High back pressure positive pressure pressure compensation system for subsea drilling rig and control method thereof

Abstract

The application discloses a high-back-pressure positive-pressure pressure compensation system for a seabed drilling machine and a control method thereof. The high-back-pressure positive-pressure pressure compensation system for the seabed drilling machine comprises a compensation device capable of elastically deforming according to pressure and a pressure device connected with the compensation device in an oil circuit feedback connection to adjust the internal pressure of the system, and the compensation device and the pressure device are vertically distributed and arranged. The cooperation of the compensation device and the pressure device guarantees the application of the compensation system, and the vertical distributed design concept is adopted, the pressure device applies pressure to the compensation device through the self-weight, and the seabed drilling machine system is always kept as constant positive pressure. Through high integration of the pressure device and the compensation device, the utilization rate of the limited space of the seabed drilling machine is remarkably improved, and the structure of the whole drilling machine is effectively lightened to adapt to the increase of the working water depth and the drilling depth.

Description

Technical Field

[0001] This invention relates to the technical field of marine engineering and deep-sea technology, and in particular to a pressure compensation system and control method for high back pressure positive pressure for seabed drilling rigs. Background Technology

[0002] The ocean holds a vast treasure trove of common resources for humankind. Deep-sea / abyssal drilling and sampling are indispensable for exploring the distribution of mineral resources and revealing key issues such as the origin of Earth science. In the extremely complex environment of the deep sea / abyss, the subsea drilling rig system needs to withstand seawater pressure of tens to hundreds of megapascals. If its component shell or installation container does not have independent pressure resistance, it is necessary to fill the system with liquid medium and take pressure compensation measures. The core components of the subsea drilling rig, such as the hydraulic system, electrical components, hydraulic control valves and various sensors, all need to be equipped with pressure compensation systems.

[0003] In deep-sea and even abyssal operating environments, the following factors must be considered to cause changes in the effective volume of the system: the oil volume compression effect under high pressure, the alternating changes in the volume of the rod-side / rodless chamber caused by the actuation of the cylinders (rod extension / retraction), and the changes in oil volume caused by thermal expansion and contraction. Therefore, the design of the pressure compensation device must effectively address all of the above factors to ensure stable system operation. In addition, with the increase in operating water depth and drilling depth, the requirements for lightweighting of the pressure compensation system and the entire subsea drilling rig also increase. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a pressure compensation system and control method for high back pressure positive pressure systems for subsea drilling rigs.

[0005] This invention is achieved by the following technical solution: A pressure compensation system for high back pressure and positive pressure for subsea drilling rigs includes a compensation device capable of elastic deformation according to pressure, and a pressure device connected to the compensation device via an oil circuit feedback to adjust the internal pressure of the system. The compensation device and the pressure device are arranged vertically. The compensation device includes a bladder compensator and an oil port connector on the bladder compensator. The bladder compensator includes an upper clamping plate, a lower clamping plate, and a bladder component pre-filled with oil between the upper clamping plate and the lower clamping plate. Multiple guide support tubes are provided between the upper clamping plate and the lower clamping plate; The end of the guide support tube away from the upper clamping plate is fitted with a guide support pad for forming an axial displacement constraint pair.

[0006] The system utilizes a combination of a compensation device and a pressure device to ensure the application of the compensation system. It also adopts a vertically distributed design concept, using the weight of the pressure device to apply pressure to the compensation device, thus maintaining a constant positive pressure on the subsea drilling rig system. By highly integrating the pressure device and the compensation device, the utilization rate of the limited space of the subsea drilling rig is significantly improved, while effectively ensuring the overall lightweight structure of the drilling rig to adapt to the increase in operating water depth and drilling depth.

[0007] As described above, in the high back pressure positive pressure pressure compensation system for subsea drilling rigs, one side of the oil port connector is connected to the pressure device, and the other side is connected to the internal flow channel of the bladder. The bladder can contract and deform when subjected to pressure, so that the oil pressure inside the bladder increases synchronously and is transmitted to the entire system through the oil port connector connecting pipeline, so that the internal pressure of the system is always higher than the external pressure.

[0008] As described above, in the high back pressure positive pressure pressure compensation system for subsea drilling rigs, a first bladder flange and a second bladder flange are respectively embedded on both sides of the elastic edge of the bladder component. Multiple sets of compensator tension springs are provided between the first bladder flange and the second bladder flange, and the compensator tension springs are located on the second bladder flange.

