1. The utility model provides an extension formula seabed combustible ice mining devices, characterized by: the device comprises a combustible ice drilling and production platform, a telescopic connecting pipeline (12) and a collecting cover (4), wherein the combustible ice drilling and production platform is connected with the collecting cover (4) through the telescopic connecting pipeline (12), the collecting cover (4) is a rigid cover body with a downward opening, an inner cavity is provided with a collecting cover inner connecting frame (18), and three communicating pipelines, namely a suction pipeline (5), a high-pressure jet flushing pipeline (6) and a gas production channel (13), are respectively arranged in the telescopic connecting pipeline (12);

the combustible ice drilling and production platform is provided with a water tank (8), a high-pressure pump (9), a suction pump (10), a natural gas collecting and processing device (11) and a mud tank, the suction pump (10) is connected with a collection cover (4) through a suction pipeline (5), and a rotary high-pressure water pipe (14) and a high-pressure nozzle (16) are arranged in the collection cover (4);

the water tank (8) is connected with the upper end of the high-pressure spraying pipeline (6) through a high-pressure pump (9), and the other end of the high-pressure spraying pipeline (6) penetrates through the telescopic connecting pipeline (12) and is connected to the rotary high-pressure water pipe (14) and the high-pressure nozzle (16) through the connectors;

the high-pressure nozzle (16) faces to the direction of the seabed sediment (15) and is positioned in the middle, lower part or bottom of the collecting cover (4); the suction end (17) of the suction pipeline (5) is positioned at the middle lower part of the collection cover (4) and can suck silt flushed by the high-pressure nozzle (16);

the natural gas collecting and processing device (11) is connected with a gas generating channel (13), the gas generating channel (13) passes through the telescopic connecting pipeline (12) and is introduced into the top end of the collecting cover (4), and the generated natural gas (3) is sent to the natural gas collecting and processing device (11).

2. The extended seafloor combustible ice mining device of claim 1, wherein: high-pressure spout towards pipeline (6) communicate through connector and rotatory high pressure water pipe (14), a plurality of high pressure nozzle (16) evenly distributed are on rotatory high pressure water pipe (14), spout to seabed silt (15) through high pressure nozzle (16) spun high pressure water.

3. The extended seafloor combustible ice mining device of claim 2, wherein: the rotary high-pressure water pipe (14) is of a straight-line structure, one end of the straight-line structure is provided with a plurality of high-pressure nozzles (16), the other end of the straight-line structure is provided with a plurality of high-pressure nozzles (16) with opposite outlet directions, and the injected high-pressure water drives the rotary high-pressure water pipe (14) to rotate.

4. The extended seafloor combustible ice mining device of claim 1, wherein: the lower end of the collecting cover (4) is provided with a flexible expansion collecting cover (24), expansion nozzles (23) are distributed in the flexible expansion collecting cover (24), and the expansion nozzles (23) are connected with a high-pressure spraying pipeline (6) through a high-pressure hose (22).

5. The extended seafloor combustible ice mining device of claim 4, wherein: the flexible expansion collecting cover (24) comprises an inner connecting ring (24.1), a flexible expansion body (24.2) and a flexible high-pressure expansion water pipe (24.3), the flexible expansion body (24.2) is in a bell mouth shape after being expanded, the inner connecting ring (24.1) is arranged at the upper end of the flexible expansion body (24.2), and the inner connecting ring (24.1) is fixedly connected with the lower end of the collecting cover (4); the inner wall of the flexible expansion body (24.2) is provided with a plurality of flexible high-pressure expansion water pipes (24.3), one ends of the flexible high-pressure expansion water pipes (24.3) are connected to the high-pressure hose (22) in a gathering manner, and each flexible high-pressure expansion water pipe (24.3) is provided with an expansion nozzle (23).

6. The extended seafloor combustible ice mining device of claim 1, wherein: the collecting cover (4) is a rigid cover body with a cylindrical structure with a downward opening, and the inner cavity of the rigid cover body is supported and connected through a collecting cover inner connecting frame (18) with a cross structure.

7. The extended seafloor combustible ice mining device of claim 1, wherein: the collecting cover (4) is a rigid cover body with a downward opening and a conical structure, and the inner cavity of the rigid cover body is supported and connected through a collecting cover inner connecting frame (18).

