Deepwater Drilling Experiment System, Experiment Method and Deepwater Drilling String

Abstract

The present invention provides a deep-water drilling experiment system, an experimental method and a deep-water drilling string. The deep-water drilling experiment system includes an outer pipe, a drill pipe, a drill bit and a capacitive array logging tool. The drill bit is installed at the lower end of the drill pipe, and the drill pipe is lowered into the outer pipe. The capacitive array logging tool includes an annular housing and a plurality of detection devices. The detection devices include a gas holdup probe and a water holdup probe circumferentially distributed around the drill pipe. The annular housing is installed outside the drill pipe. A first annular cavity is provided between the annular housing and the drill pipe, and a second annular cavity is provided between the annular housing and the outer pipe. The detection devices are arranged in the first annular cavity and are circumferentially distributed around the drill pipe, solving the technical problem of being difficult to timely understand the gas invasion phenomenon during the deep-water drilling process.

Description

Technical Field

[0001] The present invention relates to the technical field of deep - water drilling equipment, and particularly to a deep - water drilling experiment system, an experimental method, and a deep - water drilling string. Background Art

[0002] During the deep - water drilling process, affected by complex factors such as the narrow safety density window of drilling fluid, fractured carbonate reservoirs, and high - temperature and high - pressure formations, well kicks and lost circulation accidents are likely to occur, seriously affecting the safety and efficiency of drilling. If the well kick and lost circulation accidents are not properly handled, the gas - invaded fluid will enter the blowout preventer, causing hazards such as the failure of the blowout preventer; resulting in unbalanced internal and external pressures of each water pipe, the failure of the drilling fluid circulation balance, and causing high - risk blowout accidents. At present, it is still difficult to timely understand the gas - invasion phenomenon during the deep - water drilling process. Summary of the Invention

[0003] The purpose of the present invention is to provide a deep - water drilling experiment system, an experimental method, and a deep - water drilling string to solve the technical problem of being difficult to timely understand the gas - invasion phenomenon during the deep - water drilling process.

[0004] The above object of the present invention can be achieved by the following technical solutions:

[0005] The present invention provides a deep - water drilling experiment system, including: an outer pipe, a drill pipe, a drill bit, and a capacitive array logging tool. The drill bit is installed at the lower end of the drill pipe, and the drill pipe is lowered into the outer pipe; the capacitive array logging tool includes an annular housing and a plurality of detection devices. The detection device includes a gas - holdup probe and a water - holdup probe circumferentially distributed around the drill pipe. The annular housing is installed outside the drill pipe, a first annular cavity is provided between the annular housing and the drill pipe, a second annular cavity is provided between the annular housing and the outer pipe, the detection devices are arranged in the first annular cavity, and a plurality of the detection devices are circumferentially distributed around the drill pipe.

[0006] In a preferred embodiment, the capacitive array logging tool includes a movable arm, the lower end of the movable arm is installed on the drill pipe, and the detection device is installed at the upper end of the movable arm.

[0007] In a preferred embodiment, the capacitive array logging tool includes an adjustment sleeve, the adjustment sleeve is installed on the drill pipe and can be adjusted up and down relative to the drill bit, and the lower end of the movable arm is installed on the adjustment sleeve.

[0008] In a preferred embodiment, the lower end of the movable arm is hinged to the adjustment sleeve, and the movable arm can swing up and down relative to the adjustment sleeve.

[0009] In a preferred embodiment, the movable arm includes a lower arm, a first upper arm, and a second upper arm. The lower end of the lower arm is mounted on the adjustment sleeve. Both the first upper arm and the second upper arm are mounted on the upper end of the lower arm. The gas holdup probe is mounted on the first upper arm, and the water holdup probe is mounted on the second upper arm.

[0010] In a preferred embodiment, the first upper arm is hinged to the lower arm, and / or the second upper arm is hinged to the lower arm.

[0011] In a preferred embodiment, the capacitance array logging tool includes 6 of the detection devices evenly distributed in the circumferential direction.

[0012] In a preferred embodiment, the annular housing includes a cylinder, a top plate, and a bottom plate. The top plate and the bottom plate are both mounted on the drill pipe. The cylinder is fixedly connected to the top plate and the bottom plate respectively. The top plate is provided with a first channel penetrating through the top and bottom, and the bottom plate is provided with a second channel penetrating through the top and bottom.

