Gas well under-pressure operation dynamic seal test device and test method

Abstract

The invention provides a gas well under-pressure operation dynamic seal test device and method, the test device comprises a rack, a dynamic seal test unit and a wellhead tripping unit, the dynamic seal test unit is installed on the rack, the dynamic seal test unit comprises a first blowout preventer, a second blowout preventer, a simulation shaft and a mandrel, and the first blowout preventer, the second blowout preventer, the simulation shaft and the mandrel are installed on the rack. The first blowout preventer and the second blowout preventer are installed at the upper end and the lower end of the simulation wellbore, the mandrel penetrates through the simulation wellbore, and an annulus is formed between the mandrel and the simulation wellbore. The wellhead tripping unit comprises a tripping mechanism, and the tripping mechanism is connected with the upper end of the mandrel and can drive the mandrel to reciprocate; the first blowout preventer and the second blowout preventer are provided with a first movable sealing piece and a second movable sealing piece, and the first movable sealing piece and the second movable sealing piece can be clamped on the mandrel and block the annulus. The annulus can be pressurized to test the sealing performance of the dynamic seal. The upper blowout preventer and the lower blowout preventer are adopted to seal the annulus, so that safety accidents caused by the fact that the mandrel is ejected out of the blowout preventers can be prevented, the safety coefficient is improved, and the test pressure can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure - maintained operation in oil and gas drilling and production. Specifically, it relates to a dynamic seal test device and test method for pressure - maintained operation of gas wells. Background Art

[0002] Pressure - maintained operation refers to the construction operation carried out in the wellbore with the help of a pressure - maintained operation machine under the pressure - maintained state at the wellhead of a gas well or an oil - and - gas - containing well. The main technical cores are internal pipe sealing, external pipe sealing, and applying downward pressure to overcome the upward force. It has the advantages of not killing the well, not discharging the wellhead fluid, not relieving pressure, avoiding oil and gas layer pollution, maintaining formation energy, shortening the operation cycle, and zero pollution. It is a technology that is green, environmentally friendly, clean - production - oriented, and widely promoted.

[0003] Pressure - maintained operation conducts sliding sealing between the tubing and the casing through the internal seal of the blowout preventer. The annular rubber core seal can pass through the tubing or drill pipe collar, while the wear - resistant block can only seal the tubing body and cannot pass through the variable - diameter component. When there is no test bench to test the blowout preventer, accidents may occur on - site, and they occur without being fixed or with signs, resulting in casualties and property losses. Currently, the devices in the prior art for testing and evaluating the sealing performance of dynamic seals for pressure - maintained operation of gas wells only use one blowout preventer to conduct pressure sealing on the annulus between the wellbore and the mandrel. There is a risk of ejecting the mandrel under high pressure, causing safety accidents, and the safety factor is relatively low. Therefore, the test pressure cannot be increased, and thus the sealing performance of dynamic seals under higher pressures cannot be tested. Summary of the Invention

[0004] The purpose of the present invention is to solve at least one of the above - mentioned deficiencies existing in the prior art. For example, one of the purposes of the present invention is to provide a dynamic seal test device and test method for pressure - maintained operation of gas wells to solve the technical problem that the test pressure cannot be increased due to safety risks in the existing dynamic seal performance test device for pressure - maintained operation of gas wells.

[0005] To achieve the above object, on the one hand, the present invention provides a dynamic seal test device for a gas well under pressure. The test device may include a frame, a dynamic seal test unit, and a wellhead tripping unit. Among them, the dynamic seal test unit is installed on the frame. The dynamic seal test unit includes a first blowout preventer, a second blowout preventer, a simulated wellbore, and a mandrel. The simulated wellbore and the mandrel are arranged vertically. The first blowout preventer is installed at the upper end of the simulated wellbore, and the second blowout preventer is installed at the lower end of the simulated wellbore. The mandrel passes through the simulated wellbore. The upper end of the mandrel is higher than the upper end of the first blowout preventer, and the lower end of the mandrel is lower than the lower end of the second blowout preventer. An annulus is formed between the outer wall of the mandrel and the inner wall of the simulated wellbore. The wellhead tripping unit includes a tripping mechanism. The tripping mechanism is installed at the upper end of the first blowout preventer and is fixedly connected to the upper end of the mandrel. The tripping mechanism can drive the mandrel to reciprocate up and down. The first blowout preventer is provided with a first dynamic seal, and the second blowout preventer is provided with a second dynamic seal. The first blowout preventer and the second blowout preventer can respectively press the first dynamic seal and the second dynamic seal against the outer wall of the mandrel to clamp the mandrel and seal the upper and lower ends of the annulus. The annulus can be pressurized while the mandrel is clamped by the first blowout preventer and the second blowout preventer and is driven by the tripping mechanism to reciprocate up and down to test the sealing performance of the first dynamic seal and the second dynamic seal on the annulus.