8. Use of the extended seafloor combustible ice mining device of any one of claims 1 to 7, comprising the process of:

a. positioning the combustible ice drilling and production platform, lowering the collection cover (4) to the seabed mud surface through a telescopic connecting pipeline (12), and simultaneously sucking air and seawater in the collection cover (4) to enable the collection cover (4) to sink;

b. after the collection cover (4) reaches the seabed, a high-pressure pump (9) is started, high-pressure water enters a rotary high-pressure water pipe (14) in the collection cover (4) along a high-pressure jet flushing pipeline (6), and then is jetted and flushed through a high-pressure nozzle (16) to form seabed silt (15) below the collection cover (4), at the moment, a stirred mixture (2) of the silt and seawater stirred up is sucked out through a suction pipeline (5) and a suction end (17) in the collection cover (4) and stored in a mud tank on a combustible ice drilling and production platform, so that the collection cover (4) continuously sinks in the seabed mud surface;

c. after the collecting cover (4) reaches the combustible ice layer (1) below the seabed mud surface, high-pressure spraying is continued, the stirred combustible ice is depressurized and becomes gas-state natural gas (3), at the moment, the suction pump (10) stops working and closes the suction pipeline (5), and the natural gas (3) rises along a gas production channel (13) above the collecting cover (4) until the natural gas enters a natural gas collecting and processing device (11);

d. and (3) after the combustible ice in the area of the seabed is collected, returning the silt to the collection cover (4) through the suction pipeline (5), backfilling the area of the seabed to the seabed through the collection cover (4), and slowly pulling the collection cover (4) upwards after backfilling is finished.

9. The method for using an extended subsea combustible ice mining device according to claim 8, wherein: the combustible ice drilling and production platform adopts a deepwater semi-submersible platform (7) or a floating drilling ship (19).

10. The method for using an extended subsea combustible ice mining device according to claim 8, wherein: b, after the collection cover (4) reaches the seabed, starting a high-pressure pump (9), enabling high-pressure water to enter a rotary high-pressure water pipe (14) and a flexible high-pressure expansion water pipe (24.3) in the collection cover (4) along a high-pressure spraying pipeline (6), unfolding a flexible expansion body (24.2) to form a bell mouth shape under the action of the high-pressure water, increasing the collection area of the collection cover (4), spraying and flushing the seabed sediment (15) below expansion nozzles (23) distributed on the flexible high-pressure expansion water pipe (24.3), spraying and flushing the seabed sediment (15) in the range right below the collection cover (4) by the high-pressure nozzles (16) in the collection cover (4), and increasing the stirring area; at the moment, the mixture of silt and seawater stirred up is sucked out through a suction pipeline (5) and a suction end (17) in the collecting cover (4) and stored in a mud tank on a deep water semi-submersible platform (7) or a floating drilling ship (19), so that the collecting cover (4) is continuously sunk in the mud surface of the seabed.

Background

The combustible ice is made of natural gas and water molecules under high pressure>10 MPa) and low temperature (0-10 ℃), is commonly called combustible ice, the main component is methane, the combustible ice is used as fuel energy, the combustible ice is clean and pollution-free, the heat release is large, and the heat release is 1m³Combustible ice equivalent to 164m³The heat released by the combustion of natural gas. At present, combustible ice is mainly distributed in the eastern, western pacific and western ocean edges (water depth of 300-4000 m) of northern hemisphere, and in about 650m sediment layer below the ocean bottom, and polar sea land frame and high latitude land permafrost region below the ocean water depth of 100-250 m.

Research investigation and exploration of combustible ice have been conducted in more than 30 countries and regions around the world. The development and research of foreign combustible ice enter exploration tests and exploitation stages, the experimental tests and exploration identification technology are relatively mature, and the hydrate safe exploitation technology is still in the exploration stage. In particular, the development and research of the countries such as the united states, canada, japan and russia are leading, and the countries such as korea and india are intensively researched, so that japan has made a certain breakthrough in the exploitation of the submarine hydrate. In 2017, 3 months, the geological survey bureau of the national ministry of land and resources in China organizes to implement the trial production operation of south sea combustible ice, the platform of whale No. 1 is used for trial production, the trial production is continuously performed for ignition for 60 days, 30.9 million cubic meters of gas are accumulated, 5151 cubic meters are produced in average day, the highest methane content is 99.5 percent, ten thousand sets of scientific experimental data 647 are obtained, and a large amount of real and reliable data information is accumulated for subsequent scientific research.

