Christmas tree pressure testing device

Abstract

The invention discloses a Christmas tree pressure testing device which comprises a mandrel, one end of the mandrel is in threaded connection with a leather cup tray, the other end of the mandrel is in threaded connection with an upper connector, the leather cup tray and the mandrel are fixed through a first screw, the upper connector and the mandrel are fixed through a second screw, and the joint of the leather cup tray and the mandrel is sleeved with a leather cup. The Christmas tree pressure testing tool is flexible in size and can be suitable for various completion pipe strings and corresponding completion wellhead (fracturing wellhead) Christmas trees; the leather cup is sealed with an inner cavity of a well completion pipe column, and the upper connector is sealed with a screw thread connected with an upper flange of a test gate valve, so that the influence of a production pipe column channel is reasonably avoided, a Christmas tree pressure container above a large four-way joint is formed, and the sealing performance of a closed cavity and the pressure bearing capacity of a Christmas tree are tested by utilizing the principle that liquid cannot be compressed; and the whole structure is compact, maintenance is convenient, an easily-loosened part is locked through a screw, safety and reliability are achieved, and high applicability and popularization performance are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field production equipment, and in particular relates to a Christmas tree pressure testing device. Background Art

[0002] In the construction of oil and gas wells, after the completion string is lowered and the completion wellhead (fracturing wellhead) Christmas tree is installed, the Christmas tree above the large four-way is required to be pressure tested as a whole before the connection process. Because the production string with unobstructed internal channels is usually hung in the large four-way of the Christmas tree at the wellhead, it is impossible to conduct an overall pressure test on the flange connection of each gate valve above the large four-way of the Christmas tree at the wellhead to verify the sealing condition of the installation flange. In production, it often happens that the flange connection installed on site is punctured and leaked due to uneven bolt tightening, uneven force on the steel ring inside the flange, uneven flange, and poor sealing, which leaves hidden dangers for safety and environmental protection. In view of the above situation, corresponding completion wellhead pressure test tools have been invented for different Christmas tree specifications (oil production, gas production, and fracturing wellheads). After installing the Christmas tree at the wellhead, open all the gate valves of the Christmas tree above the large four-way, lower the pressure test tool and tighten it, select one of the gate valves on both wings of the Christmas tree to pressurize, and the overall pressure test of the Christmas tree is qualified, which completely eliminates the above hidden dangers. Summary of the invention

[0003] The purpose of the present invention is to provide a Christmas tree pressure test device, which has the characteristics of blocking and sealing the channel in the production pipe column, selecting a point from the gate valves on both wings of the Christmas tree to test the pressure of the entire Christmas tree to be qualified, and eliminating the safety and environmental protection risks caused by oil and gas (liquid) leakage.

[0004] The technical solution adopted by the present invention is to include a core shaft, one end of the core shaft is threadedly connected to a leather cup tray, the other end of the core shaft is threadedly connected to an upper joint, the leather cup tray and the core shaft are fixed by a first screw, the upper joint and the core shaft are fixed by a second screw, and a leather cup is sleeved at the connection between the leather cup tray and the core shaft.

[0005] The present invention is also characterized in that:

[0006] A sealing ring is sleeved on the connection core shaft of the upper joint.

[0007] The upper joint is provided with threads on the inner side and the outer side.

[0008] The diameter of the leather cup near the leather cup bottom plate end is not greater than the diameter near the mandrel end.

[0009] The core shaft is composed of no less than two steel pipes, and both ends of the steel pipes are provided with threads.

[0010] The beneficial effects of the present invention are as follows: the Christmas tree pressure test device of the present invention has flexible size and can be applied to various completion strings and corresponding completion wellhead (fracturing wellhead) Christmas trees; the sealing of the leather cup with the inner cavity of the completion string and the threaded sealing of the upper joint with the flange on the test gate valve reasonably avoid the influence of the production string channel, forming a Christmas tree pressure vessel with a large four-way or larger structure, creating conditions for testing the sealing and pressure bearing capacity of the Christmas tree flange with a large four-way or larger structure; making full use of the principle of liquid incompressibility, realizing the testing of the sealing of the closed cavity and the pressure bearing capacity of the Christmas tree; the overall structure is compact and easy to maintain, the wearing parts of the leather cup and the sealing ring rubber parts do not have high temperature resistance requirements, the processing cost is low, the supply is wide, the loose parts are locked by screws, it is safe and reliable, and has strong applicability and popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the Christmas tree pressure testing device of the present invention;

[0012] Figure 2 It is a schematic diagram of the cross-sectional structure of the leather cup in the present invention;

[0013] Figure 3 It is an enlarged schematic diagram of the core shaft in the present invention.

[0014] In the figure, 1. Leather cup tray, 2. First screw, 3. Leather cup, 4. Mandrel, 5. Upper joint, 6. Second screw, 7. Sealing ring, 8. Steel pipe DETAILED DESCRIPTION

[0015] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] like Figure 1 The oil tree pressure test device of the present invention comprises a core shaft 4, one end of the core shaft 4 is threadedly connected to a leather cup tray 1, the other end of the core shaft 4 is threadedly connected to an upper joint 5, the leather cup tray 1 and the core shaft 4 are fixed by a first screw 2, the upper joint 5 and the core shaft 4 are fixed by a second screw 6, and a leather cup 3 is sleeved at the connection between the leather cup tray 1 and the core shaft 4.