[0006] Optionally, the test device may further include a first pressurizing unit. The first pressurizing unit can communicate with the annulus and pressurize the annulus to a set pressure after the annulus is sealed, so as to test the sealing performance of the first dynamic seal and the second dynamic seal on the annulus while the mandrel reciprocates up and down.

[0007] Optionally, the wellhead tripping unit may further include at least one tripping drive. The tripping drive is fixedly connected to the tripping mechanism. The tripping drive can provide a driving force for the tripping mechanism, so that the tripping mechanism can drive the mandrel to reciprocate up and down.

[0008] Optionally, the test device may further include a second pressurizing unit. The second pressurizing unit is connected to the tripping drive. The second pressurizing unit can pressurize the tripping drive to control the tripping drive to drive the tripping mechanism.

[0009] Optionally, the test device may further include a data acquisition unit. The data acquisition unit is connected to the dynamic seal test unit and is used to measure test parameters during the test.

[0010] Optionally, the data acquisition unit may include a pressure sensor. The pressure sensor is installed on the simulated wellbore, the first blowout preventer, and the second blowout preventer and is used to measure pressure parameters during the test.

[0011] Optionally, the test device may further include a control unit, which is connected to the dynamic seal test unit, the wellhead tripping unit, and the data acquisition unit. The control unit can control the dynamic seal test unit and the wellhead tripping unit according to the parameters measured by the data acquisition unit.

[0012] Optionally, the test device may further include a water tank, which is installed above the first blowout preventer and below the second blowout preventer. The water tank can provide cooling water to cool the friction position between the blowout preventer and the mandrel.

[0013] Optionally, the test device can be placed in a foundation pit filled with cooling water to conduct a dynamic seal test of the test device as a whole in the cooling water. The cooling water can protect the high-pressure positions in the test device and cool the friction positions in the test device.

[0014] On the other hand, the present invention provides a method for dynamic seal test of pressure operation in a gas well. The test method can use the dynamic seal test device for pressure operation in a gas well as described above. The test method may include clamping the first blowout preventer and the second blowout preventer on the mandrel, making the first dynamic seal and the second dynamic seal closely adhere to the outer wall of the mandrel; pressurizing the annulus to a set pressure, driving the mandrel to reciprocate up and down through the tripping mechanism; measuring and obtaining the pressure values in the annulus and the wellhead tripping unit, and adjusting the pressure value in the annulus and / or the reciprocating speed of the mandrel according to the test requirements; obtaining the wear degrees of the first dynamic seal and the second dynamic seal, and evaluating the sealing performance of the first dynamic seal and the second dynamic seal against the annulus.

[0015] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0016] 1. The test device of the present invention uses the upper and lower double blowout preventers to seal the annulus, which can make the mandrel pass through the upper and lower ends of the annulus as a whole, so as to prevent the high pressure in the annulus from applying axial pressure to one end of the mandrel, avoiding the risk of the mandrel being axially ejected from the blowout preventer and causing safety accidents, reducing the probability of accidents, and improving the safety factor.

[0017] 2. The test device of the present invention can conduct a pressure dynamic seal test on the blowout preventer, simulate the real working conditions of the blowout preventer and its dynamic seals, determine the usage conditions and working parameters of the blowout preventer under real working conditions, and thus further evaluate the service life of the blowout preventer and its dynamic seals, providing a large amount of data guarantee for the use of the blowout preventer in drilling operations.

[0018] 3. The test device of the present invention can increase the test pressure from the original more than a dozen MPa to about 105 MPa, and there is no need to newly add anti-bending centralizers in the tests of small pipe diameters such as 60.3 mm and 73 mm, simplifying the structure of the test device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Through the following description in conjunction with the drawings, the above and other objects and / or features of the present invention will become clearer, where:

[0020] Figure 1 The structure diagram of the dynamic seal test device for pressure operation of gas wells showing an exemplary embodiment of the present invention is shown.

