Underwater wellhead liquid level detection simulation test device and detection method

Abstract

The invention discloses an underwater wellhead liquid level detection simulation test device and a detection method, which relates to the technical field of marine drilling equipment, including: a water tank; a wellhead module, the wellhead module is arranged in the water tank, and a liquid level sensor is arranged on the inner wall of the wellhead module; a drill pipe, the lower end of the drill pipe can extend into the wellhead module; a test bench, the test bench is provided with a lateral moving device, a longitudinal moving device and a rotating device, and the lateral moving device, the longitudinal moving device and the rotating device drive the drill pipe to do lateral, longitudinal and rotational movements; a mud tank, the lower end of the mud tank is connected to the lower end of the wellhead module through a return pipeline, the upper end of the mud tank is connected to the rotating device through an injection pipeline, and the mud in the injection pipeline flows into the upper end of the drill pipe through the rotating device; a controller, and the controller is used to control the operation of various electrical components. The invention can simulate different movement states of the drill pipe in the underwater wellhead, and provide a test platform and a detection method for various mud level identification technologies.

Description

Technical Field

[0001] The invention relates to the technical field of marine drilling equipment, and in particular to an underwater wellhead liquid level detection simulation test device and a detection method. Background Art

[0002] With the continuous development of marine drilling technology, the riserless mud recovery drilling process has been widely used due to its own advantages. The existing riserless mud recovery drilling process can refer to the patent number CN201963231U "A seabed mud suction system for realizing riserless mud recovery drilling", or the patent number CN108547587A "A riserless rapid coring drilling system and method based on circulating drilling fluid", etc. The main idea is to use an underwater pump and a separate small-diameter mud return pipeline to recover the mud returned to the underwater wellhead to the deck surface for processing and then use it. Since the underwater wellhead is open and connected to the external seawater, one of the technical difficulties of this process is to accurately judge the height of the underwater wellhead mud level.

[0003] In deepwater environments, the drill pipe will swing back and forth and left and right in the underwater wellhead because it is not restricted by the wellbore. In addition, the rotation of the drill pipe itself will disturb the mud and seawater inside the wellhead, which will affect the judgment of the mud level. However, there is no device in the prior art for simulating the riser-free mud recovery drilling process to study the influence of various disturbance factors on the mud level.

[0004] Therefore, those skilled in the art are in urgent need of an underwater wellhead liquid level detection simulation test device and a detection method to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide an underwater wellhead liquid level detection simulation test device and detection method, which are used to solve the technical problems existing in the above-mentioned prior art. The drill pipe is placed in different motion states by using a lateral moving device, a longitudinal moving device and a rotating device, so as to study the influence of various disturbance factors on the mud liquid level height.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The invention discloses an underwater wellhead liquid level detection simulation test device, comprising:

[0008] A water tank, wherein the water tank is filled with water;

[0009] A wellhead module, wherein the wellhead module is arranged in the water tank, the wellhead module is in communication with the water tank, and a plurality of liquid level sensors are arranged on the inner wall of the wellhead module;

[0010] A drill pipe, the lower end of which can extend into the wellhead module;

[0011] A test bench, wherein the test bench is provided with a lateral moving device, a longitudinal moving device and a rotating device, the upper end of the drill rod is connected to the rotating device, the rotating device is arranged on the lateral moving device, and the lateral moving device is arranged on the longitudinal moving device;

[0012] A mud tank, wherein the lower end of the mud tank is connected to the lower end of the wellhead module through a return pipeline, a mud return pump is provided on the return pipeline, and the upper end of the mud tank is connected to the rotating device through an injection pipeline, a mud injection pump is provided on the injection pipeline, and the mud in the injection pipeline flows into the upper end of the drill pipe through the rotating device;

[0013] The controller, the liquid level sensor, the lateral moving device, the longitudinal moving device, the rotating device, the mud return pump and the mud injection pump are all electrically connected to the controller.

[0014] Preferably, the rotating device is a rotary top drive, and a top drive moving plate is fixed to the upper end of the rotary top drive.

