are provided on the same circumferential surface of the mandrel 1. Similarly, multiple radial holes 8 are also provided on the same circumferential surface of the lower connector 4, and the holes 8 of the mandrel 1 and the lower connector 4 are positioned correspondingly. The shear pin 5 passes through both the holes 8 of the mandrel 1 and the lower connector 4 simultaneously, thereby securing the mandrel 1 and the lower connector 4. In this application, the unused ends of both the mandrel 1 and the lower connector 4 are provided with oil pipe clips for connection to oil pipes, enabling the insertion of the safety connector.

[0021] A housing 3 is provided around the mandrel 1 and the lower connector 4, such as Figure 2As shown, the mandrel 1 is located inside the safety connector, the lower connector 4 is located in the middle, and the outer shell 3 is located on the outside. The surface of the mandrel 1 near the oil pipe buckle is provided with external threads, and the inner wall of the outer shell 3 is provided with internal threads, so that the mandrel 1 and the outer shell 3 are connected by threads.

[0022] Both the shaft core 1 and the lower connector 4 of this application have axial cable grooves 9 on their outer walls. After the shaft core 1 is inserted into the lower connector 4, the cable grooves 9 of the two are joined together and located on the same straight line. The cable 2 is embedded in the cable grooves 9 of the shaft core 1 and the lower connector 4 and is located inside the outer casing 3.

[0023] The mandrel 1 is also provided with a threaded hole. The guide cam 6 is cylindrical, and its lower outer wall is provided with external threads. The guide cam 6 is inserted into the threaded hole, so that the guide cam 6 and the mandrel 1 are connected by threads. A circumferential arc-shaped cam groove 7 is formed on the outer wall of the lower connector 4. The end of the arc-shaped cam groove 7 away from the mandrel 1 is an axial linear long groove, and the end closer to the mandrel 1 is an arc-shaped groove at a 45° angle along the circumference. The arc-shaped cam groove 7 is intersected with the cable groove 9. The upper end of the guide cam 6 is inserted into the arc-shaped cam groove 7 and can slide along the arc-shaped cam groove 7 to cut the cable 2.

[0024] The working principle of the cuttable cable downhole safety connector of the present invention:

[0025] The downhole safety connector is connected to the tubing via the tubing thread of mandrel 1 and lower connector 4. Located above the positioning seal, it is lowered into the wellbore along with the tubing string. Before lowering the string, shear pins 5 are pre-installed into the round holes 8 of mandrel 1 and lower connector 4 according to the release capacity of the tubing string. At the wellhead drilling rig, the safety connector is suspended by a lifting clamp. Cable 2 is first placed into the cable groove 9 of mandrel 1 and lower connector 4. The internal thread of the outer shell 3 is used to rotate the outer shell 3 relative to mandrel 1, causing the outer shell 3 to move to the right until the thread is fully in place, ultimately covering the cable 2 completely to prevent it from slipping out of the cable groove 9 of mandrel 1 and lower connector 4. This process completes the pre-downhole installation of the safety connector.

[0026] Before working the smart well, if the sand-control section of the tubing is found to be stuck when the tubing is pulled up, the tubing can be pulled up further. When the pulling force reaches the shearing force of the shear pin 5, the mandrel 1 will separate from the lower connector 4. The mandrel 1, carrying the guide cam 6, will move to the left along the linear long groove of the arc-shaped cam groove 7 in the lower connector 4. After reaching the arc-shaped groove at a 45° angle, it will rotate to the left along the arc-shaped groove. When the moving distance reaches halfway, the guide cam 6 will contact the cable 2. Since the cable 2 cannot move in the circumferential direction in the cable groove 9, the movement of the guide cam 6 in the arc-shaped cam groove 7 will cut the cable 2. Finally, the mandrel 1, carrying the guide cam 6, will come out of the arc-shaped cam groove 7 of the lower connector as a whole, thereby realizing the separation of the upper cable and the lower cable of the downhole safety connector. Finally, the separation of the upper tubing and the lower tubing of the downhole safety connector will be completed. The separation process completes the cutting operation of the cable 2.

[0027] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A cuttable cable downhole safety connector, comprising a core (1) and a lower connector (4), characterized in that: One end of the shaft core (1) is inserted into the lower connector (4) and fixed by a shear pin (5). A housing (3) is provided over the shaft core (1) and the lower connector (4). A cable groove (9) is formed on the outer wall of both the shaft core (1) and the lower connector (4) and a cable (2) is embedded in the cable groove (9). A guide cam (6) is also connected to the shaft core (1). A circumferential arc-shaped cam groove (7) is formed on the outer wall of the lower connector (4) and the guide cam (6) is embedded in the arc-shaped cam groove (7). Both the shaft core (1) and the lower connector (4) are provided with multiple radial circular holes (8), and the shear pin (5) passes through the corresponding circular holes (8) of the shaft core (1) and the lower connector (4) at the same time. A threaded hole is formed on the shaft core (1), and the bottom end of the guide cam (6) is inserted into the threaded hole; On the outer wall of the lower connector (4), the arc-shaped cam groove (7) and the cable groove (9) are arranged intersectingly.

2. The downhole safety connector for cutable cables according to claim 1, characterized in that: Both the unused ends of the shaft core (1) and the lower connector (4) are equipped with oil pipe buckles.

3. The downhole safety connector for cutable cables according to claim 1, characterized in that: The shaft (1) and the outer shell (3) are connected by threads.

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