Multifunctional Simulation Test Device and Method for Offshore Horizontal Well Drilling System

Abstract

The present invention relates to a simulation test device and method for a multi-functional offshore horizontal well drilling system. The simulation test device for the multi-functional offshore horizontal well drilling system includes: a water tank; a test bench, on which a driving mechanism is provided; an offshore platform model, the driving mechanism is connected to the offshore platform model and can drive the offshore platform model to move; a riser model, at the top of the riser model, there is a riser water outlet; a casing model; a drill string model, which is arranged inside the riser model and the casing model; the top of the vertical section of the drill string is connected to the bottom of the offshore platform model, and at the top of the vertical section of the drill string, there is a drill string water inlet; a hydraulic system, which can be connected to the drill string water inlet and the riser water outlet through corresponding pipelines, and can adjust the pressure, flow rate and / or temperature of the liquid inside the drill string model. The present invention can more realistically simulate the vibration response and frictional resistance response tests of the offshore horizontal well drilling system under various working conditions.

Description

Technical Field

[0001] The present invention relates to the field of simulation of multi-functional offshore drilling systems, and particularly to a simulation test device and method for a multi-functional offshore horizontal well drilling system. Background Art

[0002] With the continuous growth of the demand for oil and gas resources and the rapid development of drilling technologies, the number and scale of offshore horizontal wells and extended reach wells are also increasing continuously. Horizontal wells can more effectively extract oil and gas in geological reservoirs, and can improve productivity and extend the reserve life. Horizontal wells are often used to recover thin oil and gas layers or fractured oil and gas reservoirs. Due to the characteristics of the horizontal section, horizontal wells can be used to penetrate oil layers with a relatively long horizontal distance, increasing the contact area between the well and the oil layer, improving the oil production efficiency, and reducing the production time.

[0003] Components such as risers, drill strings, and casings in an offshore oil production drilling system undergo vibration responses in the marine environment. The factors causing vibration responses are as follows: the action of the motion of the offshore platform on the riser and the drill string; the vortex-induced vibration of the riser caused by external ocean currents; the acting forces of internal fluids on the drill string, riser, and casing; the vibration of the drill string caused by the rotation of the rotary part. These vibrations will all cause fatigue failure of the drilling system. In addition, the above several situations often exist simultaneously, posing a greater threat to the drilling system. The current offshore drilling test devices are limited to test devices for individual components, such as drill strings.

[0004] In addition, compared with traditional vertical wells, horizontal wells have their special curved sections and horizontal sections. At large bending angles, due to the relatively large stiffness of the drill string, the drill strings in the curved section and the horizontal section generally adhere to the casing wall, resulting in wear between the drill string and the casing. In addition, due to the presence of rock particles generated during drilling in the drilling fluid, these particles also cause wear to the drill string and the casing, bringing huge losses to the oil field.

[0005] However, there is currently no test system to truly simulate the influence of different platform motion directions, motion speeds, and motion periods on the offshore drilling system, the influence of different internal flow velocities, internal flow temperatures, and internal pressures of the internal flow on the riser, drill string, and casing, the influence of solid-liquid two-phase flow and different solid contents on the riser, drill string, and casing, and the wear mechanism of various factors on the drill string and the casing. Summary of the Invention

[0006] The purpose of the present invention is to provide a simulation test device and method for a multi-functional offshore horizontal well drilling system, which can more truly simulate the vibration response and friction resistance response tests of the offshore horizontal well drilling system under various working conditions.

[0007] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0008] The present invention provides a simulation test device for a multi-functional offshore horizontal well drilling system, comprising:

[0009] A vertically arranged water tank, with an intermediate plate provided inside its bottom, dividing the interior of the water tank into a water-containing cavity located in the upper part and a hollow cavity located in the lower part; a flow-making pump is provided in the water-containing cavity;

[0010] A test bench, arranged on the top of the water tank, and a driving mechanism is provided on the test bench;

[0011] An offshore platform model, the driving mechanism is connected to the top of the offshore platform model and can drive the offshore platform model to move in the vertical direction and the first horizontal direction and the second horizontal direction perpendicular to each other;

[0012] A riser model, its top is connected to the bottom of the offshore platform model, and a riser water outlet is provided at the top of the riser model;

[0013] A casing model, which includes a sequentially connected casing vertical section, a casing bending section, a casing horizontal section and a casing end cap, and the top of the casing vertical section is detachably connected to the bottom of the riser model;

[0014] A drill string model, which is arranged inside the riser model and the casing model; the drill string model includes a sequentially connected drill string vertical section, a drill string bending section and a drill string horizontal section, the top of the drill string vertical section is connected to the bottom of the offshore platform model, and a drill string water inlet is provided at the top of the drill string vertical section;

[0015] A hydraulic system, which can be connected to the drill string water inlet and the riser water outlet through corresponding pipelines, and can adjust the pressure, flow rate and / or temperature of the liquid inside the drill string model.

[0016] In a preferred embodiment of the present invention, a drill string end cap is further connected to the end of the drill string horizontal section, a plurality of liquid passing holes are provided on the side wall of the drill string end cap, a transmission member is rotatably connected to the drill string end cap, and a driving member is further provided in the hollow cavity, the driving member can pass through the casing end cap and be connected to the transmission member to drive the transmission member to rotate.

[0017] In a preferred embodiment of the present invention, mounting holes are formed in the casing end cover. The first end of the transmission member is connected to the drill string end cover through a bearing, and the second end of the transmission member is inserted into the mounting holes. A convex ring is protruded on the outer wall of the first end of the transmission member. A push ring, a first ring body, and a second ring body are sequentially sleeved on the transmission member from its first end to the second end. An annular first flange is protruded on the outer wall of the end of the second ring body close to the first ring body. The first flange can enclose a first sealing ring groove between the bottom inner wall of the horizontal section of the casing and the inner wall of the casing end cover, and a first sealing ring is embedded in the first sealing ring groove. An annular second flange is protruded on the inner wall of the end of the first ring body close to the second ring body. One end of the push ring is movably inserted into the first ring body and can enclose a second sealing ring groove with the second flange, and a second sealing ring is embedded in the second sealing ring groove. A plurality of push rods are axially spaced at the other end of the push ring. The plurality of push rods are movably inserted into a plurality of through holes on the convex ring, and a spring is sleeved on each push rod. The two ends of the spring can respectively abut between the convex ring and the push ring.

[0018] In a preferred embodiment of the present invention, a rock particle inlet is provided on the bottom side wall of the horizontal section of the casing. The hydraulic system is also connected to the rock particle inlet through a corresponding pipeline to inject a fluid with rock particles into the annulus between the casing model and the drill string model.

[0019] In a preferred embodiment of the present invention, the number of the flow generating pumps is two, and the flow generating ports of the two flow generating pumps are arranged back to back.

[0020] In a preferred embodiment of the present invention, a camera is further provided outside the water tank for taking pictures of the riser model and the drill string model to record the displacements of the riser model and the drill string model.

[0021] In a preferred embodiment of the present invention, the water tank is of a transparent structure, the riser model is a transparent pipe, and a marking member is provided on the outer wall of the riser model. The drill string model is a color pipe, and the colors of the marking member and the color pipe are different.

[0022] In a preferred embodiment of the present invention, the driving mechanism includes a horizontal hydraulic cylinder, a vertical hydraulic cylinder, and a vertical hydraulic cylinder. One end of the horizontal hydraulic cylinder is connected to the vertical hydraulic cylinder and can drive the vertical hydraulic cylinder to horizontally move along a first horizontal direction, and the first horizontal direction is parallel to the axis direction of the horizontal section of the drill string. One end of the vertical hydraulic cylinder is connected to the vertical hydraulic cylinder and can drive the vertical hydraulic cylinder to horizontally move along a second horizontal direction. The vertical hydraulic cylinder is connected to the top of the offshore platform model and can drive the offshore platform model to move up and down in the vertical direction.

[0023] In a preferred embodiment of the present invention, a bushing is sleeved at the butt joint position of the bottom of the riser model and the top of the vertical section of the casing. The bushing is connected to the riser model and the vertical section of the casing through corresponding fasteners. A sealing ring is installed between the bushing and the installation hole formed on the intermediate plate, and a waterproof sealant is provided at the connection between the bushing and the intermediate plate.

[0024] In a preferred embodiment of the present invention, a bender is further sleeved outside the riser. The bender includes an installation ring and a plurality of spiral rings. The installation ring is connected to the bottom of the offshore platform model, and the top end of each spiral ring is connected to the bottom of the installation ring; the plurality of spiral rings are arranged side by side along a generatrix and spirally wound around the vertical axis of the installation ring. Adjacent spiral rings are closely arranged, and the bottom end of the spiral ring is connected to the adjacent spiral ring through a clamp.

[0025] In a preferred embodiment of the present invention, the helix radius and the number of turns of each point on the helix center line corresponding to each spiral ring satisfy the following formula:

[0026]

[0027] Wherein, y represents the helix radius of each point on the helix center line corresponding to the spiral ring, x represents the number of turns corresponding to each point on the helix center line corresponding to the spiral ring, and a, b, c, and d are all coefficients.

[0028] In a preferred embodiment of the present invention, a plurality of anti-friction structures are axially spaced and sleeved outside the horizontal section of the drill string. The anti-friction structure includes two fixed rings sleeved on the horizontal section of the drill string and arranged at intervals, and a spiral rib spirally wound around the axis of the horizontal section of the drill string. Both ends of the spiral rib are respectively connected to the two fixed rings. A plurality of rolling balls capable of rolling are sleeved on the spiral rib, and at least part of the rolling balls can rollingly contact the inner wall of the horizontal section of the casing.

