Self-locking universal slip device

Abstract

The application discloses a self-locking universal slip device, which comprises a fixed base, a rotating mechanism, a swing slip body, a clamping jaw plate and a driving mechanism; the rotating mechanism is connected to the fixed base and can rotate concentrically around the fixed base; one end of the swing slip body is hinged to the fixed base, the other end is slidably connected to the rotating mechanism, and the third end is hinged to the clamping jaw plate; the clamping jaw plate is connected to the fixed base through a radial guide mechanism; the swing slip body and the clamping jaw plate are both provided with multiple groups correspondingly; the driving mechanism can drive the rotating mechanism to rotate around the fixed base, the rotating mechanism drives the swing slip body to swing through the sliding connection, and then drives the clamping jaw plate to move towards (away from) the center along the radial guide mechanism, so that clamping (opening) is realized; the self-locking universal slip device can safely and efficiently clamp a pipe column, avoids the situation that the pipe column is clamped by a heavy load jaw plate and cannot be opened, and essentially improves the operation safety of the pipe column.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field well workover tubing tripping and tripping equipment, and in particular to a self-locking universal slip device. Background Technology

[0002] Oil and water wells and gas wells in oil and gas fields need to be inspected and maintained during the working cycle. Normally operating oil and water wells and gas wells have high well pressure. Due to different well conditions in oil fields, shallow wells (within 2500m) and low-pressure wells (wellhead pressure not higher than 10MPa) use clamp-type universal slips for tubing string control, while deep wells (depth above 2500m) and high-pressure wells (wellhead pressure greater than 10MPa) use conical self-tightening slip sets for tubing string control. Currently, the opening and closing mechanism of universal clamps is horizontal movement. This is achieved by the independent operation of two cylinders at each end of the clamp, pushing the clamp body horizontally. Due to differences in cylinder manufacturing precision and structural friction, it's difficult for both cylinders to reach the center position simultaneously, causing the tubing column to become eccentric and affecting its safety. Furthermore, under load, the downward or upward force of the tubing column generates a horizontal counter-force on the clamps. Due to limitations in cylinder size and the hydraulic system, continuous hydraulic power is required to ensure reliable clamping force. If the hydraulic system malfunctions and stops, the tubing column risks falling or flying off. In contrast, the opening and closing mechanism of the conical self-tightening clamp assembly is vertical swing opening and closing. Because it uses a combination of anti-overturning and load-bearing clamps, the overall size of the clamp assembly is tall. Operation requires following a specific logical sequence for opening and closing the clamps. If the clamps become stuck, the tubing column must be forcibly moved to open them, making the operation cumbersome and inefficient.

[0003] Currently, common solutions to hydraulic power failures are: first, when the hydraulic system loses power, use the pressure of the accumulator to close the safety slips and lock the mechanical lock to ensure the safety of the tubing string; second, configure a backup hydraulic power system so that if one hydraulic power system fails, the other will start immediately to ensure construction safety.

[0004] To address the issues of jamming and cumbersome operation associated with self-tightening slips, CN 115977557 A discloses a live-line hydraulic pipe lifting control device that uses disc springs instead of traditional compression springs. This device, with its four sets of disc spring assemblies, prevents slip locking, improves equipment efficiency, and effectively reduces labor intensity. However, this device requires manual verification of the compression status of the four sets of slips. The fixed slip assembly is located below the operating platform, presenting a visual obstruction for the operator while standing on the platform. Furthermore, the operator must strictly adhere to the logical sequence of actions for extended periods. Any operational error could result in pipe flying out or falling.

[0005] None of the above problems have been fundamentally resolved.