[0013] The present invention provides a deep-water drilling experiment method, using the above deep-water drilling experiment system. The experimental method includes: injecting drilling fluid into the drill pipe and spraying it out from the drill bit; the gas holdup probe tests the gas holdup, and the water holdup probe tests the liquid holdup.

[0014] The present invention provides a deep-water drilling string, including: a drill pipe, a drill bit, and a capacitance array logging tool. The drill bit is mounted on the lower end of the drill pipe; the capacitance array logging tool includes an annular housing and a plurality of detection devices. The detection devices include a gas holdup probe and a water holdup probe distributed circumferentially around the drill pipe. The annular housing is mounted outside the drill pipe, and a first annular cavity is provided between the annular housing and the drill pipe. The detection devices are arranged in the first annular cavity, and a plurality of the detection devices are distributed circumferentially around the drill pipe.

[0015] The features and advantages of the present invention are:

[0016] During the drilling process, the drilling fluid enters the drill pipe, is transmitted downward along the drill pipe, and sprays out through the nozzles of the drill bit. When the drilling fluid returns upward in the outer pipe, it will flow through the first annular cavity. The capacitance array logging tool detects the conductivity of the surrounding fluid through the detection devices distributed circumferentially around the drill pipe. It realizes the detection of gas invasion phenomenon during the deep-water drilling process, timely grasps the gas invasion phenomenon, and ensures the safety of deep-water drilling operations. With a dual-probe design, the water holdup probe is used to monitor the water holdup ratio during the deep-water drilling process, and the gas holdup probe is used to monitor the gas holdup ratio during the deep-water drilling process, improving the accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0018] Figure 1 It is the overall schematic diagram of the deep - water drilling experiment system provided by the present invention;

[0019] Figures 2 - 5 It is the structural schematic diagram of the capacitive array logging tool in the deep - water drilling experiment system provided by the present invention;

[0020] Figure 6 It is the structural schematic diagram of the bottom plate in the capacitive array logging tool;

[0021] Figure 7 It is the structural schematic diagram of the top plate in the capacitive array logging tool;

[0022] Figure 8 It is the cross - sectional structural schematic diagram of the inside of the adjusting sleeve and the bottom plate support rod in the capacitive array logging tool.

[0023] Explanation of the reference numerals in the drawings:

[0024] 11, sea level; 12, mud line;

[0025] 1, diverter;

[0026] 2, inner telescopic joint; 3, outer telescopic joint; 4, riser; 8, wellbore;

[0027] 5, drill pipe; 10, drill bit;

[0028] 6, subsea blowout preventer; 7, subsea wellhead;

[0029] 13, test lead; 14, data processing terminal; 15, signal receiver;

[0030] 9, capacitive array logging tool;

[0031] 103, detection device; 108, gas - holdup probe; 109, water - holdup probe;

[0032] 104, upper arm; 1041, first upper arm; 1042, second upper arm; 105, upper and lower arm connector; 106, lower arm;

[0033] 107, internal power supply;

[0034] 110, adjusting sleeve;

[0035] 111, spring hanging joint; 112, spring;

[0036] 102, cylinder; 113, bottom plate; 114, top plate; 115, bottom plate support rod; 116, top plate support rod;

[0037] 117, positioning card slot; 118, positioning snap; 119, screw;

[0038] 120, vertical positioning card slot; 121, vertical positioning snap. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] Solution 1

[0041] The present invention provides a deep - water drilling experiment system. As Figures 1 - 5 shown, the experiment system includes: an outer pipe, a drill pipe 5, a drill bit 10, and a capacitive array logging tool 9. The drill bit 10 is installed at the lower end of the drill pipe 5, and the drill pipe 5 is lowered into the outer pipe. The capacitive array logging tool 9 includes an annular housing and a plurality of detection devices 103. The detection device 103 includes a gas - hold - up probe 108 and a water - hold - up probe 109 that are circumferentially distributed around the drill pipe 5. The annular housing is installed outside the drill pipe 5. A first annular cavity is provided between the annular housing and the drill pipe 5, and a second annular cavity is provided between the annular housing and the outer pipe. The detection devices 103 are arranged in the first annular cavity and are circumferentially distributed around the drill pipe 5.

