Floating load-bearing slip flashboard used for under-pressure operation and use method of floating load-bearing slip flashboard

Abstract

The invention discloses a floating load-bearing slip flashboard for under-pressure operation and a using method, and belongs to the technical field of under-pressure workover treatment. The floating load-bearing slip flashboard comprises a flashboard body, a slip bowl, a positioning shaft and a reset spring; according to the scheme, through the floating design of the slip bowl, impact force is transferred to the reset spring, the flashboard body only bears the weight of a static tubular column, dynamic loads are absorbed by the spring, the situation that the flashboard body structure is fatigued or even damaged due to instantaneous impact force is avoided, the service life of the valve plate body structure is prolonged, and the operation cost is reduced. The slip bowl can float up and down along the positioning shaft, in the shearing or fishing process, the axial displacement of the tubular column is adjusted in a self-adaptive mode through movement of the slip bowl, manual intervention is not needed, and the problem that a traditional flashboard can only statically fix the tubular column and cannot adapt to the position of the tubular column needing to be dynamically adjusted is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of workover operations under pressure, and specifically relates to a floating load-bearing slip ram and its usage method for workover operations under pressure. Background Art

[0002] In workover operations under pressure, the load-bearing slip ram is a key device for fixing the downhole string, used to prevent the string from flying out or falling into the well under the action of wellbore pressure. The traditional load-bearing slip ram adopts a rigid fixing method and realizes fixation by the slip teeth biting with the surface of the string. However, with the increase in the complexity of workover techniques, especially in scenarios involving shearing the string and fishing for the fracture, the following technical problems are exposed in the prior art: 1. When the traditional ram shears the string, the downward pressure exerted by the shear blade is directly transmitted to the ram body through the string, resulting in the deformation of the fracture of the lower half of the sheared string. The deformed fracture is difficult to match with the fishing tool, significantly reducing the fishing success rate.

[0003] 2. The instantaneous impact force generated during the shearing process will cause the fatigue or even damage of the ram body structure, requiring frequent replacement of components and increasing the operation cost.

[0004] 3. The traditional ram can only statically fix the string and cannot adapt to workover techniques that require dynamic adjustment of the string position (such as multi-stage shearing and continuous fishing), resulting in low operation efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a floating load-bearing slip ram for workover operations under pressure, which solves the problems of direct transmission of shear impact force, deformation of the string fracture, and easy damage of equipment caused by the rigid fixation of the traditional load-bearing slip ram.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions: A floating load-bearing slip ram for workover operations under pressure, comprising: A ram body, which is composed of two symmetrically arranged valve half-plates spliced together. An axially penetrating through-hole is opened in the middle of the ram body, and a hollowed-out area is provided on the inner circumferential side of the through-hole; A slip seat, which is composed of two half-slip seats spliced together; the slip seat is embedded in the hollowed-out area, and a clamping area coaxial with the through-hole is provided at its center. The inner wall of the clamping area is provided with slip teeth for biting and fixing with the circumference of the string; a plurality of through-holes are circularly arranged around the axis of the through-hole in the slip seat, and the axes of the through-holes are parallel to the axis of the through-hole; A positioning shaft, fixed to the top of the ram body and extending downward to the hollowed-out area. The positioning shaft is slidably matched with the through-hole to enable the slip seat to move up and down axially; A return spring, sleeved on the corresponding positioning shaft, used to provide a return elastic force.

[0007] A further technical solution is that it also includes a rolling steel ball, which is arranged on the side of the slip seat away from the clamping area and contacts the inner wall of the hollowed area.

[0008] A further technical solution is that the compression stroke of the return spring matches the maximum downward displacement of the slip seat.

[0009] A further technical solution is that the surface of the slip teeth is provided with a wear-resistant coating, and the tooth shape thereof is a bidirectional sawtooth structure.

[0010] Another object of the present invention is to provide a method for using a floating load-bearing slip gate, comprising the following steps: S1. Fix the pipe string through the load-bearing slips and anti-top slips of the pressure working machine; S2, close the floating load-bearing slip gate, so that the slip seat is in the initial position under the action of the return spring; S3. When shearing the pipe string, the downward pressure applied by the shear blade is transmitted to the slip seat through the pipe string, forcing the slip seat to move downward along the positioning shaft to compress the return spring to buffer the impact force; S4. After shearing is completed, the return spring pushes the slip seat back to the initial position.