[0017] A sealing ring 7 is sleeved on the connection portion between the upper joint 5 and the core shaft 4 .

[0018] The upper joint 5 is provided with threads on the inner side and the outer side.

[0019] The diameter of the leather cup 3 near the leather cup bottom plate 1 is not greater than the diameter near the core shaft 4 end.

[0020] The core shaft 4 is composed of no less than two steel pipes 8, and both ends of the steel pipes 8 are provided with threads.

[0021] The first screw 2 serves to fix the mandrel 4 and the leather cup tray 1, and the second screw 6 serves to fix the upper joint 5 and the mandrel 4. The port diameters of the leather cup 3 are inconsistent, so that the leather cup 3 can fit more closely with the inside of the completion string to form a sealed space during pressure measurement. During pressure measurement and pressure testing, the crane puts the tool of the present invention into the Christmas tree, and the leather cup 3 passes through the Christmas tree and enters the inner cavity of the completion string. The upper joint 5 is connected and fastened with the internal thread of the upper flange of the test gate valve. The mandrel 4 above the leather cup 3 forms a closed pressure vessel with the inner cavity of the oil pipe and the inner cavity above the large four-way of the Christmas tree. Using the incompressible principle of liquid, select one point from the gate valves on both wings of the Christmas tree to inject clean water for pressure testing, wait for about 10 to 30 minutes to test the sealing of each flange and the overall pressure bearing capacity of the Christmas tree. The pressure change value between 0.1 and 0.9 indicates that the sealing is good and the pressure bearing capacity of the Christmas tree is strong.

[0022] Before the test, different leather cups 3 and upper joints 5 can be replaced according to different specifications of completion wellheads and oil (steam) trees. When replacing the leather cup 3, lubricating oil is applied to the threads of the core shaft 4 close to the leather cup tray 1 end, and the leather cup 3 to be replaced is pushed into place on the core shaft 4; when replacing the upper joint 5, lubricating oil is applied to the threads of the core shaft 4 connecting the upper joint 5, and then the required upper joint thread is fixed on the core shaft 4, and then fixed with the sealing ring 7 to complete the preparation work; the core shaft 4 is detachable, and the length of the core shaft 4 during the test is determined according to actual conditions, and the core shafts 4 are connected by threads; the model of the sealing ring 7 is generally an O-ring, and the wearing parts of the leather cup 3 and the rubber parts of the sealing ring 7 do not require high temperature resistance, so the processing cost is low and the supply is wide.

[0023] Example 1

[0024] In 2022, water injection well seal replacement operations were carried out in Yue 1640 well, Yuegeng 843 well, Ying 39-1 well, and Zhong 25-1 lower seal replacement acidification operations, and all were successful at one time; different types of leather cups need to be replaced in different wells. The Christmas tree pressure test tool of the present invention greatly improves the pressure bearing capacity of the Christmas tree and the sealing detection capability of the closed cavity. Maintenance work was done in the early stage of the Christmas tree operation. The pressure change value of about 1 indicates that the sealing is intact. After detection and adjustment, the safety and environmental protection hazards caused by oil and gas (liquid) leakage are eliminated.

[0025] Example 2

[0026] The present invention provides a Christmas tree pressure test device, comprising a core shaft 4, one end of the core shaft 4 is threadedly connected to a leather cup tray 1, the other end of the core shaft 4 is threadedly connected to an upper joint 5, the leather cup tray 1 and the core shaft 4 are fixed by a first screw 2, the upper joint 5 and the core shaft 4 are fixed by a second screw 6, and a leather cup 3 is sleeved at the connection between the leather cup tray 1 and the core shaft 4.

[0027] Example 3

[0028] The present invention provides a Christmas tree pressure testing device, comprising a core shaft 4, one end of the core shaft 4 is threadedly connected to a leather cup tray 1, the other end of the core shaft 4 is threadedly connected to an upper joint 5, the leather cup tray 1 and the core shaft 4 are fixed by a first screw 2, the upper joint 5 and the core shaft 4 are fixed by a second screw 6, a leather cup 3 is sleeved at the connection between the leather cup tray 1 and the core shaft 4, and a sealing ring 7 is sleeved at the connection between the upper joint 5 and the core shaft 4.

Claims

1. A Christmas tree pressure test device, characterized in that: The invention comprises a core shaft (4), one end of the core shaft (4) is threadedly connected to a leather cup tray (1), the other end of the core shaft (4) is threadedly connected to an upper joint (5), the leather cup tray (1) and the core shaft (4) are fixed by a first screw (2), the upper joint (5) and the core shaft (4) are fixed by a second screw (6), and a leather cup (3) is sleeved at the connection between the leather cup tray (1) and the core shaft (4).

2. The Christmas tree pressure testing device according to claim 1, characterized in that: A sealing ring (7) is sleeved on the upper joint (5) where it is connected to the core shaft (4).

3. The Christmas tree pressure testing device according to claim 2, characterized in that: The upper joint (5) is provided with threads on the inner side and the outer side.

4. The Christmas tree pressure testing device according to claim 1, characterized in that: The diameter of the leather cup (3) at the end close to the leather cup bottom plate (1) is not greater than the diameter at the end close to the core shaft (4).

5. The Christmas tree pressure testing device according to claim 1, characterized in that: The core shaft (4) is composed of no less than two steel pipes (8), and both ends of the steel pipes (8) are provided with threads.

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