A drilling system applicable to marine exploration drilling

Abstract

The present invention provides a drilling system applicable to offshore exploration drilling, belonging to the technical field of offshore exploration drilling. The drilling system applicable to offshore exploration drilling includes an offshore operation platform, an exploration drilling assembly, an adjustment assembly, and a maintenance assembly. In the present invention, the damaged drill pipe unit is separated from the drill pipe unit below, one clamping member clamps the replaced drill pipe unit, the other clamping member clamps the damaged drill pipe unit, the damaged drill pipe unit is separated from the drill pipe unit above, through the combined action of the boom group and the replacement part, the positions between the replaced drill pipe unit and the damaged drill pipe unit are exchanged, the drill pipe unit above is screwed to the replaced drill pipe unit, and the replaced drill pipe unit is screwed to the drill pipe unit below. The seabed maintenance operation effectively reduces the height that the drill pipe needs to be lifted, greatly shortens the construction period for replacing the drill pipe, replaces the cumbersome process of having to lift the drill pipe to the water surface in the traditional method, saving time and effort.

Description

Technical Field

[0001] The present invention relates to the technical field of marine exploration drilling, and particularly relates to a drilling system suitable for marine exploration drilling. Background Art

[0002] Compared with onshore exploration, offshore exploration has higher technical requirements, more capital investment, and greater risk factors, but the expected return of oil and gas exploration in the ocean is also large. The processes of offshore exploration and drilling are the same as those of onshore exploration and drilling, that is, multiple drill pipes are spliced in sequence to send the drill bit to a predetermined position, and under the rotation of the drill bit and the gravity of the drill pipe, the function of drilling is achieved.

[0003] However, due to the different drilling environments of offshore resource exploration and drilling, the drill bit needs to dive to the seabed before starting the drilling operation. When a drill pipe is damaged and needs to be replaced, the damaged drill pipe needs to be lifted from the seabed to the water surface. Compared with the scenario of replacing a damaged drill pipe in onshore exploration and drilling, lifting the drill pipe from the seabed to the water surface requires additional work and time, and it is not easy to replace the drill pipe. Summary of the Invention

[0004] The object of the present invention is to propose a drilling system suitable for marine exploration drilling to solve the problem that when a drill pipe is damaged and needs to be replaced, lifting the drill pipe from the seabed to the water surface requires additional work and time compared with onshore exploration and drilling, and it is not easy to replace the drill pipe, aiming at the above-mentioned deficiencies of the prior art.

[0005] The present invention provides a drilling system applicable to marine exploration drilling, which includes an offshore operation platform, an exploration drilling assembly, an adjustment assembly, and a maintenance assembly. The exploration drilling assembly includes a drill pipe group and a plurality of limit members; the drill pipe group includes a plurality of drill pipe monomers that are screwed together in sequence from top to bottom. The uppermost drill pipe monomer is rotatably connected to the offshore operation platform, and the uppermost drill pipe monomer can move up and down along the seawater operation platform. The bottom end of the lowermost drill pipe monomer is connected to a drill bit fixed to the seabed; the limit member has a first state and a second state. When the limit member is in the first state, one end of the limit member is connected to one drill pipe monomer and the other end is connected to another drill pipe monomer. When the limit member is in the second state, one end of the limit member is connected to one drill pipe monomer and the other end is separated from another drill pipe monomer; the adjustment assembly is used to respectively adjust each limit member to switch between the first state and the second state; the maintenance assembly includes a boom group and at least one replacement member; the boom group is rotatably connected to the offshore operation platform, and the boom group can move up and down along the seawater operation platform. The replacement member includes a fixed seat connected to the boom group, and two clamping members respectively connected to both ends of the fixed seat. The clamping members can be unfolded to release the drill pipe monomer or closed to clamp the drill pipe monomer. One clamping member is used to clamp the replaced drill pipe monomer, and the other clamping member is used to clamp the damaged drill pipe monomer when the damaged drill pipe monomer is separated from the drill pipe monomer below it. When the damaged drill pipe monomer is separated from the drill pipe monomer above it, the boom group rotates to drive the position exchange between the replaced drill pipe monomer and the damaged drill pipe monomer.

[0006] Further, the exploration drilling assembly further includes a hoist and a rotator. Both the hoist and the rotator are connected to the offshore operation platform. The top end of the uppermost drill pipe monomer passes through the offshore operation platform and is respectively connected to the output end of the hoist and the output end of the rotator. The rotator is connected to the top end of the uppermost drill pipe monomer and is used to drive the drill pipe monomer to rotate. The maintenance assembly further includes a crane and a rotating disk. Both the crane and the rotating disk are connected to the offshore operation platform. The top end of the boom group passes through the offshore operation platform and is respectively connected to the output end of the crane and the output end of the rotating disk. The crane is used to lift the boom group, and the hoist is used to lift the uppermost drill pipe monomer when the damaged drill pipe monomer is separated from the drill pipe monomer above it.

[0007] Further, an adjustment cavity and an opening communicating with the adjustment cavity are provided at the bottom end of the drill pipe unit, and a slot is provided at the top end of the drill pipe unit. The limiting member includes a piston plate, a spring, and a plug rod. The piston plate is disposed in the adjustment cavity, and the piston plate is slidably and sealingly connected to the adjustment cavity, so that the adjustment cavity is divided into a first cavity below the piston plate and a second cavity above the piston plate. The first cavity is communicated with the opening. One end of the spring is fixedly connected to the top end of the piston plate, and the other end is fixedly connected to the inner wall of the second cavity. One end of the plug rod is fixedly connected to the bottom end of the piston plate. When the limiting member is in the first state, the spring extends, so that the middle of the plug rod is slidably and sealingly connected to the opening, and the other end passes through the opening and is clamped with the slot of the adjacent drill pipe unit. When the limiting member is in the second state, the spring is compressed, so that the other end of the plug rod is slidably and sealingly connected to the opening.

[0008] Further, a first threaded hole communicating with the first cavity and a second threaded hole communicating with the second cavity are provided on the side wall of the drill pipe unit. The limiting member further includes a first plug block and a second plug block. When two adjacent drill pipe units are connected, the first plug block is screwed into the first threaded hole, and the second plug block is screwed into the second threaded hole, so that the limiting member is in the first state. The output end of the adjustment assembly can be connected to the first plug block to drive the first plug block to rotate, and can be connected to the second plug block to drive the second plug block to rotate. When it is necessary to replace a damaged drill pipe unit, the adjustment assembly drives the first plug block to rotate, so that the first plug block is screwed out of the first threaded hole, and seawater passes through the first threaded hole and enters the inner side of the first cavity, so that the pressure in the first cavity is greater than the pressure in the second cavity, the spring is compressed, and the other end of the plug rod is driven to move to the opening, so that the limiting member is in the second state. When the replaced drill pipe unit is connected to the drill pipe unit above it or the drill pipe unit below it, the adjustment assembly drives the second plug block to rotate, so that the second plug block is screwed out of the second threaded hole, and seawater passes through the second threaded hole and enters the inner side of the second cavity, so that the pressure in the second cavity is equal to the pressure in the second cavity, the spring extends, and the other end of the plug rod is pushed to pass through the opening and inserted into the slot of the adjacent drill pipe unit, so that the limiting member is in the first state.