In a word, the combustible ice drilling well completion technology is still under exploration, technical bottlenecks such as exploration and exploitation theory and technology, transportation technology, storage technology and the like are all broken through, no theory exists yet, the combustible ice formation mechanism can be scientifically and comprehensively explained, complete theoretical system guidance is lacked in development and utilization, and large-scale commercial development and production design is difficult to carry out.

Disclosure of Invention

The invention aims to provide an expanded seabed combustible ice mining device and method aiming at the defects in the prior art, the single mining area is large, the gas production rate is increased compared with the existing mode, and the expanded seabed combustible ice mining device and method are suitable for deepwater operation; the method can safely and effectively mine the deepwater combustible ice, protect the seabed environment to the maximum extent, can be repeatedly used, and reduces the mining cost.

The invention provides an extended submarine combustible ice mining device, which adopts the technical scheme that: the system comprises a combustible ice drilling and production platform, a telescopic connecting pipeline and a collecting cover, wherein the combustible ice drilling and production platform is connected with the collecting cover through the telescopic connecting pipeline, the collecting cover is a rigid cover body with a downward opening, an inner cavity is provided with a collecting cover inner connecting frame, and three communicating pipelines of a suction pipeline, a high-pressure jet flushing pipeline and a gas production channel are respectively arranged in the telescopic connecting pipeline;

the combustible ice drilling and production platform is provided with a water tank, a high-pressure pump, a suction pump, a natural gas collecting and processing device and a mud tank, the suction pump is connected with a collection cover through a suction pipeline, and a rotary high-pressure water pipe and a high-pressure nozzle are arranged in the collection cover;

the water tank is connected with the upper end of a high-pressure spraying pipeline through a high-pressure pump, and the other end of the high-pressure spraying pipeline penetrates through the telescopic connecting pipeline and is connected to the rotary high-pressure water pipe and the high-pressure nozzle through a connector;

the high-pressure nozzle faces to the direction of the seabed sediment and is positioned in the middle, lower part or bottom of the collecting cover; the suction end of the suction pipeline is positioned at the middle lower part of the collection cover and can suck silt turned up by the high-pressure nozzle;

the natural gas collecting and processing device is connected with a gas generating channel, the gas generating channel passes through the telescopic connecting pipeline and is introduced into the top end of the collecting cover, and the generated natural gas is sent to the natural gas collecting and processing device.

Preferably, the high-pressure jetting pipeline is communicated with the rotary high-pressure water pipe through a connector, the high-pressure nozzles are uniformly distributed on the rotary high-pressure water pipe, and high-pressure water jetted by the high-pressure nozzles jets sediment on the seabed.

Preferably, the rotary high-pressure water pipe is of a straight-line structure, one end of the straight-line structure is provided with a plurality of high-pressure nozzles, the other end of the straight-line structure is provided with a plurality of high-pressure nozzles with opposite outlet directions, and the injected high-pressure water drives the rotary high-pressure water pipe to rotate.

Preferably, the lower end of the collecting cover is provided with a flexible expansion collecting cover, expansion nozzles are distributed in the flexible expansion collecting cover, and the expansion nozzles are connected with a high-pressure spraying pipeline through a high-pressure hose.

Preferably, the flexible expansion collecting cover comprises an inner connecting ring, a flexible expansion body and a flexible high-pressure expansion water pipe, the flexible expansion body is in a bell mouth shape after being unfolded, and the inner connecting ring is arranged at the upper end of the flexible expansion body and is fixedly connected with the lower end of the collecting cover through the inner connecting ring; the inner wall of the flexible expansion body is distributed with a plurality of flexible high-pressure expansion water pipes, one ends of the flexible high-pressure expansion water pipes are connected to the high-pressure hose in a gathering mode, and expansion nozzles are distributed on each flexible high-pressure expansion water pipe.