[0029] In a preferred embodiment of the present invention, the hydraulic system includes a water injection hydraulic source, a pressurization hydraulic source, a first control valve, a second control valve, and a third control valve. The water injection hydraulic source is connected to the drill string water inlet through a first pipeline in a switchable manner. The pressurization hydraulic source is connected to the first control valve through a second pipeline in a switchable manner. The first control valve is further connected to the drill string water inlet and the second control valve through a third pipeline and a fourth pipeline respectively. The second control valve is further connected to the drill string water inlet through a fifth pipeline and a sixth pipeline respectively, and a pressure gauge is provided on the third pipeline, a first adjustable flow valve and a first flowmeter are provided on the fourth pipeline, a heater and a thermometer are provided on the sixth pipeline. The first control valve can control the communication between the second pipeline and the third pipeline or the fourth pipeline. The second control valve can control the communication between the fourth pipeline and the fifth pipeline or the sixth pipeline. The third control valve is connected to the riser outlet through a seventh pipeline, and the third control valve is also connected to an eighth pipeline and a ninth pipeline in a switchable manner. A filter and a cooler are sequentially provided on the seventh pipeline along the fluid flow direction, and a second adjustable flow valve is provided on the ninth pipeline. The third control valve can control the communication between the seventh pipeline and the eighth pipeline or the ninth pipeline.

[0030] In a preferred embodiment of the present invention, a rock particle inlet is provided on the bottom side wall of the horizontal section of the casing. The hydraulic system further includes a rock particle hydraulic source, and the rock particle hydraulic source is connected to the rock particle inlet through a tenth pipeline in a switchable manner, and a second flowmeter and a third adjustable flow valve are provided on the tenth pipeline.

[0031] In a preferred embodiment of the present invention, a first check valve, a second check valve, a third check valve, a fourth check valve, a fifth check valve, a sixth check valve, and a seventh check valve are respectively provided on the first pipeline, the third pipeline, the fourth pipeline, the sixth pipeline, the eighth pipeline, the ninth pipeline, and the tenth pipeline.

[0032] In a preferred embodiment of the present invention, the first control valve, the second control valve, and the third control valve are all three-position four-way valves, and a first switch valve, a second switch valve, a third switch valve, a fourth switch valve, and a fifth switch valve are respectively provided on the first pipeline, the second pipeline, the eighth pipeline, the ninth pipeline, and the tenth pipeline. The first switch valve, the second switch valve, the third switch valve, the fourth switch valve, and the fifth switch valve are all two-position two-way valves.

[0033] In a preferred embodiment of the present invention, a first pilot-operated relief valve is also bypass-connected at a position on the second pipeline close to the water injection hydraulic source, and a second pilot-operated relief valve is also bypass-connected at a position on the tenth pipeline close to the rock particle hydraulic source.

[0034] In a preferred embodiment of the present invention, the multifunctional offshore horizontal well drilling system simulation test device further includes a control device, and the control device is electrically connected to the flow pump, the driving mechanism, and the hydraulic system.

[0035] The present invention also provides a simulation test method for a multi-functional offshore horizontal well drilling system. The test is carried out by using the above-mentioned simulation test device for the multi-functional offshore horizontal well drilling system. The simulation test method for the multi-functional offshore horizontal well drilling system includes:

[0036] S1. Assemble the simulation test device for the multi-functional offshore horizontal well drilling system;

[0037] S2. Inject fluid into the inlet of the drill string to start the test. Adjust the test influencing factors. During the test, record the vibration displacements of the riser model and the drill string model.

[0038] Among them, adjusting the test influencing factors includes: using the driving mechanism to adjust the amplitude and period of the movement of the offshore platform model in the vertical direction, the first horizontal direction, and / or the second horizontal direction, and using the hydraulic system to adjust the pressure, flow rate, and / or temperature of the liquid in the drill string model;

[0039] S3. After the test, take out the drill string model after the test, and compare the drill string model after the test with the drill string model before the test to obtain the wear amount and wear position of the drill string model after the test;

[0040] S4. Repeat steps S1 - S3 with different test influencing factors to conduct multiple groups of tests.

[0041] In a preferred embodiment of the present invention, in step S2, adjusting the test influencing factors further includes using the hydraulic system to inject fluid with rock particles into the rock particle inlet on the horizontal section of the casing and adjusting the rock particle content, flow rate, temperature, and / or pressure of the fluid with rock particles, and using the driving member to drive the transmission member on the drill string end cover rotatably connected to the end of the horizontal section of the drill string and adjusting the rotation speed of the driving member.

[0042] In a preferred embodiment of the present invention, during the process of assembling the simulation test device for the multi-functional offshore horizontal well drilling system in step S1, a plurality of anti-friction structures are sleeved between the drill string model and the casing model. The anti-friction structures include a plurality of ball bearings and can rollingly contact the casing model.

[0043] In a preferred embodiment of the present invention, the simulation test method for the multi-functional offshore horizontal well drilling system further includes:

[0044] S5. Determine the influencing factors of drill string wear according to multiple groups of tests;

[0045] S6. Fit the influencing factors of drill string wear with the wear amount of the drill string model to obtain a prediction model between the maximum wear depth of the drill string and the influencing factors of drill string wear.

[0046] In a preferred embodiment of the present invention, the prediction model is: h = Ap +A v +A d +A c +A t ;

[0047] where A p = a1p 3 + b1p 2 + c1p + d1, A v = a2v 3 + b2v 2 + c2v + d2, A d = a3d 3 + b3d 2 + c3d + d3, A c = a4C 3 + b4C 2 + c4C + d4, A t = a5t 3 + b5t 2 + c5t + d5;

[0048] h represents the maximum wear depth of the worn drill string under the action of various factors, p represents the internal fluid pressure of the worn drill string, v represents the fluid flow velocity in the worn drill string, d represents the diameter of rock particles in the worn drill string, C represents the content of rock particles in the fluid in the worn drill string, A p represents the maximum wear amount of the worn drill string under the action of the internal fluid pressure, A v represents the maximum wear amount of the worn drill string under the action of the fluid flow velocity, A d represents the maximum wear amount of the worn drill string under the action of the rock particle diameter, A c represents the maximum wear amount of the worn drill string under the action of the content of rock particles in the fluid, A t represents the maximum wear amount of the worn drill string under the action of the fluid impact time, and a1, b1, c1, d1, a2, b2, c2, d2, a3, b3, c3, d3, a4, b4, c4 and d4 are all coefficients.

[0049] As described above, the simulation test device and method of the present invention utilize the driving mechanism on the test bench to drive the offshore platform model to perform transverse movement, longitudinal movement, and vertical movement in the first horizontal direction, the second horizontal direction, and the vertical direction respectively, and can adjust the amplitudes and periods of the transverse movement, longitudinal movement, and heaving of the offshore platform model, so as to simulate the vibration response of the offshore drilling system under the movement of the offshore platform. By setting a flow pump in the water-containing cavity, ocean currents and oscillating currents can be simulated, which is conducive to simulating the behavior of vortex-induced vibration of the riser caused by external ocean currents in the ocean environment. The hydraulic system can be used to inject fluid into the drill string model, and the pressure, flow rate, and / or temperature of the injected fluid can also be adjusted, so as to more realistically simulate the influence of different offshore platform movement directions, movement speeds, and movement periods on the offshore drilling system, the influence of different external ocean currents on the vortex-induced vibration of the riser, and the influence of different internal flow velocities, internal flow temperatures, and internal pressures of the internal flow on the riser, drill string, and casing; after injecting fluid into the drill string model according to the design of this device, the friction test of wear between the drill string and the casing can also be studied, so as to facilitate the simulation of the vibration response and friction response tests of the offshore horizontal well drilling system under various working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The following drawings are only intended to illustrate and explain the present invention schematically, and do not limit the scope of the present invention.

[0051] Among them:

[0052] Figure 1 is a perspective view of the multifunctional offshore horizontal well drilling system simulation test device provided by the present invention.

[0053] Figure 2 is a front view of the multifunctional offshore horizontal well drilling system simulation test device provided by the present invention.

[0054] Figure 3 is Figure 2 a sectional view along the A-A direction.

[0055] Figure 4 is Figure 2 a top view of

[0056] Figure 5 is Figure 4 a sectional view along the B-B direction.

[0057] Figure 6 is Figure 5 a partial enlarged view at the test bench in

[0058] Figure 7 is Figure 5 a partial enlarged view at the bushing in

[0059] Figure 8 is Figure 5Partial enlarged view at the driving member.

[0060] Figure 9 Isometric view of the multifunctional offshore horizontal well drilling system simulation test device provided by the present invention after removing the water tank.

[0061] Figure 10 Isometric view of the test bench provided by the present invention.

[0062] Figure 11 Isometric view of the anti-bending device provided by the present invention.

[0063] Figure 12 Isometric view of the anti-friction structure provided by the present invention.

[0064] Figure 13 Working principle diagram of the hydraulic control provided by the present invention.