[0009] Further, the adjustment assembly includes a floating sleeve, an axial driving member, a circumferential driving member, and an adjusting member. The floating sleeve is coaxially sleeved on the drill pipe unit. The axial driving member is installed on the floating sleeve and is used to drive the floating sleeve to slide axially along the drill pipe unit to adjust the vertical height of the floating sleeve. The circumferential driving member is installed on the floating sleeve and is used to drive the floating sleeve to rotate circumferentially along the drill pipe unit. The adjusting member is installed on the floating sleeve. The adjusting member can be connected to the first plug block of any one of the limiting members to drive the first plug block to rotate, and can be connected to the second plug block of any one of the limiting members to drive the second plug block to rotate, so as to adjust the switching between the first state and the second state of the limiting member.

[0010] Further, a plurality of rollers are rotatably connected to the floating sleeve, and the rollers are all tangent to the length direction of the drill pipe unit.

[0011] Further, the replacement part further includes a first driving structure, the first driving structure includes a sliding plate and a first oil cylinder, the sliding plate is connected to the suspension rod group, two clamping members are symmetrically arranged with respect to the fixed seat, the fixed seat is slidably connected to the sliding plate along the direction of the axis of the two clamping members, and one end of the first oil cylinder is connected to the sliding plate and the other end is connected to the fixed seat; the first oil cylinder expands and contracts to drive the fixed seat to slide.

[0012] Further, the clamping member includes two annular clamping plates arranged oppositely and two second driving structures for respectively pulling the two annular clamping plates. The outer walls of the two annular clamping plates are rotatably connected to one side end of the fixed seat, and the two annular clamping plates can move to a first position and a second position; when the two annular clamping plates move to the first position, the two side ends of the inner walls of the two annular clamping plates abut against each other to form an annular structure for clamping the drill pipe unit; when the two annular clamping plates move to the second position, the two annular clamping plates are spaced apart to release the drill pipe unit.

[0013] Further, a groove is provided on the inner wall of the annular clamping plate, and a protrusion for matching with the groove is provided on the drill pipe unit.

[0014] Further, the second driving structure includes a second oil cylinder and two connecting rods arranged symmetrically. One ends of the two connecting rods are rotatably connected to one side end of the fixed seat, and the other ends are connected to the outer wall of one annular clamping plate. Both ends of the second oil cylinder are slidably hinged to the two connecting rods.

[0015] The drilling system applicable to offshore exploration drilling of the present invention has the following beneficial effects:

[0016] Through the combined action of the adjusting assembly, the limiting member located on the damaged drill pipe unit and the uppermost drill pipe unit, the damaged drill pipe unit is separated from the lower drill pipe unit. One clamping member clamps the replaced drill pipe unit, and the other clamping member clamps the damaged drill pipe unit. Through the adjusting assembly, the limiting member located on the upper drill pipe unit and the uppermost drill pipe unit, the damaged drill pipe unit is separated from the upper drill pipe unit. Through the combined action of the suspension rod group and the replacement part, the positions of the replaced drill pipe unit and the damaged drill pipe unit are exchanged. The upper drill pipe unit is screwed to the replaced drill pipe unit, and the replaced drill pipe unit is screwed to the lower drill pipe unit. The underwater maintenance operation effectively reduces the height that the drill pipe needs to be lifted, greatly shortens the construction period for replacing the drill pipe, replaces the traditional cumbersome process of having to lift the drill pipe to the water surface, and saves time and effort. Description of the Drawings

[0017] The accompanying drawings incorporated herein and constituting a part of the specification illustrate embodiments of the present invention and, together with the description, are used to explain the principles of the present invention. In these drawings, like reference numerals are used to represent like elements. The drawings in the following description are some embodiments of the present invention, not all embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a schematic structural diagram of the overall structure in this embodiment of the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention;

[0019] Figure 2 It is a partial cross-sectional view when two adjacent drill pipe monomers are connected to the limiting member in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention;

[0020] Figure 3 It is a schematic structural diagram of the limiting member in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention;

[0021] Figure 4 It is a schematic structural diagram in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention, where the first plugging block is spaced from the first threaded hole, and the second plugging block is threadedly connected to the second threaded hole;

[0022] Figure 5 It is a schematic structural diagram in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention, where the first plugging block is spaced from the first threaded hole, and the second plugging block is spaced from the second threaded hole;

[0023] Figure 6 It is a schematic structural diagram of the adjusting assembly in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention;

[0024] Figure 7 It is a schematic structural diagram of the replacement part in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention;

[0025] Figure 8 It is a schematic structural diagram in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention, where a groove is provided on the side wall of the drill pipe monomer;

[0026] Figure 9 It is a schematic structural diagram of multiple replacement parts in the drilling system applicable to marine exploration drilling provided by the embodiment of the present invention.

[0027] In the figure: 100 - offshore operation platform, 200 - exploration drilling assembly, 210 - hoist, 220 - rotator, 230 - drill pipe group, 231 - single drill pipe, 232 - adjustment cavity, 233 - opening, 234 - slot, 235 - first cavity, 236 - second cavity, 237 - groove, 240 - position-limiting part, 241 - piston plate, 242 - spring, 243 - inserting rod, 244 - first plugging block, 244a - first threaded hole, 245 - second plugging block, 245a - second threaded hole, 300 - adjustment assembly, 310 - floating sleeve, 311 - roller, 320 - axial driving part, 330 - circumferential driving part, 340 - adjusting part, 400 - maintenance assembly, 410 - crane, 420 - rotating disc, 430 - boom group, 440 - replacement part, 441 - fixing seat, 442 - clamping part, 442a - protrusion, 443 - first driving structure, 443a - sliding plate, 443b - first oil cylinder, 444 - second driving structure, 444a - connecting rod, 444b - second oil cylinder. Detailed implementation manners

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other arbitrarily.

