Ground simulation device for testing underground logging pup joint

Abstract

The invention relates to a ground simulation device for testing an underground logging pup joint, which comprises a logging pup joint and a leak-off ring which are arranged in a kettle body, the logging pup joint is positioned in the leak-off ring, the kettle body is connected with a slurry injection unit, and the slurry injection unit is used for injecting slurry into a space in the leak-off ring and a space outside the leak-off ring. The slurry injection unit is also used for injecting pressure into the leak-off ring, so that the slurry in the leak-off ring is filtered into a mud cake; electromagnets and force measuring sensors are arranged on the left side and the right side of the kettle body, the electromagnets are used for providing suction force for the well logging short section, and the force measuring sensors are used for measuring the suction force of the corresponding electromagnets; the lower end of the kettle body is connected with a vertical force applying unit, and the vertical force applying unit is used for injecting a jam releasing force in the vertical direction to the lower end of the kettle body so as to research the relationship between the jam releasing force and the suction force. Potential hazards possibly caused by testing of the well logging short section in an actual well are greatly avoided, and manpower, material resources and time cost are saved to a great extent.

Description

Technical Field

[0001] This invention belongs to the field of testing device technology, specifically relating to a ground simulation device for testing downhole logging subs. Background Technology

[0002] Because the sub is in a high-temperature and high-pressure environment during downhole operations, the safety and reliability requirements for the sub and its internal instruments are high. However, if the sub is lowered into the working well for testing, it may cause damage to the working well if it malfunctions and falls off, which will seriously affect the logging efficiency and increase the logging production cost.

[0003] Existing technologies disclose a device for inserting a short section into the upper part of a water-proof guide tube under jet drilling. The primary purpose of this device is to facilitate the smooth drilling of the water-proof guide tube under jet drilling, and it is unrelated to the testing and simulation of logging short sections. Existing technologies also disclose a near-bit short section surface simulation device, which is used to test the impact performance of the drill bit. All existing simulation devices lack simulation testing of logging short sections in well and mining environments. Summary of the Invention

[0004] To address all or part of the aforementioned problems, the present invention aims to provide a surface simulation device for testing downhole logging subs. This surface simulation device for testing downhole logging subs greatly avoids potential hazards that may arise from testing logging subs in actual wells, significantly saves manpower, material resources, and time costs, and improves the efficiency of the simulation testing process.

[0005] According to one aspect of the present invention, a surface simulation device for testing a downhole logging sub is provided, comprising a logging sub to be tested and a filter ring disposed within a vessel body, the logging sub being located within the filter ring, the vessel body being connected to a mud injection unit, the mud injection unit being used to inject mud into the space within and outside the filter ring, the mud injection unit being further used to inject pressure into the filter ring to cause the mud within the filter ring to filter out into a mud cake; electromagnets and force sensors are disposed on both the left and right sides of the vessel body. An electromagnet is used to provide attraction to the logging sub, and a force sensor is used to measure the attraction force of the corresponding electromagnet. A vertical force application unit is connected to the lower end of the vessel body, which is used to inject a vertical release force into the lower end of the vessel body to study the relationship between the release force and the attraction force. A resistance sensor is provided on the surface of the logging sub, which is used to monitor the contact process between the logging sub and the mud cake, and the monitoring data is uploaded to the human-machine interface through the acquisition circuit inside the logging sub under test.

[0006] Furthermore, the mud injection unit includes an electrically heated mud mixing tank, which is connected to the inlet of a circulation pump via a first valve. One outlet of the circulation pump is connected to the upper space inside the vessel via a second valve, and the other outlet of the circulation pump is connected to one end of a third valve. The other end of the third valve is connected to one end of an outer branch and one end of an inner branch. The other end of the outer branch is connected to the space outside the filter ring. A fourth valve is provided on the outer branch. The other end of the inner branch is connected to the space inside the filter ring. A fifth valve is provided on the inner branch. A pressure injection unit is connected between the space inside the filter ring and the fifth valve. The pressure injection unit is used to inject pressure into the filter ring so that the mud inside the filter ring is filtered out into mud cake.

[0007] Furthermore, the pressure injection unit includes a pressure injection pump and an intermediate container. An isolation piston is provided inside the intermediate container, which divides the space inside the intermediate container into two parts. The inlet of the pressure injection pump is connected to a medium source, and the outlet of the pressure injection pump is connected to one part of the space inside the intermediate container through a sixth valve. The other part of the space inside the intermediate container is connected to the internal branch between the filter ring and the fifth valve through a seventh valve.