[0065] Explanation of the reference numerals in the attached drawings:

[0066] 1. Water tank; 10. Intermediate plate; 11. Test bench; 111. Longitudinal hydraulic cylinder fixing plate; 1111. Longitudinal hydraulic cylinder fixing groove; 112. Transverse hydraulic cylinder fixing plate; 1121. Transverse hydraulic cylinder fixing groove;

[0067] 2. Driving mechanism; 21. Transverse hydraulic cylinder; 22. Longitudinal hydraulic cylinder; 23. Vertical hydraulic cylinder; 231. Vertical hydraulic cylinder fixing part; 24. Roller; 25. Connecting chuck; 251. Bolt;

[0068] 3. Offshore platform model; 31. Upper platform; 32. Lower platform; 33. Connecting column;

[0069] 4. Riser model; 41. Riser water outlet; 42. Bushing; 421. Bolt; 422. Sealing ring; 423. Waterproof sealant;

[0070] 5. Casing model; 51. Casing vertical section; 52. Casing bending section; 53. Casing horizontal section; 531. Rock particle inlet; 54. Casing end cap; 541. Screw; 55. Casing fixing seat;

[0071] 6. Drill string model; 61. Drill string vertical section; 611. Drill string water inlet; 62. Drill string bending section; 63. Drill string horizontal section; 64. Drill string end cap; 641. Liquid passing hole; 642. Screw; 65. Transmission part; 651. Convex ring; 652. Pushing ring; 6521. Push rod; 653. First ring body; 654. Second ring body; 655. First sealing ring; 656. Second sealing ring; 657. Spring; 66. Bearing; 67. Driving member; 671. Support frame; 672. Bolt;

[0072] 7. Bender; 71. Installation ring; 72. Spiral ring; 721. First spiral ring; 722. Second spiral ring; 723. Third spiral ring; 73. Clamp

[0073] 8. Anti-friction structure; 81. Fixed ring; 82. Spiral rib; 83. Ball

[0074] 9. Hydraulic system

[0075] 91. Water injection hydraulic source; 911. First pipeline; 9111. First switch valve; 9112. First check valve

[0076] 92. Pressurizing hydraulic source; 921. Second pipeline; 9211. Second switch valve; 9212. First pilot-operated relief valve

[0077] 93. First control valve; 931. Third pipeline; 9311. Second check valve; 9312. Pressure gauge; 932. Fourth pipeline; 9321. Third check valve; 9322. First adjustable throttle valve; 9323. First flowmeter

[0078] 94. Second control valve; 941. Fifth pipeline; 942. Sixth pipeline; 9421. Fourth check valve; 9422. Heater; 9423. Thermometer

[0079] 95. Third control valve; 951. Seventh pipeline; 9511. Filter; 9512. Cooler; 952. Eighth pipeline; 9521. Fifth check valve; 9522. Third switch valve; 953. Ninth pipeline; 9531. Sixth check valve; 9532. Second adjustable throttle valve; 9533. Fourth switch valve

[0080] 96. Rock particle hydraulic source; 961. Tenth pipeline; 9611. Fifth switch valve; 9612. Seventh check valve; 9613. Third adjustable throttle valve; 9614. Second flowmeter; 9615. Second pilot-operated relief valve Detailed implementation manners

[0081] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings

[0082] As Figures 1 to 13 shown, the present application provides a simulation test device for a multi-functional offshore horizontal well drilling system, including:

[0083] A vertically arranged water tank 1, with an intermediate plate 10 provided inside its bottom to divide the interior of the water tank 1 into a water-containing cavity located in the upper part and a hollow cavity located in the lower part; a flow-making pump is provided in the water-containing cavity

[0084] The test bench 11 is arranged on the top of the water tank 1, and a driving mechanism 2 is provided on the test bench 11;

[0085] The offshore platform model 3, the driving mechanism 2 is connected to the top of the offshore platform model 3 and can drive the offshore platform model 3 to move in the vertical direction and the first and second horizontal directions perpendicular to each other;

[0086] The riser model 4, its top is connected to the bottom of the offshore platform model 3, and a riser water outlet 41 is provided at the top of the riser model 4;

[0087] The casing model 5, which includes a sequentially connected casing vertical section 51, a casing bending section 52, a casing horizontal section 53 and a casing end cap 54, and the top of the casing vertical section 51 is detachably connected to the bottom of the riser model 4;

[0088] The drill string model 6 is arranged inside the riser model 4 and the casing model 5; the drill string model 6 includes a sequentially connected drill string vertical section 61, a drill string bending section 62 and a drill string horizontal section 63, the top of the drill string vertical section 61 is connected to the bottom of the offshore platform model 3, and a drill string water inlet 611 is provided at the top of the drill string vertical section 61;

[0089] The hydraulic system 9 can be connected to the drill string water inlet 611 and the riser water outlet 41 through corresponding pipelines, and can adjust the pressure, flow rate and / or temperature of the liquid in the drill string model 6.

[0090] Thus, in the simulation test device of the present application, the driving mechanism 2 on the test bench 11 can drive the offshore platform model 3 to perform lateral movement, longitudinal movement and vertical movement in the first horizontal direction, the second horizontal direction and the vertical direction respectively, and can adjust the amplitudes and periods of the lateral movement, longitudinal movement and heaving of the offshore platform model 3, and can simulate the vibration response of the offshore drilling system under the movement of the offshore platform. The flow pump arranged in the water storage cavity can simulate the sea current and the oscillating flow, which is beneficial to simulating the behavior of the external sea current causing vortex-induced vibration of the riser in the marine environment. The hydraulic system 9 can inject fluid into the drill string model 6, and can also adjust the pressure, flow rate and / or temperature of the injected fluid, and further can more realistically simulate the influence of different offshore platform movement directions, movement speeds, movement periods on the offshore drilling system, the influence of different external sea currents on the vortex-induced vibration of the riser, and the influence of different internal flow velocities, internal flow temperatures and internal flow pressures on the riser, drill string and casing; after injecting fluid into the drill string model 6 according to the design of this device, the friction resistance test of the wear between the drill string and the casing can also be studied, and then it is convenient to simulate the vibration response and friction resistance response tests of the offshore horizontal well drilling system under various working conditions.

[0091] In a specific implementation manner, during the actual drilling process, the rotation of the drill bit will cause the vibration of the drill string. Therefore, a device for simulating the vibration of the drill string caused by the rotation of the drill bit is also provided in the device of the present application. Refer to Figure 8 , a drill string end cap 64 is further connected to the end of the horizontal section 63 of the drill string. A plurality of liquid passing holes 641 are formed in the side wall of the drill string end cap 64. A transmission member 65 is rotatably connected to the drill string end cap 64. A driving member 67 is further provided in the hollow cavity. The driving member 67 can pass through the casing end cap 54 and be connected to the transmission member 65 to drive the transmission member 65 to rotate.

[0092] The casing end cap 54 and the end of the horizontal section 53 of the casing can be connected by screws 541. There is a gap between the end of the horizontal section 63 of the drill string and the casing end cap 54. The drill string end cap 64 and the end of the horizontal section 63 of the drill string (i.e., the end far from the drill string bending section 62) can be connected by screws 642. The drill string end cap 64 can adopt a cylindrical structure with an open first end and a closed second end. A convex ring 651 is convexly provided on the outer wall of the first end of the drill string end cap 64. The convex ring 651 is connected to the end of the horizontal section 63 of the drill string by screws 642. A plurality of liquid passing holes 641 are formed in the side wall of the drill string end cap 64. The water in the drill string model 6 enters the annulus between the casing model 5 and the drill string model 6 through these small holes.

[0093] An installation hole is formed in the casing end cap 54. The first end of the transmission member 65 is connected to the drill string end cap 64 through a bearing 66. The second end of the transmission member 65 is inserted into the installation hole and can rotate relative to the installation hole. The driving member 67 can be, for example, a motor. The housing of the motor is fixed on the bottom plate of the water tank 1 through a support frame 671 and bolts 672. The output shaft of the motor is fixedly connected to the second end of the transmission member 65. By adjusting the rotation speed of the motor, the vibration influence of the drill bit with different rotation speeds on the drill string model 6 can be simulated.

[0094] To ensure the sealing performance, a convex ring 651 is provided on the outer wall of the first end of the transmission member 65. A push ring 652, a first ring body 653, and a second ring body 654 are sequentially sleeved on the transmission member 65 from its first end to the second end. An annular first flange is provided on the outer wall of the end of the second ring body 654 close to the first ring body 653. The first flange can form a first sealing ring groove between the inner wall of the bottom of the horizontal section 53 of the casing and the inner wall of the casing end cover 54. A first sealing ring 655 is embedded in the first sealing ring groove. An annular second flange is provided on the inner wall of the end of the first ring body 653 close to the second ring body 654. One end of the push ring 652 is movably inserted into the first ring body 653 and can form a second sealing ring groove with the second flange. A second sealing ring 656 is embedded in the second sealing ring groove. A plurality of push rods 6521 are axially spaced at the other end of the push ring 652. The plurality of push rods 6521 are movably inserted into a plurality of through holes on the convex ring 651. A spring 657 is sleeved on each push rod 6521. The two ends of the spring 657 can respectively abut between the convex ring 651 and the push ring 652. The second ring body 654 can abut against the inner wall of the casing end cover 54.

[0095] During the test, when the water pressure in the annulus increases, the push ring 652 will move to the right in the direction shown in Figure 8 and squeeze the second sealing ring 656, making the sealing effect better. The transmission member 65 forms a cylindrical structure with an open first end and a closed second end. The output shaft of the motor passes through the through hole on the second end face of the transmission member 65 and is fixed to the transmission member 65. A partition plate is further provided in the transmission member 65 so that the end of the motor is located in the closed cavity formed by the partition plate and the second end of the transmission member 65. By providing two ring bodies, namely the first ring body 653 and the second ring body 654, to respectively install two sealing rings, it can ensure that the sealing rings are pressed more tightly, and the sealing effect is good.

[0096] Further preferably, a rock particle inlet 531 is provided on the bottom side wall of the horizontal section 53 of the casing. The hydraulic system 9 is also connected to the rock particle inlet 531 through a corresponding pipeline to inject a fluid with rock particles into the annulus between the casing model 5 and the drill string model 6, so as to simulate the influence of rock particles generated during drilling in the actual drilling fluid on the drill string and the casing.

[0097] The number of the above-mentioned flow pumps is preferably two, and the flow ports of the two flow pumps are arranged back to back to form a two-way flow pump, which can simulate two-way ocean currents and oscillating currents when the water storage cavity of the water tank 1 is filled with water.

[0098] Further, a camera is also provided outside the water tank 1 for taking pictures of the riser model 4 and the drill string model 6 to record the displacements of the riser model 4 and the drill string model 6.