[0029] Please refer to Figures 1-9。A drilling system applicable to marine exploration drilling according to an embodiment of the present invention includes an offshore operation platform 100, an exploration drilling assembly 200, an adjustment assembly 300, and a maintenance assembly 400. The exploration drilling assembly 200 includes a drill pipe group 230 and a plurality of limit members 240. The drill pipe group 230 includes a plurality of drill pipe units 231 screwed together in sequence from top to bottom. The uppermost drill pipe unit 231 is rotatably connected to the offshore operation platform 100, and the uppermost drill pipe unit 231 can move up and down along the seawater operation platform. The bottom end of the lowermost drill pipe unit 231 is connected to a drill bit fixed to the seabed. The limit member 240 has a first state and a second state. When the limit member 240 is in the first state, one end of the limit member 240 is connected to one drill pipe unit 231 and the other end is connected to another drill pipe unit 231 to limit the circumferential rotation of two adjacent drill pipe units 231. When the limit member 240 is in the second state, one end of the limit member 240 is connected to one drill pipe unit 231 and the other end is separated from another drill pipe unit 231, so that the upper drill pipe unit 231 can rotate circumferentially. The adjustment assembly 300 is used to adjust the switching of each limit member 240 between the first state and the second state respectively. The maintenance assembly 400 includes a boom group 430 and at least one replacement part 440. The boom group 430 is rotatably connected to the offshore operation platform 100, and the boom group 430 can move up and down along the seawater operation platform. The replacement part 440 includes a fixed seat 441 connected to the boom group 430 and two clamping members 442 respectively connected to both ends of the fixed seat 441. The clamping members 442 can be unfolded to release the drill pipe unit 231 or closed to clamp the drill pipe unit 231. One clamping member 442 is used to clamp the replaced drill pipe unit 231, and the other clamping member 442 is used to clamp the damaged drill pipe unit 231 when the damaged drill pipe unit 231 is separated from the drill pipe unit 231 below it. When the damaged drill pipe unit 231 is separated from the drill pipe unit 231 above it, the boom group 430 rotates to drive the position exchange between the replaced drill pipe unit 231 and the damaged drill pipe unit 231.

[0030] Here, a first installation groove and a second installation groove are provided on the offshore operation platform. The uppermost drill pipe unit 231 is inserted into the first installation groove, and the uppermost drill pipe unit 231 is rotatably connected to the first installation groove. The suspension rod group 430 is inserted into the second installation groove, and the suspension rod group 430 is rotatably connected to the second installation groove. The adjusting assembly 300 adjusts the limiting member 240 located on the damaged drill pipe unit 231 to the second state, so that the limiting member 240 is separated from the drill pipe unit 231 located below the damaged drill pipe unit 231. Since the drill bit is fixed to the seabed and the bottom end of the lowermost drill pipe unit 231 is connected to the drill bit, the lowermost drill pipe unit 231 cannot rotate when the drill bit does not move. Since the limiting members 240 on the drill pipe units 231 from the drill pipe unit 231 below the damaged drill pipe unit 231 to the lowermost drill pipe unit 231 are all in the first state, when the lowermost drill pipe unit 231 cannot rotate, the drill pipe unit 231 below the damaged drill pipe unit 231 cannot rotate. Rotate the uppermost drill pipe unit 231 in the counterclockwise direction, thereby driving the damaged drill pipe unit 231 to rotate, so that the damaged drill pipe unit 231 moves away from the drill pipe unit 231 below, and the damaged drill pipe unit 231 moves upward, so that the damaged drill pipe unit 231 is separated from the drill pipe unit 231 below; the two clamping members 442 are symmetrically arranged with respect to the fixed seat 441. Initially, both clamping members 442 are in the unfolded state. Place the replaced drill pipe unit 231 in one clamping member 442, and close the clamping member 442, thereby clamping the replaced drill pipe unit 231 by one clamping member 442. Move the suspension rod group 430 downward along the seawater operation platform, thereby transporting the replaced drill pipe unit 231 to a height position matching the damaged drill pipe unit 231. Place the other clamping member 442 on the outer periphery of the damaged drill pipe unit 231, and close the clamping member 442, thereby clamping the damaged drill pipe unit 231 by the other clamping member 442, so that the damaged drill pipe unit 231 cannot rotate. The adjusting assembly 300 adjusts the limiting member 240 on the drill pipe unit 231 above the damaged drill pipe unit 231 to the second state, so that the limiting member 240 is separated from the damaged drill pipe unit 231. Rotate the uppermost drill pipe unit 231 in the counterclockwise direction again, thereby driving the drill pipe unit 231 above the damaged drill pipe unit 231 to rotate in the counterclockwise direction. Since the damaged drill pipe unit 231 cannot rotate, the damaged drill pipe unit 231 is separated from the drill pipe unit 231 above. When the drill pipe unit 231 above rotates counterclockwise, the drill pipe unit 231 above moves upward; rotate the suspension rod group 430 so that the positions between the two clamping members 442 are exchanged, driving the positions between the replaced drill pipe unit 231 and the damaged drill pipe unit 231 to be exchanged;Push the uppermost drill pipe unit 231 downward so that the upper drill pipe unit 231 abuts against the replaced drill pipe unit 231. Rotate the uppermost drill pipe unit 231 in the clockwise direction, driving the replaced drill pipe unit 231 to rotate in the clockwise direction, so that the upper drill pipe unit 231 is screwed to the replaced drill pipe unit 231; Expand a holding member 442 so that the holding member 442 is separated from the replaced drill pipe unit 231. Push the uppermost drill pipe unit 231 downward, driving the replaced drill pipe unit 231 to move downward so that the replaced drill pipe unit 231 abuts against the lower drill pipe unit 231. Rotate the uppermost drill pipe unit 231 in the clockwise direction, driving the replaced drill pipe unit 231 to rotate in the clockwise direction, so that the replaced drill pipe unit 231 is screwed to the lower drill pipe unit 231. Adjust the limit members 240 on the upper drill pipe unit 231 and the limit members 240 on the replaced drill pipe unit 231 to the first state through the adjusting assembly 300, realizing the replacement of the damaged drill pipe unit 231.;

[0031] Specifically, any two adjacent upper and lower drill pipe units 231 are connected via a limit member 240. When the limit member 240 is in the first state, the top end of the limit member 240 is connected to the upper drill pipe unit 231 and the bottom end is connected to the lower drill pipe unit 231. The limit member 240 can limit the circumferential rotation of two adjacent drill pipe units 231, so that two adjacent upper and lower drill pipe units 231 can only rotate simultaneously. When the limit member 240 is in the second state, the top end of the limit member 240 is connected to the upper drill pipe unit 231 and the bottom end is disengaged from the lower drill pipe unit 231, then the two adjacent drill pipe units 231 can rotate circumferentially. Then, when the lower drill pipe unit 231 is fixed, rotating the upper drill pipe unit 231 can separate the two screwed upper and lower drill pipe units 231.

[0032] Specifically, the drill pipe group 230 includes a plurality of drill pipe units 231 connected in sequence by threads. It can be seen that the tightening directions of the plurality of drill pipe units 231 are the same, and the loosening directions are also the same. For the convenience of understanding, the tightening direction of the plurality of drill pipe units 231 is clockwise, and the loosening direction is counterclockwise.