[0006] Therefore, it is evident that the existing slip devices used in live well workover and tubing string tripping operations in oil and gas fields still have inconveniences and defects in terms of structure, method, and use, and urgently need further improvement. How to create a new self-locking universal slip device to replace the existing universal slips and self-tightening slip assemblies, and achieve inherent safety in live well workover and tubing string tripping operations in oil and gas fields, has become a pressing goal for the industry. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a new self-locking universal slip device to replace the existing universal slips and self-tightening slip assemblies. It can not only safely and efficiently clamp the tubing string, but also avoid the tubing string being stuck under heavy load and unable to be opened, thus realizing the inherent safety of tubing string tripping operations in oil and gas fields under pressure, thereby overcoming the shortcomings of the existing technology.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A self-locking universal clamping device includes a fixed base, a rotating mechanism, a swinging clamping body, a clamping jaw, and a driving mechanism. The rotating mechanism is connected to the fixed base and can rotate concentrically around the fixed base. The driving mechanism is connected to both the fixed base and the rotating mechanism. The swinging clamping body and the clamping jaw are disposed within the fixed base. One end of the swinging clamping body is hinged to the fixed base, the other end is slidably connected to the rotating mechanism, and the third end is hinged to the clamping jaw. The clamping jaw is connected to the fixed base via a radial guide mechanism. Multiple sets of the swinging clamping body and the clamping jaw are correspondingly provided. During clamping operations, the… The drive mechanism drives the rotating mechanism to rotate around the fixed base. The rotating mechanism drives the swinging jaw body to swing through a sliding connection, which in turn drives the clamping jaw plate to move towards the center along the radial guide mechanism, thus achieving clamping. After clamping, the hinge of the swinging jaw body with the clamping jaw plate is located between the sliding connection between the swinging jaw body and the rotating mechanism and the hinge between the swinging jaw body and the fixed base, forming a self-locking mechanism. When opening, the drive mechanism reverses and drives the rotating mechanism to rotate around the fixed base. The rotating mechanism drives the swinging jaw body to swing through a sliding connection, which in turn drives the clamping jaw plate to move away from the center along the radial guide mechanism, thus achieving opening.

[0010] As a further improvement of the present invention, the rotating mechanism includes a cylindrical rotating housing, and multiple sets of fixed cam-type structures are provided inside the cylindrical rotating housing. The fixed cam-type structure includes a radial protrusion connected inside the cylindrical rotating housing. A central shaft and a roller connected to the central shaft are provided on the radial protrusion. The roller is in close contact with the roller slide provided on the swinging jaw body. Under the drive of the rotating mechanism, the roller can roll along the roller slide on the swinging jaw body, causing the swinging jaw body to swing along the hinge point with the fixed base, thereby causing the clamping jaw plate on the swinging jaw body to perform clamping and opening actions.

[0011] Furthermore, the middle section of the swinging chuck body is provided with a protruding body receiving cavity, and the upper and lower surfaces of the swinging chuck body are provided with roller tracks; a roller is provided at the upper and lower ends of the central shaft at the radial protrusion end, respectively in close contact with the roller tracks provided on the upper and lower surfaces of the swinging chuck body.

[0012] Furthermore, the fixing base includes two parts: an upper fixing base and a lower fixing base. The upper fixing base is a cover plate with a limiting protrusion, a fixing pin hole, and a fixing connection hole. The lower fixing base has multiple sets of fixing pins for installing the swinging slip body, which pass through the fixing pin holes on the cover plate to achieve the hinge connection between the fixing base and the swinging slip body. The lower fixing base also has a limiting notch and a fixing connection hole corresponding to the cover plate, and is connected to the upper fixing base as a whole by bolts.

[0013] Furthermore, the lower fixing base is provided with multiple sets of radial guide grooves, and the bottom of the clamping jaw is provided with a radial guide key, which moves along the radial guide groove.

[0014] Furthermore, the upper and lower fixed bases are respectively provided with drive mechanism connection holes, which are connected to the drive mechanism via pins; the rotating mechanism is also provided with drive mechanism connection holes, which are connected to the drive mechanism via pins.

[0015] Furthermore, the clamping jaw plate includes a jaw plate seat and two jaw plates. The two jaw plates are connected to the built-in jaw plate groove of the jaw plate seat by jaw plate fixing pins. There is a swing space between the jaw plates and the built-in jaw plate groove. The jaw plate seat is hinged to the third end of the swinging jaw body by a jaw plate seat pin.

[0016] Furthermore, the clamping jaw plate is a replaceable jaw plate during assembly, and different jaw plates are used depending on the pipe diameter.

