Test device and test method for differential pressure of expanded packer seat

Abstract

The application discloses a test device and a test method for testing differential pressure of a seat seal of an expandable packer. The test device is composed of a simulation casing, a multifunctional plug, a liquid inlet hole, a pressure relief hole, a pressure gauge assembly hole, a piston and a spring. The expandable packer is assembled in the test device. Liquid is injected from the liquid inlet hole of the piston into the simulation casing, so that the expandable packer is in a pre-set confining pressure. Then, the expandable packer is pressed, and the differential pressure of the seat seal of the expandable packer in the confining pressure state is tested. The test device and the test method are simple in structure, high in operability, accurate in test result, and can provide an accurate basis for the differential pressure design of the seat seal of the expandable packer.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field exploration and development technology, specifically relating to a test apparatus for testing the differential pressure at the seat of an expanded packer. This invention also relates to a test method for testing the differential pressure at the seat of an expanded packer. Background Technology

[0002] Expandable packers have technical advantages such as simple tool structure and ease of use, and are widely used in downhole operations such as fracturing and acidizing in oil and gas wells. Expandable packers need to be set under a certain internal and external pressure difference. In field construction, the throttling pressure difference generated when the fluid flows through the throttle nozzle is usually used to set the expandable packer.

[0003] When using expandable packers, selecting a choke nozzle that matches the packer and process parameters is a crucial design step. A choke nozzle that is too large will not generate sufficient differential pressure to set the packer and achieve inter-layer (segment) isolation, while a choke nozzle that is too small will result in high operating pressures that fail to meet process requirements. Currently, the setting differential pressure of expandable packers is determined by testing under atmospheric pressure, and the choke nozzle size is determined based on the test results. However, in field operations, some expandable packers have been found to fail to set downhole. The main reason is that when the expandable packer sets downhole, there is confining pressure, and the setting differential pressure changes with the confining pressure. Tests conducted under atmospheric pressure cannot accurately guide field implementation. Therefore, it is necessary to simulate the actual working conditions of expandable packers downhole and test their setting differential pressure under confining pressure to provide a more reliable basis for subsequent design and the selection of key tools. Summary of the Invention

[0004] The purpose of this invention is to provide a test device for testing the setting pressure differential of expandable packers. This solves the problem that existing tests on the setting pressure differential of expandable packers at atmospheric pressure cannot accurately guide field implementation, leading to the problem that some expandable packers cannot be set in the well during field construction when designed based on the test results.

[0005] Another object of the present invention is to provide a test method for testing the differential pressure of an expanded packer seat.

[0006] The first technical solution adopted in this invention is: a test device for testing the differential pressure of an expansion packer seat, including a simulated sleeve with one end open, a multi-functional plug sealed inside the open end of the simulated sleeve, a piston connected to the end of the simulated sleeve relative to the multi-functional plug by a spring, and a liquid inlet hole, a pressure relief hole near the multi-functional plug, and a pressure gauge assembly hole near the piston on the side wall of the simulated sleeve.

[0007] The first technical solution of the present invention is further characterized in that,

[0008] The multi-functional plug is located inside the simulated sleeve at one end and is connected to the expansion packer via a male thread. The multi-functional plug has a pressure hole that connects to the center tube of the expansion packer.

[0009] The pressure relief port is located between the expansion packer sleeve and the multi-functional plug, and the pressure gauge assembly port is located between the expansion packer sleeve and the piston.

[0010] The center tube of the expansion packer is sealed with a plug at one end relative to the multi-functional plug.

[0011] A pressure gauge is installed inside the pressure gauge mounting hole.

[0012] The second technical solution adopted in this invention is: a test method for testing the differential pressure at the seat of an expanded packer, using the aforementioned test apparatus for testing the differential pressure at the seat of an expanded packer, and the test method includes the following steps:

[0013] Step 1: Connect the expansion packer to the multi-functional plug via a male thread so that the pressure hole on the multi-functional plug is connected to the center tube of the expansion packer. At the same time, use the plug to seal the other end of the center tube of the expansion packer.

[0014] Step 2: Assemble the multi-functional plug into the simulated sleeve and install the pressure gauge at the pressure gauge mounting hole;

[0015] Step 3: Inject liquid through the inlet hole to allow the air in the simulated sleeve to be discharged through the pressure relief hole. Close the pressure relief hole after liquid starts to flow out.