[0033] See Figure 1 、 2, 7. The exploration drilling assembly 200 may further include a hoist 210 and a rotator 220. Both the hoist 210 and the rotator 220 are connected to the offshore operation platform 100. The top end of the uppermost drill pipe unit 231 passes through the offshore operation platform 100 and is respectively connected to the output end of the hoist 210 and the output end of the rotator 220. The rotator 220 is connected to the top end of the uppermost drill pipe unit 231 to drive the drill pipe unit 231 to rotate. The maintenance assembly 400 further includes a crane 410 and a rotating disc 420. Both the crane 410 and the rotating disc 420 are connected to the offshore operation platform 100. The top end of the boom group 430 passes through the offshore operation platform 100 and is respectively connected to the output end of the crane 410 and the output end of the rotating disc 420. The crane 410 is used to lift the boom group 430, and the hoist 210 is used to lift the uppermost drill pipe unit 231 when the damaged drill pipe unit 231 is separated from the drill pipe unit 231 above it.

[0034] Specifically, one side end of the hoist 210 can be fixed to the offshore operation platform 100, one side end of the rotator 220 can be connected to the offshore operation platform 100 through a first telescopic structure or a rope, one side end of the crane 410 can be fixed to the offshore operation platform 100, and one side end of the rotating disc 420 can be connected to the offshore operation platform 100 through a second telescopic structure or a rope. The output end of the adjusting assembly 300 can be connected to any one of the limit members 240 to adjust the switching of the limit member 240 between the first state and the second state. The clamping members 442 can also be connected to the fixed seat 441 through a third telescopic structure. When the replaced drill pipe unit 231 moves to a position matching the damaged drill pipe unit 231, the third telescopic structures connected to the two clamping members 442 respectively extend by a first preset length, so that one of the clamping members 442 moves to the outer periphery of the damaged drill pipe unit 231, facilitating the clamping member 442 to fix the damaged drill pipe unit 231. The lengths of the two telescopic structures are the same, and the two clamping members 442 are symmetrically arranged with respect to the fixed seat 441, so the distances between the two clamping members 442 and the fixed seat 441 are the same, ensuring that the distances between the damaged drill pipe unit 231 and the replaced drill pipe unit 231 and the fixed seat 441 are the same respectively. The fixed seat 441 can also slide along a direction perpendicular to the center line of the boom group 430, and the two clamping members 442 are respectively arranged at both ends of the fixed seat 441 along its sliding direction.

[0035] Specifically, generally, when the drill pipe set 230 is working, the rotator 220 drives the drill pipe set 230 to rotate clockwise. In this application, a limiting member 240 is provided. When the limiting member 240 is in the first state, multiple drill pipe units 231 can rotate synchronously clockwise or counterclockwise under the drive of the rotator 220. When one of the drill pipe units 231 is damaged, the limiting member 240 between the damaged drill pipe unit 231 and the adjacent lower drill pipe unit 231 is adjusted to the second state through the adjusting assembly 300. Under the rotation of the rotator 220, the damaged drill pipe unit 231 and the multiple upper rod units can rotate counterclockwise, so as to be thread-separated from the lower rod units. At this time, the hoist 210 pulls up the uppermost drill pipe unit 231 to prevent the damaged drill pipe unit 231 from falling, and ensure that the bottom end of the damaged drill pipe unit 231 is at the first position of the first preset height; at the same time, a drill pipe unit 231 identical to the damaged drill pipe unit 231 is selected as the replacement drill pipe unit 231. The replacement drill pipe unit 231 is fixed by one of the clamping members 442. The boom group 430 is controlled to descend by the crane 410, so that the bottom end of the replacement drill pipe unit 231 descends to the same height as the bottom end of the damaged drill pipe unit 231, and the damaged drill pipe unit 231 is fixed by closing the other clamping member 442; the limiting member 240 between the damaged drill pipe unit 231 and the adjacent upper drill pipe unit 231 is adjusted to the second state through the adjusting assembly 300. Under the rotation of the rotator 220, the multiple upper rod units can rotate counterclockwise, so as to realize the thread separation between the damaged rod unit and the multiple upper rod units. At this time, the hoist 210 pulls up the uppermost drill pipe unit 231 to prevent the upper drill pipe unit 231 from falling, and ensure that the bottom end of the upper drill pipe unit 231 is at the second position of the second preset height. The boom group 430 is driven by the rotating disk 420, so as to drive the other clamping member 442 pre-mounted with the replacement drill pipe unit 231 to rotate to the current position of the damaged drill pipe unit 231, and realize the position exchange between the replacement drill pipe unit 231 and the damaged drill pipe unit 231;The hoist 210 pushes the uppermost drill pipe unit 231 downward, causing the bottom end of the upper drill pipe unit 231 to abut against the top end of the replaced drill pipe unit 231. The rotator 220 drives the multiple upper drill pipe units 231 to rotate clockwise synchronously to achieve the threaded connection between the multiple upper drill pipe units 231 and the replaced drill pipe unit 231. The clamping member 442 expands, causing the clamping member 442 to separate from the replaced drill pipe unit 231. The hoist 210 pushes the uppermost drill pipe unit 231 to continue descending, causing the bottom end of the replaced drill pipe unit 231 to abut against the top end of the lower drill pipe unit 231, and the rotator 220 drives the replaced drill pipe unit 231 and the multiple upper drill pipe units 231 to rotate clockwise synchronously until they are screwed into the lower drill pipe unit 231, thus completing the entire drill pipe replacement process. Among them, the height difference of the up-and-down floating of the drill pipe unit 231 during the threaded connection process is controlled by the provided hoist 210 and the crane 410. The undersea maintenance operation effectively reduces the height that the drill pipe needs to be lifted, greatly shortening the construction period for replacing the drill pipe and replacing the cumbersome process of having to lift the drill pipe to the water surface in the traditional way, saving time and effort.

[0036] Specifically, the offshore operation platform 100 in the present application can be used for resource exploration or resource collection operations. When used for resource exploration, the offshore operation platform 100 is an exploration vessel, and when used for resource collection, the offshore operation platform 100 is an offshore drilling platform. That is, the drill bit replacement device in the present application is applicable to the environments of offshore resource exploration and collection. The exploration drilling assembly 200 in the present application is a structure for exploration sampling and drilling for oil production. The exploration drilling assembly 200 should also include devices such as drill bits, drill collars, and blowout preventers, which are omitted here because they are not relevant to the inventive concept of the embodiments of the present invention. Among them, when the limiting member 240 is in the first state, the multiple drill pipe units 231 can rotate clockwise or counterclockwise synchronously driven by the rotator 220. When the limiting member 240 is in the second state, if the multiple drill pipe units 231 rotate in the clockwise direction, drilling work can be achieved. If the multiple drill pipe units 231 rotate counterclockwise synchronously, there is a possibility of thread separation between two adjacent drill pipe units 231 adjacent to the limiting member 240240.