Preferably, the collecting cover is a rigid cover body with a downward opening and a cylindrical structure, and the inner cavity is in supporting connection through a cross-shaped collecting cover inner connecting frame.

Preferably, the collecting cover is a rigid cover body with a downward opening and a conical structure, and the inner cavity is in supporting connection through a connecting frame in the collecting cover.

The invention provides a using method of an extended seabed combustible ice mining device, which adopts the technical scheme that the using method comprises the following steps:

a. positioning the combustible ice drilling and mining platform, lowering the collecting cover to the seabed mud surface through a telescopic connecting pipeline, and simultaneously sucking air and seawater in the collecting cover to sink the collecting cover;

b. after the collection cover reaches the seabed, a high-pressure pump is started, high-pressure water enters a rotary high-pressure water pipe in the collection cover along a high-pressure jet flushing pipeline and then is jetted and flushed through a high-pressure nozzle to the seabed silt below the collection cover, and at the moment, a stirred mixture of the silt and seawater which are stirred up is sucked out through a suction pipeline and a suction end in the collection cover and stored in a mud tank on the combustible ice drilling and production platform, so that the collection cover continuously sinks in the seabed mud surface;

c. after the collecting cover reaches a combustible ice layer below the seabed mud surface, high-pressure spraying is continued, the stirred combustible ice is depressurized and becomes natural gas in a gas state, at the moment, the suction pump stops working and closes a suction pipeline, and the natural gas rises along a gas production channel above the collecting cover until entering a natural gas collecting and processing device;

d. and after the combustible ice in the area of the seabed is collected, the silt flows back to the collecting cover through the suction pipeline, the collecting cover is backfilled to the seabed, and the collecting cover is slowly pulled upwards after the backfilling is finished.

Preferably, the further scheme is as follows: b, after the collection cover reaches the seabed, starting a high-pressure pump, enabling high-pressure water to enter a rotary high-pressure water pipe and a flexible high-pressure expansion water pipe in the collection cover along a high-pressure spray line, unfolding a flexible expansion body to form a bell mouth shape under the action of the high-pressure water, increasing the collection area of the collection cover, spraying and flushing seabed sediment below expansion nozzles distributed on the flexible high-pressure expansion water pipe, spraying and flushing the seabed sediment in a range right below the collection cover by the high-pressure nozzles in the collection cover, and increasing the stirring area; at the moment, the mixture of silt and seawater stirred up is sucked out through a suction pipeline and a suction end in the collecting cover and stored in a mud tank on the deepwater semi-submersible platform or the floating drilling ship, so that the collecting cover continuously sinks in the mud surface of the seabed.

Compared with the prior art, the invention has the following beneficial effects:

the position of the collecting cover can be adjusted according to the water depth, the high-pressure nozzle is used for spraying and flushing the sediment on the sea bottom after the sediment reaches the sediment surface of the sea bottom, the suction pump is used for sucking, the collecting cover is made to sink, the spraying, flushing and stirring are continued after the sediment reaches a combustible ice layer, the combustible ice is decompressed and changed into gas to rise, and the gas is conveyed and collected through the gas production channel; the invention can safely and effectively mine the deep water combustible ice, has large mining area, is environment-friendly, can be repeatedly used and has wide application prospect;

in addition, the lower end of the acquisition cover can be additionally provided with a flexible expansion acquisition cover in the mining mode of the acquisition cover, so that the single mining area is larger, and the gas production is increased compared with the existing mode; moreover, the collecting cover is lowered and retracted through the telescopic connecting pipeline, the operation of the mining process is simple, the collecting cover is suitable for deepwater operation, the collecting cover can be lifted, moved and reused, the mining cost is reduced, and the mining efficiency is improved; moreover, after the exploitation of the combustible ice layer on the seabed is finished, the sediment on the seabed can be backfilled into the collecting cover, so that the method is friendly to the seabed stratum, the seabed environment is protected to the maximum extent, and the green exploitation is realized; in addition, the rotary high-pressure water pipe and the specially designed high-pressure nozzle are adopted, so that the rotary high-pressure water pipe can be driven to rotate by the sprayed high-pressure water, and the effect of spraying the seabed sediment is improved.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention using a deep water semi-submersible platform;

FIG. 2 is a schematic structural view of A-A of FIG. 1 in accordance with the present invention;