[0099] For better photographic recording, the water tank 1 is of a transparent structure, the riser model 4 is a transparent tube, and identification elements are provided on the outer wall of the riser model 4. The drill string model 6 is a colored tube, and the colors of the identification elements and the colored tube are different.

[0100] Preferably, a high-speed camera is used, and the specific number depends on the needs. The above-mentioned water tank 1 is a tank structure with an open top formed by a bottom plate and side plates, and the water tank 1 can be made of transparent acrylic plates. The above-mentioned identification elements can be colored dot pieces. For example, the riser model 4 can be made of transparent rubber tubes, and black dots are pasted on the outer wall of the riser model 4 as identification elements to facilitate the high-definition camera to capture the position of the riser model 4. The drill string model 6 is made of hollow rubber tubes with colors, and the colors are more conducive to the high-definition camera to capture the displacement of the drill string model 6.

[0101] Furthermore, to facilitate the driving mechanism 2 to drive the offshore platform model 3 to move in all directions, the driving mechanism 2 includes a transverse hydraulic cylinder 21, a longitudinal hydraulic cylinder 22, and a vertical hydraulic cylinder 23. One end of the transverse hydraulic cylinder 21 is connected to the vertical hydraulic cylinder 23 and can drive the vertical hydraulic cylinder 23 to move horizontally along a first horizontal direction, and the first horizontal direction is parallel to the axis direction of the horizontal section 63 of the drill string. One end of the longitudinal hydraulic cylinder 22 is connected to the vertical hydraulic cylinder 23 and can drive the vertical hydraulic cylinder 23 to move horizontally along a second horizontal direction. The vertical hydraulic cylinder 23 is connected to the top of the offshore platform model 3 and can drive the offshore platform model 3 to move up and down in the vertical direction.

[0102] The above-mentioned test bench 11 can adopt a frame structure and is clamped on the top of the water tank 1. The test bench 11 is provided with a longitudinal hydraulic cylinder fixing plate 111 and a transverse hydraulic cylinder fixing plate 112. The longitudinal hydraulic cylinder fixing plate 111 is provided with a longitudinal hydraulic cylinder fixing groove 1111, and the length direction of the longitudinal hydraulic cylinder fixing groove 1111 extends along the first horizontal direction. The other end of the longitudinal hydraulic cylinder 22 can be slidably inserted into the longitudinal hydraulic cylinder fixing groove 1111 so that the longitudinal hydraulic cylinder 22 can move synchronously when the transverse hydraulic cylinder 21 drives the vertical hydraulic cylinder 23 to move along the first horizontal direction. The transverse hydraulic cylinder fixing plate 112 is provided with a transverse hydraulic cylinder fixing groove 1121, and the length direction of the transverse hydraulic cylinder fixing groove 1121 extends along the second horizontal direction. The other end of the transverse hydraulic cylinder 21 can be slidably inserted into the transverse hydraulic cylinder fixing groove 1121 so that the transverse hydraulic cylinder 21 can move synchronously when the longitudinal hydraulic cylinder 22 drives the vertical hydraulic cylinder 23 to move along the second direction.

[0103] Furthermore, rollers 24 are installed at the other ends of both the longitudinal hydraulic cylinder 22 and the transverse hydraulic cylinder 21. The rollers 24 can be slidably inserted into the transverse hydraulic cylinder fixing groove 1121 and the longitudinal hydraulic cylinder fixing groove 1111 to reduce the friction during sliding.

[0104] For ease of installation, the other ends of the longitudinal hydraulic cylinder 22 and the transverse hydraulic cylinder 21 are both connected with a connection chuck 25 through fasteners (such as bolts 251), and the roller 24 is rotatably installed on the mounting shaft of the connection chuck 25. A vertical hydraulic cylinder fixing member 231 is fixedly installed outside the housing of the vertical hydraulic cylinder 23. One end of the longitudinal hydraulic cylinder 22 and one end of the transverse hydraulic cylinder 21 can both be connected to the vertical hydraulic cylinder fixing member 231 through fasteners (such as bolts). The vertical hydraulic cylinder fixing member 231 mainly serves to connect and support the vertical hydraulic cylinder 23. The end of the telescopic rod of the vertical hydraulic cylinder 23 is connected to the top of the offshore platform model 3 through fasteners (such as bolts). The bottom of the offshore platform model 3 is connected to the top of the riser model 4 and the top of the drill string model 6 through fasteners (such as bolts).

[0105] The offshore platform model 3 can, for example, be configured as Figure 6 shown, including an upper platform 31 and a lower platform 32 arranged at intervals up and down, and connecting columns 33 connecting the upper platform 31 and the lower platform 32. The top end of the drill string model 6 and the top end of the riser model 4 can be designed as a closed end or an open end as required and be closed by the lower platform 32. For example, in this embodiment, the top of the drill string model 6 is a closed end and passes through the lower platform 32 and is located in the interval between the upper platform 31 and the lower platform 32. The above-mentioned drill string water inlet 611 is provided on the closed end at the top of the drill string model 6 to facilitate connection of corresponding pipelines; the top of the riser model 4 is an open end and is closed by the lower platform 32. The riser water outlet 41 passes through the lower platform 32 from the top of the riser model 4 and is located in the interval between the upper platform 31 and the lower platform 32 to facilitate connection of corresponding pipelines.

[0106] Furthermore, a bushing 42 is sleeved at the docking position of the bottom of the riser model 4 and the top of the casing vertical section 51. The bushing 42 is connected to the riser model 4 and the casing vertical section 51 through corresponding fasteners. A sealing ring 422 is installed between the bushing 42 and the mounting hole provided on the intermediate plate 10, and a waterproof sealant 423 is provided at the connection between the bushing 42 and the intermediate plate 10.

[0107] Referring to Figure 7 , the bushing 42 covers the connection between the riser model 4 and the casing model 5 and is connected to the riser model 4 and the casing model 5 through bolts 421. The function of the bushing 42 is to connect the riser model 4 and the casing model 5. The pool 1 is a double-layer structure divided by the intermediate plate 10. The upper layer of the pool 1 is filled with water, and the lower layer of the pool 1 is a hollow layer. The bushing 42 passes through the intermediate plate 10 of the pool 1. The sealing method between the bushing 42 and the intermediate plate 10 is the sealing ring 422, and a waterproof sealant 423 is applied at the connection between the bushing 42 and the intermediate plate 10 to ensure the sealing effect here.

[0108] The casing model 5 is preferably a transparent structure. When manufacturing, casing models 5 of various specifications can be made, and the inner wall roughness of each casing model 5 of different specifications is different. By replacing the casing models 5 with different roughnesses, more experimental studies can be carried out. The casing model 5 can be made of, for example, transparent acrylic tubes. When manufacturing, multiple acrylic tubes are made, and the roughness inside each acrylic tube is different.

[0109] In order to facilitate the support and fixation of the casing model 5, a plurality of casing fixing seats 55 are axially and spacedly sleeved on the casing model 5, and the casing fixing seats 55 are connected to the bottom plate of the water tank 1 through fasteners (such as bolts).

[0110] Further preferably, referring to Figure 6 and Figure 11 , an anti-bending device 7 is also sleeved outside the riser. The anti-bending device 7 includes an installation ring 71 and a plurality of spiral rings 72. The installation ring 71 is connected to the bottom of the offshore platform model 3, and the top ends of the spiral rings 72 are all connected to the bottom of the installation ring 71; the plurality of spiral rings 72 are arranged side by side along a generatrix and spirally wound around the vertical axis of the installation ring 71. Adjacent spiral rings 72 are closely arranged, and the bottom end of the spiral ring 72 is connected to the adjacent spiral ring 72 through a clamp 73.

[0111] Through the setting of the anti-bending device 7, the riser model 4 can be effectively prevented from excessive bending. The spiral radius and the number of turns of each point on the spiral center line corresponding to each spiral ring 72 satisfy a non-linear relationship, specifically satisfying the following formula:

[0112]

[0113] where y represents the spiral radius of each point on the spiral center line corresponding to the spiral ring 72, x represents the number of turns corresponding to each point on the spiral center line corresponding to the spiral ring 72, and a, b, c, and d are all coefficients.

[0114] 0 ≤ x ≤ X, x can be a decimal, X represents the total number of rotations passed from the top end to the bottom end of the spiral ring 72 (the top end and the bottom end of the spiral ring 72 are used as the starting point and the ending point of its spiral center line), and y is also the spiral radius of the point corresponding to the x-th turn on the spiral center line corresponding to the spiral ring 72. a, b, c, d ∈ (0.001, 0.04), and these four coefficients can be taken within the range of 0.001 - 0.04 according to needs. By adjusting these coefficients a, b, c, d, the shape of the spiral ring 72 with any curvature can be obtained.

[0115] The bottom of the offshore platform model 3 can be connected to the mounting ring 71 through fasteners (such as bolts). The diameters of the spiral rings 72 are the same, and adjacent spiral rings 72 are arranged closely. The gap between two adjacent spiral rings 72 is small. The interval in the generatrix direction between two adjacent turns in the same spiral ring 72 is close to the diameters of n - 1 spiral rings 72, where n is the total number of spiral rings 72. The above-mentioned generatrix is preferably an arc, and the diameter of the entire anti-bending device 7 gradually increases from top to bottom, with better anti-bending effect. The number of spiral rings 72 is also determined according to needs.

[0116] For example, in this embodiment, the number of spiral rings 72 is three, which are respectively denoted as the first spiral ring 721, the second spiral ring 722, and the third spiral ring 723. As Figure 11 shown, the tops of the three spiral rings 72 are welded to the bottom surface of the mounting ring 71, and the tops of the three spiral rings 72 are distributed at 120°. At the bottoms of the three spiral rings 72, three clamps 73 are respectively provided to fix the three spiral rings 72. For the first spiral ring 721, the interval L in the generatrix direction between two adjacent turns in the first spiral ring 721 is close to the diameters of two spiral rings 72.

