Abstract: A double-layer coiled tubing double-gradient drilling system, on the basis of conventional drilling equipment, includes a double-layer coiled tubing system, separating fluid, a downhole lifting pump system, throttling control systems and a data monitoring system. Power fluid enters an annular space of the tubing through an adapter, passes through a downhole lifting pump, enters an inner pipe through a bridge channel, and enters the bottom hole through the drill bit. Return fluid enters an annular channel of the tubing through a recovery hole, then enters the inner pipe through the bridge channel and enters the lifting pump, and then enters a solid control system through the adapter and the control systems in sequence. Gradient control of the bottom hole pressure is realized through monitoring of the separating fluid and control of the drilling pump unit and throttling control systems. The problem of narrow safe drilling density window is solved.

Abstract: A double-layer coiled tubing double-gradient drilling system, on the basis of conventional drilling equipment, includes a double-layer coiled tubing system, spacer fluid, a downhole lifting pump system, throttling control systems and a data monitoring system. Power fluid enters an annular space of the tubing through an adapter, passes through a downhole lifting pump, enters an inner pipe through a bridge channel, and enters the bottom hole through the drill bit. Return fluid enters an annular channel of the tubing through a recovery hole, then enters the inner pipe through the bridge channel and enters the lifting pump, and then enters a solid control system through the adapter and the control systems in sequence. Gradient control of the bottom hole pressure is realized through monitoring of the spacer fluid and control of the drilling pump unit and throttling control systems. The problem of narrow safe drilling density window is solved.

Abstract: The invention discloses an experimental device for natural gas hydrate solid-state fluidized mining and crushing, the experimental device comprising a power liquid supply module, a hydrate suction module, a pipeline conveying module, a hydrate fluidized crushing module, a secondary processing module and an experimental data information collection and processing module. An experimental method for the experimental device comprises: turning on the power liquid supply module, the hydrate suction module, the pipeline conveying module, the hydrate fluidized crushing module and the secondary processing module, and collecting pressure and flow data at a plurality of locations by the experimental data information collection and processing module.

Abstract: A crushing system for large-size natural gas hydrate rock samples, which mainly includes a crushing and stirring control subsystem, crushing and stirring execution subsystem and hydrate preparation subsystem. Full automatic control to parameter acquisition and experimental process is achieved by utilizing modern automation technology, including the function of automatically crushing the large-size natural gas hydrate rock samples and also monitoring, collecting and storing the drilling pressure, the torque and the internal furnace pressure and temperature parameters during the crushing process in real time, to provide reliable guarantee for the follow-up researches on crushing mechanism, crushing efficiency, drilling parameter optimization, rock crushing ability evaluation of a crushing tool and the like of the large-size natural gas hydrate rock samples and necessary experimental verification means for optimization of on-site exploiting construction conditions of natural gas hydrate.

Abstract: The present invention relates to a combined crushing super-variable-diameter drill bit for natural gas hydrate exploitation, including a joint, an outer cylinder connected to the joint by thread, a nozzle I mounted in the outer cylinder, a mechanical locking mechanism, a blade telescoping mechanism, an end cap connected to the outer cylinder by thread, a seal ring IV mounted to the end cap, and a nozzle II mounted in the end cap by threaded connection. The present invention achieves integrated operation of conventional drilling and draw-back expanding, which can effectively solve the problems that the existing hydrate drill bit cannot drill a large borehole, cannot mechanically lock an extending position of the blade to stabilize the size of the borehole, and a single crushing method is inefficient.

Abstract: The present invention provides an automatic jet breaking tool for solid fluidization exploitation of natural gas hydrate, which mainly includes an upper joint, an outer cylinder, an inner sliding sleeve, a lockup sliding sleeve, a thrust bearing, a spring, a jet joint, a telescopic jet sprinkler, a plug block and an extrusion seal ring. The present invention mainly adopts the principle of throttling control pressure to control the position of the inner sliding sleeve by controlling a flow rate of a drilling fluid, so as to turn on and turn off the jet breaking tool. The application of the present invention can realize automatic jet breaking of solid fluidization exploitation of the natural gas hydrate, reduce procedures of a round trip operation, and effectively improve the efficiency and safety of the exploitation operation of the natural gas hydrate.

Abstract: A natural gas hydrate solid-state fluidization mining method and system under an underbalanced positive circulation condition, used for performing solid-state fluidization mining on a non-rock-forming weak-cementation natural gas hydrate layer in the ocean. Equipment includes a ground equipment system and an underwater equipment system. The construction procedure has an earlier-stage construction process, underbalanced hydrate solid-state fluidization mining construction process and silt backfilling process. Natural gas hydrates in the seafloor are mined through an underbalanced positive circulation method.

