Test device and method for testing unsealing capacity of Y211 packer under pressure difference between upper and lower parts

Abstract

The present application relates to the oil and gas field exploration and development technical field, specifically relates to a kind of test Y211 packer upper and lower pressure difference exists the ability of unblocking test device and method, by being set for simulating downhole casing simulation casing, simulation tubing in simulation casing, sealing ring, piston and pin, simulate the actual pressure difference of Y211 packer in real well, test the unblocking tension value of Y211 packer under the pressure difference, the unblocking ability test device and method of the present application simple structure, high operability, test result is accurate, can accurately test the unblocking ability of Y211 packer under the condition that upper and lower pressure difference exists, provide basis for optimizing key tool and subsequent construction preparation, solve the problem that the unblocking load of Y211 packer is not predicted due to the inconvenience caused to the site construction that upper and lower pressure difference exists.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field exploration and development technology, specifically to a test device and method for testing the unsealing capability of a Y211 packer under conditions of pressure difference. Background Technology

[0002] The Y211 packer has technical advantages such as integrated anchoring and packing, strong resetting capability, simple tool principle, and convenient use. It is widely used as a bottom packer in downhole measures such as fracturing in oil and gas wells.

[0003] Currently, the evaluation and testing of Y211 packers used in fracturing operations mainly focus on temperature resistance, pressure bearing capacity, and re-setting capability. However, with the expansion of the application scope of Y211 packers, in the repeated stimulation of old wells or coiled tubing bottom-seal drag fracturing, Y211 packers face the problem of lifting and unsealing under conditions with a certain pressure difference. Especially during construction, when the pressure difference is large, the Y211 packer requires an additional lifting load to unseal, which brings many inconveniences to the field implementation. Therefore, it is necessary to test the unsealing capability of Y211 packers under conditions of pressure difference to provide a basis for selecting key tools and preparing for subsequent construction. Summary of the Invention

[0004] This invention overcomes the shortcomings of existing technologies and provides a testing device and method for testing the unsealing capability of a Y211 packer under conditions of pressure difference. In particular, this testing device can simulate the lifting and unsealing of the Y211 packer under conditions of a certain pressure difference, testing the additional load required for unsealing, thus providing a basis for selecting key tools and preparing for subsequent construction. It solves the problem of unpredictable unsealing load caused by a certain pressure difference, which leads to inconvenience in on-site construction.

[0005] The technical problem solved by this invention can be achieved by the following technical solutions:

[0006] A test device for testing the unsealing capability of a Y211 packer under pressure differential conditions includes a simulated casing for simulating downhole casing. A simulated tubing is installed inside the simulated casing. A seal and a sealing mechanism for sealing the inner cavity of the simulated tubing are installed in the annulus between the simulated tubing and the simulated casing on one side. One end of the simulated tubing on the other side is connected to the Y211 packer. The seal is located in the annulus between the sealing mechanism and the Y211 packer. A pressure injection mechanism is also provided on the outer wall of the simulated casing located between the seal and the Y211 packer.

[0007] Furthermore, the sealing mechanism includes an assembly hole on the simulated sleeve, a sliding hole on the simulated tubing, a pin, and a piston. The pin passes through the assembly hole and the sliding hole, and the piston is installed inside the simulated tubing and is located between the pin and the Y211 packer.

[0008] Furthermore, the simulated tubing has symmetrically opened sliding holes, and the simulated casing has symmetrically opened assembly holes. The sliding holes are holes with a certain length along the length direction of the simulated tubing. The structures of the symmetrically opened sliding holes are the same. The pin passes through the symmetrically opened assembly holes and sliding holes, and the simulated tubing can move back and forth along the length direction of the sliding hole.

[0009] Furthermore, the sealing element is a sealing ring, which is installed inside the simulated sleeve. The simulated oil pipe can slide freely through the sealing ring and is in a sealed state.

[0010] Furthermore, the injection mechanism includes an inlet hole and an vent hole sequentially disposed on the outer wall of the simulated sleeve, wherein the inlet hole is used for injection and the vent hole is used for venting.

[0011] Furthermore, the simulated tubing is also provided with an annular groove for setting the Y211 packer.

[0012] A method for testing the unsealing capability of a Y211 packer under pressure differential conditions, comprising the unsealing capability testing apparatus described in any one of the above claims, and including the following method.