[0015] Preferably, the transverse moving device includes a transverse driving motor, a transverse screw and two transverse guide rails, a transverse threaded hole and two transverse guide holes are provided on the top drive moving plate, one end of the transverse screw is drivingly connected to the output shaft of the transverse driving motor, the transverse threaded hole is provided with an internal thread, the transverse threaded hole is threadedly connected to the transverse screw, the transverse driving motor is fixed to the transverse motor fixing plate, the first ends of the two transverse guide rails are respectively fixed to a surface of the transverse motor fixing plate away from the transverse driving motor, the two transverse guide rails are respectively located on both sides of the transverse screw, the two transverse guide rails respectively pass through the two transverse guide holes, and the two transverse guide rails are respectively slidably connected to the two transverse guide holes.

[0016] Preferably, the longitudinal moving device includes a longitudinal screw, a longitudinal drive motor and two longitudinal guide rails, the output shaft of the longitudinal drive motor is drivingly connected to one end of the longitudinal screw, the test bench includes two frames, the two ends of the longitudinal guide rail are respectively fixed to the inner sides of the two frames, the longitudinal drive motor is fixed to the outer side of one of the frames, the two longitudinal guide rails are respectively located on both sides of the frames, and the two longitudinal guide rails are respectively slidably connected with a first longitudinal moving plate and a second longitudinal moving plate, the first longitudinal moving plate is fixed to the lower end of the transverse motor fixing plate, the first longitudinal moving plate is provided with a longitudinal threaded hole, the longitudinal threaded hole is provided with an internal thread, the longitudinal threaded hole is threadedly connected to the longitudinal screw, the first end of the transverse guide rail is fixed to the transverse motor fixing plate, and the second end of the transverse guide rail is fixed to the second longitudinal moving plate.

[0017] Preferably, a grouting pipe is connected to the upper end of the top drive movable plate, the lower end of the grouting pipe is communicated with the rotary top drive, and the injection pipeline is communicated with the upper end of the grouting pipe.

[0018] Preferably, the wellhead module includes a wellhead barrel body, a mud discharge pipe is provided on the side wall of the wellhead barrel body, one end of the return pipeline is connected to the mud discharge pipe, a plurality of sensor brackets are provided on the inner wall of the wellhead barrel body, and the liquid level sensor is arranged on the sensor bracket.

[0019] Preferably, a reflux flowmeter is provided on the reflux pipeline, and the reflux flowmeter is electrically connected to the controller;

[0020] An injection flow meter is arranged on the injection pipeline, and the injection flow meter is electrically connected to the controller.

[0021] The present invention also discloses a detection method of an underwater wellhead liquid level detection simulation test device, comprising the following steps:

[0022] S1. Prepare and install each device;

[0023] S2. Start the mud injection pump. The mud is discharged into the drill pipe at the test bench by the mud injection pump. The mud in the drill pipe is injected into the wellhead module. At this time, the mud will slowly rise in the wellhead module.

[0024] S3, start the mud return pump to pump the mud in the wellhead module back into the mud tank, thereby forming a circulation loop;

[0025] S4. Conduct a liquid level identification simulation test, start the lateral moving device, the longitudinal moving device and the rotating device, and drive the drill rod to perform lateral movement, longitudinal movement and rotational movement through the lateral moving device, the longitudinal moving device and the rotating device;

[0026] S5, maintaining a constant pumping rate of the mud return pump, and changing the mud level height inside the wellhead module by increasing or decreasing the pumping rate of the mud injection pump;

[0027] S6. Collect data from the injection flowmeter, reflux flowmeter, cross-sectional area of ​​the wellhead module and the liquid level sensor, and calculate the rising rate and height of the mud liquid level.

[0028] Preferably, the preparation and installation work in step S1 includes: filling the water tank with clean water to simulate the marine environment;

[0029] Place the test bench and the wellhead module inside the water tank;

[0030] Install the level sensor in the wellhead module.

[0031] Preferably, the calculation step in step S6 includes: mud level rise height = (injection volume of injection flow meter - discharge volume of return flow meter) / cross-sectional area of ​​wellhead module;

[0032] The rising rate of mud level = mud level rising height ÷ time.