[0008] Furthermore, the vertical force application unit includes a vertical force injection pump, the outlet of which is connected to the lower end of the vessel body via an eighth valve, and the inlet of which is connected to a medium source.

[0009] Furthermore, pistons are provided on the left and right sides of the vessel body. Each electromagnet on each side of the vessel body cooperates with the piston on that side. A fixing block is connected to the side of the piston away from the corresponding electromagnet, and the force sensors are all fixed on the fixing block.

[0010] Furthermore, buffer cavities are provided between the upper and lower ends of the piston and the corresponding fixed blocks. The buffer cavities are used to buffer the pressure of the logging sub on the electromagnet and the piston, so as to keep the ground simulation device in a balanced state.

[0011] Furthermore, it also includes a first closed-loop control system, which is used to receive the initial suction force value from the force sensors on both sides, correct and feedback the initial suction force value with the suction force set value to obtain a feedback amount, and control the corresponding electromagnet according to the feedback amount to realize the control of the electromagnet to provide a suction force of the set value. Furthermore, it also includes an eddy current sensor and a second closed-loop control system. The eddy current sensor is provided on both the left and right sides of the vessel body. The eddy current sensor is used to monitor the real-time displacement of the logging sub under the attraction of the electromagnet. The second closed-loop control system is used to receive the real-time displacement of the eddy current sensor, correct and feed back the real-time displacement with the displacement set value to obtain feedback information, and control the corresponding electromagnet according to the feedback information to achieve the real-time displacement equal to the displacement set value.

[0012] Furthermore, a number of electromagnets and a system number of force sensors are provided on both the left and right sides of the vessel body. Pistons with the same number of electromagnets on each side of the vessel body are also provided on each side. Each electromagnet is engaged with the corresponding piston on that side. A fixing block is connected to the side of each piston away from the corresponding electromagnet. Each force sensor is fixed on the corresponding fixing block. Furthermore, the integral structure formed by the vessel body, electromagnet, and force sensor is connected to two sides of the vessel body, electromagnet, and force sensor respectively. The connecting shafts are rotatably connected to the base and fixedly connected to the motor shaft of the drive motor.

[0013] As can be seen from the above technical solution, the ground simulation device for testing downhole logging subs provided by the present invention has the following beneficial effects: This invention places the logging sub inside the vessel, and the attraction provided by the electromagnet can simulate the pressure between the mud cake and the logging sub. Similarly, by heating the mud, the performance of the logging sub at high temperature can be determined, so as to test the temperature and pressure resistance of the logging sub. This invention, by applying suction followed by vertical force, can also study the relationship between the adhesion force between the short section and the mud cake and the applied unsticking force.

[0014] This invention greatly avoids the potential hazards that may be caused by testing logging subs in actual wells, saves manpower, material resources and time costs to a great extent, improves the efficiency of the simulation testing process, and increases the reliability and safety of sub operations. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a ground simulation device for testing downhole logging subs according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the electromagnet, piston, and force sensor components according to an embodiment of the present invention; Figure 3 This is a schematic diagram showing the transmission of pressure from the vessel body to the electromagnet. Figure 4 This is a control block diagram of the first closed-loop control system according to an embodiment of the present invention; Figure 5 This is a control block diagram of the second closed-loop control system according to an embodiment of the present invention; The attached diagram is labeled as follows: 1. Boiler body; 2. Logging sub; 3. Filter ring; 4. Electromagnet; 41. Upper left area; 42. Middle left area; 43. Lower left area; 44. Upper right area; 45. Lower right area; 46. Contact area; 47. Buffer chamber; 5. Vertical force application unit; 51. Vertical force injection pump; 52. Eighth valve; 6. Mud injection unit; 61. Electric mud heating and mixing tank; 62. Second valve; 63. Circulation pump; 64. Third valve; 65. Fourth valve; 66. Outer branch; 67. Fifth valve; 68. Inner branch; 69. Sixth valve; 610. Seventh valve; 612. Pressure injection pump; 7. Piston; 8. Fixing block; 9. Force sensor; 10. First closed-loop control system; 11. Second closed-loop control system; 12. Eddy current sensor. Detailed Implementation

[0016] To better understand the purpose, structure, and function of this invention, the following detailed description, in conjunction with the accompanying drawings, describes a ground simulation device for testing downhole logging subs.