[0011] A further technical solution is to further include: S5. After the shearing is completed, the upper part of the cut pipe string is lifted up by the pressure-operated machine, the full-sealed gate is closed and the pressure is released to complete the fracture salvage.

[0012] Compared with the prior art, the present invention has the following beneficial effects: This solution transfers the impact force to the reset spring through the floating design of the slip seat. The gate body only bears the static weight of the pipe column, and the dynamic load is absorbed by the spring, avoiding the situation where the instantaneous impact force will cause fatigue or even damage to the gate body structure, thereby increasing the service life of the valve plate body structure and reducing operating costs. The slip seat can float up and down along the positioning axis. During the shearing or salvaging process, the axial displacement of the pipe column is adaptively adjusted through the movement of the slip seat without manual intervention, solving the problem that the traditional gate can only statically fix the pipe column and cannot adapt to the need to dynamically adjust the position of the pipe column. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration: Figure 1 It is a bottom view of the floating load-bearing slip gate of the present invention.

[0014] Figure 2 It is a top view of the floating load-bearing slip gate of the present invention.

[0015] Figure 3 For the present inventionFigure 2 Cross-sectional view along the A-A direction.

[0016] Figure 4 For the present invention Figure 2 Cross-sectional view along the B-B direction.

[0017] Figure 5 Schematic diagram of the application of the floating load-bearing slip ram of the present invention.

[0018] Icons: 1 - Ram body, 2 - Slip seat, 3 - Positioning shaft, 4 - Return spring, 5 - Through hole, 6 - Hollowed-out area, 7 - Fixed groove, 8 - Through hole, 9 - Positioning hole, 10 - Fixed seat, 11 - Limit groove, 12 - Pressure-operated machine, 13 - Load-bearing slip, 14 - Anti-top slip, 15 - Shearing blade, 16 - Full-closed ram.

[0019] Ram body 1, slip seat 2, positioning shaft 3, return spring 4, through hole 5, hollowed-out area 6, fixed groove 7, through hole 8, positioning hole 9, fixed seat 10, limit groove 11, pressure-operated machine 12, load-bearing slip 13, anti-top slip 14, shearing blade 15, full-closed ram 16. Detailed implementation manners

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] Embodiment:

[0022] As Figures 1 - 5 shown, the present invention provides a floating load-bearing slip ram for pressure operation, including a ram body 1, a slip seat 2, a positioning shaft 3 and a return spring 4; the ram body 1 is composed of two axially symmetrically arranged valve half-plates spliced together, and a through hole 5 axially penetrating is opened in the middle of the ram body 1, and a hollowed-out area 6 is provided on the inner peripheral side of the through hole 5; specifically, fixing grooves 7 are opened at the outer ends of the two valve half-plates; the fixing grooves 7 of the two valve half-plates are respectively hung on the left and right piston rods, and by operating the piston, the opening or closing of the two valve half-plates can be realized.

[0023] The slip seat 2 is composed of two half-slip seats spliced together; the slip seat 2 is embedded in the hollowed-out area 6, and a clamping area coaxial with the through hole 5 is provided at its center, and slip teeth are provided on the inner wall of the clamping area for clamping and fixing the periphery of the pipe string; a plurality of through holes 8 are circularly and arrayedly distributed in the slip seat 2 with the axis of the through hole 5 as the center, and the axes of the through holes 8 are parallel to the axis of the through hole 5.

[0024] The ram body 1 is provided with positioning holes 9 penetrating through the upper and lower sides; one end of the positioning hole 9 is internally threaded with a fixed seat 10; the fixed seat 10 is provided with a threaded hole coaxial with the positioning hole 9; each positioning shaft 3 passes through the corresponding positioning hole 9 and is threadedly connected with the threaded hole of the corresponding fixed seat 10; the positioning shaft 3 is in sliding fit with the through hole 8 so that the slip seat 2 can move up and down axially.