[0021] Description of the reference numerals in the drawings:

[0022] 1. Frame, 2. Dynamic seal test unit, 21. First blowout preventer, 211. First dynamic seal, 22. Second blowout preventer, 221. Second dynamic seal, 23. Simulated wellbore, 24. Mandrel, 25. Annulus, 3. Wellhead tripping unit, 31. Tripping mechanism, 32. Tripping drive, 4. First pressurization unit, 5. Second pressurization unit, 6. Data acquisition unit, 61. Pressure sensor, 7. Control unit, 8. Water tank. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] Hereinafter, the dynamic seal test device and test method of the gas well with pressure operation of the present invention will be described in detail in conjunction with the exemplary embodiments.

[0024] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0025] The terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0026] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the related art, the device for testing and evaluating the sealing performance of the dynamic seal for the pressure operation of a gas well only uses one blowout preventer to seal the pressure in the annulus between the wellbore and the mandrel. There is a risk of ejecting the mandrel under high pressure, which may cause a safety accident, and the safety factor is relatively low. Therefore, the test pressure cannot be increased, and thus the sealing performance of the dynamic seal under higher pressures cannot be tested.

[0028] Based on this, the present invention provides a dynamic seal test device and a test method for the pressure operation of a gas well. The test device includes a frame, a dynamic seal test unit, and a wellhead hoisting and lowering unit. The dynamic seal test unit is installed on the frame. The dynamic seal test unit includes a first blowout preventer, a second blowout preventer, a simulated wellbore, and a mandrel. The simulated wellbore and the mandrel are arranged vertically. The first blowout preventer is installed at the upper end of the simulated wellbore, and the second blowout preventer is installed at the lower end of the simulated wellbore. The mandrel passes through the simulated wellbore. The upper end of the mandrel is higher than the upper end of the first blowout preventer, and the lower end of the mandrel is lower than the lower end of the second blowout preventer. An annulus is formed between the outer wall of the mandrel and the inner wall of the simulated wellbore. The wellhead hoisting and lowering unit includes a hoisting and lowering mechanism, which is installed at the upper end of the first blowout preventer and fixedly connected to the upper end of the mandrel. The hoisting and lowering mechanism can drive the mandrel to reciprocate up and down. The first blowout preventer is provided with a first dynamic seal, and the second blowout preventer is provided with a second dynamic seal. The first blowout preventer and the second blowout preventer can respectively press the first dynamic seal and the second dynamic seal against the outer wall of the mandrel to clamp the mandrel and seal the upper and lower ends of the annulus. The annulus can be pressurized while the mandrel is clamped by the first blowout preventer and the second blowout preventer and driven to reciprocate up and down by the hoisting and lowering mechanism to test the sealing performance of the first dynamic seal and the second dynamic seal for the annulus.

[0029] The test device of the present invention adopts the method of using upper and lower blowout preventers to seal the annulus, which can enable the mandrel to pass through the upper and lower ends of the annulus as a whole, so as to prevent the high pressure in the annulus from applying axial pressure to one end of the mandrel, avoiding the risk of the mandrel being ejected axially from the blowout preventer and causing safety accidents, reducing the probability of accidents and improving the safety factor; the test device of the present invention can conduct a dynamic seal test on the blowout preventer under pressure, can simulate the real working conditions of the blowout preventer and its dynamic seals, determine the usage conditions and working parameters of the blowout preventer under real working conditions, and thus can further evaluate the service life of the blowout preventer and its dynamic seals, providing a large amount of data guarantee for the use of the blowout preventer in drilling operations; the test device of the present invention can increase the test pressure from the original more than a dozen MPa to about 105 MPa, and does not require a new anti-bending and centering device in small-diameter tests such as 60.3 mm and 73 mm, simplifying the structure of the test device.

[0030] Exemplary Embodiment 1

[0031] This exemplary embodiment provides a dynamic seal test device for pressure operation in gas wells.

[0032] Figure 1 The structural diagram of the dynamic seal test device for pressure operation in gas wells according to the exemplary embodiment of the present invention is shown.