[0117] Furthermore, since friction is likely to occur between the drill string model 6 and the casing model 5, the friction increases the resistance of the drill string during drilling. Therefore, the device of the present application is provided with an anti-friction structure 8. Specifically, referring to Figure 5 and Figure 12 , a plurality of anti-friction structures 8 are axially sleeved at intervals outside the horizontal section 63 of the drill string. The anti-friction structure 8 includes two fixing rings 81 sleeved on the horizontal section 63 of the drill string and arranged at intervals, and a spiral rib 82 spirally wound around the axis of the horizontal section 63 of the drill string. Both ends of the spiral rib 82 are respectively connected to the two fixing rings 81. A plurality of rolling balls 83 that can roll are sleeved on the spiral rib 82, and at least part of the rolling balls 83 can rollingly contact the inner wall of the horizontal section 53 of the casing.

[0118] The anti-friction structure 8 is connected to the drill string through the two fixing rings 81, and the spiral rib 82 is connected between the two fixing rings 81. The entire spiral rib 82 can be in the structure with smaller diameters at both ends and larger in the middle as shown in Figure 12 . Steel balls are strung on the spiral rib 82, and the steel balls can roll on the spiral rib 82. By adopting the method of sleeving steel balls and filling the spiral rib 82 with rolling balls 83 (that is, adjacent two rolling balls 83 are arranged closely with a small gap), the sliding friction between the drill string model 6 and the casing model 5 can be converted into rolling friction, reducing the resistance of drilling. In addition, due to the reduction of friction, the risk of wear between the drill string and the casing is also reduced.

[0119] During the test, it can be divided into two major groups of tests. In one group of tests, the anti-friction structure 8 is not installed to study the friction mechanism, that is, to study the wear condition of the drill string when there is friction between the drill string and the casing. In the other group of tests, the anti-friction structure 8 is installed to study the anti-friction mechanism, that is, to study the wear condition of the drill string when the anti-friction structure 8 is provided to reduce the friction between the drill string and the casing.

[0120] In an alternative embodiment, the hydraulic system 9 includes a hydraulic source. The hydraulic source is connected to the drill string water inlet 611 through an inlet pipeline in a connectable and disconnectable manner, and a pressure gauge 9312, a first adjustable flow valve 9322, a flow meter, a heater 9422, and a thermometer 9423 are provided on the inlet pipeline. An outlet pipeline is connected to the riser outlet 41, and a filter 9511, a cooler 9512, and a second adjustable flow valve 9532 are provided on the outlet pipeline. When injecting fluid into the drill string model 6, the fluid pressure can be controlled according to the data detected by the pressure gauge 9312. The flow rate of the fluid injected into the drill pipe model can be conveniently adjusted through the first adjustable flow valve 9322, the flow meter, and the second adjustable flow valve 9532. The temperature of the injected fluid can be adjusted through the heater 9422 and the thermometer 9423.

[0121] In another preferred embodiment, referring to Figure 13 , the hydraulic system 9 includes a water injection hydraulic source 91, a pressurization hydraulic source 92, a first control valve 93, a second control valve 94, and a third control valve 95. The water injection hydraulic source 91 is connected to the drill string water inlet 611 through a first pipeline 911 in a connectable and disconnectable manner. The pressurization hydraulic source 92 is connected to the first control valve 93 through a second pipeline 921 in a connectable and disconnectable manner. The first control valve 93 is further connected to the drill string water inlet 611 and the second control valve 94 through a third pipeline 931 and a fourth pipeline 932 respectively. The second control valve 94 is further connected to the drill string water inlet 611 through a fifth pipeline 941 and a sixth pipeline 942 respectively. A pressure gauge 9312 is provided on the third pipeline 931, a first adjustable flow valve 9322 and a first flow meter 9323 are provided on the fourth pipeline 932, and a heater 9422 and a thermometer 9423 are provided on the sixth pipeline 942. The first control valve 93 can control the second pipeline 921 to communicate with the third pipeline 931 or the fourth pipeline 932. The second control valve 94 can control the fourth pipeline 932 to communicate with the fifth pipeline 941 or the sixth pipeline 942.

[0122] The third control valve 95 is connected to the outlet of the riser 41 through the seventh pipeline 951. The third control valve 95 is also connected to an eighth pipeline 952 and a ninth pipeline 953 in a switchable manner. A filter 9511 and a cooler 9512 are sequentially arranged on the seventh pipeline 951 along the fluid flow direction. A second adjustable throttle valve 9532 is arranged on the ninth pipeline 953. The third control valve 95 can control the connection between the seventh pipeline 951 and the eighth pipeline 952 or the connection between the seventh pipeline 951 and the ninth pipeline 953.

[0123] The pipelines for injecting water, pressurizing, adjusting the flow rate, and adjusting the temperature into the drill string model 6 are separately arranged. Compared with the previous optional embodiment where they are integrated on one inlet pipeline, each component can operate independently without mutual influence, which can increase the success rate of the test. In addition, when a component fails, it will not affect the operation of other components, improving the reliability of the system.

[0124] In this preferred embodiment, more preferably, a rock particle inlet 531 is provided on the bottom side wall of the horizontal section 53 of the casing. The hydraulic system 9 further includes a rock particle hydraulic source 96. The rock particle hydraulic source 96 is connected to the rock particle inlet 531 in a switchable manner through a tenth pipeline 961. A second flowmeter 9614 and a third adjustable throttle valve 9613 are arranged on the tenth pipeline 961 for the transportation of rock particles.

[0125] Refer to Figure 13 , a first check valve 9112, a second check valve 9311, a third check valve 9321, a fourth check valve 9421, a fifth check valve 9521, a sixth check valve 9531, and a seventh check valve 9612 are respectively arranged on the first pipeline 911, the third pipeline 931, the fourth pipeline 932, the sixth pipeline 942, the eighth pipeline 952, the ninth pipeline 953, and the tenth pipeline 961. The first check valve 9112 allows fluid to flow into the drill string model 6. The second check valve 9311 allows fluid to flow into the drill string model 6. The third check valve 9321 allows fluid to flow into the second control valve 94. The fourth check valve 9421 allows fluid to flow into the drill string model 6. The fifth check valve 9521 allows fluid to flow to the third switching valve 9522. The sixth check valve 9531 allows fluid to flow to the fourth switching valve 9533. The seventh check valve 9612 allows fluid to flow to the rock particle inlet 531.

[0126] The first control valve 93, the second control valve 94, and the third control valve 95 are all three-position four-way valves. A first on-off valve 9111, a second on-off valve 9211, a third on-off valve 9522, a fourth on-off valve 9533, and a fifth on-off valve 9611 are respectively provided on the first pipeline 911, the second pipeline 921, the eighth pipeline 952, the ninth pipeline 953, and the tenth pipeline 961. The first on-off valve 9111, the second on-off valve 9211, the third on-off valve 9522, the fourth on-off valve 9533, and the fifth on-off valve 9611 are all two-position two-way valves to control the on-off at various locations.

[0127] Specifically, the water injection hydraulic source 91 includes a first water tank and a first hydraulic pump, the pressurized hydraulic source 92 includes a second water tank and a second hydraulic pump, and the rock particle hydraulic source 96 includes a liquid tank and a screw pump.

[0128] The three-position four-way valve and the two-position two-way valve here are both solenoid valves. The three-position four-way valve has four interfaces, one of which is closed, and the other three interfaces are respectively used to connect the three pipelines connected to the control valve. The three-position four-way valve has a first working position (i.e., the left position corresponding to Figure 1 ), a middle position, and a second working position (i.e., the right position in Figure 1 ). By switching the three-position four-way valve to the left position or the right position, the corresponding two pipelines can be conveniently connected. When the three-position four-way valve is in the middle position, the three pipelines connected to the three-position four-way valve are not connected to each other.

[0129] The first check valve 9112 is located between the first on-off valve 9111 and the drill string water inlet 611 for allowing the fluid to flow into the drill string model 6. The second check valve 9311 is located between the pressure gauge 9312 and the first control valve 93. The first adjustable throttle valve 9322 is located between the third check valve 9321 and the first flowmeter 9323, and the first flowmeter 9323 is arranged close to the second control valve 94. The heater 9422 is located between the fourth check valve 9421 and the thermometer 9423, and the thermometer 9423 is arranged close to the drill string water inlet 611. The fifth check valve 9521 is located between the third control valve 95 and the third on-off valve 9522. The sixth check valve 9531, the second adjustable throttle valve 9532, and the fourth on-off valve 9533 are arranged in sequence along the fluid flow direction. Corresponding water tanks can be connected to the ends of the fifth pipeline 941 and the sixth pipeline 942 far from the third control valve 95. The fifth on-off valve 9611, the seventh check valve 9612, the third adjustable throttle valve 9613, and the second flowmeter 9614 are arranged in sequence from the rock particle hydraulic source 96 to the rock particle inlet 531.

[0130] Generally, a first pilot-operated relief valve 9212 is also connected in parallel at a position on the second pipeline 921 and close to the water injection hydraulic source 91, and a second pilot-operated relief valve 9615 is also connected in parallel at a position on the tenth pipeline 961 and close to the rock particle hydraulic source 96.

[0131] Further, the multifunctional offshore horizontal well drilling system simulation test device further includes a control device, which is electrically connected to the flow-making pump, the driving mechanism 2 and the hydraulic system 9. Specifically, the control device is electrically connected to the pump, valves, pressure gauge 9312, flowmeter, thermometer 9423, heater 9422 and cooler 9512 in the hydraulic system 9 to control the actions of each component.