[0025] The return spring 4 is sleeved on the corresponding positioning shaft 3 for providing return elastic force; specifically, the two slip seats 2 are staggeredly distributed in the hollow area 6; the interiors of the two slip seats 2 are respectively provided with return slots with opposite openings in the vertical direction; each return slot is coaxial with the corresponding through hole 8; each return spring 4 is sleeved on the corresponding positioning shaft 3, and one end of the return spring 4 is connected to the bottom of the return slot, and the other end of the return spring 4 is connected to the fixed seat 10.

[0026] The principle and beneficial effects of the above technical solution: When the shear blade applies a downward pressure, the pressure is transmitted to the slip seat 2 through the pipe string instead of directly acting on the ram body 1. The slip seat 2 moves downward along the positioning shaft 3, compressing the return spring 4, converting the instantaneous impact force into the elastic potential energy of the spring, and realizing dynamic buffering. The buffering effect of the spring avoids the plastic deformation of the pipe string fracture caused by rigid impact, ensures that the fracture maintains a regular shape, is more easily adapted to the fishing tool, and improves the fishing success rate. In the traditional ram, the shear impact force is directly borne by the ram body 1, which is prone to stress concentration. In this solution, through the floating design of the slip seat 2, the impact force is transferred to the return spring 4, and the ram body 1 only bears the static weight of the pipe string, and the dynamic load is absorbed by the spring, avoiding the situation that the instantaneous impact force will cause the structural fatigue or even damage of the ram body 1, improving the service life of the valve plate body structure, and reducing the operation cost. The slip seat 2 can float up and down along the positioning shaft 3. During the shearing or fishing process, the axial displacement of the pipe string is adaptively adjusted through the movement of the slip seat 2 without manual intervention, solving the problem that the traditional ram can only statically fix the pipe string and cannot adapt to the need to dynamically adjust the position of the pipe string.

[0027] Since the two slip seats 2 are arranged in a staggered manner in the hollow area 6, complementary support is formed to ensure uniform force on the pipe string and avoid the wear of the slip teeth or the deviation of the pipe string caused by unilateral eccentric load.

[0028] Each slip seat 2 is provided with vertical return slots with opposite directions, which are coaxially arranged with the through hole 8, so that the installation direction of the return spring 4 is strictly aligned with the movement direction of the slip seat 2, eliminating the interference of the transverse component force.

[0029] Through the cooperation of multiple positioning shafts 3 and limiting holes, the slip seat 2 is restricted from multiple positions, thereby restricting the circumferential rotation of the slip seat 2.

[0030] In this embodiment, a C-shaped limiting groove 11 is opened on the side of the cava seat 2 away from the clamping area; a plurality of rolling steel balls are arranged in the limiting groove 11; the rolling steel balls are in contact with the inner wall of the hollow area 6 to reduce friction resistance.

[0031] The rolling steel ball can convert sliding friction into rolling friction, and the measured friction coefficient is reduced to 0.01 (the traditional sliding friction coefficient is 0.1-0.2), and the axial movement resistance of the slip seat 2 is reduced by 90%. The C-shaped limit groove 11 can wrap the rolling steel ball to prevent it from falling off, and evenly distribute the load, so that the force of the slip seat 2 is symmetrical, reducing the risk of lateral wear. The rolling contact of the steel ball avoids scratching the inner wall of the hollowed area 6 of the gate body 1, extending the service life of both.

[0032] In this embodiment, the compression stroke of the return spring 4 matches the maximum downward displacement of the slip seat 2 to ensure complete buffering of the shear impact force.

[0033] In this embodiment, the surface of the slip teeth is provided with a wear-resistant coating, which can be made of a nickel-based alloy material, and its tooth shape is a bidirectional sawtooth structure to enhance the bite and fixation effect on the pipe column.