[0009] The pressure compensation system for high back pressure and positive pressure facing the subsea drilling rig as described above includes a housing and an oil pump assembly located inside the housing. The oil pump inside the oil pump assembly is connected to the oil circuit of the compensation device.

[0010] The pressure compensation system for high back pressure positive pressure facing a subsea drilling rig as described above includes a frame and a motor installed in the frame. The compensation device and the pressure device are both installed in the frame, and a connecting device for connecting the pressure device and the motor is provided between the compensation device and the pressure device.

[0011] A pressure compensation system control method for controlling the operation of a high back pressure positive pressure pressure compensation system facing a subsea drilling rig as described above, comprising the following steps: S1: When the subsea drilling rig enters the high-pressure environment of the seabed, as the seawater pressure increases, the compensation device is subjected to the pressure of its own weight and the seawater pressure, and the internal pressure of the pressure compensation system of the high back pressure positive pressure of the subsea drilling rig is always higher than the external pressure. S2: When the subsea drilling rig reaches the working position, the motor of the subsea drilling rig drives the subsea drilling rig to work. The compensation device works in conjunction with it to absorb the axial impact of the transmission. The pressure device is driven by the compensation device to adjust the differential pressure, regulate the internal pressure of the system and the output flow. S3: When the subsea drilling rig is recovered after completing its work, as the external water pressure decreases, the compensation device releases the internal pressure, which, in conjunction with the pressure device, ensures that the internal pressure of the subsea drilling rig system remains slightly higher than the external pressure.

[0012] The pressure compensation system control method described above, wherein the compensation device includes a bladder compensator, the bladder compensator includes a bladder component pre-filled with oil, the pressure device includes an oil pump assembly, and step S1 further includes the following steps: S11: When the seabed drilling rig descends, as the seawater pressure continues to rise, the bladder component is compressed and deformed, and the oil pressure inside the bladder component increases. S12: The oil inside the bladder circulates with the oil pump of the oil pump assembly in the internal flow channel of the bladder, thereby increasing the oil pressure inside the bladder and transmitting it to the entire system through the connecting pipeline, so that the internal pressure of the system is always higher than the external pressure.

[0013] The pressure compensation system control method described above further includes the following step S2: S21: When the subsea drilling rig is drilling, the compensation device absorbs the axial impact of the transmission, and the oil inside the bladder is pressurized and enters the oil pump assembly through the internal flow channel. S22: The oil pump assembly supplies the processed oil to the subsea drilling rig, and the motor adjusts the rotation speed of the subsea drilling rig.

[0014] Compared with existing technologies, the pressure compensation system and control method for high back pressure positive pressure of subsea drilling rigs proposed in this invention have the following beneficial effects: 1. The high back pressure positive pressure pressure compensation system for subsea drilling rigs of the present invention provides a guarantee for the application of the compensation system through the cooperation of the compensation device and the pressure device. At the same time, it adopts a vertically distributed design concept, and applies pressure to the compensation device through the self-weight of the pressure device, so that the subsea drilling rig system always maintains a constant positive pressure. By highly integrating the pressure device and the compensation device, the utilization rate of the limited space of the subsea drilling rig is significantly improved, while effectively ensuring the overall lightweight structure of the drilling rig to adapt to the increase of operating water depth and drilling depth. 2. The high back pressure positive pressure pressure compensation system of the present invention, through the combination mechanism of compensation device and pressure device, can realize the adjustment mechanism covering the entire ocean depth and automatically respond to the dynamic changes of external seawater pressure. It can effectively balance the pressure difference between the inside of the subsea drilling rig and the external environment, and always keep the internal pressure of the system stable higher than the environmental pressure, thereby preventing damage to the equipment structure from the extreme environmental pressure of the deep sea. On the other hand, it can ensure the stability of pressure compensation during complex operations in the deep sea environment, and ensure the reliability and operational safety of the subsea drilling rig in the deep sea and even the abyss. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0016] Figure 1 This is a schematic diagram of the compensation device structure of the present invention; Figure 2 for Figure 1 Another perspective illustration; Figure 3 for Figure 1 Another perspective illustration; Figure 4 for Figure 3 A schematic diagram of the explosion decomposition from this perspective; Figure 5 This is an exploded view of the compensator tension spring of the present invention; Figure 6 This is a schematic diagram of the pressure device structure of the present invention; Figure 7 A schematic diagram of the structure of the subsea drilling rig that utilizes a high back pressure positive pressure pressure compensation system according to the present invention; Figure 8 for Figure 6 Another perspective illustration; Figure 9 for Figure 6 Another perspective illustration; Figure 10 for Figure 9 A schematic diagram of the AA cross-section.