[0033] Compared with the prior art, the present invention has achieved the following technical effects:

[0034] 1. It is equipped with a lateral moving device, a longitudinal moving device and a rotating device, which can drive the drill rod to move horizontally, longitudinally and rotate respectively, so as to facilitate researchers to study the influence of different interference factors on the mud level height;

[0035] 2. It can not only directly detect the change of mud level by using multiple liquid level sensors, but also calculate the change of mud level by injecting flow meter, reflux flow meter and the diameter of wellhead module. The dual detection method makes the detection result more accurate.

[0036] 3. The overall structure is simple, easy to manufacture and maintain later, and the manufacturing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a structural schematic diagram of an underwater wellhead liquid level detection simulation test device according to an embodiment of the present invention;

[0039] Figure 2 It is an overall schematic diagram of a test bench in an underwater wellhead liquid level detection simulation test device according to an embodiment of the present invention;

[0040] Figure 3 It is a front view of a test bench in an underwater wellhead liquid level detection simulation test device according to an embodiment of the present invention;

[0041] Figure 4 A top view of a test bench in an underwater wellhead liquid level detection simulation test device according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the structure of a wellhead module in an underwater wellhead liquid level detection simulation test device according to an embodiment of the present invention;

[0043] In the figure: 1. water tank; 2. wellhead module; 2-1. wellhead barrel; 2-2. sensor bracket; 2-3. mud discharge pipe; 3. test bench; 3-1. frame; 3-2. transverse guide rail; 3-3. transverse screw; 3-4. transverse drive motor; 3-5. longitudinal screw; 3-6. longitudinal guide rail; 3-7. longitudinal drive motor; 3-8. grouting pipe; 3-9. rotary top drive; 3-10. drill pipe; 4. mud return pump; 5. return flow meter; 6. mud tank; 7. mud injection pump; 8. injection flow meter. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The purpose of the present invention is to provide an underwater wellhead liquid level detection simulation test device and detection method, which are used to solve the technical problems existing in the above-mentioned prior art. The drill pipe is placed in different motion states by using a lateral moving device, a longitudinal moving device and a rotating device, so as to study the influence of various disturbance factors on the mud liquid level height.

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Embodiment 1

[0048] like Figure 1-Figure 5 As shown, this embodiment provides an underwater wellhead liquid level detection simulation test device, including:

[0049] The water tank 1 is a rectangular box structure with an opening at the top. The water tank 1 is filled with clean water to simulate the marine environment.

[0050] Wellhead module 2, wellhead module 2 is arranged at the bottom of water tank 1, wellhead module 2 is connected with water tank 1, a plurality of liquid level sensors are arranged on the inner wall of wellhead module 2, and the plurality of liquid level sensors are distributed from top to bottom. As for the specific number of liquid level sensors, it can be adjusted according to actual research needs and the height of wellhead module 2;

[0051] Drill pipe 3-10, the lower end of which can extend into the wellhead module 2;

[0052] The test bench 3 is a common supporting structure. The test bench 3 is provided with a transverse moving device, a longitudinal moving device and a rotating device. The upper end of the drill rod 3-10 is connected to the rotating device. The rotating device can be used to drive the drill rod 3-10 to rotate. The rotating device is arranged on the transverse moving device. The transverse moving device can be used to drive the rotating device and the drill rod 3-10 to move transversely together. The transverse moving device is arranged on the longitudinal moving device. The longitudinal moving device can be used to drive the transverse moving device, the rotating device and the drill rod 3-10 to move longitudinally together;

[0053] A mud tank 6, the lower end of the mud tank 6 is connected to the lower end of the wellhead module 2 through a return pipeline, a mud return pump 4 is arranged on the return pipeline, the mud return pump 4 is an existing common delivery pump structure, driven by a variable frequency motor, the mud in the wellhead module 2 is transported to the mud tank 6 under the drive of the mud return pump 4, and is used to simulate the lifting and recovery process of mud without a riser, the upper end of the mud tank 6 is connected to the rotating device through an injection pipeline, a mud injection pump 7 is arranged on the injection pipeline, the mud injection pump 7 and the mud return pump 4 can adopt the same structure, also driven by a variable frequency motor, the mud in the injection pipeline flows into the upper end of the drill pipe 3-10 through the rotating device;

[0054] The controller, the liquid level sensor, the lateral moving device, the longitudinal moving device, the rotating device, the mud return pump 4 and the mud injection pump 7 are all electrically connected to the controller, wherein the controller can be a computer or a plc controller, etc., which is mainly used to control the operation of each device.

