Retractable sliding block fishing spear

Abstract

The utility model relates to a returnable sliding block fishing spear, and belongs to the field of sliding block fishing spears. A returnable sliding block fishing spear comprises an upper connector, a spear rod, a slip, a limiting block and a guide cone, the upper connector is in threaded connection with the spear rod, the spear rod is in threaded connection with the guide cone, a sliding way is arranged on the spear rod, and the sliding way comprises an upper sliding way for the slip to slide and a lower sliding way for the limiting block to slide. The upper slide way is an expanding section from the inside to the outside of the spear rod from top to bottom, the lower slide way is a reducing section from the outside to the inside of the spear rod from top to bottom, and a limiting block is installed on the lower slide way at the joint of the upper slide way and the lower slide way in a sliding mode and located through a shear pin. And the outer side of the limiting block and the upper slideway form a continuous slideway for limiting the stroke of the slip. The fishing spear is simple in operation mode and high in fishing and unfreezing success rate for fishing falling objects and unfreezing.

Description

TECHNICAL FIELD

[0001] The utility model relates to a retractable sliding block spear belongs to the sliding block spear field. BACKGROUND

[0002] The spear is a kind of internal fishing tool for fishing downhole dropouts, ensures that wellbore is unobstructed, and the dropouts mainly include drill pipe, tubing, liner pipe, liner, packer and other tools with internal hole, when it is fished into well, it can be effectively fished out, and it can also be used for reverse make-up operation or cooperate with other tools, and has been widely applied in workover operation construction.

[0003] The types of spear include reverse make-up spear, sliding block spear, coupling spear and the like, wherein the sliding block spear is a kind of spear commonly used when fishing downhole.The sliding block spear mainly includes upper joint, spear shaft, sliding block slipper, lock block and screw and the like.When the sliding block spear enters fish cavity, the slipper slides down by gravity, and the radial component force generated by the upward movement of inclined surface forces the slipper to bite the inner wall of dropout, so as to realize fishing.However, when the sliding block spear successfully fishes on site and cannot be unblocked, it is necessary to withdraw the fishing tool, and since the slipper bites the inner wall of dropout and cannot move up and down, the tool cannot be withdrawn, which can cause damage to the tool itself or downhole equipment, increase the difficulty of processing, complicate downhole accidents, and affect the overall progress and efficiency of production plan when using jar or other special tools to attempt unblocking.Therefore, the use of retractable sliding block spear is extremely important for the case that the state of downhole dropout is not clear.

[0004] The Chinese utility model patent with the authorization announcement date of March 7, 2012 and the authorization announcement number of CN202157775U discloses a retractable double sliding block spear, mainly composed of upper joint, limiting pipe, compression spring, inner pipe, guide mechanism, sliding block, sliding sleeve and spear pipe, the sliding block is embedded in the rectangular hole on the spear pipe, the inner wall conical surface of the sliding block cooperates with the sliding sleeve to realize fishing, and the movement of the inner pipe is controlled by the compression spring and the guide mechanism.When the spear pipe enters fish, the fishing pipe string is pressed down, the guide sleeve slides up and compresses the compression spring, the guide pin enters the long track groove on the outer wall of the inner pipe, then the fishing pipe string is lifted up, the compression spring pushes the guide sleeve to move downward relatively, and the sliding block presents the fishing state;when fishing is blocked and needs to be withdrawn, the fishing pipe string is lowered, the fish pushes the guide sleeve to move upward relatively, the guide pin enters the short track groove on the outer wall of the inner pipe, the sliding sleeve moves upward, drives the sliding block to be in the state of minimum outer diameter, and realizes the safe withdrawal of the sliding block spear.The sliding block spear needs to rely on the inner pipe to control the position of the sliding sleeve to realize the functions of fishing and withdrawal, the structure is complex, the wall thickness of pressure-bearing part is thin, and the correlation between structures is strong, so that the structures can easily affect each other when fishing or unblocking, thereby reducing the unblocking success rate. UTILITY MODEL CONTENTS

[0005] The purpose of this invention is to provide a retractable slider spear retriever to solve the problem of low success rate of unlocking in existing slider spear retrievers.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows:

[0007] A retractable sliding spear includes an upper connector, a spear shaft, a slip, a limiting block, and a guide cone. The upper connector is threadedly connected to the spear shaft, and the spear shaft is threadedly connected to the guide cone. The spear shaft is provided with a slide rail, which includes an upper slide rail for sliding the slip and a lower slide rail for sliding the limiting block. The upper slide rail is an expanding section from the inside to the outside of the spear shaft from top to bottom, and the lower slide rail is a contracting section from the outside to the inside of the spear shaft from top to bottom. A limiting block is slidably installed on the lower slide rail at the junction of the upper and lower slide rails and is positioned by a shear pin, so that the outer side of the limiting block and the upper slide rail form a continuous slide rail for limiting the stroke of the slip.