[0132] More specifically, the operation process using the hydraulic system 9 is as follows:

[0133] The specific steps for injecting water into the drill string model 6 are as follows: adjust the first switch valve 9111 to the on position, adjust the third control valve 95 to the left position, and adjust the third switch valve 9522 to the on position. Then start the water injection hydraulic source 91 to inject water into the drill string model 6. The water flows in from the drill string water inlet 611, flows out from the small holes in the drill string end cap 64 into the inside of the casing model 5, then flows through the inside of the riser model 4, and finally flows out from the riser water outlet 41. When water flows out at the outlet of the third switch valve 9522 to the water tank connected to the end of the eighth pipeline 952, adjust the first switch valve 9111 and the third switch valve 9522 to the off position, and adjust the third control valve 95 to the middle position. At this time, the water injection hydraulic source 91 stops working and the water injection is completed.

[0134] The specific steps for pressurizing the inside of the drill string model 6 are as follows: after the water injection is completed, adjust the second switch valve 9211 to the on position and the first control valve 93 to the left position. The second one-way valve 9311 prevents water from flowing back and plays a role in protecting the circuit. Then the pressurizing hydraulic source 92 starts to work to inject water for pressurization. Record the pressure value in the hydraulic circuit (i.e., the third pipeline 931) through the pressure gauge 9312. When the pressure reaches the test expected value, stop pressurizing. Subsequently, adjust the second switch valve 9211 to the off position and the first control valve 93 to the middle position.

[0135] The specific steps for adjusting the flow rate inside the drill string model 6 under a certain water pressure are as follows: After pressurizing the inside of the drill string model 6, adjust the second switch valve 9211 to the open position, adjust the first control valve 93 to the right position, adjust the second control valve 94 to the left position, adjust the third control valve 95 to the right position, and adjust the fourth switch valve 9533 to the open position. Set the opening degrees of the first adjustable throttle valve 9322 and the second adjustable throttle valve 9532 to be the same. At this time, the pressurized hydraulic source 92 starts to work and injects water into the hydraulic circuit (i.e., the second pipeline 921, the fourth pipeline 932, and the fifth pipeline 941). By simultaneously adjusting the opening degrees of the first adjustable throttle valve 9322 and the second adjustable throttle valve 9532, the flow rate in the hydraulic circuit can be adjusted. The flow rate in the hydraulic circuit is recorded by the first flowmeter 9323. The third one-way valve 9321 and the sixth one-way valve 9531 can ensure that the water in the hydraulic circuit does not flow back to protect the circuit. After the test is completed, adjust the second switch valve 9211 to the closed position, adjust the first control valve 93 to the middle position, adjust the second control valve 94 to the middle position, and adjust the third control valve 95 to the middle position.

[0136] The specific steps for adjusting the temperature inside the drill string model 6 are as follows: Adjust the second switch valve 9211 to the open position, adjust the first control valve 93 to the right position, adjust the second control valve 94 to the right position, and adjust the third control valve 95 to the right position. The pressurized hydraulic source 92 starts to work and injects water into the hydraulic circuit. The temperature of the water in the hydraulic circuit (i.e., the sixth pipeline 942) is adjusted by adjusting the heater 9422. The temperature of the water in the hydraulic circuit is measured by the thermometer 9423. The temperature of the water in the hydraulic circuit (i.e., the seventh pipeline 951) is reduced by the cooler 9512 to ensure that the hydraulic components work at an appropriate temperature.

[0137] The specific steps for injecting rock particles inside the casing model 5 are as follows: After the pressurizing step inside the drill string model 6 is completed, adjust the fifth switch valve 9611 to the open position, adjust the third control valve 95 to the right position, and adjust the fourth switch valve 9533 to the open position. At this time, the screw pump starts to work and injects water with rock particles (referred to as solid-liquid two-phase flow) into the hydraulic circuit. The flow rate of the solid-liquid two-phase flow can be adjusted by adjusting the third adjustable throttle valve 9613 and the second adjustable throttle valve 9532. The flow rate of the solid-liquid two-phase flow is measured by the second flowmeter 9614. The rock particles can be filtered out of the hydraulic circuit through the filter 9511, reducing the wear of the hydraulic circuit. Finally, the solid-liquid two-phase flow is injected into the inside of the casing model 5 through the rock particle inlet 531 and flows out from the riser outlet 41. After the test is completed, stop the work of the screw pump. Adjust the fifth switch valve 9611 to the closed position, adjust the third control valve 95 to the middle position, and adjust the fourth switch valve 9533 to the closed position.

[0138] The cleaning steps for the inside of the riser model 4, the inside of the casing model 5, and the inside of the drill string model 6 are as follows: Adjust the second switching valve 9211 to the open position, adjust the first control valve 93 to the left position, adjust the third control valve 95 to the left position, and adjust the third switching valve 9522 to the open position. Subsequently, the pressurized hydraulic source 92 starts to inject water, and the inside of the entire riser model 4, the inside of the casing model 5, and the inside of the drill string model 6 will be flushed with a large flow of water, and the residual rock particles inside will be carried out.

[0139] In summary, the multifunctional offshore horizontal well drilling system simulation test device in this embodiment has the following advantages:

[0140] (1) By changing the elongation displacement and elongation period of the three hydraulic cylinders, the offshore platform model 3 can be translated horizontally, vertically, and heaving, and the vibration response of the offshore drilling system under the movement of the offshore platform can be simulated.

[0141] (2) An experimental device is proposed. This experimental device can simulate the effects of two-way external flow and internal flow on the offshore drilling system, including the vortex-induced vibration behavior of the external flow on the riser, and the friction resistance test between the drill string and the casing under the condition of drill string vibration can be carried out.

[0142] (3) A hydraulic control scheme is proposed, which can achieve the pressure of any internal fluid of the drilling system required for the test, and the vibration response tests of the drill string and the casing under different flow velocities, different temperatures, and different solid contents of the solid-liquid two-phase flow inside the drilling system can be carried out, as well as the vibration response test of the drill string with different bit rotation speeds.

[0143] (4) An anti-bending device 7 composed of spiral pipes is proposed. This anti-bending device 7 can prevent the riser from bending too much, reduce the bending stress concentration, improve the service life and is convenient for disassembly and assembly. This anti-bending device 7 can limit any bending angle of the riser.

[0144] (5) An anti-friction structure 8 is proposed, which converts the static friction and sliding friction between the drill string and the casing into rolling friction, reducing the wear of the drill string and the casing. In addition, this anti-friction structure 8 can be used for anti-friction tests, and the wear mechanisms of the drill string and the casing against ocean currents and internal solid-liquid two-phase flows can be qualitatively and quantitatively studied when the anti-friction structure 8 is adopted.

[0145] (6) The entire test device is a simulation device for the vibration response and friction resistance test of an offshore horizontal well drilling system in offshore drilling engineering. It is a test device for the vibration response and friction resistance of a multi-functional offshore horizontal well system under actual working conditions. The entire test device includes a water tank 1 and a test bench 11. The longitudinal hydraulic cylinder 22, the transverse hydraulic cylinder 21, and the vertical hydraulic cylinder 23 on the test bench 11 can be used to adjust the amplitudes and periods of the horizontal movement, longitudinal movement, and heaving of the offshore platform. The anti-bending device 7 can protect the riser model 4 to keep its bending angle within a certain range. The high-speed cameras distributed outside the water tank 1 can be used to record the vibration displacements of the riser model 4 and the drill string model 6. The anti-friction structure 8 is used for friction resistance and anti-friction resistance tests, and can also be applied to actual engineering to reduce the friction resistance between the drill string and the casing. The drill string end cap 64, the transmission part 65, the push ring 652, the spring 657, the sealing ring, the casing end cap 54, and the motor constitute a simulated bit device. By adjusting the rotation speed of the motor, the simulated bit device can simulate the influence of bits with different rotation speeds on the drill string model 6. The hydraulic system 9 can be used to transport fluids and solid-liquid two-phase flows, can achieve the pressure transmission of any internal fluid of the drilling system required for the test, can adjust the flow rate, temperature of the internal fluid of the drilling system, and the solid content in the solid-liquid two-phase flow. Thus, it can simulate the vibration response and friction resistance response of the offshore horizontal well drilling system under various working conditions.

[0146] Furthermore, the present application also provides a simulation test method for a multi-functional offshore horizontal well drilling system. The test is carried out using the above-mentioned simulation test device for a multi-functional offshore horizontal well drilling system. The simulation test method for a multi-functional offshore horizontal well drilling system includes:

[0147] S1. Assemble the simulation test device for a multi-functional offshore horizontal well drilling system;

[0148] S2. Inject fluid into the drill string water inlet 611, adjust the test influencing factors, and start the test. During the test, record the vibration displacements of the riser model 4 and the drill string model 6;

[0149] Among them, adjusting the test influencing factors includes: using the driving mechanism 2 to adjust the amplitudes and periods of the movement of the offshore platform model 3 in the vertical direction, the first horizontal direction, and / or the second horizontal direction, and using the hydraulic system 9 to adjust the pressure, flow rate, and / or temperature of the liquid in the drill string model 6;

[0150] S3. After the test, take out the test drill string model 6, and compare the test drill string model 6 with the drill string model 6 before the test to obtain the wear amount and wear position of the test drill string model 6;

[0151] S4. Repeat steps S1 - S3 with different test influencing factors to conduct multiple groups of tests.

[0152] The entire method uses the above-mentioned test device for the test, and has the same effect, which will not be elaborated here.

[0153] Further, in step S2, adjusting the test influencing factors further includes injecting a fluid with rock particles into the rock particle inlet 531 on the horizontal section 53 of the casing by means of the hydraulic system 9 and adjusting the rock particle content, flow rate, temperature and / or pressure of the fluid with rock particles, and driving the transmission member 65 rotatably connected to the end cover 64 of the drill string horizontal section 63 by the driving member 67 and adjusting the rotation speed of the driving member 67. Adjusting the test influencing factors may also include adjusting the pump speed of the flow generating pump. Adjusting the test influencing factors may also include changing the roughness of the inner wall of the casing model 5.