[0017] The corresponding reference numerals in the attached figures are as follows: 1. Compensation device; 11. Bellows compensator; 111. Upper clamping plate; 112. Lower clamping plate; 113. Bellows component; 114. Guide support pipe; 1141. Guide support gasket; 115. First bellows flange; 116. Second bellows flange; 1161. One-way valve; 117. Compensator tension spring; 1171. Connecting screw; 12. Oil port connector; 2. Pressure device; 21. Housing; 211. First housing; 2111. First exhaust port; 2112. Oil port connector; 212. Second housing; 2121. Second exhaust port; 2122. Transition port; 2123. Adjustment connector; 213. Third housing; 22. Oil pump assembly; 5. Frame; 6. Motor; 7. Connecting device. Detailed Implementation

[0018] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] Specific embodiments, combined with Figures 1 to 10 The technical solution of the present invention is further illustrated below. A high back pressure positive pressure pressure compensation system for subsea drilling rigs includes a compensation device 1 capable of elastic deformation according to pressure, and a pressure device 2 connected to the compensation device 1 via an oil circuit to adjust the internal pressure of the system. The compensation device 1 and the pressure device 2 are vertically distributed. By adopting a vertically distributed design concept, the compensation device 1 and the pressure device 2 are highly integrated, and their spatial layout can adapt to the layout under high pressure environments, optimizing the structure of the applied product while ensuring stable system operation. For example, when the high back pressure positive pressure pressure compensation system is applied to a subsea drilling rig, its spatial layout conforms to the overall design requirements and characteristics of the subsea drilling rig, significantly improving the utilization rate of the limited space of the subsea drilling rig, while effectively ensuring the overall lightweight structure of the drilling rig to adapt to the increase in operating water depth and drilling depth, ensuring stable system operation.

[0020] Based on the above overall concept, the compensation device 1 includes a bladder compensator 11 and an oil port connector 12 disposed on the bladder compensator 11. The bladder compensator 11 includes an upper clamping plate 111, a lower clamping plate 112, and a bladder component 113 pre-filled with oil and disposed between the upper clamping plate 111 and the lower clamping plate 112. One side of the oil port connector 12 is connected to the pressure device 2, and the other side is connected to the internal flow channel of the bladder component 113. The bladder component 113 can contract and deform when subjected to pressure, so that the oil pressure inside the bladder component 113 increases synchronously and is transmitted to the entire system through the connecting pipeline via the oil port connector 12, so that the internal pressure of the system is always slightly higher than the external pressure.

[0021] Specifically, a plurality of guide support tubes 114 are provided between the upper clamping plate 111 and the lower clamping plate 112, and a first bladder flange 115 and a second bladder flange 116 are respectively embedded on both sides of the elastic edge of the bladder component 113; preferably, a plurality of compensator tension springs 117 are provided between the upper clamping plate 111 and the lower clamping plate 112 to cooperate with the bladder component 113 to adjust the internal pressure of the system.

[0022] More specifically, the compensator spring 117 is provided with a connecting screw 1171. The upper end of the compensator spring 117 is connected to the upper clamping plate 111 via the thread of the connecting screw 1171, and the lower end is connected to the lower clamping plate 112 via the connecting screw 1171, so as to realize the pretension adjustment by the nut. The compensator spring 117 can work in conjunction with the bladder component 113. For example, during the recovery stage of the subsea drilling rig, when the external water pressure decreases, the bladder component 113 releases its own elasticity, and the compensator spring 117 releases its spring tension to drive the oil to ensure that the internal pressure is continuously higher than the external pressure. At the same time, the oil in the bladder component 113 and the oil in the pressure device 2 start to circulate, maintaining a positive pressure difference during the recovery stage to prevent seawater from seeping in.

[0023] Optionally, the lower clamping plate 112 is movably connected to the guide support tube 114, and the bladder component 113 can elastically contract and deform and elastically recover under the guidance of the guide support tube 114 when working on the seabed.

[0024] In addition, the bottom of the second bladder flange 116 is provided with multiple sets of one-way valves 1161 with the valve body central axis perpendicular to the horizontal plane. The end of the guide support tube 114 away from the first bladder flange 115 is fitted with a guide support gasket 1141 for forming an axial displacement constraint pair. The one-way valves 1161 can assist the contraction and rebound of the bladder component 113, and the guide support gaskets 1141 on the guide support tube 114 can form an axial displacement constraint pair, providing a guarantee for the operation of the pressure compensation system of the subsea drilling rig.