[0008] This invention relates to an improved retractable slider spear retriever. The invention utilizes an upper and lower sliding track, with a matching limiting slider on the lower track. The outer side of the limiting slider is a continuous track aligned with the upper track. The upper track and limiting slider ensure that the slips slide down under their own weight until they contact and lock the object's inner wall. Lifting the drill string completes the retrieval. If the object cannot be released, the drill string is continued to be lifted to the designed load. After the slider descends and shears the shear pin, it continues to slide down the narrowed section of the lower track, causing the slips to disengage from the object's inner wall. Lifting the drill string retrieves the spear. This invention offers a simple structure and a thicker, pressure-bearing wall, improving the success rate of retrieval and release.

[0009] Preferably, the structure of the outer slide rail of the limiting block is the same as that of the upper slide rail. When the structures of the two slide rails are the same, the resistance to the sliding of the slip can be reduced, and the construction efficiency can be improved.

[0010] Preferably, the outer slide and upper slide of the limiting block are dovetail keys or dovetail grooves that are compatible with the locking mechanism.

[0011] Preferably, the sliding track is a dovetail key or dovetail groove adapted to the limiting block.

[0012] Preferably, the sliding track is provided with a limiting screw above the limiting block to prevent the limiting block from sliding upward.

[0013] Preferably, the bottom of the limiting block is provided with an integrally formed limiting boss for supporting the slip. The integrally formed limiting block provides a better limiting effect for the slip and can withstand a higher lifting load.

[0014] Preferably, the spear shaft is provided with two sets of sliding tracks, which are distributed vertically along the axial direction of the spear shaft and located on both sides of the spear shaft. The two sets of sliding tracks distributed on both sides of the spear shaft can increase the contact area between the catch and the inner wall of the falling object, better lock the falling object, and further improve the retrieval capability of the spear. Attached Figure Description

[0015] Figure 1 This is a front view of the retractable slider spear of Embodiment 1 of this utility model;

[0016] Figure 2 This is a right view of the retractable slider spear of Embodiment 1 of this utility model;

[0017] Figure 3 This utility model Figure 1 A schematic diagram of the AA-direction cross-section;

[0018] Among them, 1-upper connector, 2-extension rod, 3-spear rod, 4-slider collet, 5-limiting slider, 6-shear pin, 7-guide cone, 8-limiting screw, 31-upper slide, 32-lower slide, 51-dovetail key. Detailed Implementation

[0019] Existing technologies for retrieving downhole objects and unsticking them using a retrieval spear are complex and have a low success rate. To address this issue, this application proposes a continuous upper and lower sliding track on the retrieval spear. The upper track allows the slips to slide freely during object retrieval, while the lower track features a limiting slider. The outer side of the limiting slider has a continuous track connecting to the upper track, allowing the slips to slide and locking in place when the object is retrieved, ensuring successful retrieval. When unsticking is required, the tubing string is raised to the design load, causing the shear pin below the limiting slider to break. The limiting slider then pulls the slips into the narrowed section of the lower track, disengaging them from the contact surface with the inner wall of the object, thus successfully unsticking them.

[0020] The technical solution of this utility model will be further described below with reference to specific embodiments.

[0021] The specific embodiments of the retractable slider spear of this utility model are as follows:

[0022] Example 1

[0023] The retractable slider spear of this embodiment has the following front view: Figure 1 As shown, the right view is as follows Figure 2 As shown, the cross-sectional view along direction AA is as follows. Figure 3As shown, the device specifically includes an upper connector 1, a spear 3, a slider chuck 4, a limiting slider 5, and a guide cone 7. The upper connector 1 is threadedly connected to the spear 3 and the guide cone 7 in sequence. The spear 3 is provided with a slide rail, which includes an upper slide rail 31 for sliding the slider chuck 4 and a lower slide rail 32 for sliding the limiting slider 5. The upper slide rail 31 is an expanding section from the inside to the outside of the spear 3 from top to bottom, and the lower slide rail 32 is a narrowing section from the outside to the inside of the spear 3 from top to bottom. The limiting slider 5 sits on the shear pin 6 of the lower slide rail 32 for releasing the clip, and the lower slide rail 32 is provided with a limiting screw 8 above the limiting slider 5 to prevent the limiting slider 5 from moving upward when the spear is lowered, thus affecting the retrieval. The limiting slider 5 is provided with a limiting boss for positioning the slider chuck 4. The outer side of the limiting slider 5 and the upper slide rail 31 form a continuous slide rail for the slider chuck 4 to retrieve the fallen object. In this embodiment, the outer slides of the upper slide 31, the lower slide 32, and the limiting slider 5 are all dovetail keys 51. The inner side of the slider 4 is a dovetail groove adapted to the upper slide 31 and the limiting slider 5, and the inner side of the limiting slider 5 is a dovetail groove adapted to the lower slide 32. In other embodiments, the outer sides of the upper slide 31, the lower slide 32, and the limiting slider 5 can also be dovetail grooves, T-shaped slides, or trapezoidal slides.

[0024] To increase the length of the spear, an extension rod 2 is connected between the upper connector 1 and the spear shaft 3. The upper connector 1 is threadedly connected to the extension rod 2 and the spear shaft 3 in sequence.

[0025] In order to increase the contact area between the spear and the inner wall of the object and improve the success rate of retrieval, the spear shaft 3 is provided with two sets of sliding tracks along its axial direction, namely double sliding tracks, and the two sets of sliding tracks are distributed on different sides of the spear shaft 3.

[0026] When in use, the slider slip 4 is in the released state and can move freely up and down. Depending on the location to be retrieved, the retrieval spear is connected to the drill string and lowered into the wellbore. Once inside the string to be retrieved, the slider slip 4 moves upward. When the object is retrieved and the drill string is lifted, the slider slip 4 moves downward to the bottom of the limiting slider 5 and is locked. Lifting the drill string will retrieve the object that fell into the well.

[0027] When a situation arises where the tool cannot be released and needs to be unlocked, continue to lift the tubing string until it reaches the design load of the shear pin 6 supporting the limit slider 5. After shearing the shear pin 6, the limit slider 5 will descend. The limit slider 5 will continue to descend, causing the slider slip 4 to slide down the narrow section of the slide channel 32, so that the slider slip 4 will detach from the inner wall of the fallen object. Then, the drill string can be lifted to retrieve the spear.

Claims

1. A retractable sliding block spear, comprising an upper connector, a spear shaft, a locking jaw, a limiting block, and a guide cone, wherein the upper connector is threadedly connected to the spear shaft, and the spear shaft is threadedly connected to the guide cone, characterized in that, The spear shaft is provided with a slide rail, which includes an upper slide rail for sliding the slip and a lower slide rail for sliding the limiting block. The upper slide rail is an expanding section from the inside to the outside of the spear shaft from top to bottom, and the lower slide rail is a narrowing section from the outside to the inside of the spear shaft from top to bottom. A limiting block is slidably installed on the lower slide rail at the junction of the upper and lower slide rails and is positioned by a shear pin, so that the outer side of the limiting block and the upper slide rail form a continuous slide rail for limiting the slip stroke.

2. The retractable sliding block spear according to claim 1, characterized in that, The structure of the outer slide of the limiting block is the same as that of the upper slide.

3. The retractable sliding block spear according to claim 2, characterized in that, The outer and upper slides of the limiting block are dovetail keys or dovetail grooves that are compatible with the locator.

4. The retractable sliding block spear according to claim 2, characterized in that, The sliding track is a dovetail key or dovetail groove adapted to the limiting block.

5. The retractable sliding block spear according to claim 1, characterized in that, The sliding track has a limiting screw above the limiting block to prevent the limiting block from sliding upwards.

6. The retractable sliding block spear according to any one of claims 1-5, characterized in that, The bottom of the limiting block is provided with an integrally formed limiting boss for supporting the slip.

7. The retractable sliding block spear according to any one of claims 1-5, characterized in that, The spear shaft is provided with two sets of sliding tracks, and the two sets of sliding sleeves are distributed up and down along the axial direction of the spear shaft and are located on both sides of the spear shaft.

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