[0017] like Figure 1 , Figure 2 The diagram illustrates a surface simulation device for testing downhole logging subs in accordance with an embodiment of the present invention. It includes a logging sub 2 to be tested and a filter ring 3 disposed within a vessel body 1. The logging sub 2 is located within the filter ring 3. A mud injection unit 6 is connected to the vessel body 1. The mud injection unit 6 is used to inject mud into the space inside and outside the filter ring 3. The mud injection unit 6 is also used to inject pressure into the filter ring 3 to cause the mud inside the filter ring 3 to be filtered out into a mud cake. Electromagnets 4 and force sensors are disposed on both the left and right sides of the vessel body 1. The apparatus includes an electromagnet 4 for providing attraction to the logging sub 2, and a force sensor 9 for measuring the attraction of the corresponding electromagnet 4. A vertical force application unit 5 is connected to the lower end of the vessel body 1. The vertical force application unit 5 is used to inject a vertical release force into the lower end of the vessel body 1 to study the relationship between the release force and the attraction force. A resistance sensor is installed on the surface of the logging sub 2. The resistance sensor is used to monitor the contact process between the logging sub 2 and the mud cake, and the monitoring data is uploaded to the human-machine interface through the acquisition circuit inside the logging sub under test.

[0018] The ground simulation device of this invention includes a logging sub 2, a filter ring 3, a mud injection unit 6, an electromagnet 4, a force sensor 9, and a vertical force application unit 5. The filter ring 3 is used to simulate the formation of a mud cake from mud filtration, specifically to simulate the filtration of mud from the wellbore into a mud cake. The electromagnet 4 provides suction to move the logging sub 2 within the vessel body 1, and the force sensor 9 tests the magnitude of the suction provided by the electromagnet 4. The mud injection unit 6 delivers pre-mixed mud to fill the surface of the logging sub 2, facilitating subsequent mud cake formation. The resistance sensor monitors the contact process between the logging sub 2 and the mud cake, and uploads the monitoring data to the human-machine interface via the acquisition circuit within the logging sub under test, allowing for assessment of the performance of the acquisition circuit based on the monitoring data.

[0019] When using the ground simulation device of this invention to test the logging sub to be tested, the following steps are taken: First, the logging sub 2 to be tested is loaded into the vessel body 1; The heated mud is injected into the vessel body 1 through the mud injection unit 6, and the mud fills the space inside and outside the filter ring 3. After the filter ring 3 is filled with mud, pressure is injected into the filter ring 3 through the mud injection unit 6 to create a pressure difference between the inside and outside of the filter ring 3, so that the mud in the filter ring 3 is filtered out into mud cake. After the mud in the filter ring 3 forms a mud cake, the electromagnet 4 is activated to provide lateral suction, causing the logging sub 2 to move laterally. The sum of the suction forces provided by the electromagnet 4 is the adsorption force between the sub and the mud cake. The force sensor 9 is used to test the magnitude of the suction force of the electromagnet 4. By adjusting the suction force of the electromagnet 4, the pressure of the mud cake that the logging sub under test can withstand is tested. The contact process between the logging sub 2 and the mud cake is monitored by the resistance change of the resistance sensor. The resistance change of the resistance sensor is recorded by the acquisition circuit designed in the thermos bottle inside the logging sub and uploaded to the human-machine interface. The performance of the logging sub is then judged based on the results of the human-machine interface. The attraction force of electromagnet 4 is continuously increased, and at the same time, vertical force application unit 5 is used to inject vertical unblocking force into the lower end of vessel 1 to study the relationship between unblocking force and attraction force, so as to simulate the unblocking operation of logging sub downhole.

[0020] The ground simulation device of this invention places the logging sub 2 inside the vessel 1 and continuously circulates mud. Under high pressure, the mud is filtered out through the filter ring 3 to form a mud cake on the surface of the sub. The attraction provided by the electromagnet 4 can simulate the pressure between the mud cake and the logging sub. The performance of the logging sub under high pressure can be judged through the results of the human-interactive interface. Similarly, by heating the mud, the performance of the logging sub under high temperature can be judged, so as to test the temperature and pressure resistance of the logging sub and evaluate whether the internal instruments of the logging sub can work continuously in the high-temperature environment downhole.

