Variable diameter protection releaser for downhole pressure tester

Abstract

The present invention discloses a variable diameter protection releaser for a downhole pressure tester, comprising a connector, a locking sleeve, an upper positioning sleeve, a center pull rod, a telescopic piece, a lower positioning sleeve and a guide head, wherein one end of the center pull rod is sleeved with a connector, and the other end is sleeved with a guide head, and a telescopic piece is provided on the periphery of the center pull rod, and a gap is provided between adjacent telescopic pieces before the diameter is reduced, and the gap is closed after the diameter is reduced; one end of the telescopic piece is connected to an upper positioning sleeve sleeved on the center pull rod, and the other end is connected to a lower positioning sleeve sleeved on the center pull rod, and the lower positioning sleeve is located in the guide head, and a locking sleeve sleeved on the center pull rod is provided between the upper positioning sleeve and the connector. The above-mentioned variable diameter protection releaser is a preset component designed to prevent encountering obstacles, which greatly reduces the risk of the test instrument falling into the well by pulling, reducing the diameter and breaking off to release, thereby reducing losses and workload.

Description

Technical Field

[0001] The invention relates to the technical field of downhole pressure testing tools for oil wells, and in particular to a variable-diameter protection releaser for a downhole pressure tester. Background Art

[0002] Xinglongtai Oilfield currently operates 736 wells in normal production and performs approximately 1,500 pressure tests annually. During pressure testing, 25-30 wells annually encounter resistance during the test instrument rundown due to various reasons downhole, resulting in soft or hard stucks and the test instrument becoming stuck in the well. This requires three to four times the manpower required for normal testing to be transported to the test site to assist in the unstuck process. If the unstuck is successful, the only losses incurred are the manpower and transportation costs. However, in 3-5 wells annually, unstuck testing fails, and the test instrument falls into the well. In these cases, the test instrument is recovered. The resulting losses and costs include: 1. Impact on normal oil well production (6 tons of daily well production x 20 days for recovering the test instrument); 2. Cost of recovering the test instrument (60,000 yuan per recovery); and 3. Damage to the test instrument itself (approximately 30,000 yuan per instrument).

[0003] Analysis has confirmed the following key factors contributing to test instrument jams: Oil wells are primarily caused by factors such as severe wax buildup within the tubing and the presence of undocumented, unrecorded objects in the downhole tubing, with the majority occurring in the Shuangtaihe, Maquanzi, and Dawa blocks. Water wells are primarily caused by factors such as pipe scale and the presence of unrecorded, unrecorded objects in the downhole tubing, with the majority occurring in the Huangjindai and Dawa blocks. Because these factors are uncontrollable, test instrument jams are unavoidable during testing, impacting not only the test progress but also the normal production of oil wells and water injection wells, resulting in significant economic losses. Summary of the Invention

[0004] The purpose of the present invention is to provide a variable diameter protection releaser for a downhole pressure tester, which is a preset component designed to prevent obstruction. It greatly reduces the risk of the test instrument falling into the well by pulling, shrinking the diameter and breaking off to release, thereby reducing losses and workload.

[0005] To achieve the above-mentioned purpose, the present application proposes a variable diameter protection releaser for a downhole pressure tester, comprising a connecting head, a locking sleeve, an upper positioning sleeve, a center pull rod, a telescopic piece, a lower positioning sleeve and a guide head, wherein one end of the center pull rod is sleeved with a connecting head, and the other end is sleeved with a guide head, a telescopic piece is provided on the outer periphery of the center pull rod, and a gap is provided between adjacent telescopic pieces before the diameter is reduced, and the gap is closed after the diameter is reduced; one end of the telescopic piece is connected to an upper positioning sleeve sleeved on the center pull rod, and the other end is connected to a lower positioning sleeve sleeved on the center pull rod, the lower positioning sleeve is located in the guide head, and a locking sleeve sleeved on the center pull rod is provided between the upper positioning sleeve and the connecting head.

[0006] Furthermore, there are three expansion pieces, which form a cylinder with a shrinkable diameter.

[0007] Furthermore, each expansion piece is provided with a plurality of limit grooves inside, and a clamping platform corresponding to each limit groove is provided on the central pull rod; before the diameter is reduced, the limit groove abuts against the clamping platform, and after the diameter is reduced, the limit groove is located inside the clamping platform.