[0033] As Figure 1 shown, the dynamic seal test device for pressure operation in gas wells described in this exemplary embodiment may include a frame 1, a dynamic seal test unit 2, and a wellhead tripping unit 3. Among them, the dynamic seal test unit 2 can be installed on the frame 1. The dynamic seal test unit 2 may include a first blowout preventer 21, a second blowout preventer 22, a simulated wellbore 23, and a mandrel 24. The simulated wellbore 23 and the mandrel 24 are arranged vertically. The first blowout preventer 21 can be fixedly installed at the upper end of the simulated wellbore 23, and the second blowout preventer 22 can be fixedly installed at the lower end of the simulated wellbore 23; the mandrel 24 is arranged in the simulated wellbore 23. Here, since the inner diameter of the simulated wellbore 23 is significantly larger than the outer diameter of the mandrel 24, after the mandrel 24 is arranged in the simulated wellbore 23, an annular space (annulus 25) with a certain distance can be formed between the outer wall of the mandrel 24 and the inner wall of the simulated wellbore 23; the mandrel 24 can extend upward from the upper end of the simulated wellbore 23 so that its upper end is higher than the upper end of the first blowout preventer 21. Similarly, the mandrel 24 can also extend downward from the lower end of the simulated wellbore 23 so that its lower end is lower than the lower end of the second blowout preventer 22.

[0034] The tripping unit 3 at the wellhead may include a tripping mechanism 31. The tripping mechanism 31 may be installed at the upper end of the first blowout preventer 21. At the same time, the tripping mechanism 31 may be fixedly connected to the upper end of the mandrel 24. That is to say, the tripping mechanism 31 can hold the mandrel 24 and drive the mandrel 24 to reciprocate up and down in the simulated wellbore 23. Here, the tripping mechanism 31 can clamp the upper end of the mandrel 24 in a way of slip clamping, can provide sufficient clamping force for the mandrel 24, and can bear the overall suspended weight of the mandrel 24. However, the present invention is not limited thereto. The tripping mechanism 31 and the mandrel 24 may also be connected by other fixed connection methods. For example, they may be connected by screw threads, etc., which can be arbitrarily selected according to actual needs. The present invention does not make specific limitations on this.

[0035] The first blowout preventer 21 may be provided with a first dynamic seal 211, and the second blowout preventer 22 may be provided with a second dynamic seal 221. The first dynamic seal 211 may be located on the left and right sides of the mandrel 24, and the second dynamic seal 221 may also be located on the left and right sides of the mandrel 24. The first blowout preventer 21 and the second blowout preventer 22 may move the first dynamic seal 211 and the second dynamic seal 221 located on the left and right sides of the mandrel 24 towards each other, so that both the first dynamic seal 211 and the second dynamic seal 221 can closely adhere to the outer wall of the mandrel 24, thereby clamping the mandrel 24. At the same time, the first dynamic seal 211 and the second dynamic seal 221 can also seal the upper and lower ends of the annulus 25, making the annulus 25 a closed space.

[0036] When it is necessary to test the sealing performance of the first dynamic seal 211 and the second dynamic seal 221 using the dynamic seal test device for gas well workover under pressure described in this exemplary embodiment, the first dynamic seal 211 and the second dynamic seal 221 can be closely adhered to the outer wall of the mandrel 24 to clamp the mandrel 24, then the annulus 25 is pressurized to a set pressure, and then the tripping mechanism 31 is used to drive the mandrel 24 to reciprocate up and down, so as to test the sealing performance of the first dynamic seal 211 and the second dynamic seal 221 for the annulus 25 under repeated friction and high pressure with the mandrel.

[0037] In this embodiment, the dynamic seal test device for gas well workover under pressure described in this exemplary embodiment may further include a first pressurizing unit 4. The first pressurizing unit 4 may be connected to the side wall of the simulated wellbore 23 through a pressurizing pipeline and communicate with the annulus 25. The first pressurizing unit 4 can pressurize the annulus 25 to provide a high-pressure environment. Here, the pressure in the annulus 25 can rise to about 105 MPa, which can meet the high-pressure test requirements for dynamic seals. The pressurizing medium used by the first pressurizing unit 4 may be water or air, as long as it can provide a sufficient pressure environment. The present invention does not make specific limitations on this.

[0038] Optionally, the wellhead tripping unit 3 may include a tripping driver 32. Here, the tripping driver 32 may be a hydraulic cylinder, and the number of the tripping drivers 32 may be two. The two hydraulic cylinders may be connected to the lower end of the tripping mechanism 31 and arranged vertically. The two hydraulic cylinders may be respectively located on the left and right sides of the simulated wellbore 23. Hydraulic oil may be input into the hydraulic cylinders to push the pistons to provide a driving force for the up-and-down reciprocating movement of the tripping mechanism 31, so as to drive the tripping mechanism 31 and drive the mandrel 24 to perform up-and-down reciprocating movement in the vertical direction. However, the present invention is not limited thereto. The specific type of the tripping driver 32 may also be other mechanisms besides the hydraulic cylinder, such as a push rod driven by a motor, etc. The number of the tripping drivers 32 may also be arbitrarily selected according to actual needs, and the present invention does not make specific limitations thereto.