[0017] Furthermore, the driving mechanism is a driving cylinder, with one end connected to the fixed base and the other end connected to the rotating mechanism. It drives the rotating mechanism to rotate around the fixed base by extending; and drives the rotating mechanism to rotate around the fixed base by retracting in the opposite direction; and / or, the swinging jaw body and the clamping jaw are each provided with three sets.

[0018] Furthermore, the self-locking universal slip device is a self-locking universal slip device used in pressurized well workover operations in oil and gas fields for running and pulling tubing.

[0019] By adopting the above technical solution, the present invention has at least the following advantages:

[0020] The self-locking universal clamping device of the present invention drives the swinging clamping jaws to swing through a rotating mechanism, which in turn drives the clamping jaws to move closer to the center. The self-locking state formed after the rotating mechanism and the swinging clamping jaws are pre-tightened achieves reliable clamping of the pipe column. It realizes the synchronous operation of multiple sets of swinging clamping jaws and clamping jaws, which can not only clamp the pipe column safely and efficiently, but also avoid the pipe column being stuck under heavy load and unable to be opened, thus fundamentally improving the operational safety of the pipe column. Attached Figure Description

[0021] The above is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 This is a schematic diagram illustrating the self-locking principle of a self-locking universal slip device according to the present invention;

[0023] Figure 2 This is a schematic diagram of the exploded state structure of a self-locking universal slip device according to the present invention;

[0024] Figure 3 This is a schematic diagram of the clamping state structure of a self-locking universal slip device according to the present invention;

[0025] Figure 4 This is a schematic diagram of the open state of a self-locking universal slip device according to the present invention;

[0026] Figure 5 This is a schematic diagram of the rotating mechanism structure of a self-locking universal slip device according to the present invention;

[0027] Figure 6 This is a schematic diagram of the upper and lower fixing base structure of a self-locking universal slip device according to the present invention;

[0028] Figure 7 This is a schematic diagram of the clamping jaw structure of a self-locking universal slip device according to the present invention;

[0029] Figure 8 This is a schematic diagram of the tooth plate installation of a self-locking universal locking device according to the present invention.

[0030] In the diagram: 1-Fixed base; 2-Rotating mechanism; 3-Oscillating slip; 4-Clamping jaw plate; 5-Drive mechanism; O1-Hinge between the oscillating slip and the fixed base (fixed rotation center); O2-Sliding connection between the oscillating slip and the rotating mechanism (cam structure rotation center); O3-Hinge between the oscillating slip and the clamping jaw plate (jaw plate force center); F2-Force exerted by the cam structure on the oscillating slip when clamping the tube column; F3-Force exerted by the tube column load on the oscillating slip when clamping the tube column; 11-Upper fixed base; 12-Lower fixed base; 111-Limiting protrusion; 112-Fixed 113 - Pin hole; 115 - Fixed connection hole; 121 - Drive mechanism connection hole; 122 - Limiting notch; 123 - Fixed pin; 124 - Radial guide groove; 125 - Drive mechanism connection hole; 201 - Cylindrical rotating housing; 202 - Radial protrusion; 203 - Central shaft; 204 - Roller; 205 - Drive mechanism connection hole; 301 - Protrusion receiving cavity; 302 - Roller slideway; 401 - Tooth plate seat; 402 - Tooth plate; 403 - Tooth plate fixing pin; 404 - Internal tooth plate groove; 405 - Tooth plate seat pin; 406 - Radial guide key. Detailed Implementation

[0031] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that a more thorough understanding of the invention will be achieved and that the full scope of the invention will be conveyed to those skilled in the art.

[0032] This invention provides a self-locking universal slip device that can be applied to well workover operations in oil and gas fields, ensuring operational safety.

[0033] like Figure 1-2 As shown, a self-locking universal locking device of this embodiment includes a fixed base 1, a rotating mechanism 2, a swinging locking body 3, a clamping jaw 4, and a driving mechanism 5. The rotating mechanism 2 is connected to the fixed base 1 and can rotate concentrically around the fixed base 1; the driving mechanism 5 is connected to both the fixed base 1 and the rotating mechanism 2 and can drive the rotating mechanism 2 to rotate around the fixed base 1.