[0021] By applying suction followed by vertical force in this embodiment of the invention, the relationship between the adsorption force and the release force between the short section and the mud cake can also be studied.

[0022] The embodiments of the present invention greatly avoid the potential hazards that may be caused by testing logging subs in actual wells, save manpower, material resources and time costs to a great extent, improve the efficiency of the simulation testing process, and increase the reliability and safety of sub operations.

[0023] The mud injection unit 6 includes a mud electric heating mixing tank 61, which is connected to the inlet of a circulation pump 63 via a first valve. One outlet of the circulation pump 63 is connected to the upper space inside the vessel body 1 via a second valve 62, and the other outlet of the circulation pump 63 is connected to one end of a third valve 64. The other end of the third valve 64 is connected to one end of an outer branch 66 and one end of an inner branch 68. The other end of the outer branch 66 is connected to the space outside the filter ring 3. A fourth valve 65 is provided on the outer branch 66. The other end of the inner branch 68 is connected to the space inside the filter ring 3. A fifth valve 67 is provided on the inner branch 68. A pressure injection unit is connected between the space inside the filter ring 3 and the fifth valve 67 in the inner branch 68. The pressure injection unit is used to inject pressure into the filter ring 3 so that the mud inside the filter ring 3 is filtered out into mud cake.

[0024] Regarding the specific mud injection process: After being heated, the mud in the electric heating mixing tank 61 enters the circulation pump 63 through the first valve. The mud entering the circulation pump 63 is divided into two paths. One path enters the upper space inside the vessel body 1 through the second valve 62, and the other path is divided into two branches after passing through the third valve 64. One branch enters the space outside the filter ring 3 through the fourth valve 65 and the outer branch 66, and the other branch enters the space inside the filter ring 3 through the fifth valve 67 and the inner branch 68, thereby achieving the purpose of filling both the inside and outside of the filter ring 3 with mud. During this process, the first valve, the second valve 62, the third valve 64, the fourth valve 65, and the fifth valve 67 are all in an open state that allows the mud to pass through.

[0025] The pressure injection unit includes a pressure injection pump 612 and an intermediate container. An isolation piston 7 is installed inside the intermediate container, which divides the space inside the intermediate container into two parts. The inlet of the pressure injection pump 612 is connected to a medium source. The outlet of the pressure injection pump 612 is connected to one part of the space inside the intermediate container through a sixth valve 69. The other part of the space inside the intermediate container is connected to the space inside the filter ring 3 and the inner branch 68 between the fifth valve 67 through a seventh valve 610.

[0026] Specifically, the medium in the medium source enters one part of the intermediate container through the pressure injection pump 612 and the sixth valve 69, thereby pushing the isolation piston 7 in the intermediate container to move. This pushes the high-pressure medium in the other part of the intermediate container into the space within the filter ring 3 through the seventh valve 610 and the inner branch 68, thereby achieving the purpose of injecting pressure into the space within the filter ring 3. The high-pressure medium in the other part of the intermediate container is, for example, high-pressure air. During this process, the sixth valve 69 and the seventh valve 610 are in an open state that allows the high-pressure medium to pass through, while the fifth valve 67 is in a closed state that prevents the high-pressure medium from passing through.

[0027] The vertical force application unit 5 includes a vertical force injection pump 51. The outlet of the vertical force injection pump 51 is connected to the lower end of the vessel body 1 through an eighth valve 52, and the inlet of the vertical force injection pump 51 is connected to a medium source.

[0028] Specifically, the vertical force injection pump 51 is started, and the vertical force injection pump 51 injects the medium in the medium source into the lower end of the vessel body 1 through the eighth valve 52; during this process, the mud in the filter ring 3 has been filtered out into mud cake that wraps around the logging sub 2, and the outside of the filter ring 3 is filled with mud, and the logging sub 2 is attracted by the electromagnet 4.

[0029] Among them, such as Figure 2 As shown, pistons 7 are also provided on the left and right sides of the vessel body 1. Each electromagnet 4 on each side of the vessel body 1 is engaged with the piston 7 on that side. A fixing block 8 is connected to the side of the piston 7 away from the corresponding electromagnet 4. Force sensors 9 are all fixed on the fixing block 8.