[0025] Based on the overall design concept described above, the pressure device 2 includes a housing 21 and an oil pump assembly 22 disposed inside the housing 21. The oil pump inside the oil pump assembly 22 is connected to the oil circuit of the compensation device 1. Optionally, the oil pump assembly 22 may be equipped with multiple oil pumps.

[0026] Based on the above overall design concept, the subsea drilling rig includes a frame 5 and a motor 6 installed in the frame 5. The compensation device 1 and the pressure device 2 are both installed in the frame 5. A connecting device 7 for connecting the pressure device 2 and the motor 6 is provided between the compensation device 1 and the pressure device 2.

[0027] Specifically, the housing 21 includes a first housing 211, a second housing 212, and a third housing 213 arranged sequentially. The oil pump assembly 22 is located inside the first housing 211. The top and sides of the first housing 211 are provided with multiple first exhaust ports 2111 and oil ports 2112 for debugging or expansion according to the sea trial hydraulic system. Optionally, one first exhaust port 2111 is located at the top of the first housing 211, and the remaining first exhaust ports 2111 are spaced apart on the sides of the first housing 211. The oil ports 2112 are located on the sides of the first housing 211 for easy connection with the oil pump. The connecting device 7 is located inside the second housing 212. The sides of the second housing 212 are provided with multiple second exhaust ports 2121, multiple transition ports 2122, and multiple control connectors 2123 selected according to the control requirements of the subsea drilling rig. Optionally, four control connectors 2123 are spaced apart on the sides of the second housing 212. The motor 6 is located inside the third housing 213. The first exhaust port 2111, the second exhaust port 2121, and the oil port 2112 can be used for system debugging or expansion based on the seabed hydraulic delivery port.

[0028] The connecting device 7 includes a pump coupling that is installed and connected to the oil pump assembly 22 and a motor coupling that is installed and connected to the motor 6. The bottom is sealed by a sealing ring, and the pump coupling and the motor coupling are nested and coupled together.

[0029] A control method for a high back pressure positive pressure system for subsea drilling rigs, used to control the subsea drilling rig to operate using the high back pressure positive pressure system for subsea drilling rigs as described above, includes the following steps: S1: When the subsea drilling rig enters the high-pressure environment of the seabed, as the seawater pressure increases, the compensation device 1 is subjected to the self-weight pressure of the pressure device 2 and the seawater pressure, so that the internal pressure of the pressure compensation system of the high back pressure positive pressure of the subsea drilling rig is always higher than the external pressure. During this process, the hydraulic medium pre-charged inside the oil pump assembly 22 starts circulating, and the oil pressure inside the bladder 113 increases synchronously and is transmitted to the entire system through the connecting pipeline, so that the internal pressure of the system is always higher than the external pressure. This process dynamically compensates for the volume loss of the oil due to high pressure compression and low temperature contraction, while maintaining a positive pressure difference to prevent seawater from seeping in.

[0030] S2: When the subsea drilling rig reaches the working position, the motor 6 drives the subsea drilling rig to work, the compensation device 1 cooperates to absorb the axial impact of the transmission, and the pressure device 2 performs differential pressure adjustment under the drive of the compensation device 1 to adjust the internal pressure and output flow of the system. In this process, the oil is processed by the oil pump and drives the drilling tool to rotate and cut, realizing stepless adjustment of the drilling tool speed. The oil pipeline forms a closed-loop feedback to achieve constant power control. During the operation, the externally cooled oil will also flow back into the high back pressure positive pressure compensation system of the subsea drilling rig.

[0031] Meanwhile, the bladder compensator 11 continuously absorbs oil pump flow pulsations, reducing pressure fluctuations. When the drill string gets stuck, it supplies a large flow to the power head and applies a force to help the drill string "get out of trouble"; it can also function as a hydraulic device when the drill pipe is being unloaded or when the hydraulic manipulator is moving the pipe.

[0032] S3: When the subsea drilling rig is recovered after completing its work, as the external water pressure decreases, the compensation device 1 releases the internal pressure, which, together with the pressure device 2, ensures that the internal pressure of the subsea drilling rig system remains slightly higher than the external pressure.