[0042] During the drilling process, the drilling fluid enters the drill pipe 5, is transmitted downward along the drill pipe 5, and is ejected through the nozzles of the drill bit 10. When the drilling fluid returns upward in the outer pipe, it will flow through the first annular cavity. The capacitive array logging tool 9 detects the conductivity of the surrounding fluid through the detection devices 103 that are circumferentially distributed around the drill pipe 5. It realizes the detection of gas invasion phenomena during the deep - water drilling process, timely grasps the gas invasion phenomena, and ensures the safety of deep - water drilling operations. Adopting a dual - probe design, the water - hold - up probe 109 is used to monitor the water - hold ratio during the deep - water drilling process, and the gas - hold - up probe 108 is used to monitor the gas - hold ratio during the deep - water drilling process, improving the accuracy.

[0043] The outer pipe includes a riser string group, a subsea blowout preventer 6, and a wellbore 8. As Figure 1As shown in the figure, the riser string assembly includes a diverter 1, a telescopic joint, and a riser 4 arranged in sequence. The diverter 1 is communicated with the mud pit, and the telescopic joint is connected to the riser 4; the lower part of the riser 4 is connected to the subsea blowout preventer 6, and the subsea blowout preventer 6 is installed at the subsea wellhead 7 on the wellbore 8, and the subsea blowout preventer 6 is located above the subsea wellhead 7. The telescopic joint includes a telescopic joint inner cylinder 2 and a telescopic joint outer cylinder 3, and the inner cylinder and the outer cylinder can be nested. The drill pipe 5 passes through the riser 4, the subsea blowout preventer 6, and the subsea wellhead 7 and enters the wellbore 8, and the drill bit 10 is at the bottom of the drill pipe 5. Preferably, the inner diameters of the diverter 1, the telescopic joint inner cylinder 2, the telescopic joint outer cylinder 3, and the riser 4 are relatively close. The inner diameter of the 21in riser 4 used in deepwater drilling is about 20in. The outer diameter of the annulus formed by the riser 4 and the drill pipe 5 is about 508mm, and the inner diameter is about 127mm. The outer diameter of the annulus formed by the wellbore 8 and the drill pipe 5 is about 444.5mm, and the inner diameter is about 127mm.

[0044] The detection device 103 can adopt a miniature capacitance sensor. The capacitance array logging tool 9 further includes a test lead 13 installed on the housing of the capacitance array logging tool. The test lead 13 is attached to the drill string and connected to the capacitance array logging tool 9. The capacitance array logging tool 9 at the bottom is connected to the signal receiver 15 through the test lead 13. The signal emitted by the miniature capacitance sensor extends along the drill pipe 5 in the direction of the subsea wellhead 7 through the test lead 13, and the signal is transmitted to the signal receiver 15 installed at the bottom of the telescopic joint outer cylinder 3, and finally the signal is analyzed and processed by the data processing terminal 14 on the ground.

[0045] The analysis unit on the data processing terminal 14 analyzes and processes the relevant data generated by the gas holdup probe 108 and the water holdup probe 109 on the capacitance array logging tool to obtain the monitoring results. The analysis unit is used to according to the liquid holdup data information recorded in the reference capacitance array logging tool 9. The data acquisition unit is used to measure the liquid holdup parameters of the gas-invaded drill string.

[0046] The test lead 13 extends along the drill string in the direction of the subsea wellhead 7, and the information obtained by the capacitance array logging tool downhole is finally transmitted through the test lead 13 to the data processing terminal 14 for acquisition, analysis and processing.

[0047] During the upward return of the drilling fluid between the wellbore 8 and the drill pipe 5 below the mud line 12, it passes through the first annulus. The capacitance array logging tool 9 includes a movable arm, the lower end of the movable arm is installed on the drill pipe 5, and the detection device 103 is installed at the upper end of the movable arm.

[0048] In one embodiment, the capacitance array logging tool 9 includes an adjustment sleeve 110. The adjustment sleeve 110 is mounted on the drill pipe 5 and can be adjusted vertically relative to the drill bit 10. The lower end of the movable arm is mounted on the adjustment sleeve 110. Further, the lower end of the movable arm is hinged to the adjustment sleeve 110, and the movable arm can swing vertically relative to the adjustment sleeve 110. By means of the adjustment sleeve 110, the vertical position of the movable arm and the detection device 103 can be adjusted. When the movable arm swings vertically relative to the adjustment sleeve 110, the radial position and the vertical position of the detection device 103 can also be adjusted.