FIG. 3 is a schematic view of the overall structure of the present invention using a floating drill ship;

FIG. 4 is a schematic diagram showing a rolled-up structure of the collecting cover with the flexible extension collecting cover in embodiment 2 of the present invention;

FIG. 5 is a schematic view showing a state of an acquisition cover with a flexible extension acquisition cover in mining according to embodiment 2 of the present invention;

fig. 6 is a bottom view of the flexible extended collecting cover in embodiment 2 of the present invention;

fig. 7 is a schematic structural diagram illustrating a deployment process of the flexible extended acquisition cover in embodiment 2 of the present invention;

fig. 8 is a schematic structural view of the flexible extended acquisition cover in embodiment 2 of the present invention after being fully unfolded;

fig. 9 is a schematic structural view of a collecting cover according to embodiment 3 of the present invention;

FIG. 10 is a schematic cross-sectional view of a collecting cover according to example 3 of the present invention;

in the figure: the system comprises a combustible ice layer 1, a stirring mixture 2, natural gas 3, a collecting cover 4, a suction pipeline 5, a high-pressure jet flushing pipeline 6, a deepwater semi-submersible platform 7, a water tank 8, a high-pressure pump 9, a suction pump 10, a natural gas collecting and processing device 11, a telescopic connecting pipeline 12, a gas production channel 13, a rotary high-pressure water pipe 14, seabed sediment 15, a high-pressure nozzle 16, a suction end 17, a collecting cover inner connecting frame 18, a floating drilling ship 19, a high-pressure hose 22, an expansion nozzle 23, a flexible expansion collecting cover 24, an inner connecting ring 24.1, a flexible expansion body 24.2 and a flexible high-pressure expansion water pipe 24.3.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

Embodiment 1, with reference to fig. 1 to 3, an extended submarine combustible ice mining device according to the present invention includes a combustible ice drilling and mining platform, a telescopic connecting pipeline 12, and a collecting cover 4, where the combustible ice drilling and mining platform and the collecting cover 4 are connected by the telescopic connecting pipeline 12, the collecting cover 4 is a rigid cover body with a downward opening, an inner cavity of the rigid cover body is provided with a collecting cover inner connecting frame 18, and three connecting pipelines, namely a suction pipeline 5, a high-pressure jetting pipeline 6, and a gas production channel 13, are respectively arranged in the telescopic connecting pipeline 12;

the combustible ice drilling and production platform is provided with a water tank 8, a high-pressure pump 9, a suction pump 10, a natural gas collecting and processing device 11 and a mud tank, the suction pump 10 is connected with the collection cover 4 through a suction pipeline 5, and a rotary high-pressure water pipe 14 and a high-pressure nozzle 16 are arranged in the collection cover 4;

the water tank 8 is connected with the upper end of the high-pressure spraying pipeline 6 through a high-pressure pump 9, and the other end of the high-pressure spraying pipeline 6 penetrates through a telescopic connecting pipeline 12 and is connected to a rotary high-pressure water pipe 14 and a high-pressure nozzle 16 through a connector;

the high-pressure nozzle 16 faces the direction of the seabed sediment 15 and is positioned in the middle, lower part or bottom of the collecting cover 4; the suction end 17 of the suction pipeline 5 is positioned at the middle lower part of the collection cover 4 and can suck silt flushed by the high-pressure nozzle 16;

the natural gas collecting and processing device 11 is connected with a gas generating channel 13, the gas generating channel 13 passes through the telescopic connecting pipeline 12 and is introduced into the top end of the collecting cover 4, and the generated natural gas 3 is sent to the natural gas collecting and processing device 11.

Preferably, the high pressure jetting pipeline 6 is communicated with the rotary high pressure water pipe 14 through a connector, and a plurality of high pressure nozzles 16 are uniformly distributed on the rotary high pressure water pipe 14, and the high pressure water jetted by the high pressure nozzles 16 is jetted to the sediment 15 on the seabed.

