An experimental device and method for testing the setting throttling pressure difference of K344 packers under confining pressure

Abstract

The present invention relates to the technical field of oil and gas field exploration and development, and specifically to a test device and method for testing the throttling pressure differential of a K344 packer under confining pressure. The device comprises a simulated casing sealed at one end, a multifunctional plug capable of injecting liquid into the other end of the simulated casing being sealed and connected thereto, a K344 packer being connected to the end face of the multifunctional plug located within the simulated casing, a throttling mechanism being connected to the other end of the K344 packer, a liquid inlet and a liquid outlet being provided on the exterior of the simulated casing, and a pressure regulating mechanism being connected to the liquid outlet. The present invention tests the throttling pressure differential of the K344 packer under confining pressure by subjecting the K344 packer to a predetermined confining pressure and generating a certain throttling pressure differential within the K344 packer through liquid injection and the action of the throttling mechanism. The device and method have a simple principle, high operability, and accurate test results, and can provide an accurate basis for the design of the throttling pressure differential of the K344 packer during construction.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field exploration and development, and in particular to a test device and method for testing the seating throttling pressure difference of a K344 packer under confining pressure. Background Art

[0002] The K344 packer boasts technical advantages such as simple structure and ease of use, making it widely used in downhole operations such as fracturing and acidizing in oil and gas wells. During field installation, the K344 packer typically utilizes the throttling pressure differential generated by the flow of liquid through the tubing string to achieve seating.

[0003] Currently, the K344 packer's seating pressure differential is tested under atmospheric pressure. The choke size is then calculated based on the test results and the designed displacement. However, during field operations, it was discovered that some K344 packers failed to seat underground. The primary reason for this is that when the K344 packer is seated underground, a certain confining pressure exists around it, and the seating pressure differential varies with this pressure. The results of tests conducted under atmospheric pressure cannot accurately guide field implementation. Therefore, it is necessary to simulate the actual operating conditions of the K344 packer underground and test its seating and choke pressure differential under confining pressure to provide a more reliable basis for subsequent design and the selection of key tools. Summary of the Invention

[0004] The present invention overcomes the shortcomings of the existing technology and provides a test device and method for testing the sealing throttling pressure difference of the K344 packer under confining pressure. In particular, it can simulate the actual working conditions of the K344 packer working underground and test its sealing throttling pressure difference under confining pressure, providing a more reliable basis for subsequent design and selection of key tools.

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

[0006] A test device for testing the throttling pressure difference of the K344 packer seat under confining pressure, comprising a simulated casing sealed at one end, the other end of the simulated casing being sealed and connected to a multifunctional plug capable of injecting liquid inward, the end face of the multifunctional plug located in the simulated casing being connected to the K344 packer, the other end of the K344 packer being connected to a throttling mechanism, a liquid inlet and a liquid outlet being provided on the outside of the simulated casing, and a pressure regulating mechanism being also connected to the liquid outlet.

[0007] Furthermore, the multifunctional plug is provided with a liquid inlet channel communicating with the interior of the simulated casing, and the liquid inlet channel located in the simulated casing is connected to the K344 packer.

[0008] Furthermore, the K344 packer and the simulated casing form an upper annulus and a lower annulus after being isolated, the liquid inlet is located on the outer wall of the upper annulus, and the liquid outlet is located on the outer wall of the lower annulus.

[0009] Furthermore, the liquid inlet channel in the simulated casing is also connected to a tubing short circuit, and the K344 packer is connected to the tubing short circuit.

[0010] Furthermore, the pressure regulating mechanism is a throttle valve, the throttling mechanism is a throttle plug, and the throttle plug is provided with a throttle nozzle.

[0011] A method for testing a K344 packer seat seal throttling pressure difference under confining pressure, comprising any one of the above-mentioned test devices, including the following method:

[0012] According to the actual pressure value in the downhole casing, the actual pressure value is set to P, which is the set confining pressure value of the K344 packer;

[0013] Install the K344 packer on the multifunctional plug, and then install the whole into the simulated casing, so that the K344 packer is located in the simulated casing and the multifunctional plug is sealed and connected to one end of the simulated casing;

[0014] Liquid is injected into the annulus between the K344 packer and the simulated casing and into the K344 packer through the liquid inlet and the multifunctional plug, respectively. A small displacement injection is performed at the multifunctional plug. The pressure regulating mechanism on the liquid outlet is adjusted so that the pressure value in the annulus between the K344 packer and the simulated casing is the same as the actual pressure value P. Liquid is continuously injected to keep the pressure in the annulus between the K344 packer and the simulated casing constant, that is, the pressure value at the liquid inlet is equal to the actual pressure value P.