[0016] Step 4: Continue to inject liquid through the inlet to bring the expansion packer into the preset confining pressure;

[0017] Step 5: Pressurize through the pressure hole of the multi-functional plug and observe the pressure change of the pressure gauge. If the pressure gauge pressure starts to increase, the expansion packer begins to expand and set. When the pressure value recorded by the pressure gauge is p, open the pressure relief hole and observe the pressure change. If the pressure gauge pressure remains unchanged, it proves that the expansion packer has set. The difference between p and the preset confining pressure is the setting pressure difference of the expansion packer under the preset confining pressure.

[0018] The second technical solution of the present invention is further characterized in that,

[0019] Step 5 is as follows: Pressurize through the pressure hole of the multi-functional plug and observe the pressure change of the pressure gauge. If the pressure gauge pressure starts to increase, the expansion packer begins to expand and set. When the pressure value recorded by the pressure gauge is p-, open the pressure relief hole. If the pressure gauge returns to zero, the pressure inside the expansion packer is also released. Repeat steps 3 to 5, each time increasing the pressure by 1 MPa based on the pressure p-, until the pressure gauge pressure remains unchanged when the pressure relief hole is opened. The difference between the pressure value p at this time and the preset confining pressure is the setting pressure difference of the expansion packer under the preset confining pressure.

[0020] The beneficial effects of this invention are as follows: The test apparatus and method for testing the seat pressure differential of an expandable packer, as described in this invention, place the expandable packer under a pre-set confining pressure, and then pressurize the expandable packer to simulate the actual working conditions of the expandable packer downhole, thus testing its seat pressure differential under the confining pressure condition. This test apparatus and method are simple in structure, highly operable, and provide accurate test results, offering a more reliable basis for the construction design and selection of key tools for the use of expandable packers. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the test apparatus for testing the differential pressure of an expanded packer seat according to the present invention.

[0022] In the diagram, 1. Simulated sleeve, 2. Multifunctional plug, 3. Liquid inlet, 4. Pressure relief hole, 5. Pressure gauge assembly hole, 6. Piston, 7. Spring, 8. Expansion packer, 9. Plug. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] This invention provides a test apparatus for testing the differential pressure at the seat of an expanded packer, such as... Figure 1 As shown, the test apparatus for testing the differential pressure of an expandable packer seat includes a simulated sleeve 1 with one open end. A multi-functional plug 2 is sealed inside the open end of the simulated sleeve 1. One end of the multi-functional plug 2 inside the simulated sleeve 1 is connected to an expandable packer 8 via a male thread. A pressure-pressing hole is formed on the multi-functional plug 2, leading to the central tube of the expandable packer 8. A plug 9 is sealed at the end of the central tube of the expandable packer 8 opposite to the multi-functional plug 2. A piston 6 is connected to the end of the simulated sleeve 1 opposite to the multi-functional plug 2 via a spring 7. An inlet hole 3, a pressure relief hole 4 near the multi-functional plug 2, and a pressure gauge mounting hole 5 near the piston 6 are provided on the side wall of the simulated sleeve 1. The pressure relief hole 4 is located between the expandable packer 8 sleeve and the multi-functional plug 2, and the pressure gauge mounting hole 5 is located between the expandable packer 8 sleeve and the piston 6.

[0025] Through the above method, the test apparatus and method for testing the setting pressure difference of an expandable packer according to the present invention injects liquid through the inlet 3. With the thrust of the piston 6 and spring 7, the expandable packer 8 is placed in a pre-set confining pressure. Then, pressure is applied to the expandable packer 8. During the pressure application process, the rubber sleeve of the expandable packer 8 expands. As the rubber sleeve expands, the high-pressure liquid in the simulated sleeve 1 pushes the piston 6, further compressing the spring 7, resulting in a further increase in the liquid pressure in the simulated sleeve 1. This pressure increase process can be observed using a pressure gauge. Finally, by opening the pressure relief hole 4 and observing that the pressure gauge pressure remains unchanged, it can be determined that the expandable packer 8 has completed setting, and its setting pressure difference under confining pressure is tested. Specifically, the following steps are included:

[0026] Step 1: Connect the expansion packer 8 to the multi-functional plug 2 via a male thread so that the pressure hole on the multi-functional plug 2 is connected to the center tube of the expansion packer 8. At the same time, use the plug 9 to seal the other end of the center tube of the expansion packer 8.