[0039] In this embodiment, the dynamic seal test device for pressure-bearing operation of a gas well described in this exemplary embodiment may further include a second pressurizing unit 5. The second pressurizing unit 5 may be connected to the tripping driver 32 through a pressurizing pipeline and communicate with the oil cylinder of the tripping driver 32. The second pressurizing unit 5 may use hydraulic oil as a pressurizing medium to pressurize the tripping driver 32, so that the piston in the oil cylinder of the tripping driver 32 makes up-and-down reciprocating movement, thereby providing a driving force for the up-and-down reciprocating movement of the tripping mechanism 31, and further enabling the tripping mechanism 31 to drive the mandrel 24 to make up-and-down reciprocating movement. However, the present invention is not limited thereto. The pressurizing medium used by the second pressurizing unit 5 may also be other types of media besides hydraulic oil, such as water or gas, etc., which may be arbitrarily selected according to actual needs, and the present invention does not make specific limitations thereto.

[0040] In this embodiment, the dynamic seal test device for pressure-bearing operation of a gas well described in this exemplary embodiment may further include a data acquisition unit 6. The data acquisition unit 6 may be connected to the dynamic seal test unit 2. The data acquisition unit 6 may be used to measure various parameters in the dynamic seal test unit 2 during the dynamic seal test process, and record and store the collected various parameters.

[0041] Optionally, the data acquisition unit 6 may include pressure sensors 61. Here, the number of the pressure sensors 61 may include a plurality. The plurality of pressure sensors 61 may be installed at multiple positions such as the simulated wellbore 23, the first blowout preventer 21, the second blowout preventer 22, the tripping mechanism 31, and the tripping driver 32, and may measure the pressure parameters in the annulus 25, the pressure parameters of the tripping driver 32 on the tripping mechanism 31, and the pressure parameters of the tripping mechanism 31 on the mandrel 24 during the dynamic seal test process. However, the present invention is not limited thereto. The installation quantity and installation positions of the pressure sensors 61 may be arbitrarily selected according to actual test needs, and the present invention does not make specific limitations thereto.

[0042] In this embodiment, the dynamic seal test device for gas well under pressure operation described in this exemplary embodiment may further include a control unit 7. The control unit 7 can be connected to the dynamic seal test unit 2, the wellhead tripping unit 3, the first pressurizing unit 4, the second pressurizing unit 5, and the data acquisition unit 6 respectively through cables. The control unit 7 can display and store various parameters measured and collected by the data acquisition unit 6 in real time, enabling the test personnel to obtain various parameter information collected by the data acquisition unit 6 in a timely manner, so that the test process of the dynamic seal test unit 2 and the wellhead tripping unit 3 can be adjusted by using the control unit 7 in a timely manner.

[0043] Specifically, the control unit 7 can be a control terminal device such as a console or a computer. For example, when the pressure sensor 61 in the data acquisition unit 6 monitors that the pressure in the annulus 25 rises too fast, there are abnormal pressure fluctuations, or the pressure exceeds the preset test pressure, the pressure sensor 61 can transmit the real-time pressure parameter value to the control unit 7. Devices such as the display in the control unit 7 can display the real-time pressure parameters measured by the pressure sensor 61. The test personnel can obtain the corresponding real-time pressure parameters in a timely manner, and then can operate the control unit 7 to control the first pressurizing unit 4 to stop pressurizing the annulus 25 or perform a pressure relief operation, so as to protect the simulated wellbore 23 and prevent related components from being damaged due to abnormal high pressure.

[0044] The control unit 7 can adjust the test pressure value in the annulus 25 through the first pressurizing unit 4 during the dynamic seal test process, so as to obtain the sealing performance of the first dynamic seal 211 and the second dynamic seal 221 for the annulus 25 under different annulus pressures. The test personnel can compare and analyze the performance changes of the dynamic seal under different annulus pressure conditions.

[0045] Similarly, the control unit 7 can also display the pressure parameters in the tripping drive 32 by the pressure sensor 61 in real time. The test personnel can also control the tripping drive 32 through the control unit 7, so as to adjust the up and down reciprocating movement speed of the tripping mechanism 31 and the mandrel 24, and thus control the test process of the dynamic seal test to obtain the wear degree of the first dynamic seal 211 and the second dynamic seal 221 under different reciprocating movement speeds.