[0037] See Figure 3, the bottom end of the drill pipe unit 231 may be provided with an adjustment cavity 232 and an opening 233 communicating with the adjustment cavity 232. The top end of the drill pipe unit 231 is provided with a slot 234. The limiting member 240 includes a piston plate 241, a spring 242, and a plug rod 243. The piston plate 241 is disposed inside the adjustment cavity 232. The piston plate 241 is slidably and sealingly connected to the adjustment cavity 232, so that the adjustment cavity 232 is divided into a first cavity 235 below the piston plate 241 and a second cavity 236 above the piston plate 241. The first cavity 235 is communicated with the opening 233. The spring 242 is disposed inside the second cavity 236. One end of the spring 242 is fixedly connected to the top end of the piston plate 241, and the other end is fixedly connected to the inner wall of the second cavity 236. One end of the plug rod 243 is fixedly connected to the bottom end of the piston plate 241. When the limiting member 240 is in the first state, the spring 242 extends, so that the middle of the plug rod 243 is slidably and sealingly connected to the opening 233, and the other end passes through the opening 233 and is clamped with the slot 234 of the adjacent drill pipe unit 231. When the limiting member 240 is in the second state, the spring 242 is compressed, so that the other end of the plug rod 243 is slidably and sealingly connected to the opening 233.

[0038] Specifically, the adjustment cavity 232 communicates with the outside through the opening 233. The piston plate 241 can slide in the adjustment cavity 232, and when the piston plate 241 slides to any position in the adjustment cavity 232, the adjustment cavity 232 is divided into a first cavity 235 and a second cavity 236. The piston plate 241 can seal the connection between the first cavity 235 and the second cavity 236, so that the first cavity 235 and the second cavity 236 are disconnected. One end of the plug rod 243 is fixedly connected to the piston plate 241. The other end of the plug rod 243 is slidably and sealingly connected to the opening 233 and passes out of the opening 233 to be clamped with the slot 234 opened on the end face of the adjacent drill pipe unit 231. The plug rod 243 can slide in the opening 233, and when the plug rod 243 is inserted into the opening 233, it can seal the opening 233 to prevent seawater from passing through the opening 233 and entering the first cavity 235.

[0039] See Figures 3-5, on the side wall of the single drill pipe 231, a first threaded hole 244a communicating with the first cavity 235 and a second threaded hole 245a communicating with the second cavity 236 can be provided. The limiting member 240 further includes a first plug block 244 and a second plug block 245. When two adjacent single drill pipes 231 are connected, the first plug block 244 is screwed into the first threaded hole 244a, and the second plug block 245 is screwed into the second threaded hole 245a, so that the limiting member 240 is in the first state. The output end of the adjusting assembly 300 can be connected to the first plug block 244 to drive the first plug block 244 to rotate, and can be connected to the second plug block 245 to drive the second plug block 245 to rotate. When it is necessary to replace the damaged single drill pipe 231, the adjusting assembly 300 drives the first plug block 244 to rotate, so that the first plug block 244 is screwed out of the first threaded hole 244a, and seawater passes through the first threaded hole 244a and enters the inside of the first cavity 235, so that the pressure in the first cavity 235 is greater than the pressure in the second cavity 236, the spring 242 is compressed, and the other end of the insertion rod 243 is driven to move to the opening 233, so that the limiting member 240 is in the second state. When the replaced single drill pipe 231 is connected to the single drill pipe 231 above it or the single drill pipe 231 below it, the adjusting assembly 300 drives the second plug block 245 to rotate, so that the second plug block 245 is screwed out of the second threaded hole 245a, and seawater passes through the second threaded hole 245a and enters the inside of the second cavity 236, so that the pressure in the second cavity 236 is equal to the pressure in the second cavity 236, the spring 242 extends, and the other end of the insertion rod 243 is pushed to pass through the opening 233 and inserted into the slot 234 of the adjacent single drill pipe 231, so that the limiting member 240 is in the first state.

[0040] Specifically, by providing the first plug block 244 and the second plug block 245, it is convenient to control the movement of the insertion rod 243. The output end of the adjusting assembly 300 is connected to the first plug block 244 to drive the first plug block 244 to rotate, so that the first plug block 244 is screwed out of the first threaded hole 244a. The output end of the adjusting assembly 300 is connected to the second plug block 245 to drive the second plug block 245 to rotate, so that the second plug block 245 is screwed out of the second threaded hole 245a.

[0041] Specifically, refer to Figure 3 , before lowering the well, when the first plug block 244 in each single drill pipe 231 is threadedly connected to the first threaded hole 244a and the second plug block 245 is threadedly connected to the second threaded hole 245a, the pressure in the first cavity 235 is equal to the pressure in the second cavity 236, the spring 242 extends, the insertion rod 243 is clamped with the slot 234, and the limiting member 240 is in the first state. Refer to Figure 4, when the drill pipe needs to be replaced after being damaged, first, it is necessary to unlock the damaged drill pipe unit 231 from the adjacent drill pipe unit 231. The first plugging block 244 and the first threaded hole 244a are arranged at intervals, that is, the first plugging block 244 disengages from the first threaded hole 244a. When the second plugging block 245 is threadedly connected to the second threaded hole 245a, under the action of water pressure, seawater enters the first cavity 235, making the pressure in the first cavity 235 greater than the pressure in the second cavity 236. The spring 242 is compressed, and the insertion rod 243 and the slot 234 are arranged at intervals, that is, the insertion rod 243 disengages from the slot 234, so that the limiting member 240 is in the second state, thereby realizing the function of unlocking the damaged drill pipe unit 231 from the drill pipe unit 231 below or above. At the same time, since the first plugging block 244 on the damaged drill pipe unit 231 and the first threaded hole 244a are arranged at intervals and the second plugging block 245 and the second threaded hole 245a are threadedly connected at this time, the replacement drill pipe unit 231 to be replaced and the damaged drill pipe unit 231 need to be adjusted to be the same. The first plugging block 244 on the pre-installed replacement drill pipe unit 231 held by the holding member 442 and the first threaded hole 244a are arranged at intervals, and the second plugging block 245 and the second threaded hole 245a are threadedly connected. See Figure 5 , after exchanging the positions of the replacement drill pipe unit 231 and the damaged drill pipe unit 231, the first plugging block 244 and the first threaded hole 244a are arranged at intervals, and the second plugging block 245 and the second threaded hole 245a are arranged at intervals. Seawater enters the first cavity 235 and the second cavity 236 at the same time. The pressure in the first cavity 235 is equal to the pressure in the second cavity 236. The spring 242 elongates, the insertion rod 243 is clamped with the slot 234, and the limiting member 240 is in the first state, thereby completing the circumferential limiting function between the replaced drill pipe unit 231 and the adjacent drill pipe unit 231, without affecting the replacement of the remaining drill pipe units 231 subsequently.