Preferably, the rotating high pressure water pipe 14 is a straight structure, one end of the straight structure is provided with a plurality of high pressure nozzles 16, the other end of the straight structure is provided with a plurality of high pressure nozzles 16 with opposite outlet directions, and the middle position of the straight structure is communicated with the high pressure jetting pipeline 6 through a connector, so that the high pressure water jetted by the high pressure nozzles 16 arranged in the opposite direction drives the rotating high pressure water pipe 14 to rotate.

Preferably, the collecting cover 4 is a rigid cover body with a downward opening cylindrical structure, and the inner cavities are supported and connected through a collecting cover inner connecting frame 18 with a cross-shaped structure.

Referring to fig. 1, the combustible ice drilling and production platform can adopt a deepwater semi-submersible platform 7, referring to fig. 3, the combustible ice drilling and production platform can also adopt a floating drilling ship 19, and the floating drilling ship 19 is more convenient to move.

The use method of the extended seabed combustible ice mining device comprises the following steps:

a. positioning the deepwater semi-submersible platform 7 or the floating drilling ship 19, lowering the collection cover 4 to the seabed mud surface through the telescopic connecting pipeline 12, and simultaneously sucking air and seawater in the collection cover 4 to make the collection cover 4 sink;

b. after the collection cover 4 reaches the seabed, the high-pressure pump 9 is started, high-pressure water enters the rotary high-pressure water pipe 14 in the collection cover 4 along the high-pressure jet flushing pipeline 6 and then is jetted and flushed through the seabed silt 15 below the collection cover 4 through the high-pressure nozzle 16, at the moment, the stirred mixture 2 of the silt and seawater is stirred up, the stirred mixture 2 is sucked out through the suction pipeline 5 and the suction end 17 in the collection cover 4 and is stored in a mud tank on the deepwater semi-submersible platform 7 or the floating drilling ship 19, and the collection cover 4 is made to continuously sink in the seabed mud surface;

c. after the collecting cover 4 reaches the combustible ice layer 1 below the seabed mud surface, high-pressure spraying is continued, the stirred combustible ice is depressurized and becomes the natural gas 3 in a gas state, at the moment, the suction pump 10 stops working and closes the suction pipeline 5, and the natural gas 3 rises along the gas production channel 13 above the collecting cover 4 until entering the natural gas collecting and processing device 11;

d. and when the collection of combustible ice in the area of the seabed is finished, the silt flows back to the collection cover 4 through the suction pipeline 5, and is backfilled to the seabed through the collection cover 4, and after the backfilling is finished, the collection cover 4 is slowly pulled out upwards.

It should be noted that: the high-pressure nozzle 16 arranged in the opposite direction of the rotary high-pressure water pipe 14 drives the rotary high-pressure water pipe 14 to rotate when high-pressure water is sprayed out, so that the spraying and stirring effects on the seabed silt 15 and combustible ice are better.

Embodiment 2, referring to fig. 4 to 8, the extended submarine combustible ice mining device according to the present invention includes a combustible ice drilling and mining platform, a telescopic connecting pipeline 12, and a collecting cover 4, where the combustible ice drilling and mining platform and the collecting cover 4 are connected by the telescopic connecting pipeline 12, the collecting cover 4 is a rigid cover body with a downward opening, an inner cavity of the rigid cover body is provided with a collecting cover inner connecting frame 18, and three connecting pipelines, namely a suction pipeline 5, a high-pressure jetting pipeline 6, and a gas generation channel 13, are respectively arranged in the telescopic connecting pipeline 12;

the combustible ice drilling and production platform is provided with a water tank 8, a high-pressure pump 9, a suction pump 10, a natural gas collecting and processing device 11 and a mud tank, the suction pump 10 is connected with the collection cover 4 through a suction pipeline 5, and a rotary high-pressure water pipe 14 and a high-pressure nozzle 16 are arranged in the collection cover 4;

the water tank 8 is connected with the upper end of the high-pressure spraying pipeline 6 through a high-pressure pump 9, and the other end of the high-pressure spraying pipeline 6 penetrates through a telescopic connecting pipeline 12 and is connected to a rotary high-pressure water pipe 14 and a high-pressure nozzle 16 through a connector;

the high-pressure nozzle 16 faces the direction of the seabed sediment 15 and is positioned in the middle, lower part or bottom of the collecting cover 4; the suction end 17 of the suction pipeline 5 is positioned at the middle lower part of the collection cover 4 and can suck silt flushed by the high-pressure nozzle 16;

the natural gas collecting and processing device 11 is connected with a gas generating channel 13, the gas generating channel 13 passes through the telescopic connecting pipeline 12 and is introduced into the top end of the collecting cover 4, and the generated natural gas 3 is sent to the natural gas collecting and processing device 11.