[0049] The capacitance array logging tool is installed on the outer surface of the drill pipe 5 and is connected to the test lead 13. The test lead 13 is waterproofed. The internal power supply 107 is installed at the bottom of the capacitance array logging tool to maintain the normal operation of the capacitance array logging tool. The normal operation and data transmission of the tool are maintained through the internal power supply 107 and the test lead 13. The adjustment sleeve 110 is provided with a positioning system, which can ensure that the 6 movable arms are evenly distributed and do not interfere with each other. In one embodiment, the positioning system is of a snap-fastener design. As Figure 8 shown, the positioning system includes a positioning slot 117 provided at the bottom position of the connecting instrument and a positioning buckle 118 adapted to the positioning slot 117 along the outer side of the adjustment sleeve 110. By aligning the positioning slot 117 with the positioning buckle 118 at a designed angle, the movable arms on the capacitance array logging tool can be evenly distributed. The positioning slot 117 and the positioning buckle 118 are fixed by screws 119 to ensure that the movable arms are evenly distributed and do not interfere with each other.

[0050] The inventor has improved the structure of the movable arm: As Figure 4 and Figure 5 shown, the movable arm includes a lower arm 106 and an upper arm 104. The upper arm 104 includes a first upper arm 1041 and a second upper arm 1042. The lower end of the lower arm 106 is mounted on the adjustment sleeve 110. Both the first upper arm 1041 and the second upper arm 1042 are mounted on the upper end of the lower arm 106. The gas holdup probe 108 is mounted on the first upper arm, and the water holdup probe 109 is mounted on the second upper arm.

[0051] The lower arm 106 is sleeved on the outer ring of the adjustment sleeve 110 and fixed to the drill pipe 5. Considering the characteristic that the volume of gas continuously expands as it rises along the annulus, the gas holdup measured at different depth cross-sections and at different test points with different radii at the same cross-section is different. In this embodiment, the movable arm can change the longitudinal position and the lateral position of the detection device 103 to obtain the gas invasion information at different positions.

[0052] Further, the first upper arm is hinged to the lower arm 106, and / or the second upper arm is hinged to the lower arm 106, and the position of the probe can be changed by correcting the angle between the upper and lower arms 106. An upper and lower arm connector 105 can be provided at the upper end of the lower arm 106, and the first upper arm 1041 and the second upper arm 1042 are both installed on the upper and lower arm connector 105.

[0053] In one embodiment, the lower arm 106 is connected to the positioning buckle 118, the positioning buckle 118 and the positioning slot 117 are fixedly connected by a screw 119, the upper end of the spring 112 is connected to the spring hanging joint 111, the lower end of the spring 112 is fixed to the base plate 113, and the adjustment sleeve 110 and the spring hanging joint 111 are fixed.

[0054] Furthermore, the capacitance array logging instrument 9 includes 6 detection devices 103 evenly distributed along the circumferential direction. The drilling fluid flows into the drill string and is ejected through the water hole of the drill bit 10. The ejected drilling fluid carries the gas invasion fluid upward and passes through the first annular cavity, and each phase holdup is measured at the same depth through each detection device 103.

[0055] In one embodiment, the annular housing includes a cylinder 102, a top plate 114 and a bottom plate 113, both of which are mounted on the drill pipe 5, the cylinder 102 is fixedly connected to the top plate 114 and the bottom plate 113, the top plate 114 is provided with a first channel extending vertically, and the bottom plate 113 is provided with a second channel extending vertically. Figure 6 and Figure 7 As shown, the top plate 114 and the bottom plate 113 are fixed to the cylinder 102 by the top plate support rod 116 and the bottom plate support rod 115, respectively. The distance between the top plate 114 and the bottom plate 113 is fixed, and a plurality of vertical positioning slots 120 arranged in parallel are arranged inside the instrument, and the vertical positioning slots 120 are fixed between the inner side of the adjustment sleeve 110 and the drill rod 5, and the position of the spring hanging joint 111 can be changed with the position of the spring 112, and the vertical positioning buckle 121 is installed inside the adjustment sleeve 110, and the adjustment sleeve 110 is adjusted up and down with the spring 112, and any vertical positioning slot 120 is selected to buckle with the vertical positioning buckle 121, and the selected vertical positioning slot 120 changes the position of the probe along the drill rod 5.

[0056] The deepwater drilling experimental system can be applied on site, using a deepwater drilling platform and processed according to relevant process methods of production operations.