[0030] Here, a force-measuring device consisting of electromagnet 4, piston 7, and force sensor 9 measures force by moving piston 7 behind it due to the magnitude of the attraction force applied by electromagnet 4. Slight movement of piston 7 causes strain gauges in force sensor 9 to deform, and the magnitude of the attraction force provided by electromagnet 4 can be calculated from the degree of strain gauge deformation. This method accurately measures the attraction force acting on logging sub 2, reflecting the force exerted by logging sub 2 on the mud cake.

[0031] Among them, buffer chambers 47 are provided between the upper and lower ends of the piston 7 and the corresponding fixed blocks 8. The buffer chambers 47 are used to buffer the pressure of the logging sub 2 on the electromagnet 4 and the piston 7 so that the ground simulation device is in a balanced state.

[0032] Specifically, such as Figure 3 As shown, when internal pressure acts on the inner wall of the vessel 1, this force acts on the left side of the electromagnet 4 through the inner wall of the vessel 1. Specifically, it acts on the upper left region 41, the middle left region 42, and the lower left region 43 on the left side of the electromagnet 4. At this time, the pressure acting on the upper left region 41 and the lower left region 43 on the left side of the electromagnet 4 will be balanced to the upper right region 44 and the lower right region 45 on the right side of the electromagnet 4. The pressure acting on the middle left region 42 on the left side of the electromagnet 4 will be transmitted to the contact area 46 between the electromagnet 4 and the corresponding piston 7, and then act on the buffer cavity 47 between the piston 7 and the corresponding fixed block 8 through the piston 7. In turn, by compressing the medium in the buffer cavity 47, the pressure at both ends of the electromagnet 4 is balanced, thus achieving pressure self-balancing, such as self-balancing when applying vertical force and self-balancing when pressing into the filter ring 3.

[0033] Among them, such as Figure 4 As shown, the ground simulation device of this embodiment of the invention also includes a first closed-loop control system 10. The first closed-loop control system 10 is used to receive the initial suction force value of the force sensors 9 on both sides, correct and feedback the initial suction force value with the suction force setting value to obtain the feedback amount, and control the corresponding electromagnet 4 according to the feedback amount to realize the control of the electromagnet 4 to provide a suction force of the magnitude of the suction force setting value.

[0034] In the specific simulation test, for example, an initial attraction force value is first set for each electromagnet 4. During the control of electromagnet 4, the initial attraction force value of each electromagnet 4 is aggregated to the first closed-loop control system. By correcting and feeding back the attraction force setting value set in the first closed-loop control system, the feedback quantity is input to each electromagnet 4, so that each electromagnet 4 adjusts its initial attraction force value to equal the attraction force setting value. Through this continuous correction feedback, automatic control of electromagnet 4 can be achieved. That is, the system control can be completed simply by setting the attraction force measurement value in the system.

[0035] The specific control process is as follows: The initial attraction force of the left and right electromagnets 4 is 1000N on both sides, resulting in a force balance on both sides of the logging sub 2. Now, the logging sub 2 needs to move a certain distance to the right. The magnitude of the attraction force required for this movement is calculated. For example, when the logging sub 2 moves 2mm to the right, the resultant force of the attraction force on the logging sub 2 needs to be 3500N, and the direction of the resultant force is to the right. Therefore, the attraction force setting value is set to -3500N in the first closed-loop control system. The negative sign indicates that the suction force on the right side is greater than that on the left side. The system will continuously correct and provide feedback until the sum of the suction forces applied by the electromagnets 4 on both sides equals the suction force setting value, thereby enabling the short section to move 2mm to the right. For example, if the first closed-loop control system controls the suction force on the right side to increase by 3000N and controls the suction force on the left side to decrease by 500N, then the difference between the suction forces on the right and left ends is (1000N+3000N)-(1000N-500N)=3500N, which achieves the requirement of a suction force setting value of -3500N.

[0036] As an alternative, such as Figure 5 As shown, the ground simulation device of this embodiment of the invention also includes an eddy current sensor 12 and a second closed-loop control system 11. Eddy current sensors 12 are provided on both the left and right sides of the vessel body 1. The eddy current sensors 12 are used to monitor the real-time displacement of the logging sub 2 under the attraction of the electromagnet 4. The second closed-loop control system 11 is used to receive the real-time displacement of the eddy current sensor 12, correct and feed back the real-time displacement with the displacement set value to obtain feedback information, and control the corresponding electromagnet 4 according to the feedback information to realize that the real-time displacement is equal to the displacement set value.