[0055] When in use, start each device, and the mud inside the wellhead module 2 is transported to the mud tank 6 by the mud return pump 4, and the mud in the mud tank 6 enters the upper end of the drill pipe 3-10 by the mud injection pump 7, and finally flows back to the wellhead module 2 from the lower end of the drill pipe 3-10, thus forming a complete circulation process. In this circulation process, the lower part of the wellhead module 2 is mud, the upper part is clean water, and the middle is a mixed solution of mud and clean water. When it is necessary to study the influence of different disturbance factors of the drill pipe 3-10 on the mud liquid level, it is only necessary to start the lateral moving device, the longitudinal moving device and the rotating device respectively, which can drive the drill pipe 3-10 to move horizontally, longitudinally and rotate respectively, and observe the detection data of the liquid level sensor, so as to facilitate researchers to study the influence of different interference factors on the mud liquid level.

[0056] In this embodiment, the rotating device is a rotary top drive 3-9, which is driven by a servo motor, is hollow in the axial direction, is connected to the drill pipe 3-10 at the lower end, and is used to connect the injection pipeline at the upper end for passing mud, and the mud enters the upper end of the drill pipe 3-10 through the rotary top drive 3-9. Since the rotary top drive 3-9 is a common top drive structure in the existing drilling field, its specific structure will not be described in detail here. A top drive moving plate is fixed to the upper end of the rotary top drive 3-9, and the top drive moving plate is a common rectangular plate, which is used to drive the rotary top drive 3-9 to move left and right on the lateral moving device. When in use, it is only necessary to start the rotary top drive 3-9 to drive the drill pipe 3-10 located below to rotate.

[0057] In this embodiment, the transverse moving device includes a transverse drive motor 3-4, a transverse screw rod 3-3 and two transverse guide rails 3-2. A transverse threaded hole and two transverse guide holes are provided on the top drive moving plate. The transverse threaded hole is located in the middle of the top drive moving plate, and the two transverse guide holes are located on both sides of the transverse threaded hole and are symmetrically distributed. One end of the transverse screw rod 3-3 is drivingly connected to the output shaft of the transverse drive motor 3-4. The transverse threaded hole is provided with an internal thread. The transverse threaded hole is threadedly connected to the transverse screw rod 3-3. When the output shaft of the transverse drive motor 3-4 rotates, the top drive moving plate can be moved left and right on the transverse screw rod 3-3. The transverse drive motor 3-4 is fixed to the transverse motor fixing plate (i.e. Figure 2 The first ends of the two transverse guide rails 3-2 are respectively fixed to the side of the transverse motor fixing plate away from the transverse drive motor 3-4 (i.e. Figure 2 The two transverse guide rails 3-2 are respectively located on both sides of the transverse screw rod 3-3, and the two transverse guide rails 3-2 pass through the two transverse guide holes respectively. The two transverse guide rails 3-2 are respectively connected with the two transverse guide holes in a sliding manner. The function of the two transverse guide rails 3-2 is to provide guidance for the top drive moving plate, so that the top drive moving plate can only move horizontally left and right under the rotation of the transverse screw rod 3-3. When in use, the transverse drive motor 3-4 drives the transverse screw rod 3-3 to rotate. Due to the limiting effect of the transverse guide rail 3-2, the top drive moving plate can only drive the rotary top drive 3-9 and the drill rod 3-10 to do reciprocating linear motion along the direction of the transverse screw rod 3-3.