[0154] Further, in step S1, during the process of assembling the simulation test device for the multifunctional offshore horizontal well drilling system, a plurality of anti-friction structures 8 are sleeved between the drill string model 6 and the casing model 5. The anti-friction structure 8 includes a plurality of balls 83 and can be in rolling contact with the casing model 5.

[0155] By simulating ocean currents and oscillatory currents through the flow generating pump, driving the movement of the offshore platform model 3, adjusting the relevant parameters of the fluid in the drill string model 6, introducing the rock particle fluid, and adjusting the rotation speed of the driving member 67, the vibration response test under the conditions of external ocean currents, offshore platform movement, internal fluid, and bit vibration can be simulated. By introducing rock particles and adjusting the relevant parameters, changing the roughness of the inner wall of the casing model 5, and whether to add the anti-friction structure 8, the friction resistance test of the wear between the drill string and the casing under different working conditions can be simulated, which can more comprehensively and realistically simulate the vibration and wear conditions of the riser, drill string, and casing in the marine environment, and more realistically simulate the influence of different platform movement directions, movement speeds, and movement periods on the offshore drilling system, the influence of different internal flow velocities, internal flow temperatures, and internal flow pressures on the riser, drill string, and casing, the influence of solid-liquid two-phase flow and different solid contents on the riser, drill string, and casing, as well as the wear mechanism of various factors on the drill string and the casing.

[0156] Further, the following takes a specific embodiment as an example to illustrate the test method. The implementation process of the test method is as follows:

[0157] Step 1, set up the test device as shown in Figure 5 For studying the friction resistance mechanism and anti-friction resistance mechanism, the test is divided into two large groups. One group is the test without the anti-friction structure 8, and the other group is the test with the anti-friction structure 8. When conducting the test without the anti-friction structure 8, the anti-friction structure 8 is removed; when conducting the test with the anti-friction structure 8, the anti-friction structure 8 is added.

[0158] Step 2: Adjust the factors affecting the friction resistance test respectively. For example, adjust the amplitudes and periods of the longitudinal movement, transverse movement, and heaving of the offshore platform model 3 by adjusting the elongation and elongation-shortening periods of the longitudinal hydraulic cylinder 22, transverse hydraulic cylinder 21, and vertical hydraulic cylinder 23 respectively; adjust the rock particle content, flow rate, temperature, and pressure of the solid-liquid two-phase flow; adjust the rotational speed of the motor to simulate the rotational speeds of different drill bits.

[0159] Step 3: After the test starts, use a high-speed camera to capture the vibration patterns of the riser model 4 and the drill string model 6.

[0160] Step 4: After the test ends, take out the drill string model 6 and scan the drill string model 6 using a 3D scanner. Import the scanned model into Geomagic software (existing software, and other software can also be used for comparative analysis according to needs), compare this model with the untested drill string model 6, and compare the wear amount and wear location of the drill string model 6.

[0161] Step 5: After the data processing is completed, repeat the above steps to study the wear mechanism and anti-friction mechanism of the drill string and casing under different factors.

[0162] Furthermore, the simulation test method for the multifunctional offshore horizontal well drilling system further includes:

[0163] S5. Determine the influencing factors of drill string wear based on multiple groups of tests;

[0164] S6. Fit the influencing factors of drill string wear and the wear amount of the drill string model to obtain a prediction model between the maximum wear depth of the drill string and the influencing factors of drill string wear. The wear depth of the drill string in actual working conditions can be predicted through this prediction model.

[0165] Furthermore, the prediction model is: h = A p +A v +A d +A c +A t ;

[0166] where, A p = a1p 3 + b1p 2 + c1p + d1, A v = a2v 3 + b2v 2 + c2v + d2, A d = a3d 3 + b3d 2 + c3d + d3, A c = a4C 3 + b4C 2 + c4C + d4, A t = a5t3 +b5t 2 +c5t + d5;

[0167] h represents the maximum wear depth of the worn drill string under the action of various factors, p represents the internal fluid pressure of the worn drill string, v represents the fluid flow velocity in the worn drill string, d represents the diameter of the rock particles in the worn drill string, C represents the content of rock particles in the fluid in the worn drill string, A p represents the maximum wear amount of the worn drill string under the action of the internal fluid pressure, A v represents the maximum wear amount of the worn drill string under the action of the fluid flow velocity, A d represents the maximum wear amount of the worn drill string under the action of the rock particle diameter, A c represents the maximum wear amount of the worn drill string under the action of the content of rock particles in the fluid, A t represents the maximum wear amount of the worn drill string under the action of the fluid impact time, and a1, b1, c1, d1, a2, b2, c2, d2, a3, b3, c3, d3, a4, b4, c4 and d4 are all coefficients.

[0168] Specifically, based on the above test method for the offshore horizontal well drilling system, this embodiment also provides a prediction method for the maximum wear depth of the worn drill string, and its main implementation process is as follows:

[0169] This embodiment considers the drill string wear factors as the internal fluid pressure p, the fluid flow velocity v, the rock particle diameter d, and the content of rock particles C in the fluid.

[0170] First, fit the relationship between the wear amount and various factors. The fitting formula can adopt linear fitting, exponential fitting, logarithmic fitting or polynomial fitting. This embodiment adopts polynomial fitting. The other fitting methods can also be adopted according to the test results. The fitting formulas for each influencing factor are as follows:

[0171] A p = a1p 3 + b1p 2 + c1p + d1

[0172] A v = a2v 3 + b2v 2 + c2v + d2

[0173] A d = a3d 3 + b3d 2 + c3d + d3

[0174] A c = a4C 3 + b4C 2 + c4C + d4

[0175] A t = a5t 3 + b5t 2 + c5t + d5

[0176] Therefore, the maximum wear depth of the worn drill string under the action of various factors is: h = A p + A v + A d + A c + A t .

[0177] The coefficient range in the above formula is These coefficients are empirical values obtained from experiments and can be specifically taken within the range of 0.001 - 0.5 according to the actual situation. By using the above formula, the wear depth of the drill string in actual engineering can be predicted.

[0178] The above is only a schematic specific embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A simulation test device for a multi-functional offshore horizontal well drilling system, characterized in that Comprising: A vertically arranged water tank, with an intermediate plate provided inside its bottom and dividing the interior of the water tank into a water storage cavity located in the upper part and a hollow cavity located in the lower part; A flow generating pump is provided in the water storage cavity; A test bench is provided on the top of the water tank, and a driving mechanism is provided on the test bench; An offshore platform model, the driving mechanism is connected to the top of the offshore platform model and can drive the offshore platform model to move in the vertical direction and the first horizontal direction and the second horizontal direction perpendicular to each other; A riser model, its top is connected to the bottom of the offshore platform model, and a riser water outlet is provided at the top of the riser model; A casing model, which includes a sequentially connected casing vertical section, a casing bending section, a casing horizontal section and a casing end cap, and the top of the casing vertical section is detachably connected to the bottom of the riser model; A drill string model is arranged inside the riser model and the casing model; the drill string model includes a sequentially connected drill string vertical section, a drill string bending section and a drill string horizontal section, the top of the drill string vertical section is connected to the bottom of the offshore platform model, and a drill string water inlet is provided at the top of the drill string vertical section; a drill string end cap is also connected to the end of the drill string horizontal section, a plurality of liquid passing holes are opened on the side wall of the drill string end cap, a transmission member is rotatably connected to the drill string end cap, and a driving member is also provided in the hollow cavity, the driving member can pass through the casing end cap and be connected to the transmission member to drive the transmission member to rotate; A hydraulic system can be connected to the drill string water inlet and the riser water outlet through corresponding pipelines, and can adjust the pressure, flow rate and / or temperature of the liquid in the drill string model.

2. The simulation test device for a multi-functional offshore horizontal well drilling system according to claim 1, characterized in that An installation hole is opened on the casing end cap, the first end of the transmission member is connected to the drill string end cap through a bearing, and the second end of the transmission member is inserted into the installation hole; a convex ring is convexly provided on the outer wall of the first end of the transmission member, and a push ring, a first ring body and a second ring body are sequentially sleeved on the transmission member from its first end to the second end; The outer wall of the end of the second ring body close to the first ring body is convexly provided with an annular first flange, the first flange can enclose a first sealing ring groove between the inner wall of the bottom of the casing horizontal section and the inner wall of the casing end cap, and a first sealing ring is embedded in the first sealing ring groove; the inner wall of the end of the first ring body close to the second ring body is convexly provided with an annular second flange, one end of the push ring can be movably inserted into the first ring body and can enclose a second sealing ring groove with the second flange, and a second sealing ring is embedded in the second sealing ring groove; a plurality of push rods are axially spaced at the other end of the push ring, the plurality of push rods can be movably inserted into a plurality of through holes on the convex ring, and a spring is sleeved on each push rod, and both ends of the spring can respectively abut between the convex ring and the push ring.

3. The simulation test device for a multi-functional offshore horizontal well drilling system according to claim 1, characterized in that A rock particle inlet is provided on the bottom side wall of the horizontal section of the casing. The hydraulic system is also connected to the rock particle inlet through a corresponding pipeline to inject a fluid with rock particles into the annulus between the casing model and the drill string model.

4. The simulation test device for a multifunctional offshore horizontal well drilling system according to claim 1, wherein The number of the flow generating pumps is two, and the flow generating ports of the two flow generating pumps are arranged back to back.

5. The simulation test device for a multifunctional offshore horizontal well drilling system according to claim 1, wherein A camera is further provided outside the water tank for taking pictures of the riser model and the drill string model to record the displacements of the riser model and the drill string model.