[0034] Another object of the present invention is to provide a method for using a floating load-bearing slip 13 gate, comprising the following steps: S1, fix the pipe column by the load-bearing slips 13 and the anti-top slips 14 of the pressure working machine 12; S2, close the gate of the floating load-bearing slip 13 to hold the pipe string, so that the slip seat 2 is in the initial position under the action of the return spring 4; lift the pipe string with pressure operation machine 12 to confirm whether the gate of the floating load-bearing slip 13 controls the pipe string; S3, when shearing the pipe string, the downward pressure applied by the shear blade 15 is transmitted to the slip seat 2 through the pipe string, forcing the slip seat 2 to move downward along the positioning shaft 3 to compress the return spring 4 to buffer the impact force; Specifically, the shear gate is used to shear the pipe column, and the oil pipe is sheared under the action of radial thrust. During the shearing process, the blade applies an upward force to the upper part of the sheared pipe column (since the upper part of the sheared pipe column is longer, the upward force applied by the blade can be ignored and has no impact), but the lower part of the sheared pipe column will also be subjected to a downward pressure by the blade. This downward pressure is transmitted to the floating load-bearing slip seat 13 through the pipe column, forcing the slip seat 2 to move downward along the axis on the gate body 1. The spring plays a buffering role at this time to avoid damage to the gate body 1 due to the impact force generated by the deadweight of the pipe column. In this way, the deformation of the fracture of the lower part caused by the influence of the downward pressure is completely eliminated, which is conducive to the salvage of the salvage tool; S4, after the shearing is completed, the return spring 4 pushes the slip seat 2 to return to the initial position; S5. Lift the upper half of the cut pipe string by the workover rig 12, close it and release the pressure to complete the fishing of the fracture opening. Specifically, the workover rig 12 lifts the upper half of the cut pipe string above the blind ram 16, closes the blind ram; releases the pressure above the blind ram 16, and removes the cut pipe string; the workover rig 12 moves two sets of slips to control the lowering of the fishing pipe string above the blind ram 16, and completes the procedure of lowering the fishing pipe string into the well according to the requirements of the workover operation procedures, and fishes the lower half of the cut pipe string.

[0035] Although the present invention has been described herein with reference to a number of illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and embodiments that will fall within the scope of the principles and spirit disclosed in this application. More specifically, within the scope of the disclosure, the drawings and the claims of this application, various variations and improvements can be made to the components and / or the layout of the subject combination layout. In addition to the variations and improvements made to the components and / or the layout, other uses will also be apparent to those skilled in the art.

Claims

1. A floating load-bearing slip gate for pressure operation, characterized in that: include: The gate body is composed of two symmetrically arranged valve half plates, an axial through hole is opened in the middle of the gate body, and a hollow area is provided on the inner circumference of the through hole; The slip seat is composed of two half-slot seats spliced ​​together; the slip seat is embedded in the hollowed-out area, and a clamping area coaxial with the through hole is provided at the center thereof, and slip teeth are provided on the inner wall of the clamping area for engaging and fixing with the peripheral side of the pipe column; a plurality of through holes are distributed in a circular array in the slip seat with the axis of the through hole as the center, and the axis of the through hole is parallel to the axis of the through hole; A positioning shaft is fixed to the top of the gate body and extends downward to the hollowed-out area, and the positioning shaft is slidably matched with the through hole to enable the slip seat to move up and down along the axial direction; The return spring is sleeved on the corresponding positioning shaft and is used to provide return elastic force.

2. The floating load-bearing slip gate for pressure operation according to claim 1, characterized in that: It also includes a rolling steel ball, which is arranged on the side of the slip seat away from the clamping area and contacts the inner wall of the hollowed area.

3. The floating load-bearing slip gate for pressure operation according to claim 1 is characterized in that: The compression stroke of the return spring matches the maximum downward displacement of the slip seat.

4. The floating load-bearing slip gate for pressure operation according to claim 1, characterized in that: The surface of the slip teeth is provided with a wear-resistant coating, and the tooth shape thereof is a bidirectional sawtooth structure.

5. A method for using a floating load-bearing slip gate for pressure operation according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Fix the pipe string through the load-bearing slips and anti-top slips of the pressure working machine; S2, close the floating load-bearing slip gate, so that the slip seat is in the initial position under the action of the return spring; S3. When shearing the pipe string, the downward pressure applied by the shear blade is transmitted to the slip seat through the pipe string, forcing the slip seat to move downward along the positioning shaft to compress the return spring to buffer the impact force; S4. After shearing is completed, the return spring pushes the slip seat back to the initial position.

6. The method for using a floating load-bearing slip gate for pressure operation according to claim 5, characterized in that: Also includes the steps: S5. After the shearing is completed, the upper part of the cut pipe string is lifted up by the pressure-operated machine, the full-sealed gate is closed and the pressure is released to complete the fracture salvage.

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