[0013] Connect the Y211 packer to the simulated tubing;

[0014] Install the installed Y211 packer and simulated tubing inside the simulated casing;

[0015] The simulated oil pipe is raised and lowered to put the Y211 packer in the setting track, and pressure is applied to set the Y211 packer.

[0016] The pressure is injected into the annulus formed between the seal and the Y211 packer by the pressure injection mechanism, so that the pressure in the annulus is the same as the preset pressure difference, where the preset pressure difference is the actual pressure difference between the upper and lower parts of the Y211 packer after it is set in the well.

[0017] The simulated tubing test, under the aforementioned pre-set pressure difference, measures the pull force required to release the Y211 packer;

[0018] The tensile force measured above provides a guarantee for the release force of the Y211 packer under the pressure difference between the upper and lower parts during actual fracturing operations.

[0019] The beneficial effects of this invention are:

[0020] Compared with existing technologies, this invention uses a simulated casing to simulate downhole casing, a simulated tubing located inside the simulated casing 1, a sealing ring in the annulus between the simulated tubing and the simulated casing on one side, and a piston and pin for sealing the inner cavity of the simulated tubing. This simulates the actual pressure difference of the Y211 packer in a real well and tests the unsealing pull value of the simulated Y211 packer under the presence of a pressure difference. The test device and method of this invention for testing the unsealing capacity of the Y211 packer under pressure difference conditions have a simple structure, high operability, and accurate test results. It can accurately test the unsealing capacity of the Y211 packer under pressure difference conditions, providing a basis for selecting key tools and preparing for subsequent construction. It solves the problem of unpredictable unsealing load caused by a certain pressure difference between the upper and lower parts of the Y211 packer, which leads to inconvenience in on-site construction. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the present invention.

[0023] Figure 2 This is a cross-sectional structural diagram showing the location of the sliding hole in the simulated oil pipe of the present invention.

[0024] In the diagram: 1-simulated casing; 2-simulated tubing; 3-piston; 4-sealing ring; 5-inlet port; 6-vent port; 7-pin; 8-Y211 packer; 9-sliding hole. Detailed Implementation

[0025] The following will provide a detailed description of the technical solution of the test device and method for testing the unsealing capability of a Y211 packer under the condition of pressure difference between the top and bottom, provided by the present invention, through several specific embodiments.

[0026] Reference Figure 1As shown, a test device for testing the unsealing capability of a Y211 packer under a pressure difference includes a simulated casing 1 to simulate downhole casing. A simulated tubing 2 is installed inside the simulated casing 1. A seal and a sealing mechanism for sealing the inner cavity of the simulated tubing 2 are installed in the annulus between the simulated tubing 2 and the simulated casing 1 on one side. The seal seals the annulus between the simulated tubing 2 and the simulated casing 1, and the sealing mechanism seals the inner cavity of the simulated tubing 2. The simulated tubing 2 can be moved up or down along the sealing mechanism. One end of the simulated tubing 2 on the other side is connected to a Y211 packer 8. The seal is located in the annulus between the sealing mechanism and the Y211 packer 8. The purpose is to ensure that after the Y211 packer 8 is set, the seal and the simulated casing 1 can unseal the packer. A sealed cavity is formed between the inner wall of pipe 1, the outer wall of simulated tubing 2, and the setting sleeve of Y211 packer 8. A pressure injection mechanism is also provided on the outer wall of simulated casing 1 between the seal and Y211 packer 8. Pressure is injected into the sealed cavity formed between the seal, the inner wall of simulated casing 1, the outer wall of simulated tubing 2, and the setting sleeve of Y211 packer 8 through the pressure injection mechanism to simulate the annular pressure in real wells. After Y211 packer 8 is set, simulated tubing 2 is raised and lowered to put Y211 packer 8 in the setting track. Pressure is applied to set Y211 packer 8. After pressurizing through the pressure injection mechanism to put Y211 packer 8 under a preset pressure difference, simulated tubing 2 is raised to test the pull force required for Y211 packer 8 to unseal under the preset pressure difference.