[0027] Step 2: Assemble the multi-functional plug 2 into the simulated sleeve 1, and assemble the pressure gauge at the pressure gauge assembly hole 5;

[0028] Step 3: Inject liquid through inlet hole 3 to allow air in simulated sleeve 1 to be discharged through pressure relief hole 4. Close pressure relief hole 4 after liquid starts to flow out of pressure relief hole 4.

[0029] Step 4: Continue to inject liquid through the inlet port 3 to bring the expansion packer 8 into the preset confining pressure. Observe whether it is in the preset confining pressure through the pressure gauge.

[0030] Step 5: Pressurize through the pressure hole of the multi-functional plug 2 and observe the pressure change of the pressure gauge. If the pressure gauge pressure starts to increase, the expansion packer 8 begins to expand and set. When the pressure value recorded by the pressure gauge is p, open the pressure relief hole 4 and observe the pressure change. If the pressure gauge pressure remains unchanged, it proves that the expansion packer 8 has been set. The setting pressure difference can be calculated by subtracting the preset confining pressure from p. If the pressure gauge returns to zero, release the pressure inside the expansion packer 8 and repeat until the pressure gauge pressure remains unchanged.

[0031] Example 1

[0032] Step 1: Connect the expandable packer 8 to the multi-functional plug 2 via a male thread, so that the pressure hole on the multi-functional plug 2 is connected to the central tube of the expandable packer 8. At the same time, use the plug 9 to seal the other end of the central tube of the expandable packer 8. Step 2: Assemble the multi-functional plug 2 into the simulation sleeve 1, and install the pressure gauge at the pressure gauge mounting hole 5. Step 3: Inject liquid through the inlet hole 3 to allow the air in the simulation sleeve 1 to be discharged through the pressure relief hole 4. Close the pressure relief hole 4 after liquid starts to flow out. Step 4: Continue to inject liquid through the inlet hole 3 to place the expandable packer 8 in the preset confining pressure. Step 5: Pressurize through the pressure hole of the multi-functional plug 2 to make the pressure difference between the inside and outside of the expandable packer 8 1 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge pressure remains unchanged, it proves that the expandable packer 8 has been set. 1 MPa is the setting pressure difference of the expandable packer 8 under the preset confining pressure.

[0033] Example 2

[0034] Steps 1-4 are the same as in Example 1. Then, pressurize through the pressure hole of the multi-functional plug 2 to make the pressure difference between the inside and outside of the expansion packer 8 1 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge returns to zero, the pressure inside the expansion packer 8 is also released. Repeat steps 3 to 5 to increase the pressure difference between the inside and outside of the expansion packer 8 to 2 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge pressure remains unchanged, it proves that the expansion packer 8 has been set. 2 MPa is the setting pressure difference of the expansion packer 8 under the preset confining pressure.

[0035] Example 3

[0036] Steps 1-4 are the same as in Example 1. Then, pressurize through the pressure hole of the multi-functional plug 2 to make the pressure difference between the inside and outside of the expandable packer 8 1 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge returns to zero, the pressure inside the expandable packer 8 has also been released. Repeat steps 3 to 5 to increase the pressure difference between the inside and outside of the expandable packer 8 to 2 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge returns to zero, the pressure inside the expandable packer 8 has also been released. Repeat steps 3 to 5 again to increase the pressure difference between the inside and outside of the expandable packer 8 to 3 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge pressure remains unchanged, it proves that the expandable packer 8 has been set. 3 MPa is the setting pressure difference of the expandable packer 8 under the preset confining pressure.