[0037] In this embodiment, closed-loop control is achieved using an eddy current sensor 12, an electromagnet 4, and a force sensor 9. The principle is displacement closed-loop control, meaning that the eddy current sensor 12 monitors the real-time displacement of the internal logging sub 2 for closed-loop control. The main steps are as follows: When the initial electromagnet 4 applies an unbalanced suction force, the logging sub 2 shifts due to the suction force. At this time, the eddy current sensor 12 monitors the real-time displacement of the sub and uploads the data to the second closed-loop control system. The second closed-loop control system corrects and feeds back the received real-time displacement with the set displacement value to obtain feedback information. This feedback information may be, for example, increasing the suction force of the left electromagnet 4 and decreasing the suction force of the right electromagnet 4. The second closed-loop control system controls the change in the suction force of the electromagnet 4 based on this feedback information. Simultaneously, the eddy current sensor 12 continues to monitor the real-time displacement of the internal logging sub 2 until the real-time displacement matches the displacement set value. At this point, the suction force of the electromagnet 4 no longer changes, completing the closed-loop control operation.

[0038] The specific control process is as follows: If the initial attraction force provided by the electromagnets 4 on both sides is 1000N, the short section is in equilibrium and will not move. At this time, the eddy current sensors 12 on both sides record that the real-time displacement of the logging short section 2 is 0. Now, the displacement setpoint is set to -2 in the second closed-loop control system, which means that the logging short section 2 needs to move 2mm to the right. By calculating the relationship between the moving distance and the attraction force, it is determined that the attraction force of the right electromagnet 4 is increased and the attraction force of the left electromagnet 4 is decreased. The feedback information is fed back to each electromagnet 4 and the eddy current sensor 12 through the second closed-loop control system. The displacement of the logging short section 2 is monitored by the eddy current sensor 12, and the attraction force of the electromagnet 4 is continuously corrected until the real-time displacement of the short section reaches the displacement setpoint.

[0039] As an alternative, several electromagnets 4 and a number of force sensors 9 are provided on both the left and right sides of the vessel body 1. The same number of pistons 7 as the electromagnets 4 on each side of the vessel body 1 are also provided on each side of the vessel body 1. Each electromagnet 4 cooperates with the corresponding piston 7 on that side. Each piston 7 is connected to a fixing block 8 on the side away from the corresponding electromagnet 4. Each force sensor 9 is fixed on the corresponding fixing block 8.

[0040] For the case where several electromagnets 4 are set on both the left and right sides: When using electromagnets 4 and the first closed-loop control system, each electromagnet 4 is connected to the first closed-loop control system, and the first closed-loop control system can independently control the two upper and lower electromagnets 4 to apply attraction force, or the three upper left electromagnets 4 to apply attraction force together. That is, the series and parallel connection of different electromagnets 4 can be adjusted, thereby applying forces of different magnitudes and directions to the short section. When using the displacement closed-loop control of the second closed-loop control system, each electromagnet 4 is also connected to the second closed-loop control system, and the second closed-loop control system can independently control the two upper and lower electromagnets 4 to apply attraction force, or the three upper left electromagnets 4 to apply attraction force together. That is, the series and parallel connection of different electromagnets 4 can be adjusted, thereby applying forces of different magnitudes and directions to the short section.

[0041] The integral structure formed by the vessel body 1, electromagnet 4, and force sensor 9 is connected to two connecting shafts on both sides. The connecting shafts are rotatably connected to the base and fixedly connected to the motor shaft of the drive motor.

[0042] The drive motor here is used to enable the device to be tilted horizontally in order to study the effect of different angles of the device on the performance test results of the internal logging sub 2.

[0043] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0044] Furthermore, the terms "a," "two," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly defined.