[0034] The swinging jaw 3 and the clamping jaw 4 are disposed within the fixed base 1. Multiple sets of both can be disposed, and in this embodiment, three sets are preferably disposed. One end of the swinging jaw 3 is hinged to the fixed base 1, and O1 is the hinge point between the swinging jaw 3 and the fixed base 1 (fixed rotation center). The other end of the swinging jaw 3 is slidably connected to the rotating mechanism 2, and O2 is the slidable connection point between the swinging jaw 3 and the rotating mechanism 2 (cam structure rotation center). The third end of the swinging jaw 3 is hinged to the clamping jaw 4, and O3 is the hinge point between the swinging jaw 3 and the clamping jaw 4 (jaw plate force center). The clamping jaw 4 is connected to the fixed base 1 through a radial guide mechanism.

[0035] Cooperate Figure 1 , 3 As shown, during clamping, the drive mechanism 5 drives the rotating mechanism 2 to rotate around the fixed base 1. The rotating mechanism 2 drives the swinging jaw 3 to swing through a sliding connection, which in turn drives the clamping jaw 4 to move towards the center along the radial guide mechanism, thereby clamping the pipe column. After clamping the pipe column, the swinging jaw 3, at its hinge point with the clamping jaw 4 (corresponding to...) Figure 1 Point O3 in the diagram is located at its sliding connection with the rotating mechanism (corresponding to...) Figure 1 (point O2 in the middle) and its hinge with the fixed base (corresponding to Figure 1 Between point O1 in the middle, after the column is clamped, it can be concluded from the basic mechanics knowledge that the mechanism is in a self-locking state: no matter how big the force of F3 is, as long as the strength of the mechanism itself is not a problem, the rotating mechanism 2 will not move backward, so the clamping tooth plate 4 will not move, so that the swinging jaw body 3 and the rotating mechanism 2 form a self-locking structure, realizing the mechanism self-locking.

[0036] Cooperate Figure 4 As shown, when the operation is started, the drive mechanism 5 drives the rotating mechanism 2 to rotate around the fixed base 1 in the opposite direction. The rotating mechanism 2 drives the swinging jaw body 3 to swing through the sliding connection, which in turn drives the clamping jaw 4 to move away from the center along the radial guide mechanism, thereby opening and releasing the tubing.

[0037] The preferred structures of each part will be further described below with reference to the accompanying drawings:

[0038] Cooperate Figure 2 , Figure 5 As shown, the rotating mechanism 2 includes a cylindrical rotating housing 201. The cylindrical rotating housing 201 is provided with three sets of fixed cam-type structures, including radial protrusions 202 connected to the cylindrical rotating housing 201. A central shaft 203 and rollers 204 connected to the central shaft 203 are provided on the radial protrusions 202. Preferably, two rollers 204 are provided at the same time, located at the upper and lower ends of the central shaft 203 respectively.

[0039] The middle section of the swinging chuck body 3 is provided with a protrusion receiving cavity 301, and the upper and lower surfaces of the swinging chuck body 3 are provided with roller slides 302; during assembly, the radial protrusion 202 is placed into the protrusion receiving cavity 301, and the roller 204 is in close contact with the roller slide 302.

[0040] The drive mechanism 5 drives the rotating mechanism 2 to rotate around the fixed base 1. The radial protrusion 202 of the rotating mechanism 2 drives the roller 204. When the roller 204 is driven by the rotating mechanism 2, it can roll along the roller slide 302 on the swinging slip body 3, causing the swinging slip body 3 to swing along its hinge with the fixed base 1, thereby causing the clamping tooth plate 4 on the swinging slip body 3 to perform clamping and opening actions.

[0041] Cooperate Figure 2 , Figure 6 As shown, the fixing base 1 comprises two parts: an upper fixing base 11 and a lower fixing base 12. The upper fixing base 11 is a cover plate, on which a limiting protrusion 111, a fixing pin hole 112, and a fixing connection hole 113 are provided. The lower fixing base 12 is provided with a limiting notch 121 corresponding to the cover plate, a fixing pin 122, and a fixing connection hole 123. The fixing pin 121 is used to install the swinging slip body 3. It passes through the rotary pin hole provided on the swinging slip body 3 and then further passes through the fixing pin hole 112 on the cover plate to achieve the hinge connection between the fixing base 1 and the swinging slip body 3. The upper fixing base 11 and the lower fixing base 12 are connected as a whole by bolts inserted into the fixing connection holes 113 and 123.