[0037] Example 4

[0038] Steps 1-4 are the same as in Example 1. Then, pressurize through the pressure hole of the multi-functional plug 2 to make the pressure difference between the inside and outside of the expandable packer 8 1 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge returns to zero, the pressure inside the expandable packer 8 has also been released. Repeat steps 3 to 5 to increase the pressure difference between the inside and outside of the expandable packer 8 to 2 MPa. Open the pressure relief hole 4 and observe the pressure change. If the pressure gauge returns to zero, the pressure inside the expandable packer 8 has also been released. Repeat steps 3 to 5. Step 5: Increase the pressure difference between the inside and outside of the expansion packer 8 to 3 MPa, open the pressure relief port 4, observe the pressure change, and if the pressure gauge returns to zero, then the pressure inside the expansion packer 8 has also been released; repeat steps 3 to 5 again to increase the pressure difference between the inside and outside of the expansion packer 8 to 4 MPa, open the pressure relief port 4, observe the pressure change, and if the pressure gauge pressure remains unchanged, then it proves that the expansion packer 8 has been set. 4 MPa is the setting pressure difference of the expansion packer 8 under the preset confining pressure.

Claims

1. A test apparatus for testing the differential pressure at the seat of an expanded packer, characterized in that, The device includes a simulated sleeve (1) with one open end. A multi-functional plug (2) is sealed inside the open end of the simulated sleeve (1). One end of the multi-functional plug (2) inside the simulated sleeve (1) is connected to an expansion packer (8) via a male thread. A pressure hole is opened on the multi-functional plug (2) and connected to the central tube of the expansion packer (8). A piston (6) is connected to one end of the simulated sleeve (1) relative to the multi-functional plug (2) via a spring (7). An inlet hole (3), a pressure relief hole (4) near the multi-functional plug (2), and a pressure gauge assembly hole (5) near the piston (6) are opened on the side wall of the simulated sleeve (1). The pressure relief hole (4) is located between the expansion packer (8) rubber sleeve and the multi-functional plug (2). The pressure gauge assembly hole (5) is located between the expansion packer (8) rubber sleeve and the piston (6).

2. The test apparatus for testing the differential pressure at the seat of an expanded packer as described in claim 1, characterized in that, The expansion packer (8) has a plug (9) sealing one end of its central tube relative to the multifunctional plug (2).

3. The test apparatus for testing the differential pressure at the seat of an expanded packer as described in claim 1, characterized in that, A pressure gauge is installed inside the pressure gauge assembly hole (5).

4. A test method for testing the differential pressure at the seat of an expanded packer, characterized in that, The test apparatus for testing the differential pressure at the seat of an expanded packer as described in claim 1 includes the following steps: Step 1: Connect the expansion packer (8) to the multi-functional plug (2) through the male thread so that the pressure hole on the multi-functional plug (2) is connected to the center tube of the expansion packer (8), and at the same time use the plug (9) to seal the other end of the center tube of the expansion packer (8); Step 2: Assemble the multi-functional plug (2) into the simulated sleeve (1) and assemble the pressure gauge at the pressure gauge assembly hole (5); Step 3: Inject liquid through the inlet hole (3) to allow the air in the simulated sleeve (1) to be discharged through the pressure relief hole (4). Close the pressure relief hole (4) after liquid starts to flow out. Step 4: Continue to inject liquid through the inlet (3) to bring the expansion packer (8) into the preset confining pressure; Step 5: Pressurize through the pressure hole of the multi-functional plug (2) and observe the pressure change of the pressure gauge. If the pressure gauge pressure starts to increase, the expansion packer (8) will start to expand and set. When the pressure value recorded by the pressure gauge is... p At this time, open the pressure relief hole (4) and observe the pressure change. If the pressure gauge pressure remains unchanged, it proves that the expansion packer (8) has been set. p The difference between the pressure and the preset confining pressure is the seat pressure difference of the expansion packer (8) under the preset confining pressure.

5. The test method for testing the differential pressure at the seat of an expanded packer as described in claim 4, characterized in that, Step 5 specifically involves: applying pressure through the pressure hole of the multi-functional plug (2) and observing the pressure change of the pressure gauge. If the pressure gauge pressure begins to increase, the expansion packer (8) begins to expand and set. When the pressure value recorded by the pressure gauge is... p- When the pressure gauge returns to zero, open the pressure relief port (4). If the pressure gauge returns to zero, release the pressure inside the expansion packer (8). Repeat steps 3 to 5, each time releasing the pressure. p- Increase the pressure by 1 MPa on top of the pressure, until the pressure gauge pressure remains unchanged when the pressure relief hole (4) is opened. Then the pressure value at this time is... p The difference between the pressure and the preset confining pressure is the seat pressure difference of the expansion packer (8) under the preset confining pressure.

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