[0042] See Figure 6 , the adjusting assembly 300 may include a floating sleeve 310, an axial driving member 320, a circumferential driving member 330, and an adjusting member 340. The floating sleeve 310 is coaxially sleeved on the drill pipe unit 231; the axial driving member 320 is installed on the floating sleeve 310 to drive the floating sleeve 310 to slide axially along the drill pipe unit 231 to adjust the vertical height of the floating sleeve 310; the circumferential driving member 330 is installed on the floating sleeve 310 to drive the floating sleeve 310 to rotate circumferentially along the drill pipe unit 231; the adjusting member 340 is installed on the floating sleeve 310. The adjusting member 340 can be connected to the first plugging block 244 of any one of the limiting members 240 to drive the first plugging block 244 to rotate, and connected to the second plugging block 245 of any one of the limiting members 240 to drive the second plugging block 245 to rotate, so as to adjust the switching of the limiting member 240 between the first state and the second state.

[0043] Specifically, the floating sleeve 310 is coaxially sleeved on a plurality of drill pipe units 231 of the drill pipe group 230. The adjusting end of the adjusting member 340 faces the first plugging block 244 or the second plugging block 245. The adjusting end of the adjusting member 340 extends into the interior of the floating sleeve 310 and can be connected to any one of the limiting members 240 to adjust the switching of the limiting member 240 between the first state and the second state.

[0044] Specifically, in order to facilitate the connection or disconnection between the first plugging block 244 and the first threaded hole 244a, and the connection or disconnection between the second plugging block 245 and the second threaded hole 245a, a cross cutter is connected to the adjusting end of the adjusting member 340. The adjusting member 340 is used to drive the cross cutter to rotate and move in the direction close to or away from the drill pipe group 230. The cross cutter can be connected to a cross groove opened on the first plugging block 244 or the second plugging block 245. When the cross cutter is stuck in the cross groove, by rotating the cross cutter and driving the cross cutter to move in the direction away from the drill pipe group 230, the first plugging block 244 can be separated from the first threaded hole 244a. Similarly, the second plugging block 245 can be separated from the second threaded hole 245a. Among them, the axial driving member 320 and the circumferential driving member 330 can be realized by a thruster, which is a structure that can be conceived by those skilled in the art and will not be elaborated and described in detail here.

[0045] See Figure 6 , a plurality of rollers 311 can be rotatably connected to the floating sleeve 310, and the rollers 311 are all tangent to the length direction of the drill pipe unit 231.

[0046] Specifically, in order to make the floating sleeve 310 slide more smoothly, a plurality of rollers 311 are rotatably connected to the inner wall of the floating sleeve 310. The plurality of rollers 311 are evenly arranged along the circumferential direction of the floating sleeve 310, and each roller 311 is tangent to the length direction of the drill pipe group 230.

[0047] See Figure 7 , the replacement part 440 can further include a first driving structure 443. The first driving structure 443 includes a sliding plate 443a and a first oil cylinder 443b. The sliding plate 443a is connected to the suspension rod group 430. The two holding members 442 are symmetrically arranged with respect to the fixed seat 441. The fixed seat 441 is slidably connected to the sliding plate 443a along the axis direction of the two holding members 442. One end of the first oil cylinder 443b is connected to the sliding plate 443a and the other end is connected to the fixed seat 441; the first oil cylinder 443b expands and contracts to drive the fixed seat 441 to slide.

[0048] Specifically, the first driving structure 443 is used to drive the fixed seat 441 to rotate and slide, and the sliding plate 443a is fixedly connected to the bottom end of the suspension rod group 430. One end of the first oil cylinder 443b is fixedly connected to the sliding plate 443a, and the other end is connected to the fixed seat 441, and is used to drive the fixed seat 441 to slide along the axis direction of the two clamping members 442. One of the clamping members 442 on the left side of the suspension rod group 430 is connected to the left end of the outer wall of the fixed seat 441, and the other clamping member 442 on the right side of the suspension rod group 430 is connected to the right end of the outer wall of the fixed seat 441. The clamping member 442 on the right side clamps the replaced drill pipe unit 231. The first oil cylinder 443b includes two telescopic rods on the left and right sides. The telescopic rod on the left side is connected to the left end of the inner wall of the fixed seat 441, and the telescopic rod on the right side is connected to the right end of the inner wall of the fixed seat 441. The telescopic rod on the left side is extended by a second preset length, and the telescopic rod on the right side is shortened by a third preset length, so as to push the fixed seat 441 to move towards the left, and push one of the clamping members 442 on the left to the damaged drill pipe unit 231. When it is necessary to exchange the positions of the replaced drill pipe unit 231 and the damaged drill pipe unit 231, the telescopic rod on the left side is shortened by a fourth preset length, and the telescopic rod on the right side is extended by a fifth preset length, which is convenient for rotating the replaced drill pipe unit 231 to the position where the damaged drill pipe unit 231 is located when the suspension rod group 430 rotates.

[0049] See Figure 7 , the clamping member 442 may include two annular clamping plates arranged oppositely and two second driving structures 444 for respectively pulling the two annular clamping plates. The outer walls of the two annular clamping plates are rotatably connected to one side end of the fixed seat 441, and the two annular clamping plates can move to the first position and the second position; when the two annular clamping plates move to the first position, the two side ends of the inner walls of the two annular clamping plates abut against each other to form an annular structure for clamping the drill pipe unit 231; when the two annular clamping plates move to the second position, the two annular clamping plates are arranged at intervals to release the drill pipe unit 231.

[0050] Specifically, the annular clamping plate may be a semi-circular clamping plate. Both of the two annular clamping plates are movably connected to the fixed seat 441. When the two semi-circular clamping plates move to the first position, the two semi-circular clamping plates are butted to form an annular structure for clamping the damaged drill pipe unit 231 or the replaced drill pipe unit 231. When the two semi-circular clamping plates move to the second position, the two semi-circular clamping plates are arranged at intervals to release the damaged drill pipe unit 231 or the replaced drill pipe unit 231. The second driving structures 444 may be two symmetrically arranged ones. Both of the two second driving structures 444 are connected to the fixed seat 441, and the output ends of the two second driving structures 444 are respectively connected to the two annular clamping plates in the two clamping members 442, and are used to respectively drive the two annular clamping plates in each clamping member 442 to move between the first position and the second position.

[0051] See Figure 8 , a groove 237 may be provided on the inner wall of the annular splint, and a protrusion 442a for matching with the groove 237 is provided on the drill pipe unit 231.

[0052] Specifically, the two annular splints are symmetrically arranged, grooves 237 are provided on both annular splints, the grooves 237 on the two annular splints are symmetrically arranged, and two protrusions 442a may be symmetrically provided on the drill pipe unit 231. The protrusion 442a is inserted into the groove 237 to fix the damaged drill pipe unit 231 or the replaced drill pipe unit 231.