[0046] However, the present invention is not limited to this. The connection manner between the above control unit 7 and the dynamic seal test unit 2, the wellhead tripping unit 3, the first pressurizing unit 4, the second pressurizing unit 5, and the data acquisition unit 6 can be connected by other means in addition to being connected by cables, such as wireless connection, etc., as long as parameter signal transmission can be carried out. The present invention does not make specific limitations on this.

[0047] In this embodiment, the dynamic seal test device for pressure - operated well work in this exemplary embodiment may further include a water tank 8. The number of water tanks 8 may be two. One water tank 8 may be installed above the first blowout preventer 21, at the upper end of the frame 1, and the other water tank 8 may be installed below the second blowout preventer 22. The water tank 8 may contain cooling water, and the cooling water can be output from the water tank 8 through mechanisms such as a water pump (not shown in the figure) and sprayed along the cooling water pipe (not shown in the figure) at the joint clamped between the blowout preventer and the mandrel, so as to cool the dynamic seal during the friction process with the mandrel, avoid damage to the dynamic seal and the blowout preventer caused by the high temperature generated by friction, thus affecting the dynamic seal performance of the dynamic seal and further affecting the test process. However, the present invention is not limited thereto, and the water tank 8 may also be installed at other positions in the device where frictional high temperature may occur, and the present invention does not make specific limitations on this.

[0048] In this embodiment, the dynamic seal test device for pressure - operated well work in this exemplary embodiment may be integrally installed in a foundation pit filled with cooling water (except for electrical equipment such as the control unit), so that the entire test device can be submerged in the cooling water of the foundation pit for dynamic seal testing. The cooling water can protect the high - pressure positions (such as the annulus 25, etc.) in the test device. Even if an accident such as bursting and damage occurs to the device due to high pressure during the test, the loss can be minimized under the buffering of the cooling water in the foundation pit.

[0049] The cooling water can also cool the frictional positions in the test device (such as between the first dynamic seal 211 and the mandrel 24, and between the second dynamic seal 221 and the mandrel 24).

[0050] If it is selected to install the test device in a foundation pit filled with cooling water for testing, the water tank 8 can be cancelled, and the cooling water in the foundation pit can be directly used for cooling. If it is selected to install the test device on the ground for testing, then the water tank 8 needs to be installed for cooling.

[0051] The working process of the dynamic seal test device for pressure - operated well work in this exemplary embodiment is described in detail as follows:

[0052] Fix the mandrel 24 to the lower end of the tripping mechanism 31 and pass it through the first blowout preventer 21, the simulated wellbore 23, and the second blowout preventer 22 from top to bottom, so that the upper end of the mandrel 24 is higher than the first blowout preventer 21 and the lower end of the mandrel 24 is lower than the second blowout preventer 22. Clamp the first blowout preventer 21 and the second blowout preventer 22 on the mandrel 24, and make the first dynamic seal 211 and the second dynamic seal 221 closely adhere to the outer wall of the mandrel 24, thereby sealing the upper and lower ends of the annulus 25. Operate the first pressurizing unit 4 through the control unit 7 to pressurize the annulus 25 to a set pressure, for example, 105 MPa. Then, operate the second pressurizing unit 5 through the control unit 7 to pressurize the tripping drive 32 and adjust the reciprocating movement speed of the tripping mechanism 31 to a preset speed, for example, 0.6 m / s. At this time, the dynamic seal test starts. During the test, it is necessary to spray cooling water on the friction position between the dynamic seal and the mandrel through the water tank 8 at any time for cooling, and monitor the pressure parameters at the high-pressure position measured by the pressure sensor 61 through the control unit 7 at any time to ensure the safe and stable progress of the test process; during the test, it is also necessary to monitor the leakage situation and leakage amount of the blowout preventer in a timely manner and adjust the test process at any time; after the test, close the first pressurizing unit 4 and the second pressurizing unit 5 through the control unit 7, relieve the pressure of the annulus 25, stop the reciprocating movement of the tripping mechanism 31, open the first blowout preventer 21 and the second blowout preventer 22, loosen the clamping of the dynamic seal on the mandrel, remove the mandrel, and observe and record the wear conditions of the first dynamic seal 211 and the second dynamic seal 221.

[0053] Exemplary Embodiment 2

[0054] This exemplary embodiment provides a dynamic seal test method for pressure - controlled operation in gas wells.

[0055] The dynamic seal test method for pressure - controlled operation in gas wells described in this exemplary embodiment can adopt the dynamic seal test device described in Exemplary Embodiment 1.

