A system including a hydrocarbon extraction system (10), including a well boring apparatus (12) configured to drill through a subterranean formation without rotating a drill string, and a seabed support system (14) configured to support drilling operations of the well boring apparatus.

In some embodiments, a system may include a harvesting unit configured to operate under water to traverse and extract gas from clathrate hydrate deposits. The harvesting unit can include a housing defining an enclosure at least partially open along a bottom portion to receive a clathrate slurry associated with a selected one of the clathrate hydrate deposits. The harvesting unit may further include a separator chamber within the housing defining a negative pressure and configured to receive the clathrate slurry and a skirt coupled to the enclosure adjacent to the bottom portion and configured to form a flexible barrier between the enclosure and an external environment. The skirt may be formed from a plurality of elements configured to allow fluid flow therethrough.

An offshore methane hydrate production assembly (1), having a tubing (41) extending into a subsea well (5) that extends down to a methane hydrate formation (7) below the seabed (3). A submersible pump (45) is arranged in the tubing (41). A methane conduit (35,35) extends down from a surface installation (49). A well control package (15) landed on a wellhead (13) is positioned at the upper end of the subsea well (5). Moreover, an emergency disconnection package (25) is arranged between the methane conduit (35,135) and the well control package (15). The tubing (41) is suspended from the well control package (15). Other aspects of the invention are also disclosed.

The invention provides a method and system for extracting stranded gas (such as natural gas or hydrogen) or a mixture of oil and natural gas from a subterranean environment such as beneath the ocean floor and converting it into a solid hydrate such as a clathrate featuring a) extracting stranded gas (such as natural gas or hydrogen) or a mixture of oil and natural gas; b) optionally separating the natural gas from the mixture of oil and natural gas in a first tank or vessel; c) transporting the stranded gas to a second tank or vessel; d) introducing sea water into the second tank or vessel; e) mixing the stranded gas and water to form a clathrate hydrate/water slurry; f) removing excess water from the clathrate hydrate slurry to form a solid comprising a clathrate hydrate; and g) processing the solid comprising a clathrate hydrate into a transportable form; and h) optionally collecting the gas into a transportable vessel.

A simulation device of an entire natural gas hydrate exploitation process includes a high pressure reaction kettle, a gas-liquid separation device, a hydrate accumulation simulation subsystem simulating a hydrate accumulation process, a hydrate formation drilling simulation subsystem simulating a hydrate formation drilling process, a hydrate exploitation simulation subsystem simulating a hydrate decomposition and gas production process, and a produced gas collecting and processing simulation subsystem simulating a produced gas collecting and processing process. A method for simulating an entire natural gas hydrate exploitation process includes a hydrate accumulation process, a hydrate formation drilling process, a hydrate exploitation process and a produced gas collecting and processing process. With this simulation device and method, the external environment can be truly simulated, so that the authenticity and accuracy are better, and the entire natural gas hydrate exploitation process is continuously simulated and comprehensively evaluated to provide guidance for natural gas hydrate exploitation.

A system for hydrate production is configured to separate a water component from a multi-phase gas and water mixture present in a wellbore, the system being configured such that said separation occurs within the wellbore. The system comprises a first flow line disposed in the wellbore and arranged such that an inlet of the first flow line is disposed in and receives the water component, so as to separate the water component from said multi-phase gas and water mixture. A control system is configured to receive an output signal indicative of the water level from a sensor arrangement of the system and control a flow control device based on the water level so as to control the flow of the water component through the first flow line.

A self-entry exploitation device and method for marine natural gas hydrates is provided. The exploitation device includes a self-entry structural body (1), a sand control device (2) and a gas-liquid lifting system. The self-entry structural body (1) is a gravity anchor. The sand control device (2) and the gas-liquid lifting system are mounted on the self-entry structural body (1). At least one cavity (21) is formed between the self-entry structural body (1) and the sand control device (2), and the cavity (21) is communicated with at least one channel. The sand control device (2) allows liquid and gas to pass through to enter the cavity (21) and is able to filter out silt. The gas-liquid lifting system includes at least one lifting power device (31) and has an end connected to the cavity (21) and an end extending out through a pipeline. By adoption of the exploitation device, drilling is not needed, the self-entry structural body (1) can enter a natural gas hydrate reservoir or a free gas layer below the natural gas hydrate reservoir, so that depressurizing exploitation can be realized, an exploitation system can be withdrawn, and the exploitation cost of natural gas hydrates can be greatly reduced.

A magnetofluid enhanced electromagnetic heating device and method for preventing and treating secondary hydrates around a well are provided. When exploiting natural gas hydrates by depressurization, secondary hydrates or ice can form due to the decreasing temperature around the well, so that gas migration in sediment is blocked, and the gas production is reduced. According to this disclosure, a coil is arranged outside a casing pipe to generate an alternating electromagnetic field radiated to sediment. As a result, magnetite nanoparticles naturally contained in the sediment generate magnetothermal effect to heat the sediment. Additionally, the magnetofluid containing the ferromagnetic nanoparticles can be injected together with fracturing fluid during hydraulic fracturing of the reservoir, so that the magnetothermal effect of the sediment is further enhanced. Thus, secondary hydrates or ice can be prevented from forming around the well so that the exploitation efficiency of natural gas hydrates is improved.

A nitrogen-carbon dioxide mixed gas jet apparatus for a horizontal well and an exploitation method is presented. The jet apparatus includes: an offshore platform, a natural gas processing unit, and a pressurizing unit, wherein a portion of the gas exploitation pipe in the hydrate layer is provided with a gas injection horizontal well; a mixed gas jet unit and a nozzle assembly are disposed in the gas injection horizontal well; the mixed gas jet unit is configured to mix nitrogen and carbon dioxide, and then inject the mixed gas into a hydrate deposition layer through the nozzle assembly, so that the mixed gas replaces methane gas in the hydrate deposition layer; the portion of the gas exploitation pipe in the hydrate layer is provided with a gas exploitation horizontal well configured to collect the methane gas and convey the methane gas to the natural gas processing unit.

A system and method for exploiting a marine natural gas hydrate resource including a vertical well, comprising a sleeve configured to penetrate through a marine layer and a hydrate reservoir covering layer, and penetrate downwards into a natural gas hydrate reservoir; a section of the sleeve in the natural gas hydrate reservoir is provided with a perforating channel; a horizontal well, connected to a bottom end of the sleeve; a production string, disposed in the sleeve and extending downwards into the horizontal well, wherein a bottom of the production string is provided with a gas/water collection inlet; a hot water injection pipe, disposed in the production string; and a bottom of the hot water injection pipe is provided with a hot water injection opening; and a gas bladder, disposed in the horizontal well and connected to the hot water injection opening in the hot water injection pipe.