[0015] The injection volume of liquid is gradually increased from the multifunctional plug, so that the K344 packer forms a throttling pressure difference under the action of the throttling mechanism to make it seal;

[0016] Test the throttling pressure difference required for the K344 packer to seal under confining pressure.

[0017] Furthermore, a method for testing a test device for testing a K344 packer seat throttling pressure differential under confining pressure also includes the following method:

[0018] When the K344 packer is seated under confining pressure, observe the fluid discharge from the outlet and the injection pressure from the inlet;

[0019] When the outlet stops discharging liquid and the pressure value of the inlet suddenly increases, the liquid injection into all the inlet channels is stopped;

[0020] Record the inlet pressure value on the multifunctional plug at this time, let the inlet pressure value on the multifunctional plug be P1, and calculate the seat throttling pressure difference of the K344 packer when the confining pressure is P as P1-P.

[0021] The beneficial effects of the present invention are:

[0022] Compared to existing technologies, this test device and method exposes the K344 packer to a preset confining pressure. Liquid injection and the action of a throttling plug create a certain throttling pressure differential within the K344 packer, allowing for testing of the throttling pressure differential during seating under confining pressure. This test device and method offer a simple principle, high operability, and accurate test results, providing a reliable basis for designing the throttling pressure differential during K344 packer seating during construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and examples.

[0024] Figure 1 It is a schematic diagram of the overall cross-sectional structure of the present invention.

[0025] In the figure: 1-simulated casing, 2-multi-function plug, 3-liquid inlet hole, 4-liquid outlet hole, 5-throttling plug, 6-K344 packer, 7-liquid inlet channel. DETAILED DESCRIPTION

[0026] Hereinafter, the technical solutions of the test device and method for testing the seat seal throttling pressure difference of the K344 packer under confining pressure provided by the embodiments of the present invention will be described in detail through several specific embodiments.

[0027] Reference Figure 1As shown, a test device for testing the throttling pressure difference of the K344 packer seat under confining pressure includes a simulated casing 1 with a sealed plug at one end, which is used to simulate the casing outside the downhole oil pipe, wherein one end of the simulated casing 1 is sealed, and a multifunctional plug 2 for injecting liquid is sealed and connected to the other end of the simulated casing 1. Liquid can be injected into the multifunctional plug 2, and the end face of the multifunctional plug 2 located in the simulated casing 1 is connected to the K344 packer. A male buckle connected to the K344 packer can also be provided on the end face of the multifunctional plug 2 for connecting the K344 packer. The other end of the K344 packer is connected to a throttling mechanism, through which a throttling mechanism can be formed inside the K344 packer when water is injected into the K344 packer from the multifunctional plug 2. Pressure, so that the K344 packer can be sealed. A liquid inlet hole 3 and a liquid outlet hole 4 are provided on the outside of the simulated casing 1. The liquid inlet hole 3 and the liquid outlet hole 4 can form an external confining pressure in the annulus between the K344 packer and the simulated casing 1, thereby simulating the actual pressure in the casing downhole. The liquid outlet hole 4 is also connected to a pressure regulating mechanism, and the pressure regulating mechanism is used to adjust the pressure value in the annulus between the K344 packer of the present invention and the simulated casing 1 so that the pressure value is the same as the actual downhole casing pressure, thereby realizing the real simulation of the throttling pressure difference required for the K344 packer to be sealed under the confining pressure state downhole, thereby ensuring that the K344 packer can achieve a 100% sealing effect after being lowered into the well, thereby improving the work efficiency for the well site construction.

[0028] Reference Figure 1 As shown, the multifunctional plug 2 is provided with a liquid inlet channel 7 connected to the interior of the simulated casing 1, so as to facilitate the injection of liquid into the K344 packer through the liquid inlet channel 7. The K344 packer is connected to the liquid inlet channel 7 located in the simulated casing 1, and a male buckle can be provided on the liquid inlet channel 7 located in the simulated casing 1 for connecting the K344 packer.