[0058] In this embodiment, the longitudinal moving device includes a longitudinal screw rod 3-5, a longitudinal drive motor 3-7 and two longitudinal guide rails 3-6. The output shaft of the longitudinal drive motor 3-7 is drivingly connected to one end of the longitudinal screw rod 3-5. The test bench 3 includes two frames 3-1. Figure 2As shown, each frame 3-1 is an n-shaped frame structure, and the two frames 3-1 are spaced apart, the two ends of the longitudinal guide rail 3-6 are respectively fixed to the inner sides of the two frames 3-1, the longitudinal drive motor 3-7 is fixed to the outer side of one frame 3-1, and the two longitudinal guide rails 3-6 are respectively located on both sides of the frame 3-1. The two longitudinal guide rails 3-6 are respectively slidably connected with the first longitudinal movable plate and the second longitudinal movable plate, and the first longitudinal movable plate and the second longitudinal movable plate are respectively provided with corresponding longitudinal guide holes for the longitudinal guide rail 3-6 to pass through, the first longitudinal movable plate is fixed to the lower end of the transverse motor fixing plate, the first longitudinal movable plate is provided with a longitudinal threaded hole, the longitudinal threaded hole is provided with an internal thread, and the longitudinal threaded hole is threadedly connected with the longitudinal screw rod 3-5. The first end of the transverse guide rail 3-2 is fixed to the transverse motor fixing plate, and the second end of the transverse guide rail 3-2 is fixed to the second longitudinal movable plate. When in use, start the longitudinal drive motor 3-7, and the longitudinal drive motor 3-7 drives the longitudinal screw 3-5 to rotate. Under the action of the longitudinal guide rail 3-6, the first longitudinal movable plate makes a longitudinal reciprocating motion on the longitudinal screw 3-5, and the second longitudinal movable plate, driven by the first longitudinal movable plate, makes a longitudinal reciprocating motion on the longitudinal guide rail 3-6 synchronously with the first longitudinal movable plate, finally achieving the technical effect of the lateral moving device, the rotating device and the drill rod 3-10 making longitudinal movements together.

[0059] In this embodiment, the upper end of the top drive movable plate is connected to a grouting pipe 3-8, the lower end of the grouting pipe 3-8 is connected to the rotary top drive 3-9, the injection pipeline is connected to the upper end of the grouting pipe 3-8, and the mud from the injection pipeline flows into the rotary top drive 3-9 through the grouting pipe 3-8, and then flows into the drill pipe 3-10 through the rotary top drive 3-9.

[0060] In this embodiment, the specific structure of the wellhead module 2 includes a wellhead barrel 2-1, a mud discharge pipe 2-3 is provided on the bottom side wall of the wellhead barrel 2-1, one end of the return line is connected to the mud discharge pipe 2-3, and the mud inside the wellhead barrel 2-1 flows out from the mud discharge pipe 2-3 under the drive of the mud return pump 4. A plurality of sensor brackets 2-2 are provided on the inner wall of the wellhead barrel 2-1, such as Figure 5 As shown, there are two sensor brackets 2-2, which are respectively located on the inner walls on both sides of the wellhead barrel 2-1, and the liquid level sensor is arranged on the sensor bracket 2-2. The number and position relationship of the liquid level sensors arranged on each sensor bracket 2-2 can be adjusted by technicians in this field according to actual needs.

[0061] In this embodiment, a reflux flowmeter 5 is provided on the reflux pipeline, and the reflux flowmeter 5 is electrically connected to the controller; similarly, an injection flowmeter 8 is provided on the injection pipeline, and the injection flowmeter 8 is electrically connected to the controller. The data detected by the reflux flowmeter 5 and the injection flowmeter 8 can be used to verify the accuracy of the liquid level sensor.