[0008] Furthermore, the connector is fixed to the central pull rod via a safety pin.

[0009] Furthermore, blocking pieces are provided on both sides of the safety pin, and the blocking pieces are fixed in the I-shaped grooves outside the connector.

[0010] Furthermore, the safety pin is a copper pin and will be cut off when a force of 9.4KN is applied.

[0011] Furthermore, a wire diameter retaining spring is sleeved on the central pull rod, and the wire diameter retaining spring is located in the guide head and contacts the lower positioning sleeve.

[0012] Furthermore, the connector is provided with a threaded opening, through which it is connected to the bottom of the testing instrument.

[0013] Furthermore, the locking sleeve is a circular threaded ring with a threaded opening.

[0014] Furthermore, the upper positioning sleeve and the lower positioning sleeve are steel circles with guide grooves, which are used to guide the trajectory of the telescopic piece during movement.

[0015] Furthermore, each of the expansion pieces is provided with inserting pieces at both ends, and the inserting pieces move in the guide grooves of the upper and lower positioning sleeves.

[0016] Furthermore, the central pull rod is a steel shaft with a convex chamfer. When the central pull rod is pulled, the expansion piece moves along the guide grooves of the upper positioning sleeve and the lower positioning sleeve to complete the diameter reduction.

[0017] Furthermore, the guide head is a steel conical structure.

[0018] Compared with the existing technology, the above technical solution adopted by the present invention has the following advantages: after using the variable diameter protection releaser of the downhole pressure tester of the present application, the construction process of salvaging the test instrument after it encounters an obstruction and falls into the well can be avoided to a large extent, which greatly reduces economic losses and workload, and has the advantages of small size, simple structure, easy operation, etc., and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a variable diameter protection releaser for a downhole pressure tester;

[0020] Explanation of the serial numbers in the figure: 1-connector; 2-safety pin; 3-blocking piece; 4-locking sleeve; 5-upper positioning sleeve; 6-center pull rod; 7-expansion piece; 8-lower positioning sleeve; 9-guide head; 10-wire diameter retaining spring. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application. That is, the embodiments described herein are only some embodiments of this application, not all embodiments. Generally, the components of the embodiments of this application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present application.

[0023] It should be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, the elements defined by the phrase "comprises..." do not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the elements.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0025] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0026] Example 1

[0027] like Figure 1 As shown, this embodiment provides a variable diameter protection releaser for a downhole pressure tester, including a connecting head, a locking sleeve, an upper positioning sleeve, a center pull rod, a telescopic piece, a lower positioning sleeve and a guide head. One end of the center pull rod is sleeved with a connecting head, and the other end is sleeved with a guide head. A telescopic piece is provided on the outer periphery of the center pull rod. A gap is provided between adjacent telescopic pieces before the diameter is reduced, and the gap is closed after the diameter is reduced; one end of the telescopic piece is connected to an upper positioning sleeve sleeved on the center pull rod, and the other end is connected to a lower positioning sleeve sleeved on the center pull rod. The lower positioning sleeve is located in the guide head, and a locking sleeve sleeved on the center pull rod is provided between the upper positioning sleeve and the connecting head.

[0028] The three expansion pieces are arranged to form a cylinder capable of shrinking in diameter. Each expansion piece is provided with a plurality of limiting grooves, and a clamping platform corresponding to each limiting groove is provided on the central pull rod. Before shrinking, the limiting grooves abut against the clamping platform, and after shrinking, the limiting grooves are located inside the clamping platform.

[0029] The connector is secured to the central rod via a safety pin. Flanking plates are located on either side of the safety pin and securely fit within an I-shaped slot on the connector's exterior. These plates prevent the safety pin from falling out. The safety pin is made of copper and will shear when subjected to a force of 9.4 kN.

[0030] The central pull rod is also sleeved with a wire diameter retaining spring, which is located in the guide head and contacts the lower positioning sleeve. The wire diameter retaining spring plays the role of elastically fixing the central pull rod, and the central pull rod will only be pulled when a certain pulling force is reached.

[0031] The connector is provided with a threaded opening, through which the variable diameter protection releaser is connected to the bottom of the testing instrument.