[0056] The dynamic seal test method for pressure - controlled operation in gas wells described in this exemplary embodiment may include the following steps:

[0057] S1: Preparation before the test

[0058] Fix the mandrel to the lower end of the tripping mechanism and pass it through the first blowout preventer, the simulated wellbore, and the second blowout preventer from top to bottom, so that the upper end of the mandrel is higher than the first blowout preventer and the lower end of the mandrel is lower than the second blowout preventer. Clamp the first blowout preventer and the second blowout preventer on the mandrel, and make the first dynamic seal and the second dynamic seal closely adhere to the outer wall of the mandrel, sealing the upper and lower ends of the annulus.

[0059] S2: Start the test

[0060] The control unit operates the first pressurizing unit to pressurize the annulus to a set pressure, such as 105 MPa. Then, the control unit operates the second pressurizing unit to pressurize the tripping drive member to adjust the reciprocating speed of the tripping mechanism to a preset speed, such as 0.6 m / s. At this time, the dynamic seal test begins. During the test, it is necessary to spray cooling water on the friction position between the dynamic seal and the mandrel through the water tank at any time for cooling, and monitor the pressure parameters at the high-pressure position measured by the pressure sensor through the control unit at any time to ensure the safe and stable progress of the test.

[0061] S3: Test process adjustment

[0062] After the test starts, the blowout preventer can be closed with the closing pressure recommended by the blowout preventer manufacturer, and the rated well pressure can be applied in the annulus. At this time, there is no leakage in the blowout preventer. Gradually reduce the closing pressure of the blowout preventer until leakage occurs in the blowout preventer, and control the leakage rate not to exceed 4 L / Min, and make the test mandrel reciprocate at a speed of 0.6 m / s. If the leakage rate exceeds 4 L / Min, the closing pressure of the blowout preventer should be increased until the recommended maximum closing pressure of the blowout preventer is reached. Record data such as the well pressure situation, leakage situation, tripping speed of the mandrel, and equivalent length of the tripping test mandrel in the annulus during the test process. Under the action of the repeated movement and expansion of the tripping drive member, the mandrel moves up and down in the simulated wellbore to simulate the same working environment as the field. The operator can monitor various data in front of the console of the control unit, and install sensors to be tested at each key part of the test to transmit real data in real time. The operator can make a judgment according to the standard whether the test meets the requirements.

[0063] S4: Evaluate the dynamic seal performance after the test

[0064] After the test is over, the control unit closes the first pressurizing unit and the second pressurizing unit, relieves the pressure of the annulus, stops the reciprocating movement of the tripping mechanism, opens the first blowout preventer and the second blowout preventer, releases the clamping of the mandrel by the dynamic seal, removes the mandrel, observes and records the wear conditions of the first dynamic seal and the second dynamic seal, and analyzes and evaluates the change of the dynamic seal performance of the dynamic seal according to the recorded parameters.

[0065] Generally, during the test process according to the above test method, for the first dynamic seal in the first blowout preventer, its service life is mainly tested according to its wear degree, and for the second dynamic seal in the second blowout preventer, its dynamic seal performance is mainly tested by high-pressure testing; in actual tests, the test direction can also be adjusted according to requirements.

[0066] In summary, the test device of the present invention uses upper and lower blowout preventers to seal the annulus, enabling the mandrel to pass through the upper and lower ends of the annulus as a whole, preventing the high pressure in the annulus from applying axial pressure to one end of the mandrel, avoiding the risk of the mandrel being ejected axially from the blowout preventer and causing a safety accident, reducing the probability of accidents and enhancing the safety factor; the test device of the present invention can conduct a pressure dynamic sealing test on the blowout preventer, simulate the real working conditions of the blowout preventer and its dynamic sealing parts, determine the usage conditions and working parameters of the blowout preventer under real working conditions, thereby further evaluating the service life of the blowout preventer and its dynamic sealing parts, and providing a large amount of data guarantee for the use of the blowout preventer in drilling operations; the test device of the present invention can increase the test pressure from the original more than a dozen MPa to about 105 MPa, and does not require a new anti-bending and centralizing device in small-diameter tests such as 60.3 mm and 73 mm, simplifying the structure of the test device.