[0053] See Figure 7 , the second driving structure 444 may include a second oil cylinder 444b and two symmetrically arranged connecting rods 444a. One end of each of the two connecting rods 444a is rotatably connected to one side end of the fixed seat 441, and the other end is connected to the outer wall of an annular splint. Both ends of the second oil cylinder 444b are slidably hinged to the two connecting rods 444a. When the second oil cylinder 444b extends, the distance between the two connecting rods 444a becomes larger, and the distance between the two annular splints becomes larger, so as to realize the expansion of the clamping member 442; when the second oil cylinder 444b contracts, the distance between the two connecting rods 444a becomes smaller, and the distance between the two annular splints becomes smaller, so as to realize the closing of the clamping member 442.

[0054] Specifically, one end of each of the two connecting rods 444a is hinged to the fixed seat 441, and the other ends are respectively fixedly connected to the two annular splints in the clamping member 442. A collar is sleeved on the two connecting rods 444a, and the collar can slide along the connecting rods 444a. Both ends of the second oil cylinder 444b are respectively hinged to the two collars, that is, both ends of the second oil cylinder 444b are slidably hinged to the two connecting rods 444a.

[0055] Specifically, in order to increase the replacement times of the drill pipe unit 231, reduce the number of times of raising and lowering the drill, and save time, the number of replacement parts 440 is multiple, and the multiple replacement parts 440 are arranged in sequence along the length direction of the suspension rod group 430, and the projections of the multiple clamping members 442 on the horizontal plane are arranged in sequence along the circumferential direction of the suspension rod group 430.

[0056] Specifically, see Figure 9 , the number of replacement parts 440 is four, and the drill pipe unit 231 can be replaced seven times. Specifically, one of the clamping members 442 needs to be unloaded to remove the damaged drill pipe unit 231, and the remaining clamping members 442 can be pre-placed with the drill pipe units 231 to be replaced.

[0057] It should be noted that the control principles of the first oil cylinder 443b and the second oil cylinder 444b in this application are the same as those of the blowout preventer, which are structures that can be thought of by those skilled in the art, and will not be elaborated and described in detail here.

[0058] Compared with the prior art: The drill pipe group 230 includes a plurality of drill pipe units 231 that are sequentially thread - connected. It can be seen that the tightening directions of the plurality of drill pipe units 231 are the same. For the sake of easy understanding, the tightening direction of the plurality of drill pipe units 231 is clockwise. Usually, when the drill pipe group 230 is working, the rotator 220 drives the drill pipe group 230 to rotate clockwise. In this application, a limiting member 240 is provided. When the limiting member 240 is in the first state, the plurality of drill pipe units 231 can rotate synchronously clockwise or counterclockwise under the drive of the rotator 220. When one of the drill pipe units 231 is damaged, the limiting member 240 between the damaged drill pipe unit 231 and the adjacent lower drill pipe unit 231 is adjusted to the second state through the adjusting assembly 300. Under the rotation of the rotator 220, the damaged drill pipe unit and the plurality of drill pipe units above it can rotate counterclockwise, so as to be thread - separated from the drill pipe units below. At the same time, the damaged drill pipe unit 231 is fixed by one of the clamping members 442. The limiting member 240 between the damaged drill pipe unit 231 and the adjacent upper drill pipe unit 231 is adjusted to the second state through the adjusting assembly 300. Under the rotation of the rotator 220, the plurality of drill pipe units above can rotate counterclockwise, so as to realize the thread - separation of the damaged drill pipe unit from the plurality of drill pipe units above. The other clamping member 442 pre - loaded with the replacement drill pipe unit 231 is driven by the rotating disk 420 to rotate to the current position of the damaged drill pipe unit 231. The rotator 220 drives the plurality of drill pipe units above to rotate clockwise synchronously, so as to realize the thread connection between the plurality of drill pipe units above and the replacement drill pipe unit 231. The clamping member 442 is separated from the replacement drill pipe unit 231, and the rotator 220 drives the replacement drill pipe unit 231 and the plurality of drill pipe units above to rotate clockwise synchronously until they are screwed into the lower drill pipe unit 231, thus completing the entire drill pipe replacement process. Among them, the height difference of the up - and - down floating of the drill pipe unit 231 during the thread connection process is controlled by the provided hoist 210 and crane 410. The subsea maintenance operation effectively reduces the height that the drill pipe needs to be lifted, greatly shortens the construction period of replacing the drill pipe, and replaces the traditional cumbersome process of having to lift the drill pipe to the water surface, saving time and effort.

[0059] The content described above can be implemented alone or in various combinations, and these variant ways are all within the protection scope of the present invention.

[0060] It should be noted that in the description of the present application, the terms "upper end", "lower end", and "bottom end" indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this application is customarily placed during use. These are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application. Moreover, the term "comprise", "include" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drilling system applicable to marine exploration drilling, Characterized in that: It includes an offshore operation platform (100), an exploration drilling assembly (200), an adjustment assembly (300) and a maintenance assembly (400). The exploration drilling assembly (200) includes a drill pipe group (230) and a plurality of limit members (240); the drill pipe group (230) includes a plurality of drill pipe monomers (231) screwed together in sequence from top to bottom. The uppermost drill pipe monomer (231) is rotatably connected to the offshore operation platform (100), and the uppermost drill pipe monomer (231) can move up and down along the seawater operation platform. The bottom end of the lowermost drill pipe monomer (231) is connected to a drill bit fixed to the seabed; the limit member (240) has a first state and a second state. When the limit member (240) is in the first state, one end of the limit member (240) is connected to one drill pipe monomer (231), and the other end is connected to another drill pipe monomer (231). When the limit member (240) is in the second state, one end of the limit member (240) is connected to one drill pipe monomer (231), and the other end is separated from another drill pipe monomer (231); the adjustment assembly (300) is used to respectively adjust the switching of each limit member (240) between the first state and the second state; the maintenance assembly (400) includes a boom group (430) and at least one replacement part (440); the boom group (430) is rotatably connected to the offshore operation platform (100), and the boom group (430) can move up and down along the seawater operation platform. The replacement part (440) includes a fixing seat (441) connected to the boom group (430) and two clamping members (442) respectively connected to both ends of the fixing seat (441). The clamping members (442) can be unfolded to release the drill pipe monomer (231) or closed to clamp the drill pipe monomer (231). One clamping member (442) is used to clamp the replaced drill pipe monomer (231), and the other clamping member (442) is used to clamp the damaged drill pipe monomer (231) when the damaged drill pipe monomer (231) is separated from the drill pipe monomer (231) below it. When the damaged drill pipe monomer (231) is separated from the drill pipe monomer (231) above it, the boom group (430) rotates to drive the position exchange between the replaced drill pipe monomer (231) and the damaged drill pipe monomer (231).