Abstract: A hydrate solid-state fluidization mining method and system under an underbalanced reverse circulation condition are used for solid-state fluidization mining on a non-rock-forming weak-cementation natural gas hydrate layer in the ocean. Equipment includes a ground equipment system and an underwater equipment system. The construction procedure includes an earlier-stage construction process, pilot hole drilling construction process, reverse circulation jet fragmentation process, underbalanced reverse circulation fragment recovery process and silt backfilling process. Natural gas hydrates in the seafloor are mined through an underbalanced reverse circulation method. Problems such as shaft safety, production control and environmental risks faced by conventional natural gas hydrate mining methods such as depressurization, heat injection, agent injection and replacement are effectively solved.

Abstract: The present invention relates to a combined crushing super-variable-diameter drill bit for natural gas hydrate exploitation, including a joint, an outer cylinder connected to the joint by thread, a nozzle I mounted in the outer cylinder, a mechanical locking mechanism, a blade telescoping mechanism, an end cap connected to the outer cylinder by thread, a seal ring IV mounted to the end cap, and a nozzle II mounted in the end cap by threaded connection. The present invention achieves integrated operation of conventional drilling and draw-back expanding, which can effectively solve the problems that the existing hydrate drill bit cannot drill a large borehole, cannot mechanically lock an extending position of the blade to stabilize the size of the borehole, and a single crushing method is inefficient.

Abstract: The present invention provides an automatic jet breaking tool for solid fluidization exploitation of natural gas hydrate, which mainly includes an upper joint, an outer cylinder, an inner sliding sleeve, a lockup sliding sleeve, a thrust bearing, a spring, a jet joint, a telescopic jet sprinkler, a plug block and an extrusion seal ring. The present invention mainly adopts the principle of throttling control pressure to control the position of the inner sliding sleeve by controlling a flow rate of a drilling fluid, so as to turn on and turn off the jet breaking tool. The application of the present invention can realize automatic jet breaking of solid fluidization exploitation of the natural gas hydrate, reduce procedures of a round trip operation, and effectively improve the efficiency and safety of the exploitation operation of the natural gas hydrate.

Abstract: The invention discloses an experimental device for natural gas hydrate solid-state fluidized mining and crushing, the experimental device comprising a power liquid supply module, a hydrate suction module, a pipeline conveying module, a hydrate fluidized crushing module, a secondary processing module and an experimental data information collection and processing module. An experimental method for the experimental device comprises: turning on the power liquid supply module, the hydrate suction module, the pipeline conveying module, the hydrate fluidized crushing module and the secondary processing module, and collecting pressure and flow data at a plurality of locations by the experimental data information collection and processing module.

Abstract: Disclosed is a device for solid-state fluidized mining of natural gas hydrates in a shallow seabed, including: a sea surface support system, a pipeline delivery system, and an undersea drilling system. The sea surface support system includes a hydrate drilling vessel floating on seawater. The pipeline delivery system includes a continuous double-layer oil pipe, a recyclable conduit installed in a sediment cover, an open-hole steering packer installed outside the recyclable conduit. The undersea drilling system includes a hydrate slurry separator, a single screw pump, a hydraulic motor, a jet head and a differential pressure sliding sleeve close to the hydrate drill bit. The present invention has the following beneficial effects. The device achieves a multi-directionally horizontal drilling and production in the hydrate reservoir with a single well head, improving the drilling efficiency and single well production.

Abstract: A natural gas hydrate solid-state fluidization mining method and system under an underbalanced positive circulation condition, used for performing solid-state fluidization mining on a non-rock-forming weak-cementation natural gas hydrate layer in the ocean. Equipment includes a ground equipment system and an underwater equipment system. The construction procedure has an earlier-stage construction process, underbalanced hydrate solid-state fluidization mining construction process and silt backfilling process. Natural gas hydrates in the seafloor are mined through an underbalanced positive circulation method, and problems such as shaft safety, production control and environmental risks faced by conventional natural gas hydrate mining methods such as depressurization, heat injection, agent injection and replacement are effectively solved.

Abstract: A hydrate solid-state fluidization mining method and system under an underbalanced reverse circulation condition are used for solid-state fluidization mining on a non-rock-forming weak-cementation natural gas hydrate layer in the ocean. Equipment includes a ground equipment system and an underwater equipment system. The construction procedure includes an earlier-stage construction process, pilot hole drilling construction process, reverse circulation jet fragmentation process, underbalanced reverse circulation fragment recovery process and silt backfilling process. Natural gas hydrates in the seafloor are mined through an underbalanced reverse circulation method. Problems such as shaft safety, production control and environmental risks faced by conventional natural gas hydrate mining methods such as depressurization, heat injection, agent injection and replacement are effectively solved.