[0067] Although the present invention has been described above in connection with exemplary embodiments and the accompanying drawings, those of ordinary skill in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A dynamic seal test device for pressure - maintained operation of a gas well, characterized in that, The test device includes a frame, a dynamic seal test unit, and a wellhead tripping unit. Among them, The dynamic seal test unit is installed on the frame. The dynamic seal test unit includes a first blowout preventer, a second blowout preventer, a simulated wellbore, and a mandrel. The simulated wellbore and the mandrel are vertically arranged. The first blowout preventer is installed at the upper end of the simulated wellbore, and the second blowout preventer is installed at the lower end of the simulated wellbore. The mandrel passes through the simulated wellbore. The upper end of the mandrel is higher than the upper end of the first blowout preventer, and the lower end of the mandrel is lower than the lower end of the second blowout preventer. An annulus is formed between the outer wall of the mandrel and the inner wall of the simulated wellbore. The wellhead tripping unit includes a tripping mechanism. The tripping mechanism is installed at the upper end of the first blowout preventer and is fixedly connected to the upper end of the mandrel. The tripping mechanism can drive the mandrel to reciprocate up and down. The first blowout preventer is provided with a first dynamic seal, and the second blowout preventer is provided with a second dynamic seal. The first blowout preventer and the second blowout preventer can respectively press the first dynamic seal and the second dynamic seal against the outer wall of the mandrel to clamp the mandrel and seal the upper and lower ends of the annulus. The annulus can be pressurized while the mandrel is clamped by the first blowout preventer and the second blowout preventer and driven to reciprocate up and down by the tripping mechanism to test the sealing performance of the first dynamic seal and the second dynamic seal for the annulus.

2. The dynamic seal test device for pressure operation of gas wells according to claim 1, wherein, The test device further includes a first pressurizing unit. The first pressurizing unit can communicate with the annulus and pressurize the annulus to a set pressure after the annulus is sealed, so as to test the sealing performance of the first dynamic seal and the second dynamic seal for the annulus while the mandrel reciprocates up and down.

3. The dynamic seal test device for pressure operation of gas wells according to claim 1, wherein The wellhead tripping unit further includes at least one tripping drive. The tripping drive is fixedly connected to the tripping mechanism. The tripping drive can provide a driving force for the tripping mechanism to enable the tripping mechanism to drive the mandrel to reciprocate up and down.

4. The dynamic seal test device for pressure - bearing operation of gas wells according to claim 3, characterized in that, The test device further includes a second pressurizing unit. The second pressurizing unit is connected to the tripping drive. The second pressurizing unit can pressurize the tripping drive to control the tripping drive to drive the tripping mechanism.

5. The dynamic seal test device for gas well pressure - bearing operation according to claim 1, wherein, The test device further includes a data acquisition unit. The data acquisition unit is connected to the dynamic seal test unit and is used to measure test parameters during the test.

6. The dynamic seal test device for pressure - maintained operation of gas wells according to claim 5, wherein, The data acquisition unit includes a pressure sensor. The pressure sensor is installed on the simulated wellbore, the first blowout preventer, and the second blowout preventer and is used to measure pressure parameters during the test.

7. The dynamic seal test device for gas well under pressure operation according to claim 5, characterized in that, The test device further includes a control unit. The control unit is connected to the dynamic seal test unit, the wellhead tripping unit, and the data acquisition unit. The control unit can control the dynamic seal test unit and the wellhead tripping unit according to the parameters measured by the data acquisition unit.

8. The dynamic seal test device for pressure - bearing operation of gas wells according to claim 1, wherein, The test device further includes a water tank. The water tank is installed above the first blowout preventer and below the second blowout preventer. The water tank can provide cooling water to cool the friction position between the blowout preventer and the mandrel.

9. The dynamic seal test device for pressure operation of gas wells according to claim 1, characterized in that, The test device can be placed in a foundation pit filled with cooling water so that the whole test device conducts a dynamic seal test in the cooling water. The cooling water can protect the high-pressure positions in the test device and cool the friction positions in the test device.

10. A dynamic seal test method for pressure - maintained operation of a gas well, characterized in that, The test method uses the dynamic seal test device for pressure - bearing operation of gas wells as described in any one of claims 1 to 9; the test method includes clamping the first blowout preventer and the second blowout preventer on the mandrel, so that the first dynamic seal and the second dynamic seal are closely attached to the outer wall of the mandrel; pressurizing the annulus to a set pressure, driving the mandrel to reciprocate up and down through the hoisting mechanism; measuring and obtaining the pressure values in the annulus and the hoisting unit at the wellhead, adjusting the pressure value in the annulus and / or the reciprocating speed of the mandrel according to the test requirements; obtaining the wear degrees of the first dynamic seal and the second dynamic seal, and evaluating the sealing performance of the first dynamic seal and the second dynamic seal for the annulus.

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