2. A drilling system applicable to marine exploration drilling according to claim 1, Characterized in that: The exploration drilling assembly (200) further includes a hoist (210) and a rotator (220). Both the hoist (210) and the rotator (220) are connected to the offshore operation platform (100). The top end of the uppermost drill pipe unit (231) passes through the offshore operation platform (100) and is respectively connected to the output end of the hoist (210) and the output end of the rotator (220). The rotator (220) is connected to the top end of the uppermost drill pipe unit (231) to drive the drill pipe unit (231) to rotate. The maintenance assembly (400) further includes a crane (410) and a rotating disc (420). Both the crane (410) and the rotating disc (420) are connected to the offshore operation platform (100). The top end of the boom group (430) passes through the offshore operation platform (100) and is respectively connected to the output end of the crane (410) and the output end of the rotating disc (420). The crane (410) is used to lift the boom group (430). The hoist (210) is used to lift the uppermost drill pipe unit (231) when the damaged drill pipe unit (231) is separated from the drill pipe unit (231) above it.

3. A drilling system applicable to marine exploration drilling as claimed in claim 1 or 2, characterized in that: An adjustment cavity (232) and an opening (233) communicating with the adjustment cavity (232) are provided at the bottom end of the drill pipe unit (231). A slot (234) is provided at the top end of the drill pipe unit (231). The limiting member (240) includes a piston plate (241), a spring (242), and a plug rod (243). The piston plate (241) is disposed inside the adjustment cavity (232). The piston plate (241) is slidably and sealingly connected to the adjustment cavity (232), so that the adjustment cavity (232) is divided into a first cavity (235) below the piston plate (241) and a second cavity (236) above the piston plate (241). The first cavity (235) is communicated with the opening (233). One end of the spring (242) is fixedly connected to the top end of the piston plate (241), and the other end is fixedly connected to the inner wall of the second cavity (236). One end of the plug rod (243) is fixedly connected to the bottom end of the piston plate (241). When the limiting member (240) is in the first state, the spring (242) extends, so that the middle of the plug rod (243) is slidably and sealingly connected to the opening (233), and the other end passes through the opening (233) and is clamped with the slot (234) of the adjacent drill pipe unit (231). When the limiting member (240) is in the second state, the spring (242) is compressed, so that the other end of the plug rod (243) is slidably and sealingly connected to the opening (233).

4. A drilling system applicable to marine exploration drilling as claimed in claim 3, characterized in that: A first threaded hole (244a) communicating with the first cavity (235) and a second threaded hole (245a) communicating with the second cavity (236) are provided on the side wall of the drill pipe unit (231). The limiting member (240) further includes a first plug block (244) and a second plug block (245). When two adjacent drill pipe units (231) are connected, the first plug block (244) is screwed into the first threaded hole (244a), and the second plug block (245) is screwed into the second threaded hole (245a), so that the limiting member (240) is in the first state. The output end of the adjusting assembly (300) can be connected to the first plug block (244) to drive the first plug block (244) to rotate, and can be connected to the second plug block (245) to drive the second plug block (245) to rotate. When it is necessary to replace a damaged drill pipe unit (231), the adjusting assembly (300) drives the first plug block (244) to rotate, so that the first plug block (244) is screwed out of the first threaded hole (244a), and seawater passes through the first threaded hole (244a) and enters the inner side of the first cavity (235), so that the pressure in the first cavity (235) is greater than the pressure in the second cavity (236), and the spring (242) is compressed, driving the other end of the insertion rod (243) to move to the opening (233), so that the limiting member (240) is in the second state. When the replaced drill pipe unit (231) is connected to the drill pipe unit (231) above it or the drill pipe unit (231) below it, the adjusting assembly (300) drives the second plug block (245) to rotate, so that the second plug block (245) is screwed out of the second threaded hole (245a), and seawater passes through the second threaded hole (245a) and enters the inner side of the second cavity (236), so that the pressure in the second cavity (236) is equal to the pressure in the second cavity (236), the spring (242) extends, and pushes the other end of the insertion rod (243) to pass through the opening (233) and be inserted into the slot (234) of the adjacent drill pipe unit (231), so that the limiting member (240) is in the first state.

5. A drilling system suitable for offshore exploration drilling as described in claim 4, characterized in that: The adjusting assembly (300) includes a floating sleeve (310), an axial driving member (320), a circumferential driving member (330), and an adjusting member (340). The floating sleeve (310) is coaxially sleeved on the drill pipe unit (231); the axial driving member (320) is installed on the floating sleeve (310) and is used to drive the floating sleeve (310) to slide axially along the drill pipe unit (231) to adjust the vertical height of the floating sleeve (310); the circumferential driving member (330) is installed on the floating sleeve (310) and is used to drive the floating sleeve (310) to rotate circumferentially along the drill pipe unit (231); the adjusting member (340) is installed on the floating sleeve (310), and the adjusting member (340) can be connected to the first blocking block (244) of any one of the limiting members (240) to drive the first blocking block (244) to rotate, and can be connected to the second blocking block (245) of any one of the limiting members (240) to drive the second blocking block (245) to rotate, so as to adjust the switching of the limiting member (240) between the first state and the second state.

6. A drilling system suitable for offshore exploration drilling as described in claim 5, wherein: A plurality of rollers (311) are rotatably connected to the floating sleeve (310), and the rollers (311) are all tangent to the length direction of the drill pipe unit (231).

7. A drilling system suitable for offshore exploration drilling as described in claim 1 or 2, wherein: The replacement member (440) further includes a first driving structure (443). The first driving structure (443) includes a sliding plate (443a) and a first oil cylinder (443b). The sliding plate (443a) is connected to the suspension rod group (430). Two clamping members (442) are symmetrically arranged with respect to the fixed seat (441). The fixed seat (441) is slidably connected to the sliding plate (443a) along the axis direction of the two clamping members (442). One end of the first oil cylinder (443b) is connected to the sliding plate (443a), and the other end is connected to the fixed seat (441); the first oil cylinder (443b) expands and contracts to drive the fixed seat (441) to slide.

8. A drilling system suitable for offshore exploration drilling as described in claim 1 or 2, wherein: The clamping member (442) includes two relatively arranged annular clamping plates and two second driving structures (444) for respectively pulling the two annular clamping plates. The outer walls of the two annular clamping plates are rotatably connected to one side end of the fixed seat (441), and the two annular clamping plates can move to a first position and a second position; when the two annular clamping plates move to the first position, the two side ends of the inner walls of the two annular clamping plates abut against each other to form an annular structure for clamping the drill pipe unit (231); when the two annular clamping plates move to the second position, the two annular clamping plates are arranged at intervals to release the drill pipe unit (231).

9. A drilling system suitable for offshore exploration drilling as described in claim 8, wherein: The inner wall of the annular splint is provided with a groove (237), and the drill pipe unit (231) is provided with a protrusion (442a) adapted to match the groove (237).

10. A drilling system applicable to offshore exploration drilling according to claim 8, characterized in that: The second driving structure (444) includes a second oil cylinder (444b) and two symmetrically arranged connecting rods (444a). Both ends of the two connecting rods (444a) are rotatably connected to one side end of the fixed seat (441), and the other ends are connected to the outer wall of an annular splint. Both ends of the second oil cylinder (444b) are slidably hinged to the two connecting rods (444a).

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