[0062] Embodiment 2

[0063] This embodiment provides a detection method of an underwater wellhead liquid level detection simulation test device, comprising the following steps:

[0064] S1. Prepare and install each device, and then prepare for testing;

[0065] S2, start the mud injection pump 7, the mud is discharged into the drill pipe 3-10 at the test bench 3 by the mud injection pump 7, and the mud in the drill pipe 3-10 is injected into the wellhead module 2. At this time, the mud will slowly rise in the wellhead module 2, simulating the process of mud returning to the underwater wellhead during deepwater drilling;

[0066] S3, start the mud return pump 4 to pump the mud in the wellhead module 2 back into the mud tank 6, simulating the mud lifting and recovery process without a riser, thereby forming a circulation loop. During this circulation process, the lower part of the wellhead module 2 is mud, the upper part is clean water, and the middle part is a mixed solution of mud and clean water;

[0067] S4, conduct a liquid level identification simulation test, start the lateral moving device, the longitudinal moving device and the rotating device, and drive the drill pipe 3-10 to perform lateral movement, longitudinal movement and rotational movement through the lateral moving device, the longitudinal moving device and the rotating device, which can accurately simulate the front and back left and right movement and rotational movement of the drill pipe 3-10 in the wellhead in a deep-water environment. According to the diameter of different wellheads, the number of rotations of the lateral drive motor 3-4 and the longitudinal drive motor 3-7 can be set to limit the swing amplitude of the drill pipe 3-10 in the wellhead module 2; according to different sea conditions, the operating speed of the lateral drive motor 3-4 and the longitudinal drive motor 3-7 can be set to limit the swing speed of the drill pipe 3-10 in the wellhead module 2;

[0068] S5, maintaining a constant pumping rate of the mud return pump 4, and changing the mud level height inside the wellhead module 2 by increasing or decreasing the pumping rate of the mud injection pump 7;

[0069] S6. Collect data from the injection flowmeter 8, the return flowmeter 5, the cross-sectional area of ​​the wellhead module 2 and the liquid level sensor, and calculate the rising rate and height of the mud liquid level.

[0070] In this embodiment, the preparation and installation work in step S1 includes: filling the water tank 1 with clean water to simulate the marine environment;

[0071] Place the test bench 3 and the wellhead module 2 inside the water tank 1, first place the wellhead module 2, place the wellhead module 2 at the bottom of the water tank 1, temporarily store mud in the wellhead module 2, then place the test bench 3 above the wellhead module 2, and extend the drill pipe 3-10 on the test bench 3 into the wellhead module 2;

[0072] The liquid level sensor is installed on the sensor bracket 2 - 2 in the wellhead module 2 .

[0073] In this embodiment, the calculation step in step S6 includes: mud level rise height = (injection volume of injection flow meter 8 - discharge volume of return flow meter 5) / cross-sectional area of ​​wellhead module 2;

[0074] The rising rate of mud level = mud level rising height ÷ time.

[0075] By using this calculation step, the rising height and rising speed of the mud level can be accurately calculated, which can not only verify the accuracy of the level sensor, but also further accurately determine the rising height and rising speed of the mud level in combination with the detection data of the level sensor.

[0076] The present specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An underwater wellhead liquid level detection simulation test device, characterized in that: include: A water tank, wherein the water tank is filled with water; A wellhead module, wherein the wellhead module is arranged in the water tank, the wellhead module is in communication with the water tank, and a plurality of liquid level sensors are arranged on the inner wall of the wellhead module; A drill pipe, the lower end of which can extend into the wellhead module; A test bench, wherein the test bench is provided with a lateral moving device, a longitudinal moving device and a rotating device, the upper end of the drill rod is connected to the rotating device, the rotating device is arranged on the lateral moving device, and the lateral moving device is arranged on the longitudinal moving device; A mud tank, wherein the lower end of the mud tank is connected to the lower end of the wellhead module through a return pipeline, a mud return pump is provided on the return pipeline, and the upper end of the mud tank is connected to the rotating device through an injection pipeline, a mud injection pump is provided on the injection pipeline, and the mud in the injection pipeline flows into the upper end of the drill pipe through the rotating device; A controller, the liquid level sensor, the lateral moving device, the longitudinal moving device, the rotating device, the mud return pump and the mud injection pump are all electrically connected to the controller; The rotating device is a rotary top drive, and a top drive moving plate is fixed on the upper end of the rotary top drive; A reflux flowmeter is provided on the reflux pipeline, and the reflux flowmeter is electrically connected to the controller; an injection flowmeter is provided on the injection pipeline, and the injection flowmeter is electrically connected to the controller.