[0033] During this process, the external water pressure decreases, the bladder component 113 releases its own elasticity, and the compensator spring 117 releases its spring tension to drive the oil to ensure that the internal pressure is always higher than the external pressure. At the same time, the oil in the bladder compensator 11 and the oil in the oil pump assembly 22 start to circulate, maintaining a positive pressure difference during the recovery phase to prevent seawater from seeping in.

[0034] Step S1 further includes the following steps: S11: When the seabed drilling rig descends, as the seawater pressure continues to rise, the bladder component 113 is compressed and deformed, and the oil pressure inside the bladder component 113 increases. S12: The oil inside the bladder 113 circulates with the oil pump of the oil pump assembly 22 in the internal flow channel of the bladder 113, thereby increasing the oil pressure inside the bladder 113 and transmitting it to the entire system through the connecting pipeline, so that the internal pressure of the system is always higher than the external pressure.

[0035] Step S2 further includes the following steps: S21: When the subsea drilling rig is drilling, the compensation device 1 absorbs the axial impact of the transmission, and the oil inside the bladder 113 is pressurized and enters the oil pump assembly 22 through the internal flow channel. S22: The oil pump assembly 22 supplies the oil pumped to the subsea drilling rig after processing, and the motor 6 adjusts the rotation speed of the subsea drilling rig.

[0036] Optionally, the high back pressure positive pressure compensation system of the subsea drilling rig is equipped with a pressure sensor to monitor the oil outlet pressure in real time, and the closed-loop feedback realizes constant power control. Under the closed-loop feedback, the externally cooled oil will flow back into the system of the high back pressure positive pressure compensation system of the subsea drilling rig.

[0037] The working principle of this embodiment is as follows: This invention proposes a pressure compensation system and control method for high back pressure positive pressure applications in subsea drilling rigs. The high back pressure positive pressure compensation system employs a vertically distributed design concept, highly integrating the compensation device 1 and the pressure device 2. Its spatial layout can adapt to high-pressure environments, optimizing the structure of the applied products while ensuring stable system operation. When applied to subsea drilling rigs, its specific working principle is as follows: When the subsea drilling rig enters the high-pressure environment of the seabed, as the seawater pressure increases, the compensation device 1 operates under the pressure of the pressure device 2's own weight and the seawater pressure, ensuring that the internal pressure of the high back pressure positive pressure compensation system of the subsea drilling rig is always higher than the external pressure. During this process, the hydraulic medium pre-charged inside the pressure device 2 starts to circulate, and the oil pressure inside the bladder 113 increases synchronously and is transmitted to the entire system through the connecting pipeline, so that the internal pressure of the system is always slightly higher than the external pressure. This process dynamically compensates for the volume loss of the oil due to high pressure compression and low temperature contraction, while maintaining a positive pressure difference to prevent seawater from seeping in.

[0038] Once the subsea drilling rig reaches its working position, motor 6 drives the rig to operate. Compensation device 1 works in conjunction with it to absorb axial impact during transmission. The oil pump assembly 22 within the pressure device 2 works with compensation device 1 to regulate the system's internal pressure and output flow. During this process, the oil, after being processed by the oil pump, forms a closed-loop feedback with the oil pipeline to achieve constant power control. During operation, externally cooled oil also flows back into the subsea drilling rig's high back pressure positive pressure compensation system. Simultaneously, the bladder compensator 11 continuously absorbs oil pump flow pulsations, reducing pressure fluctuations.

[0039] When the subsea drilling rig is recovered after completing its work, as the external water pressure decreases, the compensation device 1 releases its internal pressure. This, in conjunction with the oil circulation channel inside the pressure device 2, ensures that the internal pressure of the high back pressure positive pressure compensation system of the subsea drilling rig remains higher than the external pressure. During this process, as the external water pressure decreases, the bladder element 113 inside the bladder compensator 11 releases its elasticity. In addition, the compensator tension spring 117 releases its spring tension to drive the oil to ensure that the internal pressure remains higher than the external pressure. At the same time, the oil inside the bladder compensator 11 and the oil inside the pressure device 2 begin to circulate, maintaining the positive pressure difference during the recovery phase to prevent seawater from seeping in.

