Downhole hand drop device

Abstract

This utility model relates to downhole release devices and belongs to the field of downhole tool technology. The purpose of this utility model is to address the problems existing in the prior art by providing a downhole release device, including an upper connector, with a casing female thread and a trapezoidal thread male thread at both ends; and a lower connector, with a trapezoidal thread female thread and a casing male thread at both ends; the ends of the trapezoidal thread male and female threads are tapered. The upper and lower connectors of this utility model are connected by trapezoidal threads at the tapered ends; after connection, an effective seal is formed, isolating internal and external mud. Even under high pump pressure circulation, the tapered trapezoidal threads will not be eroded by mud and can withstand various complex stresses (but not torque) together with the tubing string.

Description

Technical Field

[0001] This utility model relates to a downhole hand release device and belongs to the field of downhole tool technology. Background Technology

[0002] A downhole release device is a safety tool that is easily released from the tubing string inside the well. It is installed at the position where the tubing string needs to be detached and can withstand various complex stresses together with the tubing string. In the event of a fault in the well or when the downhole tubing string becomes stuck later, the release device is operated through the wellhead to release the stuck tubing string, providing a tool to prevent and resolve downhole accidents.

[0003] Downhole release devices are key supporting tools for the tubing string in open-hole completions. Their core function is to release the tubing through a relatively simple and easy-to-operate rotary release mechanism. Existing release tools mostly rely on hydraulic or other mechanisms, which are complex in structure and lack sufficient erosion resistance. Utility Model Content

[0004] The purpose of this utility model is to provide a downhole release device to address the problems existing in the prior art.

[0005] The technical solution provided by this utility model to solve the above-mentioned technical problems is: a downhole release device, comprising:

[0006] The upper connector is provided with a sleeve female thread and a trapezoidal thread male thread at its upper and lower ends, respectively;

[0007] The lower connector is provided with a trapezoidal female thread and a sleeve male thread at its upper and lower ends, respectively;

[0008] The ends of both the male and female trapezoidal threads are tapered.

[0009] A further technical solution is that both the female and male threads of the sleeve are trapezoidal thread structures.

[0010] A further technical solution is that a pin is provided between the upper connector and the lower connector.

[0011] A further technical solution is that the pin is a copper pin.

[0012] A further technical solution is that the pin is located at the connection between the trapezoidal thread male thread and the trapezoidal thread female thread.

[0013] A further technical solution is that the shear strength of the pin is less than or equal to 40% of the designed rotational torque of the tubing column.

[0014] The present invention has the following advantages: The upper and lower joints of the present invention are connected by trapezoidal threads at the tapered ends; after connection, an effective seal can be formed to isolate the mud inside and outside. Even under high pump pressure circulation, the tapered trapezoidal thread will not be eroded by the mud and can withstand various composite stresses together with the tubing (but not torque). Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the upper connector structure of the hand-dropping device of this utility model;

[0017] Figure 3 This is a schematic diagram of the lower connector structure of the hand-dropping device of this utility model.

[0018] As shown in the figure: 1-Upper connector, 2-Lower connector, 3-Pin, 4-Trapezoidal thread male thread, 5-Trapezoidal thread female thread, 6-Sleeve male thread, 7-Sleeve female thread. Detailed Implementation

[0019] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0022] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0023] Downhole release devices are key supporting tools for the support string in open-hole completions. Their core function is to quickly and efficiently separate the required well section from the stuck support string during later sidetracking or workover operations through a relatively simple and easy-to-operate rotary release mechanism.

[0024] The core purpose of this design is to address the high-risk environment of open-hole sections. Due to the lack of casing protection, open-hole sections are highly susceptible to entrapment by formation sand, solid deposits, or wellbore debris. Without a release device, this entrapment can lock the entire tubing string, making it impossible to retrieve any part during subsequent operations. This can lead to costly retrieval operations, equipment damage risks, and even well control problems, resulting in significant economic losses and operational delays. Dealing with this type of entrapment is extremely difficult, requiring complex retrieval operations (milling, casing milling), potentially taking weeks or even months, utilizing large equipment, and carrying the risk of well abandonment due to retrieval failure.

[0025] While droppers increase initial costs, they significantly reduce the probability of later catastrophic events and associated costs. The purpose of a dropper is to isolate risk; it ensures that even if the lower support column is severely embedded, the upper column (above the dropper point) can still be lifted out with a simple rotation.

[0026] like Figures 1-3 As shown, the downhole release device provided by this utility model includes an upper connector 1 and a lower connector 2 connected to each other. The upper connector 1 is provided with a casing female thread 7 and a trapezoidal thread male thread 4 at its upper and lower ends, respectively. The lower connector 2 is provided with a trapezoidal thread female thread 5 and a casing male thread 6 at its upper and lower ends, respectively. The ends of the trapezoidal thread male thread 4 and the trapezoidal thread female thread 5 are both tapered.