[0027] Reference Figure 1 and Figure 2 As shown, the sealing mechanism includes an assembly hole on the simulated sleeve 1, a sliding hole 9 on the simulated oil pipe 2, a pin 7, and a piston 3. The pin 7 passes through the assembly hole and the sliding hole 9. The piston 3 is installed inside the simulated oil pipe 2 and is located between the pin 7 and the Y211 packer 8. The piston 3 can seal the inner cavity of the simulated oil pipe 2. The pin 7 is used to block the piston 3 to prevent the pressure from squeezing the piston 3 out of the simulated oil pipe 2. At the same time, the simulated oil pipe 2 is connected to the pin 7 and can move along the sliding hole 9.

[0028] Specifically, the simulated tubing 2 has symmetrically opened sliding holes 9, and the simulated casing 1 has symmetrically opened assembly holes. The assembly holes are circular holes that match the pins 7. The sliding holes 9 are holes with a certain length along the length of the simulated tubing 2. The length of the hole can be determined according to the stroke of the simulated tubing 2 when it is raised or lowered during the setting and unsetting of the Y211 packer 8. The structures of the symmetrically opened sliding holes 9 are the same. The pins 7 pass through the symmetrically opened assembly holes and sliding holes 9 to ensure that the simulated tubing 2 can be lowered or raised normally and smoothly. The simulated tubing 2 can move back and forth along the length of the sliding holes 9 to realize the setting and unsetting of the Y211 packer 8.

[0029] It should be noted that the sealing element is a sealing ring 4, which is installed inside the simulated sleeve 1 and is fixedly connected to the inner wall of the simulated sleeve 1. The simulated oil pipe 2 can slide freely through the sealing ring 4, and the outer wall of the simulated oil pipe 2 is in a sealed state with the sealing ring 4 to ensure the overall sealing performance.

[0030] The injection mechanism includes an inlet hole 5 and an vent hole 6 sequentially arranged on the outer wall of the simulated sleeve 1. The inlet hole 5 is used for injection, and the vent hole 6 is used for venting. Liquid is injected through the inlet hole 5, so that the air in the sealed cavity formed by the sealing ring 4, the inner wall of the simulated sleeve 1, the outer wall of the simulated oil pipe 2, and the seated rubber sleeve of the Y211 packer 8 is released through the vent hole 6. After the vent hole 6 starts to discharge liquid, the vent hole 6 is closed, so that the pressure in the cavity is the same as the preset pressure difference.

[0031] It should be noted that the simulated tubing 2 is also provided with an annular groove for the Y211 packer to be set. The annular groove has a certain length, which is not less than the Y211 packer's track changing and setting stroke. After the unsealing capability test device of the present invention is assembled, it can ensure that the Y211 packer can be lifted and lowered smoothly.

[0032] A method for testing the unsealing capability of a Y211 packer under a pressure difference, comprising the unsealing capability testing device described in any of the above embodiments, and including the following method.

[0033] Connect the Y211 packer 8 to the simulated tubing 2;

[0034] Install the installed Y211 packer 8 and the simulated tubing 2 inside the simulated casing 1;

[0035] The simulated oil pipe 2 is raised and lowered to put the Y211 packer 8 in the setting track, and pressure is applied to set the Y211 packer 8.

[0036] Pressure is injected into the annulus formed between the sealing ring 4 and the Y211 packer 8 through the inlet port 5. In this invention, liquid is injected to make the pressure in the annulus the same as the pre-set pressure difference between the upper and lower pressures after the Y211 packer 8 is set. The pre-set pressure difference is the actual pressure difference between the upper and lower pressures after the Y211 packer 8 is set downhole. The gas in the cavity is discharged from the vent port 6. After the vent port 6 starts to discharge liquid, the vent port 6 is closed. Liquid continues to be injected through the inlet port 5 so that the annulus cavity between the Y211 packer and the sealing ring 4 is at the pre-set pressure difference.

[0037] It should be noted that the pre-set pressure difference between the upper and lower parts of the Y211 packer 8 after setting in this invention can be calculated or measured in the well using a downhole pressure gauge. The specific calculation method is as follows:

[0038] The lower pressure of the packer can be calculated based on the formation pressure gradient or the fluid level in the old well. At the same time, the upper pressure of the packer can be calculated based on the wellhead pressure and the height of the hydrostatic column after construction. The pressure difference between the upper and lower parts of the packer is the upper pressure of the packer minus the lower pressure of the packer.