Claims

1. A pressure compensation system for high back pressure positive pressure in subsea drilling rigs, characterized in that, It includes a compensation device (1) capable of elastic deformation under pressure, and a pressure device (2) connected to the compensation device (1) via an oil circuit to adjust the internal pressure of the system. The compensation device (1) and the pressure device (2) are arranged vertically. The compensation device (1) includes a bladder compensator (11) and an oil port connector (12) provided on the bladder compensator (11). The bladder compensator (11) includes an upper clamping plate (111), a lower clamping plate (112), and a bladder component (113) pre-filled with oil and located between the upper clamping plate (111) and the lower clamping plate (112). Multiple guide support tubes (114) are provided between the upper clamping plate (111) and the lower clamping plate (112). The end of the guide support tube (114) away from the upper clamping plate (111) is fitted with a guide support pad (1141) for forming an axial displacement constraint pair. The elastic body edge of the bladder component (113) is respectively fitted with a first bladder flange (115) and a second bladder flange (116). Multiple sets of compensator tension springs (117) are provided between the first bladder flange (115) and the second bladder flange (116). The compensator tension springs (117) are provided on the second bladder flange (116). The compensator tension spring (117) is provided with a connecting screw (1171). The upper end of the compensator tension spring (117) is connected to the upper clamping plate (111) through the thread of the connecting screw (1171), and the lower end is connected to the lower clamping plate (112) through the connecting screw (1171) so as to realize the pretension adjustment through the nut.

2. The pressure compensation system for high back pressure positive pressure facing subsea drilling rigs according to claim 1, characterized in that, One side of the oil port connector (12) is connected to the pressure device (2), and the other side is connected to the internal flow channel of the bladder (113). The bladder (113) can contract and deform when subjected to pressure, so that the oil pressure inside the bladder (113) increases synchronously and is transmitted to the entire system through the connecting pipeline via the oil port connector (12), so that the internal pressure of the system is always higher than the external pressure.

3. The pressure compensation system for high back pressure positive pressure facing subsea drilling rigs according to claim 1, characterized in that, The pressure device (2) includes a housing (21) and an oil pump assembly (22) located inside the housing (21). The oil pump inside the oil pump assembly (22) is connected to the oil circuit of the compensation device (1).

4. The pressure compensation system for high back pressure positive pressure facing a subsea drilling rig according to any one of claims 1-3, characterized in that, The subsea drilling rig includes a frame (5) and a motor (6) installed in the frame (5). The compensation device (1) and the pressure device (2) are both installed in the frame (5). A connecting device (7) for connecting the pressure device (2) and the motor (6) is provided between the compensation device (1) and the pressure device (2).

5. A pressure compensation system control method, used to control the operation of the high back pressure positive pressure pressure compensation system for subsea drilling rigs as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: When the seabed drilling rig enters the high-pressure environment of the seabed and goes underwater, as the seawater pressure increases, the compensation device (1) is subjected to the self-weight pressure of the pressure device (2) and the seawater pressure, and the internal pressure of the pressure compensation system of the high back pressure positive pressure of the seabed drilling rig is always higher than the external pressure. S2: When the subsea drilling rig reaches the working position, the motor (6) of the subsea drilling rig drives the subsea drilling rig to work. The compensation device (1) works in conjunction with it to absorb the axial impact of the transmission. The pressure device (2) is driven by the compensation device (1) to adjust the differential pressure, adjust the internal pressure of the system and the output flow. S3: When the subsea drilling rig is recovered after completing its work, as the external water pressure decreases, the compensation device (1) releases the internal pressure and works with the pressure device (2) to ensure that the internal pressure of the subsea drilling rig system remains slightly higher than the external pressure.

6. The pressure compensation system control method according to claim 5, characterized in that, The compensation device (1) includes a bladder compensator (11), the bladder compensator (11) includes a bladder component (113) pre-filled with oil, the pressure device (2) includes an oil pump assembly (22), and step S1 further includes the following steps: S11: When the seabed drilling rig descends, as the seawater pressure continues to rise, the bladder (113) is compressed and deformed, and the oil pressure inside the bladder (113) increases. S12: The oil inside the bladder (113) circulates with the oil pump of the oil pump assembly (22) in the internal flow channel of the bladder (113), thereby increasing the oil pressure inside the bladder (113) and transmitting it to the entire system through the connecting pipeline, so that the internal pressure of the system is always higher than the external pressure.

7. The pressure compensation system control method according to claim 6, characterized in that, Step S2 also includes the following steps: S21: When the subsea drilling rig is drilling, the compensation device (1) absorbs the axial impact of the transmission, and the oil inside the bladder (113) is pressurized and enters the oil pump assembly (22) through the internal flow channel. S22: The oil pump of the oil pump assembly (22) is supplied to the seabed drilling rig after oil processing, and the motor (6) adjusts the speed of the seabed drilling rig.

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