The difference from the embodiment 1 is that:

referring to fig. 6-8, the lower end of the collecting cover 4 is provided with a flexible extended collecting cover 24, extended nozzles 23 are distributed in the flexible extended collecting cover 24, and the extended nozzles 23 are connected with the high-pressure spray pipeline 6 through a high-pressure hose 22.

The flexible expansion collecting cover 24 comprises an inner connecting ring 24.1, a flexible expansion body 24.2 and a flexible high-pressure expansion water pipe 24.3, the flexible expansion body 24.2 is in a bell mouth shape after being expanded, the upper end of the flexible expansion body 24.2 is provided with the inner connecting ring 24.1, and the inner connecting ring 24.1 is fixedly connected with the lower end of the collecting cover 4; the inner wall of the flexible expansion body 24.2 is distributed with a plurality of flexible high-pressure expansion water pipes 24.3, one ends of the plurality of flexible high-pressure expansion water pipes 24.3 are collected and connected to the high-pressure hose 22, and each flexible high-pressure expansion water pipe 24.3 is distributed with an expansion nozzle 23.

In addition, the flexible expansion body 24.2 can be in the shape of a circle, a regular octagon, a regular hexagon and the like, and after mining is finished, the flexible expansion body 24.2 can be rolled up again for reuse.

The combustible ice drilling and production platform can adopt a deepwater semi-submersible platform 7 or a floating drilling ship 19.

The use method of the extended seabed combustible ice mining device comprises the following steps:

a. positioning the deepwater semi-submersible platform 7 or the floating drilling ship 19, lowering the collection cover 4 to the seabed mud surface through the telescopic connecting pipeline 12, and simultaneously sucking air and seawater in the collection cover 4 to make the collection cover 4 sink;

b. after the collection cover 4 reaches the seabed, the high-pressure pump 9 is started, high-pressure water enters the rotary high-pressure water pipe 14 and the flexible high-pressure expansion water pipe 24.3 in the collection cover 4 along the high-pressure spray pipeline 6, the flexible expansion body 24.2 is unfolded to form a bell mouth shape under the action of the high-pressure water, the collection area of the collection cover 4 is increased, the expansion nozzles 23 distributed on the flexible high-pressure expansion water pipe 24.3 spray and flush seabed sediment 15 below the collection cover 4, and the high-pressure nozzles 16 in the collection cover 4 spray and flush the seabed sediment 15 in the range right below the collection cover 4, so that the stirring area is increased; at the moment, the stirred mixture 2 of silt and seawater which is stirred up is sucked out through a suction pipeline 5 and a suction end 17 in the collecting cover 4 and stored in a mud tank on the deepwater semi-submersible platform 7 or the floating drilling ship 19, so that the collecting cover 4 is continuously sunk in the mud surface of the seabed;

c. after the collecting cover 4 reaches the combustible ice layer 1 below the seabed mud surface, high-pressure spraying is continued, the stirred combustible ice is depressurized and becomes the natural gas 3 in a gas state, at the moment, the suction pump 10 stops working and closes the suction pipeline 5, and the natural gas 3 rises along the gas production channel 13 above the collecting cover 4 until entering the natural gas collecting and processing device 11;

d. and when the collection of combustible ice in the area of the seabed is finished, the silt flows back to the collection cover 4 through the suction pipeline 5, and is backfilled to the seabed through the collection cover 4, and after the backfilling is finished, the collection cover 4 is slowly pulled out upwards.