2. The underwater wellhead liquid level detection simulation test device according to claim 1 is characterized in that: The transverse moving device includes a transverse driving motor, a transverse screw and two transverse guide rails. A transverse threaded hole and two transverse guide holes are provided on the top drive moving plate. One end of the transverse screw is drivingly connected to the output shaft of the transverse driving motor. The transverse threaded hole is provided with an internal thread. The transverse threaded hole is threadedly connected to the transverse screw. The transverse driving motor is fixed to the transverse motor fixing plate. The first ends of the two transverse guide rails are respectively fixed to a surface of the transverse motor fixing plate away from the transverse driving motor. The two transverse guide rails are respectively located on both sides of the transverse screw. The two transverse guide rails respectively pass through the two transverse guide holes, and the two transverse guide rails are respectively slidably connected to the two transverse guide holes.

3. The underwater wellhead liquid level detection simulation test device according to claim 2 is characterized in that: The longitudinal moving device includes a longitudinal screw, a longitudinal drive motor and two longitudinal guide rails, the output shaft of the longitudinal drive motor is drivingly connected to one end of the longitudinal screw, the test bench includes two frames, the two ends of the longitudinal guide rail are respectively fixed to the inner sides of the two frames, the longitudinal drive motor is fixed to the outer side of one of the frames, the two longitudinal guide rails are respectively located on both sides of the frames, and the two longitudinal guide rails are respectively slidably connected with a first longitudinal moving plate and a second longitudinal moving plate, the first longitudinal moving plate is fixed to the lower end of the transverse motor fixing plate, the first longitudinal moving plate is provided with a longitudinal threaded hole, the longitudinal threaded hole is provided with an internal thread, the longitudinal threaded hole is threadedly connected to the longitudinal screw, the first end of the transverse guide rail is fixed to the transverse motor fixing plate, and the second end of the transverse guide rail is fixed to the second longitudinal moving plate.

4. The underwater wellhead liquid level detection simulation test device according to claim 1, characterized in that: The upper end of the top drive moving plate is connected with a grouting pipe, the lower end of the grouting pipe is communicated with the rotary top drive, and the injection pipeline is communicated with the upper end of the grouting pipe.

5. The underwater wellhead liquid level detection simulation test device according to claim 1, characterized in that: The wellhead module comprises a wellhead barrel body, a mud discharge pipe is arranged on the side wall of the wellhead barrel body, one end of the return pipeline is connected with the mud discharge pipe, a plurality of sensor brackets are arranged on the inner wall of the wellhead barrel body, and the liquid level sensor is arranged on the sensor bracket.

6. A detection method based on the underwater wellhead liquid level detection simulation test device according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Prepare and install each device; S2. Start the mud injection pump. The mud is discharged into the drill pipe at the test bench by the mud injection pump. The mud in the drill pipe is injected into the wellhead module. At this time, the mud will slowly rise in the wellhead module. S3, start the mud return pump to pump the mud in the wellhead module back into the mud tank, thereby forming a circulation loop; S4. Conduct a liquid level identification simulation test, start the lateral moving device, the longitudinal moving device and the rotating device, and drive the drill rod to perform lateral movement, longitudinal movement and rotational movement through the lateral moving device, the longitudinal moving device and the rotating device; S5, maintaining a constant pumping rate of the mud return pump, and changing the mud level height inside the wellhead module by increasing or decreasing the pumping rate of the mud injection pump; S6. Collect data from the injection flowmeter, reflux flowmeter, cross-sectional area of ​​the wellhead module and the liquid level sensor, and calculate the rising rate and height of the mud liquid level.

7. The detection method of the underwater wellhead liquid level detection simulation test device according to claim 6 is characterized in that: The preparation and installation work in step S1 includes: filling the water tank with clean water to simulate the marine environment; Place the test bench and the wellhead module inside the water tank; Install the level sensor in the wellhead module.

8. The detection method of the underwater wellhead liquid level detection simulation test device according to claim 6 is characterized in that: The calculation steps in step S6 include: mud level rise height = (injection volume of injection flow meter - discharge volume of return flow meter) / cross-sectional area of ​​wellhead module; The rising rate of mud level = mud level rising height ÷ time.

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