[0045] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A surface simulation device for testing downhole logging subs, characterized in that, The test apparatus includes a logging sub and a filter ring housed within a test vessel. The logging sub is located within the filter ring. The test vessel is connected to a mud injection unit, which injects mud into the space inside and outside the filter ring. The mud injection unit also injects pressure into the filter ring to cause the mud to filter out as a mud cake. Electromagnets and force sensors are installed on both sides of the test vessel. The electromagnets provide attraction to the logging sub, and the force sensors measure the attraction force of the corresponding electromagnet. A vertical force application unit is connected to the lower end of the test vessel. This unit injects a vertical release force into the lower end of the test vessel to study the relationship between the release force and the attraction force. A resistance sensor is installed on the surface of the logging sub to monitor the contact process between the logging sub and the mud cake, and the monitoring data is uploaded to a human-machine interface via a data acquisition circuit within the logging sub.

2. The surface simulation device for testing downhole logging subs as described in claim 1, characterized in that, The mud injection unit includes an electrically heated mud mixing tank. The electrically heated mud mixing tank is connected to the inlet of a circulation pump via a first valve. One outlet of the circulation pump is connected to the upper space inside the vessel via a second valve. The other outlet of the circulation pump is connected to one end of a third valve. The other end of the third valve is connected to one end of an outer branch and one end of an inner branch. The other end of the outer branch is connected to the space outside the filter ring. A fourth valve is provided on the outer branch. The other end of the inner branch is connected to the space inside the filter ring. A fifth valve is provided on the inner branch. A pressure injection unit is connected between the space inside the filter ring and the fifth valve. The pressure injection unit is used to inject pressure into the filter ring so that the mud inside the filter ring is filtered out into mud cake.

3. The surface simulation device for testing downhole logging subs according to claim 2, characterized in that, The pressure injection unit includes a pressure injection pump and an intermediate container. An isolation piston is installed inside the intermediate container, which divides the space inside the intermediate container into two parts. The inlet of the pressure injection pump is connected to a medium source. The outlet of the pressure injection pump is connected to one part of the space inside the intermediate container through a sixth valve. The other part of the space inside the intermediate container is connected to the internal branch between the filter ring and the fifth valve through a seventh valve.

4. The surface simulation device for testing downhole logging subs according to claim 1, characterized in that, The vertical force application unit includes a vertical force injection pump. The outlet of the vertical force injection pump is connected to the lower end of the vessel body through an eighth valve, and the inlet of the vertical force injection pump is connected to a medium source.

5. The surface simulation device for testing downhole logging subs according to claim 1, characterized in that, Pistons are also provided on the left and right sides of the vessel body. Each electromagnet on each side of the vessel body cooperates with the piston on that side. A fixing block is connected to the side of the piston away from the corresponding electromagnet. The force sensors are all fixed on the fixing blocks.

6. The surface simulation device for testing downhole logging subs according to claim 5, characterized in that, Buffer chambers are provided between the upper and lower ends of the piston and the corresponding fixed blocks. The buffer chambers are used to buffer the pressure of the logging sub on the electromagnet and the piston so that the ground simulation device is in a balanced state.

7. The surface simulation device for testing downhole logging subs according to claim 5, characterized in that, It also includes a first closed-loop control system, which is used to receive the initial suction force value from the force sensors on both sides, correct and feedback the initial suction force value with the suction force set value to obtain a feedback amount, and control the corresponding electromagnet according to the feedback amount to realize the control of the electromagnet to provide a suction force of the set value.

8. The surface simulation device for testing downhole logging subs according to claim 7, characterized in that, It also includes an eddy current sensor and a second closed-loop control system. The eddy current sensor is provided on both the left and right sides of the vessel body. The eddy current sensor is used to monitor the real-time displacement of the logging sub under the attraction of the electromagnet. The second closed-loop control system is used to receive the real-time displacement of the eddy current sensor, correct and feed back the real-time displacement with the displacement set value to obtain feedback information, and control the corresponding electromagnet according to the feedback information to achieve the real-time displacement equal to the displacement set value.

9. The surface simulation device for testing downhole logging subs according to claim 1, characterized in that, Several electromagnets and a system number of force sensors are provided on both the left and right sides of the vessel body. Pistons with the same number of electromagnets on each side of the vessel body are also provided on each side. Each electromagnet is matched with the corresponding piston on that side. A fixing block is connected to the side of each piston away from the corresponding electromagnet. Each force sensor is fixed on the corresponding fixing block.

10. The surface simulation device for testing downhole logging subs according to claim 1, characterized in that, The integrated structure formed by the vessel body, electromagnet, and force sensor is connected to two sides by connecting shafts. The connecting shafts are rotatably connected to the base and fixedly connected to the motor shaft of the drive motor.

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