Embodiment 3, the extended submarine combustible ice exploitation device provided by the invention comprises a floating drilling ship 19, a telescopic connecting pipeline 12 and an acquisition cover 4, wherein the floating drilling ship 19 and the acquisition cover 4 are connected through the telescopic connecting pipeline 12, the acquisition cover 4 is a rigid cover body with a downward opening, an acquisition cover inner connecting frame 18 is arranged in an inner cavity of the rigid cover body, and three connecting pipelines, namely a suction pipeline 5, a high-pressure jet flushing pipeline 6 and a gas production channel 13, are respectively arranged in the telescopic connecting pipeline 12;

the floating drilling ship 19 is provided with a water tank 8, a high-pressure pump 9, a suction pump 10, a natural gas collecting and processing device 11 and a mud tank, the suction pump 10 is connected with the collection cover 4 through a suction pipeline 5, and a rotary high-pressure water pipe 14 and a high-pressure nozzle 16 are arranged in the collection cover 4;

the water tank 8 is connected with the upper end of the high-pressure spraying pipeline 6 through a high-pressure pump 9, and the other end of the high-pressure spraying pipeline 6 penetrates through a telescopic connecting pipeline 12 and is connected to a rotary high-pressure water pipe 14 and a high-pressure nozzle 16 through a connector;

the high-pressure nozzle 16 faces the direction of the seabed sediment 15 and is positioned in the middle, lower part or bottom of the collecting cover 4; the suction end 17 of the suction pipeline 5 is positioned at the middle lower part of the collection cover 4 and can suck silt flushed by the high-pressure nozzle 16;

the natural gas collecting and processing device 11 is connected with a gas generating channel 13, the gas generating channel 13 passes through the telescopic connecting pipeline 12 and is introduced into the top end of the collecting cover 4, and the generated natural gas 3 is sent to the natural gas collecting and processing device 11.

The difference from the embodiment 2 is that: referring to fig. 9 and 10, the collecting cover 4 of the present invention is a rigid cover body with a downward opening and a conical structure, the lower end of the rigid cover body is thick, the upper end of the rigid cover body is thin, the inner cavity of the rigid cover body is supported and connected by a collecting cover inner connecting frame 18, and the collecting cover inner connecting frame 18 is connected and fixed by a plurality of support rods to form a three-fork shape, so that the structure is more stable.

The collecting cover 4 with the conical structure can be beneficial to the ascending and the collection of the natural gas 3 and the suction of the mixture of silt and seawater; of course, the bottom of the collecting cover 4 with a conical structure can be additionally provided with the flexible expanding collecting cover 24 according to needs, so that a larger expanding collecting area can be realized.

The use method of the extended seabed combustible ice mining device comprises the following steps:

a. positioning the floating drilling ship 19, lowering the collection cover 4 to the seabed mud surface through the telescopic connecting pipeline 12, and simultaneously sucking air and seawater in the collection cover 4 to make the collection cover 4 sink;

b. after the collection cover 4 reaches the seabed, the high-pressure pump 9 is started, high-pressure water enters the rotary high-pressure water pipe 14 in the collection cover 4 along the high-pressure jet flushing pipeline 6, and then is jetted and flushed through the seabed silt 15 below the collection cover 4 through the high-pressure nozzle 16, and the stirred mixture 2 of the silt and the seawater which are stirred up is sucked out through the suction pipeline 5 and the suction end 17 in the collection cover 4 with the conical structure and is stored in a mud tank on the floating drilling ship 19, so that the collection cover 4 continuously sinks in the seabed mud surface;

c. after the collecting cover 4 reaches the combustible ice layer 1 below the seabed mud surface, the spraying and flushing are continued, the stirred combustible ice is depressurized and becomes the natural gas 3 in a gas state, at the moment, the suction pump 10 stops working and closes the suction pipeline 5, and the natural gas 3 rises along the gas production channel 13 above the collecting cover 4 with a conical structure until entering the natural gas collecting and processing device 11;

d. and after the combustible ice in the area of the seabed is collected, the silt flows back to the collecting cover 4 through the suction pipeline 5, the collecting cover 4 with the conical structure is backfilled to the seabed, and after the backfilling is completed, the collecting cover 4 is slowly pulled out upwards. Because the collecting cover 4 with the conical structure is adopted, the pressure of silt is not concentrated but diffused and reduced during backfilling, and backfilling can be better realized.

The above description is only a few of the preferred embodiments of the present invention, and any person skilled in the art may modify the above-described embodiments or modify them into equivalent ones. Therefore, the technical solution according to the present invention is subject to corresponding simple modifications or equivalent changes, as far as the scope of the present invention is claimed.