[0042] Three sets of radial guide grooves 124 are also provided on the lower fixed base 12 for guiding the clamping jaw plate 4. In addition, drive mechanism connection holes 115 and 125 are respectively provided on the upper fixed base 11 and the lower fixed base 12, which are connected to the drive mechanism 5 through pins; Figure 5 As shown, the rotating mechanism 2 is also provided with a drive mechanism connection hole 205, which is connected to the drive mechanism 5 through a pin.

[0043] Cooperate Figure 7 , 8 As shown, the clamping jaw plate 4 includes a jaw plate seat 401 and two jaw plates 402. The two jaw plates 402 are connected to the jaw plate seat 401 in the built-in jaw plate groove 404 by jaw plate fixing pins 403. There is a swing space between the jaw plates 402 and the built-in jaw plate groove 404, forming a certain range of swing angles to automatically adapt to changes in the clamping angle. The jaw plate seat 401 is hinged to the pin hole on the third end of the swinging jaw body 3 by a jaw plate seat pin 405. A radial guide key 406 is provided at the bottom of the clamping jaw plate 4. The radial guide key 406 can move along the radial guide groove 124 on the lower fixed base 12.

[0044] Preferably, the clamping jaw plate 402 is a replaceable jaw plate during assembly, and different jaw plates can be replaced according to different pipe diameters.

[0045] The drive mechanism 5, driven by power, enables the relative rotation of the rotating mechanism 2 and the fixed base 1, thereby causing the internal swinging locking body 3 to swing. The drive mechanism 5 is preferably a drive cylinder, with one end connected to the fixed base 1 and the other end connected to the rotating mechanism 2. Extending it drives the rotating mechanism 2 to rotate around the fixed base 1; retracting it drives the rotating mechanism 2 to rotate around the fixed base 1 in the opposite direction. Of course, the form of drive power can vary, as long as it achieves this function.

[0046] In this embodiment, multiple sets of swinging slip bodies 3 and clamping jaws 4 are evenly distributed on the fixed base 1, and synchronous movement is achieved through the rotating mechanism 2, thereby achieving all-round clamping of the pipe column, ensuring that the pipe column is completely centered. The driving mechanism 5 can drive the rotating mechanism 2 to rotate around the fixed base 1, and the roller 204 drives the swinging slip body 3 to swing, thereby pushing the clamping jaws 4 to the pipe column clamping position. At this time, the position point of the roller on the swinging slip body 3 passes the force point of the clamping jaws 4, forming a self-locking mechanism. When the horizontal thrust generated by the drop of the pipe column increases, due to the self-locking mechanism, the greater the horizontal thrust, the more firmly the pipe column is clamped. At this time, the driving mechanism 5 is basically unaffected by this increase in horizontal force, thereby reducing the requirement for hydraulic clamping force. When it is necessary to open the slip, the driving mechanism 5 acts in the opposite direction, and the swinging slip body 3 drives the clamping jaws 4 to retract radially, without any jamming of the clamping jaws. The structural components are strong enough. The swing arm self-locking structure formed by the rotating mechanism 2 and the swinging slip body essentially ensures the inherent safety of the pipe column operation. The clamping tooth plate 4 achieves radial centering movement along the pipe column under the action of the roller 204 and the swinging slip body 3, which improves the centering and clamping accuracy and opening reliability, thereby improving the operation efficiency.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, or alterations made by those skilled in the art using the disclosed technical content shall fall within the protection scope of the present invention.