[0057] Solution 2

[0058] The present invention provides a deepwater drilling experimental method, using the above-mentioned deepwater drilling experimental system, the experimental method includes: injecting drilling fluid into the drill pipe 5 and spraying it out from the drill bit 10; the gas holdup rate probe 108 tests the gas holdup rate, and the water holdup rate probe 109 tests the liquid holdup rate.

[0059] The specific steps of this deep - water drilling experiment method include:

[0060] (1) Set the drilling test string, diverter 1, expansion joint, subsea blowout preventer 6, subsea wellhead 7, and capacitive array logging tool as a test assembly. Install the riser 4 above the subsea blowout preventer 6, and install the wellbore 8 structure below the subsea wellhead 7 to maintain the sealing of the entire test environment and realize the test system for deep - water drilling gas invasion detection;

[0061] (2) Install the above - mentioned capacitive array logging tool on the outer surface of the deep - water drilling string, connect a test lead 13 starting from the capacitive array logging tool, connect it above the water surface, and do a good job in waterproof treatment;

[0062] (3) Fix the top plate 114 and bottom plate 113 on the capacitive array logging tool to the drill string. Select the required vertical positioning slot 120, buckle the vertical positioning buckle 121 inside the adjustment sleeve 110 on the vertical positioning slot 120, and fix the positioning slot 117 and positioning buckle 118 on the adjustment sleeve 110 together with screws 119;

[0063] (4) The drilling fluid flows through the annular space formed between the capacitive array logging tool and the drill string. The micro - sensors inside the capacitive array logging tool detect the conductivity of different fluids in the drilling fluid, and transmit this signal through the test lead 13 to the signal receiver 15 above the water surface;

[0064] (5) During the experiment, inject the drilling fluid into the drill pipe 5. The drilling fluid sprays out from the nozzles of the drill bit 10, and in the state of deep - water drilling encountering gas invasion through the bubbles generated at the bottom, adjust the positions of the gas - holdup probe 108 and water - holdup probe 109 inside the capacitive array logging tool to monitor the gas - holdup and liquid - holdup of the fluid at different test points;

[0065] (6) A data processing terminal 14 is connected to the outside of the device test assembly. Through the above - mentioned operation steps, the drilling fluid circulates in the system, and the change of data information inside the capacitive array logging tool is collected. Take the oil - holdup data of the drilling fluid in the terminal system as a reference for the experimental data, and further obtain the capacitive array for deep - water drilling gas invasion monitoring.

[0066] Solution Three

[0067] The present invention provides a deep-water drilling string, comprising: a drill pipe 5, a drill bit 10, and a capacitance array logging tool 9. The drill bit 10 is installed at the lower end of the drill pipe 5. The capacitance array logging tool 9 includes an annular housing and a plurality of detection devices 103. The detection device 103 includes a gas holdup probe 108 and a water holdup probe 109 that are circumferentially distributed around the drill pipe 5. The annular housing is installed outside the drill pipe 5. A first annular cavity is provided between the annular housing and the drill pipe 5. The detection devices 103 are arranged in the first annular cavity and are circumferentially distributed around the drill pipe 5.

[0068] The above are only several embodiments of the present invention. Those skilled in the art can make various changes or modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention based on the content disclosed in the application documents.

