Abstract: A comprehensive three-dimensional exploitation experimental system for large-scale and full-sized exploitation wells includes a reactor, configured to prepare a natural gas hydrate sample, for simulating an environment for forming a natural gas hydrate reservoir in seafloor sediments. The reactor includes a reactor body, an upper cover disposed at an upper surface of the reactor body, and a lower cover disposed at a lower surface of the reactor body; a gas introducing module, configured to introduce gas to the reactor during hydrate formation; a liquid introducing module, configured to introduce liquid to the reactor during hydrate formation; a temperature regulating module, configured to regulate a temperature in the reactor; a data collecting-processing-displaying module, configured to collect, store, process and display data of the comprehensive three-dimensional exploitation experimental system during an experiment.

Abstract: A device for measuring stratum deformation caused by natural gas hydrate dissociation is provided. The device is configured to be disposed inside a natural gas hydrate reactor, wherein the natural gas hydrate reactor is configured to simulate natural gas hydrate formation layers in the natural gas hydrate reactor, and the natural gas hydrate formation layers include a superstratum layer, a sediment layer and a substratum layer from top to bottom. The device includes a displacement sensor fixing plate, displacement sensors and a flexible elastic plate. A plurality of displacement sensors are provided and evenly distributed, wherein a first end of each displacement sensor is fixed to the displacement sensor fixing plate and a second end of each displacement sensor is stretchably and sealingly fixed to the flexible elastic plate. The flexible elastic plate is tightly attached to the superstratum layer.

Abstract: A flow field measurement device and a method for a scale model of a natural gas hydrate reservoir are provided. The measurement device includes non-central vertical well pressure sensors, non-central vertical well outlet valves, communicating vessel valves, differential pressure sensors, a communicating vessel, a central vertical well outlet valve, and a central vertical well pressure sensor. By providing differential pressure sensors, between a measuring point of the central vertical well and a measuring point of each of the non-central vertical wells, to measure pressure differences, the flow field measurement device enables a reasonable distribution of a three-dimensional space inside the reactor to analyze gas-liquid flow trends in the reactor with a simulated flow field. Determining whether to turn on the differential pressure sensors according to a predetermination based on a feedback from the pressure sensors, allows flow field measurements in the reactor under both high and low pressure differences.

Abstract: A method for detecting node types in a directed network is provided. In the method, flow direction feature information of data traffic between network nodes in the directed network is acquired. The flow direction feature information includes a directed graph of nodes representing the network nodes. Layer scores of the nodes in the directed graph are determined based on whether the directed graph includes a directed cycle. The node types of the network nodes represented by the nodes in the directed network are determined according to the layer scores of the nodes.

Abstract: A hydrate formation promoter and the use thereof in methane storage. The hydrate formation promoter is a mixed aqueous solution including cyclopentane, sodium dodecyl sulfate and water, wherein a volume fraction of the cyclopentane is 5% to 23.4% and a mass fraction of the sodium dodecyl sulfate is 0.01% to 0.08%. The hydrate formation promoter can realize effective and rapid formation of methane hydrate at approximate room temperature (25° C.), and can remain stable at higher temperatures.

Abstract: An in-situ hydraulic jet exploiting device and method of a low-permeability natural gas hydrate reservoir. The device includes a high-pressure reaction kettle configured for formation, fracturing and exploiting of a hydrate, a stable-pressure gas supply module configured to adjust and control a gas flow rate, a constant-speed constant-pressure liquid supply module configured to control a liquid flow rate or keep liquid injection pressure constant, a thermostatic water bath configured to provide a constant-temperature environment for a device system, a back-pressure module configured to automatically control an exploiting rate or exploiting pressure, an in-situ hydraulic jet permeability enhancement module, a data collection and processing module configured to collect and process basic system parameters, and a pipeline connecting various components.

Abstract: An exploiting method and device of marine facies natural gas hydrate. The exploiting method comprises the following steps: (1) after the construction of a vertical well, a fixed pipe is constructed, the exploiting well is set in the center of the fixed pipe, and the mixture is filled between the inner wall of the fixed pipe and the outer wall of the exploiting well; (2) the self-excited oscillating jet nozzle enters the exploiting well along the vertical well to the designated position through an orifice on the exploiting well and sprays the mixture, so that the mixture is broken evenly to form artificial fractures; (3) under the corresponding temperature, the hydrate decomposes to produce gas by depressurized exploiting; (4) the gas-liquid mixture exploited by the exploiting well is separated into liquid and gas in the gas-liquid separation device to collect liquid and gas.

Abstract: A hydrate formation promoter and the use thereof in methane storage. The hydrate formation promoter is a mixed aqueous solution including cyclopentane, sodium dodecyl sulfate and water, wherein a volume fraction of the cyclopentane is 5% to 23.4% and a mass fraction of the sodium dodecyl sulfate is 0.01% to 0.08%. The hydrate formation promoter can realize effective and rapid formation of methane hydrate at approximate room temperature (25° C.), and can remain stable at higher temperatures.

Abstract: A method for recovering gas in natural gas hydrate exploitation is disclosed, in which a gas-water mixture at a bottom of a exploitation well is delivered to an ocean surface platform through a marine riser, by adopting the gas-lift effect of methane gas derived from the dissociation of natural gas hydrate, so as to achieve a controllable flowing production of marine natural gas hydrate. In the startup stage, the pressure in the bottom of the well is decreased by the gas-lift effect of the injected gas to allow dissociation of the hydrate. In the flowing production stage, the flowing production is achieved by the gas-lift effect of the gas derived from the dissociation of the natural gas hydrate, wherein a seafloor gas tank is employed to control the flowing rate and replenish the consumed gas.