[0039] The test simulates the pulling force required to release packer 8 under the pre-set pressure difference when the tubing 2 is pulled up.

[0040] The tensile force measured above provides a guarantee for the release of Y211 packer 8 during actual fracturing operations.

[0041] The present invention provides a test device and method for testing the unsealing capability of Y211 packer 8 under pressure difference, which is simple in structure, highly operable, and provides accurate test results. It can accurately test the unsealing capability of Y211 packer 8 under pressure difference, providing a basis for the selection of key tools and subsequent construction preparation. It solves the problem that the unpredictable unsealing load of Y211 packer 8 due to a certain pressure difference causes inconvenience to on-site construction.

[0042] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention, and all such changes are within the protection scope of the technology.

[0043] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0044] The technical solutions of the various embodiments can be combined with each other, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. A test apparatus for testing the unsealing capability of a Y211 packer under a pressure difference, characterized in that: The system includes a simulated casing (1) for simulating downhole casing, a simulated tubing (2) is provided inside the simulated casing (1), a seal and a sealing mechanism for sealing the inner cavity of the simulated tubing (2) are provided in the annulus between the simulated tubing (2) and the simulated casing (1) on one side, and one end of the simulated tubing (2) on the other side is connected to a Y211 packer (8), the seal is located in the annulus between the sealing mechanism and the Y211 packer (8), and a pressure injection mechanism is also provided on the outer wall of the simulated casing (1) between the seal and the Y211 packer (8); The sealing mechanism includes an assembly hole on the simulated sleeve (1), a sliding hole (9) on the simulated oil pipe (2), a pin (7) and a piston (3). The pin (7) passes through the assembly hole and the sliding hole (9). The piston (3) is installed inside the simulated oil pipe (2) and is located between the pin (7) and the Y211 packer (8). The simulated tubing (2) has symmetrically opened sliding holes (9), and the simulated casing (1) has symmetrically opened assembly holes. The sliding holes (9) are holes with a certain length along the length direction of the simulated tubing (2). The symmetrically opened sliding holes (9) have the same structure. The pin (7) passes through the symmetrically opened assembly holes and sliding holes (9) to ensure that the simulated tubing (2) can be lowered or raised normally and smoothly. The simulated tubing (2) can move back and forth along the length direction of the sliding hole (9) to realize the setting and unsealing of the Y211 packer (8).

2. The test device for testing the unsealing capability of a Y211 packer under a pressure difference as described in claim 1, characterized in that: The sealing element is a sealing ring (4), which is installed inside the simulated sleeve (1). The simulated oil pipe (2) passes through the sealing ring (4) and can slide freely and is in a sealed state.

3. The test device for testing the unsealing capability of a Y211 packer under a pressure difference as described in claim 2, characterized in that: The injection mechanism includes an inlet hole (5) and an exhaust hole (6) sequentially disposed on the outer wall of the simulated sleeve (1). The inlet hole (5) is used for injection, and the exhaust hole (6) is used for exhaust.

4. The test device for testing the unsealing capability of a Y211 packer under a pressure difference as described in claim 1, characterized in that: The simulated tubing (2) is also provided with an annular groove for setting the Y211 packer.

5. A method for testing the unsealing capability of a Y211 packer under a pressure difference, comprising the unsealing capability testing device according to any one of claims 1-4, characterized in that: Including the following methods, Connect the Y211 packer (8) to the simulated tubing (2); Install the installed Y211 packer (8) and the simulated tubing (2) inside the simulated casing (1); Raise and lower the simulated oil pipe (2) to put the Y211 packer (8) in the setting track, and apply pressure to set the Y211 packer (8); The pressure is injected into the annulus formed between the seal and the Y211 packer (8) by the pressure injection mechanism, so that the pressure in the annulus is the same as the preset pressure difference, wherein the preset pressure difference is the actual pressure difference between the upper and lower parts of the Y211 packer (8) after it is set in the well. The simulated tubing (2) was lifted to test the pull force required to release the Y211 packer (8) under the pre-set pressure difference. The tensile force measured above provides a guarantee for the release force of Y211 packer (8) under the pressure difference between the upper and lower parts during actual fracturing operations.

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