6. The simulation test device for a multifunctional offshore horizontal well drilling system according to claim 5, wherein The water tank is of a transparent structure, the riser model is a transparent pipe, a marking member is provided on the outer wall of the riser model, the drill string model is a colored pipe, and the color of the marking member is different from that of the colored pipe.

7. The simulation test device for a multifunctional offshore horizontal well drilling system according to claim 1, wherein The driving mechanism includes a transverse hydraulic cylinder, a longitudinal hydraulic cylinder and a vertical hydraulic cylinder. One end of the transverse hydraulic cylinder is connected to the vertical hydraulic cylinder and can drive the vertical hydraulic cylinder to move horizontally along the first horizontal direction, and the first horizontal direction is parallel to the axis direction of the horizontal section of the drill string; one end of the longitudinal hydraulic cylinder is connected to the vertical hydraulic cylinder and can drive the vertical hydraulic cylinder to move horizontally along the second horizontal direction; the vertical hydraulic cylinder is connected to the top of the offshore platform model and can drive the offshore platform model to move up and down in the vertical direction.

8. The simulation test device for a multifunctional offshore horizontal well drilling system according to claim 1, wherein A bushing is sleeved at the docking position of the bottom of the riser model and the top of the vertical section of the casing. The bushing is connected to the riser model and the vertical section of the casing through corresponding fasteners. A sealing ring is installed between the bushing and the installation hole formed on the intermediate plate, and a waterproof sealant is provided at the connection between the bushing and the intermediate plate.

9. The simulation test device for a multifunctional offshore horizontal well drilling system according to claim 1, wherein An anti-bending device is further sleeved outside the riser. The anti-bending device includes an installation ring and a plurality of spiral rings. The installation ring is connected to the bottom of the offshore platform model, and the top ends of the spiral rings are all connected to the bottom of the installation ring; the plurality of spiral rings are arranged side by side along a generatrix and spirally wound around the vertical axis of the installation ring. Adjacent spiral rings are closely arranged, and the bottom end of the spiral ring is connected to the adjacent spiral ring through a clamp.

10. The simulation test device for a multifunctional offshore horizontal well drilling system according to claim 9, wherein The spiral radius and the number of turns of each point on the spiral center line corresponding to each spiral ring satisfy the following formula: Among them, y represents the spiral radius of each point on the spiral center line corresponding to the spiral ring, x represents the number of turns corresponding to each point on the spiral center line corresponding to the spiral ring, and a, b, c, and d are all coefficients.

11. The simulation test device for a multi-functional offshore horizontal well drilling system according to claim 1, wherein a plurality of anti-friction structures are axially sleeved outside the horizontal section of the drill string at intervals. The anti-friction structure includes two fixed rings sleeved on the horizontal section of the drill string and arranged at intervals, and a spiral rib spirally wound around the axis of the horizontal section of the drill string. Both ends of the spiral rib are respectively connected to the two fixed rings. A plurality of rolling balls are sleeved on the spiral rib, and at least part of the rolling balls can rollingly contact the inner wall of the horizontal section of the casing.

12. The simulation test device for a multi-functional offshore horizontal well drilling system according to claim 1, wherein The hydraulic system includes a water injection hydraulic source, a pressurization hydraulic source, a first control valve, a second control valve, and a third control valve. The water injection hydraulic source is connected to the water inlet of the drill string through a first pipeline in a switchable manner. The pressurization hydraulic source is connected to the first control valve through a second pipeline in a switchable manner. The first control valve is also connected to the water inlet of the drill string and the second control valve through a third pipeline and a fourth pipeline respectively. The second control valve is also connected to the water inlet of the drill string through a fifth pipeline and a sixth pipeline respectively. A pressure gauge is provided on the third pipeline, a first adjustable throttle valve and a first flow meter are provided on the fourth pipeline, and a heater and a thermometer are provided on the sixth pipeline. The first control valve can control the second pipeline to communicate with the third pipeline or with the fourth pipeline. The second control valve can control the fourth pipeline to communicate with the fifth pipeline or with the sixth pipeline. The third control valve is connected to the outlet of the riser through a seventh pipeline. The third control valve is also connected to an eighth pipeline and a ninth pipeline in a switchable manner. A filter and a cooler are sequentially provided on the seventh pipeline along the fluid flow direction. A second adjustable throttle valve is provided on the ninth pipeline. The third control valve can control the seventh pipeline to communicate with the eighth pipeline or with the ninth pipeline.

13. The simulation test device for a multi-functional offshore horizontal well drilling system according to claim 12, wherein A rock particle inlet is provided on the bottom side wall of the horizontal section of the casing. The hydraulic system further includes a rock particle hydraulic source, which is connected to the rock particle inlet through a tenth pipeline in a switchable manner, and a second flow meter and a third adjustable throttle valve are provided on the tenth pipeline.

14. The simulation test device for a multi-functional offshore horizontal well drilling system according to claim 13, wherein A first check valve, a second check valve, a third check valve, a fourth check valve, a fifth check valve, a sixth check valve, and a seventh check valve are respectively provided on the first pipeline, the third pipeline, the fourth pipeline, the sixth pipeline, the eighth pipeline, the ninth pipeline, and the tenth pipeline.

15. The multifunctional offshore horizontal well drilling system simulation test device according to claim 13, wherein the first control valve, the second control valve, and the third control valve are all three-position four-way valves, and a first on-off valve, a second on-off valve, a third on-off valve, a fourth on-off valve, and a fifth on-off valve are respectively provided on the first pipeline, the second pipeline, the eighth pipeline, the ninth pipeline, and the tenth pipeline. The first on-off valve, the second on-off valve, the third on-off valve, the fourth on-off valve, and the fifth on-off valve are all two-position two-way valves.

16. The multifunctional offshore horizontal well drilling system simulation test device according to claim 13, wherein a first pilot-operated relief valve is also bypass-connected at a position on the second pipeline close to the water injection hydraulic source, and a second pilot-operated relief valve is also bypass-connected at a position on the tenth pipeline close to the rock particle hydraulic source.

17. The multifunctional offshore horizontal well drilling system simulation test device according to claim 1, wherein the multifunctional offshore horizontal well drilling system simulation test device further includes a control device, and the control device is electrically connected to the flow generating pump, the driving mechanism, and the hydraulic system.

18. A simulation test method for a multi-functional offshore horizontal well drilling system, characterized in that, When conducting tests using the multifunctional offshore horizontal well drilling system simulation test device according to any one of claims 1-17, the multifunctional offshore horizontal well drilling system simulation test method includes: S1. Assemble the multifunctional offshore horizontal well drilling system simulation test device; S2. Inject fluid into the drill string water inlet, start the test, adjust the test influencing factors, and record the vibration displacements of the riser model and the drill string model during the test. Among them, adjusting the test influencing factors includes: using the driving mechanism to adjust the amplitude and period of the movement of the offshore platform model in the vertical direction, the first horizontal direction, and / or the second horizontal direction, and using the hydraulic system to adjust the pressure, flow rate, and / or temperature of the liquid in the drill string model. S3. After the test is completed, take out the drill string model after the test, and compare the drill string model after the test with the drill string model before the test to obtain the wear amount and wear position of the drill string model after the test. S4. Repeat steps S1-S3 with different test influencing factors to conduct multiple groups of tests.

19. The multifunctional offshore horizontal well drilling system simulation test method according to claim 18, wherein in step S2, adjusting the test influencing factors further includes using the hydraulic system to inject a fluid with rock particles into the rock particle inlet on the horizontal section of the casing and adjusting the rock particle content, flow rate, temperature, and / or pressure of the fluid with rock particles, and using the driving member to drive the transmission member on the drill string end cover rotatably connected to the end of the horizontal section of the drill string and adjusting the rotation speed of the driving member.

20. The multifunctional offshore horizontal well drilling system simulation test method according to claim 18, wherein In step S1, during the process of assembling the simulation test device for the multifunctional offshore horizontal well drilling system, a plurality of anti-friction structures are sleeved between the drill string model and the casing model. The anti-friction structures include a plurality of ball bearings and can be in rolling contact with the casing model.

21. The simulation test method for the multi-functional offshore horizontal well drilling system according to claim 18, characterized in that, The simulation test method for the multifunctional offshore horizontal well drilling system further includes: S5. Determine the influencing factors of drill string wear according to multiple groups of tests; S6. Fit the influencing factors of drill string wear and the wear amount of the drill string model to obtain a prediction model between the maximum wear depth of the drill string and the influencing factors of drill string wear.

22. The simulation test method for the multifunctional offshore horizontal well drilling system according to claim 21, wherein The prediction model is: h = A p + A v + A d + A c + A t ; Among them, A p = a1p 3 + b1p 2 + c1p + d1, A v = a2v 3 + b2v 2 + c2v + d2, A d = a3d 3 + b3d 2 + c3d + d3, A c = a4C 3 + b4C 2 + c4C + d4, A t = a5t 3 + b5t 2 + c5t + d5; Let \(h\) denote the maximum wear depth of the worn drill string under the action of various factors, \(p\) denote the internal fluid pressure of the worn drill string, \(v\) denote the fluid flow velocity inside the worn drill string, \(d\) denote the diameter of the rock particles inside the worn drill string, \(C\) denote the content of rock particles in the fluid inside the worn drill string, \(A\) p denotes the maximum wear amount of the worn drill string under the action of the internal fluid pressure, \(A\) v denotes the maximum wear amount of the worn drill string under the action of the fluid flow velocity, \(A\) d denotes the maximum wear amount of the worn drill string under the action of the rock particle diameter, \(A\) c denotes the maximum wear amount of the worn drill string under the action of the content of rock particles in the fluid, \(A\) t denotes the maximum wear amount of the worn drill string under the action of the fluid impact time. \(a1, b1, c1, d1, a2, b2, c2, d2, a3, b3, c3, d3, a4, b4, c4\) and \(d4\) are all coefficients.

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