[0029] After the K344 packer and the simulated casing 1 are isolated, an upper annulus and a lower annulus are formed. The liquid inlet 3 is located on the outer wall of the upper annulus, and the liquid outlet 4 is located on the outer wall of the lower annulus. The purpose is to form two downward annuli after the K344 packer is seated. At this time, the pressure of the upper annulus is the pressure of the outer annulus after the K344 packer is seated. The pressure inside the K344 packer is the seating pressure. The throttling pressure difference required for seating is the difference between the two pressures.

[0030] Another implementation method is: the liquid inlet channel 7 located in the simulated casing 1 is also connected to an oil pipe short-circuit, and the K344 packer is connected to the oil pipe short-circuit. A male buckle connected to the K344 packer is provided on the oil pipe short-circuit for easy connection. This structure is purchased to better simulate the environment of the K344 packer seat in the oil pipe, and at the same time ensure that the liquid inlet hole 3 and the liquid outlet hole 4 are respectively located on the outer walls of the upper annulus and the lower annulus.

[0031] The pressure regulating mechanism is a throttle valve, which can be manually adjusted to make the internal pressure meet the pressure in the actual outer annulus underground. The throttle mechanism is a throttle plug 5, which is provided with a throttle nozzle, which can generate throttling pressure in the K344 packer to achieve seat sealing.

[0032] Reference Figure 1 As shown, a method for testing a test device for testing the throttling pressure difference of a K344 packer seat under confining pressure includes the test device described in any one of the above, including the following methods:

[0033] According to the actual pressure value in the downhole casing, the actual pressure value is set to P, which is the set confining pressure value of the K344 packer;

[0034] Install the K344 packer on the multifunctional plug 2, and then install the whole into the simulated casing 1, so that the K344 packer is located in the simulated casing 1, and the multifunctional plug 2 is sealed and connected to one end of the simulated casing 1;

[0035] Liquid is injected into the annulus between the K344 packer and the simulated casing 1 and into the K344 packer through the liquid inlet hole 3 and the multifunctional plug 2 respectively, wherein a small displacement injection is performed at the multifunctional plug 2, and the pressure regulating mechanism on the liquid outlet hole 4, i.e., the throttle valve, is adjusted so that the pressure value in the annulus between the K344 packer and the simulated casing 1 is the same as the actual pressure value P, in order to truly simulate the pressure in the downhole casing, i.e., the confining pressure value of the K344 packer described in the present invention; and liquid is continuously injected to keep the pressure in the annulus between the K344 packer and the simulated casing 1 unchanged, i.e., at this time, the pressure value obtained by the liquid inlet hole 3 is equal to the actual pressure value P;

[0036] The displacement of the injected liquid is gradually increased from the multifunctional plug 2. During the injection, the injection displacement can be increased in a step-by-step manner to increase the injection pressure, so that the K344 packer forms a throttling pressure difference under the action of the throttling mechanism to make it seal;

[0037] Test the throttling pressure difference required for the K344 packer to seal under confining pressure.

[0038] Among them, a method for testing a test device for testing the throttling pressure difference of a K344 packer seat under confining pressure also includes the following method:

[0039] After the K344 packer is seated under confining pressure, observe the liquid outflow from the outlet 4 and the injection pressure from the inlet 3.

[0040] When the liquid outlet 4 stops discharging liquid and the pressure value of the liquid inlet 3 suddenly increases, the liquid injection into all liquid inlet channels is stopped;

[0041] Record the liquid inlet pressure value on the multifunctional plug 2 at this time, and let the liquid inlet pressure value on the multifunctional plug 2 be P1. Calculate the sealing throttling pressure difference of the K344 packer when the confining pressure is P as P1-P.

[0042] In the present invention, a pressure gauge can be set outside the liquid inlet hole 3, the liquid outlet hole 4 and the liquid inlet channel 7 to facilitate pressure observation. A pressure gauge can also be set on the injection equipment to facilitate observation of the injection pressure at different positions.