Claims

1. A deep - water drilling experimental system, characterized in that, Comprising: An outer pipe, a drill pipe, a drill bit, and a capacitance array logging tool. The drill bit is installed at the lower end of the drill pipe, and the drill pipe is lowered into the outer pipe. The capacitance array logging tool includes an annular housing and a plurality of detection devices. The detection devices include a gas holdup probe and a water holdup probe circumferentially distributed around the drill pipe. The annular housing is installed outside the drill pipe, and a first annular cavity is provided between the annular housing and the drill pipe. A second annular cavity is provided between the annular housing and the outer pipe. The detection devices are arranged in the first annular cavity, and a plurality of the detection devices are circumferentially distributed around the drill pipe. The capacitance array logging tool includes a movable arm. The lower end of the movable arm is installed on the drill pipe, and the detection device is installed at the upper end of the movable arm. The capacitance array logging tool includes an adjustment sleeve. The adjustment sleeve is installed on the drill pipe and can be adjusted up and down relative to the drill bit. The lower end of the movable arm is installed on the adjustment sleeve. The lower end of the movable arm is hinged to the adjustment sleeve, and the movable arm can swing up and down relative to the adjustment sleeve. The movable arm includes an upper arm and a lower arm. The lower end of the lower arm is hinged to the adjustment sleeve, and the upper arm is hinged to the upper end of the lower arm. The gas holdup probe and the water holdup probe are both installed on the upper arm. The annular housing includes a cylinder, a top plate, and a bottom plate. The top plate and the bottom plate are both installed on the drill pipe, the cylinder is fixedly connected to the top plate and the bottom plate respectively. The top plate is provided with a first through hole penetrating up and down, and the bottom plate is provided with a second through hole penetrating up and down. The deep water drilling experiment system further includes a positioning system provided at the adjustment sleeve. The positioning system includes a positioning slot and a positioning buckle in snap fit. A plurality of the positioning slots are circumferentially spaced on the outer periphery of the adjustment sleeve, and the lower arm is hinged to the positioning buckle. The positioning system further includes a positioning sleeve sleeved on the outer periphery of the drill pipe. A plurality of vertical positioning slots are provided on the outer periphery of the positioning sleeve, and vertical positioning buckles capable of being buckled with the vertical positioning slots are provided on the inner periphery of the adjustment sleeve. A spring is provided between the adjustment sleeve and the bottom plate.

2. The deep-water drilling experiment system according to claim 1, characterized in that, The upper arm includes a first upper arm and a second upper arm. The first upper arm and the second upper arm are both installed at the upper end of the lower arm. The gas holdup probe is installed on the first upper arm, and the water holdup probe is installed on the second upper arm.

3. The deepwater drilling experiment system according to claim 2, characterized in that, The first upper arm is hinged to the lower arm, and / or the second upper arm is hinged to the lower arm.

4. The deepwater drilling experiment system according to claim 1, characterized in that The capacitance array logging tool includes 6 of the detection devices evenly distributed in the circumferential direction.

5. A deep-water drilling experiment method, characterized in that Using the deep water drilling experiment system according to any one of claims 1-4, the experimental method includes: injecting drilling fluid into the drill pipe and spraying it out from the drill bit; the gas holdup probe tests the gas holdup, and the water holdup probe tests the liquid holdup.

6. A deepwater drilling string, characterized in that, Comprising: A drill pipe, a drill bit and a capacitance array logging tool. The drill bit is installed at the lower end of the drill pipe. The capacitance array logging tool includes an annular housing and a plurality of detection devices. The detection devices include a gas holdup probe and a water holdup probe circumferentially distributed around the drill pipe. The annular housing is installed outside the drill pipe. A first annular cavity is provided between the annular housing and the drill pipe. The detection devices are arranged in the first annular cavity, and a plurality of the detection devices are circumferentially distributed around the drill pipe. The capacitance array logging tool includes a movable arm. The lower end of the movable arm is installed on the drill pipe, and the detection device is installed at the upper end of the movable arm. The capacitance array logging tool includes an adjustment sleeve. The adjustment sleeve is installed on the drill pipe and can be adjusted up and down relative to the drill bit. The lower end of the movable arm is installed on the adjustment sleeve. The lower end of the movable arm is hinged to the adjustment sleeve, and the movable arm can swing up and down relative to the adjustment sleeve. The movable arm includes an upper arm and a lower arm. The lower end of the lower arm is hinged to the adjustment sleeve, the upper arm is hinged to the upper end of the lower arm, and both the gas holdup probe and the water holdup probe are installed on the upper arm. The annular housing includes a cylinder, a top plate and a bottom plate. The top plate and the bottom plate are both installed on the drill pipe, the cylinder is fixedly connected to the top plate and the bottom plate respectively. The top plate is provided with a first through hole penetrating up and down, and the bottom plate is provided with a second through hole penetrating up and down. The deepwater drilling string further includes a positioning system provided at the adjustment sleeve. The positioning system includes a positioning card slot and a positioning buckle that are snap-fitted. A plurality of the positioning card slots are circumferentially spaced and opened on the outer periphery of the adjustment sleeve, and the lower arm is hinged to the positioning buckle. The positioning system further includes a positioning sleeve sleeved on the outer periphery of the drill pipe. A plurality of vertical positioning card slots are provided on the outer periphery of the positioning sleeve, and a vertical positioning buckle that can be engaged with the vertical positioning card slots is provided on the inner periphery of the adjustment sleeve. A spring is provided between the adjustment sleeve and the bottom plate.

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