Abstract: Disclosed is an experimental device for studying the sediment yield behavior and the radial deformation of porous media during the exploitation of natural gas hydrates, comprising a high-pressure reactor, a hydrate sample chamber, a simulated wellbore, a deformation measurement unit, an ambient temperature control unit, an outlet control unit, an inlet control unit and a data processing unit. Further disclosed is a method using the above-mentioned experimental device to carry out experiments.

Abstract: A method for recovering gas in natural gas hydrate exploitation is disclosed, in which a gas-water mixture at a bottom of a exploitation well is delivered to an ocean surface platform through a marine riser, by adopting the gas-lift effect of methane gas derived from the dissociation of natural gas hydrate, so as to achieve a controllable flowing production of marine natural gas hydrate. In the startup stage, the pressure in the bottom of the well is decreased by the gas-lift effect of the injected gas to allow dissociation of the hydrate. In the flowing production stage, the flowing production is achieved by the gas-lift effect of the gas derived from the dissociation of the natural gas hydrate, wherein a seafloor gas tank is employed to control the flowing rate and replenish the consumed gas.

Abstract: An experimental device of polyphase separation of natural gas hydrate drilling fluid, and method of use thereof, comprising a solid-phase separator, a liquid injection module, a gas injection module and a gas-liquid separator. The solid-phase separator comprises a first filter device and a second filter device, the gas injection module injects gas into the solid-phase separator while the liquid injection module injects liquid into the solid-phase separator, and the gas-liquid separator is communicated with the solid-phase separator through a pressure control valve.

Abstract: A gas-liquid separation apparatus suitable for gas hydrate slurry, comprising an upper chamber, a middle chamber, and a lower chamber; a gas-phase outlet and a pressurizing unit are disposed in a top of the upper chamber, the middle chamber is provided with a material inlet and a wire mesh demister, and the lower chamber is provided with a liquid-phase outlet and a plurality of deflector baffles. The arrangement of divided chambers can reduce the degree of hydrate dissociation in the slurry (i.e., loss of the sought gas) and improve the separation efficiency. With the pressurizing unit, it facilitates the setting of the required pressure for gas-liquid separation without introducing a pressure maintaining valve in the subsequent separation process, prevents the hydrate in the slurry from dissociating in the apparatus, and allows rapid separation between the slurry and the gas.

Abstract: An apparatus and a combined process for carbon dioxide gas separation, combining the hydrate-based process with the chemical absorption process, which reduces secondary pollution and allows the efficient continuous separation of carbon dioxide gas without increasing the pressure and thereby the operating cost is reduced significantly. The apparatus and combined process can be applied in the separation of carbon dioxide in IGCC synthetic gas, natural gas and biogas, and address the issues of the existing processes such as high energy consumption, low throughput, and secondary pollution.

Abstract: 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.

Abstract: A gas-liquid separation apparatus suitable for gas hydrate slurry, comprising an upper chamber, a middle chamber, and a lower chamber; a gas-phase outlet and a pressurizing unit are disposed in a top of the upper chamber, the middle chamber is provided with a material inlet and a wire mesh demister, and the lower chamber is provided with a liquid-phase outlet and a plurality of deflector baffles. The arrangement of divided chambers can reduce the degree of hydrate dissociation in the slurry (i.e., loss of the sought gas) and improve the separation efficiency. With the pressurizing unit, it facilitates the setting of the required pressure for gas-liquid separation without introducing a pressure maintaining valve in the subsequent separation process, prevents the hydrate in the slurry from dissociating in the apparatus, and allows rapid separation between the slurry and the gas.

Abstract: An experimental device of polyphase separation of natural gas hydrate drilling fluid, and method of use thereof, comprising a solid-phase separator, a liquid injection module, a gas injection module and a gas-liquid separator. The solid-phase separator comprises a first filter device and a second filter device, the gas injection module injects gas into the solid-phase separator while the liquid injection module injects liquid into the solid-phase separator, and the gas-liquid separator is communicated with the solid-phase separator through a pressure control valve.

Abstract: Disclosed is an experimental device for studying the sediment yield behavior and the radial deformation of porous media during the exploitation of natural gas hydrates, comprising a high-pressure reactor, a hydrate sample chamber, a simulated wellbore, a deformation measurement unit, an ambient temperature control unit, an outlet control unit, an inlet control unit and a data processing unit. Further disclosed is a method using the above-mentioned experimental device to carry out experiments.

Abstract: An apparatus and a combined process for carbon dioxide gas separation, combining the hydrate-based process with the chemical absorption process, which reduces secondary pollution and allows the efficient continuous separation of carbon dioxide gas without increasing the pressure and thereby the operating cost is reduced significantly. The apparatus and combined process can be applied in the separation of carbon dioxide in IGCC synthetic gas, natural gas and biogas, and address the issues of the existing processes such as high energy consumption, low throughput, and secondary pollution.

Abstract: A device for simulating exploitation of a natural gas hydrate in a permeable boundary layer includes a high pressure reaction kettle, a formation simulation unit and an aquifer maintaining unit. A water bath jacket externally connected with constant temperature water bath is arranged on the outer wall of the high pressure reaction kettle for providing a necessary temperature condition for the high pressure reaction kettle. A simulative well at the center of the top of the high pressure reaction kettle is connected with liquid injection, gas injection, gas production and water production equipment. An aquifer interface at the bottom of the high pressure reaction kettle is connected to the aquifer maintaining unit through a pipeline. The simulation device simulates the geological environment of a hydrate reservoir, allowing comprehensive evaluation of hydrate exploitation under different formation permeability and different formation pressure gradients.