[0032] The locking sleeve is a circular threaded ring with a threaded opening, which has a limiting effect on the upper positioning sleeve.

[0033] The upper and lower positioning sleeves are steel circles with guide grooves for guiding the movement of the expansion piece. Each expansion piece is provided with an insert at both ends, and the insert moves in the guide grooves of the upper and lower positioning sleeves.

[0034] The central pull rod is a steel shaft with a convex chamfer. When the central pull rod is pulled, the expansion piece moves along the guide grooves of the upper positioning sleeve and the lower positioning sleeve to complete the diameter reduction.

[0035] The guide head is a steel cone structure, which serves as a guide when lowering the test instrument.

[0036] The above-mentioned downhole pressure tester has a variable diameter protection releaser. The diameter of the cylinder formed by the expansion piece before shrinking is 4mm larger than the maximum outer diameter of the test instrument body. During the test, the protection releaser is connected to the bottom of the test instrument. During the lowering test process, the protection releaser will first encounter resistance and get stuck. At this time, the test instrument is pulled up to drive the center pull rod of the protection releaser to pull up, the expansion piece retracts, and the protection releaser shrinks, thereby creating a gap between the protection releaser and the resistance surface, allowing the test instrument to be released and finally unstuck; if the unstuck is not successful, when the pulling force reaches 9.4KN, the safety pin in the protection releaser is cut off, and the test instrument is disconnected and released from the pin connection part, avoiding the instrument from getting stuck in the well and causing losses.

[0037] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A variable diameter protection releaser for a downhole pressure tester, characterized in that: It includes a connecting head, a locking sleeve, an upper positioning sleeve, a center pull rod, a telescopic piece, a lower positioning sleeve and a guide head. One end of the center pull rod is sleeved with the connecting head, and the other end is sleeved with the guide head. A telescopic piece is provided on the outer periphery of the center pull rod. A gap is provided between adjacent telescopic pieces before the diameter is reduced, and the gap is closed after the diameter is reduced. One end of the telescopic piece is connected to the upper positioning sleeve sleeved on the center pull rod, and the other end is connected to the lower positioning sleeve sleeved on the center pull rod. The lower positioning sleeve is located in the guide head. A locking sleeve sleeve sleeved on the center pull rod is provided between the upper positioning sleeve and the connecting head. There are three expansion pieces, which form a cylinder with a shrinkable diameter; Each expansion piece is provided with a plurality of limit grooves inside, and a clamping platform corresponding to each limit groove is provided on the central pull rod; before the diameter is reduced, the limit groove abuts against the clamping platform, and after the diameter is reduced, the limit groove is located inside the clamping platform; The connecting head is fixed to the central pull rod via a safety pin; Blocking pieces are provided on both sides of the safety pin and are fixed in the I-shaped groove outside the connector; The central pull rod is also sleeved with a wire diameter retaining spring, which is located in the guide head and contacts the lower positioning sleeve.

2. A variable diameter protection releaser for a downhole pressure tester according to claim 1, characterized in that: The safety pin is a copper pin and will be cut off when a force of 9.4KN is applied.

3. A variable diameter protection releaser for a downhole pressure tester according to claim 1, characterized in that: The connector is provided with a threaded opening and is connected to the bottom of the testing instrument through the threaded opening.

4. A variable diameter protection releaser for a downhole pressure tester according to claim 1, characterized in that: The locking sleeve is a circular threaded ring with a threaded opening.

5. The variable diameter protection releaser of a downhole pressure tester according to claim 1, characterized in that: The upper positioning sleeve and the lower positioning sleeve are steel circles with guide grooves, and are used to guide the trajectory of the telescopic piece during movement.

6. A variable diameter protection releaser for a downhole pressure tester according to claim 5, characterized in that: Insert pieces are provided at both ends of each expansion piece, and the insert pieces move in the guide grooves of the upper and lower positioning sleeves.

7. A variable diameter protection releaser for a downhole pressure tester according to claim 5, characterized in that: The central pull rod is a steel shaft with a convex chamfer. When the central pull rod is pulled, the expansion piece moves along the guide grooves of the upper positioning sleeve and the lower positioning sleeve to complete the diameter reduction.

8. The variable diameter protection releaser of a downhole pressure tester according to claim 1, characterized in that: The guide head is a steel cone structure.

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