Abstract: A crushing system for large-size natural gas hydrate rock samples, which mainly includes a crushing and stirring control subsystem, crushing and stirring execution subsystem and hydrate preparation subsystem. Full automatic control to parameter acquisition and experimental process is achieved by utilizing modern automation technology, including the function of automatically crushing the large-size natural gas hydrate rock samples and also monitoring, collecting and storing the drilling pressure, the torque and the internal furnace pressure and temperature parameters during the crushing process in real time, to provide reliable guarantee for the follow-up researches on crushing mechanism, crushing efficiency, drilling parameter optimization, rock crushing ability evaluation of a crushing tool and the like of the large-size natural gas hydrate rock samples and necessary experimental verification means for optimization of on-site exploiting construction conditions of natural gas hydrate.

Abstract: The present invention discloses a device for solid-state fluidization mining of seabed shallow layer non-diagenetic natural gas hydrates. The device comprises a hydraulic jet nozzle set, a coiled tubing, a hydrate collecting ship arranged on the sea surface, a transfer station arranged in sea water and a riser arranged in a seabed surface layer. A guide seat is arranged in the riser. The hydraulic jet nozzle set is arranged in the guide seat. A delivery pipe connected with the transfer station sleeves a nozzle body. An opening is formed in a position where the delivery pipe is in contact with the nozzle body. The transfer station is connected with the hydrate collecting ship. The present invention further discloses a method for collecting seabed shallow layer non-diagenetic hydrates.

Abstract: The present invention discloses a device for solid-state fluidization mining of seabed shallow layer non-diagenetic natural gas hydrates. The device comprises a hydraulic jet nozzle set, a coiled tubing, a hydrate collecting ship arranged on the sea surface, a transfer station arranged in sea water and a riser arranged in a seabed surface layer. A guide seat is arranged in the riser. The hydraulic jet nozzle set is arranged in the guide seat. A delivery pipe connected with the transfer station sleeves a nozzle body. An opening is formed in a position where the delivery pipe is in contact with the nozzle body. The transfer station is connected with the hydrate collecting ship. The present invention further discloses a method for collecting seabed shallow layer non-diagenetic hydrates.

Abstract: Disclosed is a device for solid-state fluidized mining of natural gas hydrates in a shallow seabed, including: a sea surface support system, a pipeline delivery system, and an undersea drilling system. The sea surface support system includes a hydrate drilling vessel floating on seawater. The pipeline delivery system includes a continuous double-layer oil pipe, a recyclable conduit installed in a sediment cover, an open-hole steering packer installed outside the recyclable conduit. The undersea drilling system includes a hydrate slurry separator, a single screw pump, a hydraulic motor, a jet head and a differential pressure sliding sleeve close to the hydrate drill bit. The present invention has the following beneficial effects. The device achieves a multi-directionally horizontal drilling and production in the hydrate reservoir with a single well head, improving the drilling efficiency and single well production.

Abstract: The present disclosure provides an experimental loop system for fluidization exploitation of solid-state marine gas hydrate, comprising: four modules, namely a gas hydrate sample large-amount and rapid preparation module, a gas hydrate multi-scale smashing and slurry fidelity transfer module, a gas hydrate slurry pipeline conveying characteristic experiment module, and a data collection and monitoring and safety control module. The gas hydrate experimental loop device provided by the present disclosure may be used for researching the synthesis, decomposition, gas storage rate and phase equilibrium of gas hydrate, and researching the pipeline conveying flow resistance and heat transfer characteristics, and is significant for solving the blockage problem in the gas pipeline conveying process, storage and conveying of the gas hydrate, solid-state fluidization exploitation of the marine gas hydrate and pipeline conveying experimental simulation thereof.

Abstract: The present disclosure provides an experimental loop system for fluidization exploitation of solid-state marine gas hydrate, comprising: four modules, namely a gas hydrate sample large-amount and rapid preparation module, a gas hydrate multi-scale smashing and slurry fidelity transfer module, a gas hydrate slurry pipeline conveying characteristic experiment module, and a data collection and monitoring and safety control module. The gas hydrate experimental loop device provided by the present disclosure may be used for researching the synthesis, decomposition, gas storage rate and phase equilibrium of gas hydrate, and researching the pipeline conveying flow resistance and heat transfer characteristics, and is significant for solving the blockage problem in the gas pipeline conveying process, storage and conveying of the gas hydrate, solid-state fluidization exploitation of the marine gas hydrate and pipeline conveying experimental simulation thereof.