Claims

1. A self-locking universal slip device, characterized in that, Includes a fixed base, a rotating mechanism, a swinging jaw body, a clamping jaw, and a drive mechanism; The rotating mechanism is connected to the fixed base and can rotate concentrically around the fixed base; the driving mechanism is connected to both the fixed base and the rotating mechanism. The swinging jaw and clamping jaw are disposed within the fixed base; one end of the swinging jaw is hinged to the fixed base, the other end is slidably connected to the rotating mechanism, and the third end is hinged to the clamping jaw; the clamping jaw is connected to the fixed base through a radial guide mechanism; multiple sets of the swinging jaw and clamping jaw are provided respectively. During clamping, the drive mechanism drives the rotating mechanism to rotate around the fixed base. The rotating mechanism drives the swinging jaw body to swing through the sliding connection, which in turn drives the clamping jaw plate to move towards the center along the radial guide mechanism to achieve clamping. After clamping, the hinge of the swinging jaw body and the clamping jaw plate is located between the sliding connection between the swinging jaw body and the rotating mechanism and the hinge between the swinging jaw body and the fixed base, forming a self-locking mechanism. When the opening operation is performed, the drive mechanism reverses and drives the rotating mechanism to rotate around the fixed base. The rotating mechanism drives the swinging jaw body to swing through the sliding connection, which in turn drives the clamping jaw to move away from the center along the radial guide mechanism, thus realizing the opening.

2. The self-locking universal slip device according to claim 1, characterized in that, The rotating mechanism includes a cylindrical rotating housing, within which multiple sets of fixed cam structures are arranged. Each fixed cam structure includes a radial protrusion connected within the cylindrical rotating housing, a central shaft and rollers connected to the central shaft on the radial protrusion, and the rollers are in close contact with roller tracks on the swinging jaws. Driven by the rotating mechanism, the rollers can roll along the roller tracks on the swinging jaws, causing the swinging jaws to swing along the hinge point with the fixed base, thereby causing the clamping jaws on the swinging jaws to perform clamping and opening actions.

3. The self-locking universal slip device according to claim 2, characterized in that, The middle section of the swinging chuck body is provided with a protruding body receiving cavity, and the upper and lower surfaces of the swinging chuck body are provided with roller tracks; the upper and lower ends of the central shaft at the radial protrusion end are each provided with a roller, which is in close contact with the roller tracks provided on the upper and lower surfaces of the swinging chuck body.

4. The self-locking universal slip device according to any one of claims 1-3, characterized in that, The fixing base consists of two parts: an upper fixing base and a lower fixing base. The upper fixing base is a cover plate, which is provided with a limiting protrusion, a fixing pin hole and a fixing connection hole; the lower fixing base is provided with multiple sets of fixing pins for installing the swinging slip body, and passes through the fixing pin holes on the cover plate to realize the hinge connection between the fixing base and the swinging slip body; the lower fixing base is also provided with a limiting notch and a fixing connection hole corresponding to the cover plate, and is connected to the upper fixing base as a whole by bolts.

5. The self-locking universal slip device according to claim 4, characterized in that, The lower fixing base is provided with multiple sets of radial guide grooves, and the bottom of the clamping tooth plate is provided with a radial guide key, which moves along the radial guide groove.

6. The self-locking universal slip device according to claim 4, characterized in that, The upper and lower fixed bases are respectively provided with drive mechanism connection holes, which are connected to the drive mechanism through pins; the rotating mechanism is also provided with drive mechanism connection holes, which are connected to the drive mechanism through pins.

7. The self-locking universal slip device according to any one of claims 1-3, characterized in that, The clamping jaw plate includes a jaw plate seat and two jaw plates. The two jaw plates are connected to the built-in jaw plate groove of the jaw plate seat by jaw plate fixing pins. There is a swing space between the jaw plates and the built-in jaw plate groove. The tooth plate seat is hinged to the third end of the swinging jaw body via a tooth plate seat pin.

8. The self-locking universal slip device according to claim 7, characterized in that, The clamping jaw plate is a replaceable jaw plate during assembly, and different jaw plates are used depending on the pipe diameter.

9. The self-locking universal slip device according to any one of claims 1-3, characterized in that, The driving mechanism is a driving cylinder, with one end connected to the fixed base and the other end connected to the rotating mechanism. It extends to drive the rotating mechanism to rotate around the fixed base; it retracts to drive the rotating mechanism to rotate around the fixed base in the opposite direction. And / or, the swinging jaws and clamping teeth are each provided with three sets.

10. The self-locking universal slip device according to any one of claims 1-3, characterized in that, The self-locking universal slip device is a self-locking universal slip device used in pressurized well workover operations in oil and gas fields for running and pulling tubing.

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