[0027] When the upper connector 1 and the lower connector 2 are connected, the trapezoidal thread male thread 4 and the trapezoidal thread female thread 5 are engaged to form a metal sealing surface, which isolates the mud in the well. At the same time, the conical end can enhance the sealing pressure, making it able to withstand high pump pressure circulation >70MPa, thereby avoiding erosion failure and improving the composite stress bearing capacity.

[0028] like Figure 2 and Figure 3 As shown, in this embodiment, both the female sleeve thread 7 and the male sleeve thread 6 have trapezoidal thread structures.

[0029] like Figure 1 As shown, in this embodiment, the lower connector 2 has a through hole at the trapezoidal threaded female thread 5, and a copper pin 3 is provided in the through hole. The end of the pin 3 extends to the trapezoidal threaded male thread 4 of the upper connector 1.

[0030] The working principle of this downhole release device is as follows: During use, the downhole release device is connected to the completion support string. The outer and inner diameters are generally the same as the matched string, and the connector thread matches the string. Avoid using adapters as much as possible. Considering that the formation may trap the lower string during production, it is generally connected below the position required for later sidetracking. If needed, the string can be adjusted to rotate forward to release the release device. Before lowering it into the well, clean the tapered ladder thread, apply grease, and tighten it according to the designed torque. Then, secure the copper pin 3 in the through hole and connect it to the string for lowering into the well. After lowering, the string must not be rotated. When the predetermined depth is reached, record the suspended weight of the string above the release device. This suspended weight serves as the basis for later release operations and must be recorded. If the user needs to release the device, the device must be raised and lowered multiple times. Move the tubing string to accurately locate the downhole release device. Rotate the tubing string clockwise, the number of turns depending on the running depth. If production time is long and releasing the device is difficult, while maintaining torque, quickly lower the drill string to subject the downhole release device to a certain impact force. Then, lift and lower repeatedly several times to loosen the tapered ladder buckle of the downhole release device. At the same time, do not allow the downhole release device to be under tension, because under tension, it will not only be difficult to open but also risk damaging the tapered ladder buckle. Next, lift the tubing string to maintain an overlift of 5-10 kN for the downhole release device. Slowly rotate the drill string to determine if it has opened. Finally, if the downhole release device has opened, the suspended weight will drop, and the tubing string above the downhole release device can move freely.

[0031] Key parameter design:

[0032] Shear strength of pin 3: ≤ 40% of the design rotation torque of the tubing column;

[0033] Tapered thread: balancing sealing performance and unlocking force, with pin shear mechanics design;

[0034] Applicable well depth: ≤8000m (high temperature and high pressure wells require reinforcement with other materials).

[0035] Technical advantages:

[0036] Improved reliability: The conical reverse-lock seal prevents mud intrusion and avoids erosion-induced corrosion or premature unlocking;

[0037] Cost savings: Reduces salvage operation costs by more than 95%, avoids the high daily cost risk of salvage operations in complex deep well environments, and avoids the risk of side-drilling location not matching the design or well abandonment.

[0038] Operational safety: Purely mechanical rotation operation, with no risk of hydraulic system failure;

[0039] Compatibility: Outer diameter / inner diameter / thread matches standard tubing strings, no adapter required, and can be manufactured according to wellbore and support string dimensions.

[0040] The above description is not intended to limit the present invention in any way. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A downhole hand release device, characterized in that, include: The upper connector (1) is provided with a sleeve female thread (7) and a trapezoidal thread male thread (4) at its upper and lower ends respectively; The lower connector (2) is provided with a trapezoidal threaded female thread (5) and a sleeve male thread (6) at its upper and lower ends respectively; The ends of both the trapezoidal thread male thread (4) and the trapezoidal thread female thread (5) are tapered.

2. The downhole release device according to claim 1, characterized in that, Both the female thread (7) and the male thread (6) of the sleeve are trapezoidal thread structures.

3. The downhole release device according to claim 1, characterized in that, A pin (3) is provided between the upper connector (1) and the lower connector (2).

4. The downhole release device according to claim 3, characterized in that, The pin (3) is a copper pin.

5. The downhole release device according to claim 3, characterized in that, The pin (3) is located at the connection between the trapezoidal thread male thread (4) and the trapezoidal thread female thread (5).

6. The downhole release device according to claim 3, characterized in that, The shear strength of the pin (3) is less than or equal to 40% of the design column rotation torque.

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