Disclosed is a method for deep-sea extraction of natural gas hydrates with reservoir top control and sand prevention, belonging to the technical field of natural gas hydrates mining. A grouting layer is constructed between a natural gas hydrates reservoir layer and an upper overburden layer by adopting a multi-branch horizontal well process, a vertical shaft is drilled further into the natural gas hydrates reservoir layer after the grouting layer is stabilized, and a mining device and a bottom plugging device are installed in the vertical shaft according to a thickness of the reservoir.

The invention provides an efficient gas hydrate production system using flue gas waste heat/solar absorption heat pump to compensate reservoir heat, includes a heat source absorption system, heat pump heating system and reservoir heat compensation system and realizes efficient exploitation of submarine natural gas hydrate in the way of heat compensation. The invention uses the low-grade heat energy of offshore platform to solve the problems of heat source and energy consumption in the process of natural gas hydrate exploitation by. It provides a commercial feasible scheme for large-scale exploitation of natural gas hydrate. The condenser module, evaporator module and injection well module of the invention can be flexibly increased or decreased, and can adapt to a variety of actual hydrate reservoir distribution; the injection well module adopts ball-nozzle, which can disperse and evenly inject the hot injected water into the reservoir.

A deep-sea submarine gas hydrate collecting method and a production house for the first time, the collecting method comprises the steps of: determining an active methane leakage zone near a landward limit of a submarine gas hydrate stability zone, acquiring submarine methane leakage in-situ observation data, determining a methane leakage rate and evaluating its economy; mounting a production house on the seabed, opening a monitoring system after the mounting, monitoring the submarine methane leakage condition and hydrate generation progress in real time, evaluating a hydrate generation amount, and performing hydrate acquisition work; and rapidly processing the gas hydrate in the house by a gas hydrate collecting system of an offshore platform, and continuously monitoring the methane leakage condition. A large amount of methane leaked can be collected, thereof, the method has dual meanings of resources and environment.

A system and method for exploiting deepwater shallow low-abundance unconventional natural gas by artificial enrichment is provided. The system includes a metallogenic system, a transport system and a collection system. The metallogenic system is used for clustering and enriching the deepwater shallow low-abundance nonconventional natural gas to form a natural gas hydrate reservoir. The metallogenic system includes an artificial foundation pit and a dome cap covering the top of the artificial foundation pit. The transport system is used for transporting low-abundance natural gas in a deepwater shallow low-abundance nonconventional natural gas stratum to the metallogenic system to provide a gas source for synthesizing the natural gas hydrate reservoir for the metallogenic system. The transport system includes oriented communication wells connecting the artificial foundation pit and the deepwater shallow low-abundance nonconventional natural gas stratum and filled with gravel particles. The collection system is used for exploiting the natural gas hydrate reservoir.

The invention discloses a suction cylinder exploitation device and method for marine natural gas hydrates. The exploitation device comprises an exploitation cylinder, a water pump, a sand control device, a liquid-gas filling system and the like. Through the specially-designed exploitation cylinder and mating devices thereof, the exploitation cylinder can sink below a seabed surface to exploit natural gas hydrates deep below the seabed surface and can be withdrawn. A series of problems such as high well drilling and completion cost of traditional deep-sea drilling exploitation methods, and damage, collapses and sand generation of plain concrete wellbores under the effect of formation pressure are solved, and the limitations that traditional capping depressurization methods can only exploit submarine superficial hydrates and are low in exploitation efficiency are overcome. The invention can greatly reduce the exploitation cost of natural gas hydrates deep below the seabed surface and is of great significance for commercial exploitation of marine natural gas hydrates.

A pressure-control temperature-control hypergravity experimental device includes a high pressure reactor, a hydraulic oil station, a manifold board, a hypergravity water pressure control module, a hypergravity mining control module, a kettle body temperature control module, and a data collection box. The hydraulic oil station is connected to the manifold board and then two paths are formed. The two paths are respectively connected to the high pressure reactor via the hypergravity water pressure control module and the hypergravity mining control module. The kettle body temperature control module is connected to the high pressure reactor. The high pressure reactor, the manifold board, the data collection box, the hypergravity water pressure control module and the hypergravity mining control module are disposed on a hypergravity centrifuge air-conditioning chamber. The hydraulic oil station, a computer and the kettle body temperature control module are disposed outside the hypergravity centrifuge air-conditioning chamber.

A methane gas production facility or the like capable of efficiently producing a methane gas from a wide range of a methane hydrate layer. In a methane gas production facility that produces a methane gas from a methane hydrate layer MHL, a first horizontal well is provided along the methane hydrate layer MHL and injection water supply units supply injection water obtained by dispersing a carbon dioxide gas in water to the first horizontal well. A second horizontal well is provided along an area in which methane released from methane hydrate by replacement with carbon dioxide rises, a decompression and suction unit decompresses the inside of the second horizontal well by pumping water and sucks water containing methane, and a gas-liquid separation unit separates a methane gas from the sucked water.

A resource collection device of a resource collection system has a resource collection pipe, a protection pipe, and a coiled tubing device. The protection pipe is disposed around the resource collection pipe and protects the resource collection pipe. The coiled tubing device is fed from a winding reel disposed on the sea surface or inside the protection pipe by way of a feeding device and penetrates a side wall of the protection pipe to extend from the interior to the exterior. The resource collection system cracks the sea floor layer by way of: supplying undiluted solutions of foaming material, fuel gas, and air containing oxygen into the sea floor layer through the coiled tubing device; mixing the undiluted solutions of foaming material together to expand in an atmosphere that includes fuel gas and air; and causing the fuel gas accumulated in the hollows of the foaming material to explosively combust.

Portable/transportable apparatuses, methods, and systems for generating and delivering sulfur trioxide on-site or near an item to be treated is provided. A method for extracting hydrocarbons from deposits containing a clathrate hydrate such as methane hydrates includes a step of delivering sulfur trioxide to an ice deposit containing a clathrate hydrate and subsequently extracting linear or branched hydrocarbons.

The present application relates to a permeability evaluation method for hydrate-bearing sediment, including a complex conductivity spectrum obtaining step, a hydrate saturation calculating step based on the spectrum, a formation factor calculating step based on Archie's first law or from the complex conductivity real part, imaginary part and a conductivity of pore water; and a permeability calculating step based on relaxation time, hydrate saturation, hydrate occurrence mode correction factor and formation factor, or based on the polarization amplitude, hydrate saturation, occurrence mode correction factor and formation factor, or based on the CEC, hydrate saturation and occurrence mode correction factor, or based on the pore radius, fractal dimension, hydrate saturation and occurrence mode correction factor. The application allows a large measuring range, low cost and high accuracy, and can accurately obtain the permeability of hydrate-bearing sediment and effectively reflect the micro-pore structure thereof.