[0043] The test device and method of the present invention have simple principles, high operability and accurate test results. They can provide an accurate basis for the design of the throttling pressure difference of the K344 packer during construction, and solve the problem that the sealing pressure difference of the K344 packer is determined under normal pressure, and the test results cannot accurately guide the on-site implementation, resulting in the design based on the test results, and some K344 packers cannot be sealed underground during on-site construction.

[0044] The above describes the embodiments of the present invention in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by ordinary technicians in this field, various changes can be made without departing from the purpose of the present invention, which are all within the scope of protection of this technology.

[0045] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0046] The technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A test device for testing the throttling pressure difference of the K344 packer under confining pressure, characterized by: The invention comprises a simulation casing (1) with a sealed plug at one end, the other end of the simulation casing (1) is sealedly connected to a multifunctional plug (2) capable of injecting liquid inwardly, the end face of the multifunctional plug (2) located in the simulation casing (1) is connected to a K344 packer, the other end of the K344 packer is connected to a throttling mechanism, the outside of the simulation casing (1) is provided with a liquid inlet (3) and a liquid outlet (4), and the liquid outlet (4) is also connected to a pressure regulating mechanism; After the K344 packer and the simulated casing (1) are sealed, an upper annulus and a lower annulus are formed. The liquid inlet (3) is located on the outer wall of the upper annulus, and the liquid outlet (4) is located on the outer wall of the lower annulus.

2. A test device for testing the seat seal throttling pressure differential of a K344 packer under confining pressure according to claim 1, characterized in that: The multifunctional plug (2) is provided with a liquid inlet channel (7) communicating with the interior of the simulation casing (1), and the liquid inlet channel (7) located in the simulation casing (1) is connected to a K344 packer.

3. The test device for testing the seat seal throttling pressure difference of a K344 packer under confining pressure according to claim 1, characterized in that: The liquid inlet channel (7) located in the simulation casing (1) is also connected to an oil pipe short circuit, and the K344 packer is connected to the oil pipe short circuit.

4. The test device for testing the seat seal throttling pressure differential of a K344 packer under confining pressure according to claim 1, characterized in that: The pressure regulating mechanism is a throttle valve, the throttling mechanism is a throttle plug (5), and the throttle plug (5) is provided with a throttle nozzle.

5. A method for testing the K344 packer seating throttling pressure differential under confining pressure, comprising the test device according to any one of claims 1 to 4, characterized in that: Including the following methods, According to the actual pressure value in the downhole casing, the actual pressure value is set to P, which is the set confining pressure value of the K344 packer; The K344 packer is installed on the multifunctional plug (2), and then the whole is installed in the simulated casing (1), so that the K344 packer is located in the simulated casing (1), and the multifunctional plug (2) is sealed and connected to one end of the simulated casing (1); Liquid is injected into the annulus between the K344 packer and the simulated casing (1) and into the K344 packer through the liquid inlet hole (3) and the multifunctional plug (2) respectively, wherein a small displacement injection is performed at the multifunctional plug (2), and the pressure regulating mechanism on the liquid outlet hole (4) is adjusted so that the pressure value in the annulus between the K344 packer and the simulated casing (1) is the same as the actual pressure value P, and liquid is continuously injected to keep the pressure in the annulus between the K344 packer and the simulated casing (1) unchanged, that is, at this time, the pressure value obtained at the liquid inlet hole (3) is equal to the actual pressure value P; The displacement of the liquid injected from the multifunctional plug (2) is gradually increased, so that the K344 packer forms a throttling pressure difference under the action of the throttling mechanism to make it seated; Test the throttling pressure difference required for the K344 packer to seal under confining pressure.

6. The method for testing the K344 packer seating throttling pressure differential under confining pressure according to claim 5, characterized in that: Also includes the following methods: After the K344 packer is seated under confining pressure, observe the liquid discharge from the outlet (4) and the injection pressure from the inlet (3); When the liquid outlet (4) stops discharging liquid and the pressure value of the liquid inlet (3) suddenly increases, the liquid injection into all liquid inlet channels is stopped; Record the liquid inlet pressure value on the multifunctional plug (2) at this time, let the liquid inlet pressure value on the multifunctional plug (2) be P1, and calculate the sealing throttling pressure difference of the K344 packer when the confining pressure is P as P1-P.

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