40 results about "Hydrate dissociation" patented technology

In hydrate-based desalination or other water purification conducted using naturally buoyant or trapped-gas-assisted buoyancy hydrate in a hydrate fractionation column, a portion of fresh or purified product water is extracted from an upper, hydrate dissociation region of the fractionation column and reintroduced into a lower portion of the fractionation column at a point above but generally near a product water / saline water interface. The difference in density between the reintroduced product water and the fluid in the hydrate fractionation column above the point of reintroduction (water, hydrate, and gas) drives a natural circulation system which enhances the rate at which hydrate rises into the hydrate dissociation region.

Warm water is pumped up by a pump from an underground aquifer present 1000 to 1500 m below the seabed, geothermal energy is caused to flow through a permeable layer below a methane hydrate layer, a dissociation boundary surface of an un-dissociated area of the methane hydrate layer is dissociated to generate methane gas, the methane gas is led into a production well from peripheral areas and through a gas inlet screen and caused to rise so that the methane gas is collected on the sea.

The invention discloses a well structure design and method for exploiting geothermal energy and gas hydrate reservoir at the same time of water injection. The design mainly comprises a dual branch injection well and a horizontal producing well, wherein cold fluid is injected into the dual branch injection well, heated by a geothermal layer and returned to the gas hydrate reservoir; the self-carrying heat is transmitted to hydrate, and the hydrate dissociation is promoted. The method comprises the steps that a well group system which is composed of the dual branch injection well and the horizontal producing well is built on the sea level, wherein the dual branch injection well comprises a vertical mineshaft which extends from the sea level to the geothermal layer, a first branch mineshaft which is located on the gas hydrate reservoir and a second branch mineshaft which is located on the geothermal layer; the cold fluid is injected into a wellhead oil tube of the dual branch injection well, the cold fluid enters an oil sleeve annulus at the tail end of the second branch mineshaft and is subjected to heat exchange with the geothermal layer, after the heated fluid enters the gas hydrate reservoir, the heat is transmitted to the gas hydrate reservoir, the hydrate dissociation is caused, and mixed fluid which is composed of natural gas and injection fluid generated by the dissociation passes through a hydraulic power fracturing fracture under the gravity and pressure effect and is exploited by the horizontal producing well. According to the well structure design and method, the geothermal energy provides energy for the hydrate dissociation, the shortages such as low heat utilization efficiency and high exploiting cost in a traditional thermal excitation exploiting method are overcome, the device is simple, the operation is convenient, the economy is high, and the well structure design and method can provide guidance for reasonable exploiting of the gas hydrate reservoir.

The invention discloses an experimental simulation method for hydrate production and a confining pressure loading and thermal insulation integrated system. The confining pressure loading and thermal insulation integrated system comprises a refrigerating machine, a hydraulic press, a temperature sensor and a liquid cavity; the temperature sensor is connected with the refrigerating machine and is used for feeding the temperature of the surface of a sample back to the refrigerating machine; the refrigerating machine is connected with the hydraulic press and is used for adjusting the temperature of liquid of the hydraulic press into the temperature of the surface of the sample; the hydraulic press is used for inputting the liquid to the liquid cavity, wherein the temperature of the liquid is adjusted by the refrigerating machine; and the liquid cavity is connected with the hydraulic press and is used for supplying a confining pressure to the sample through the circulating liquid, enabling the sample to be isolated from the heat of environments, receiving the liquid input by the hydraulic press and outputting the circulated liquid to the refrigerating machine. The confining pressure loading and thermal insulation integrated system can provide a practical environment for the accurate testing of temperature variation caused by hydrate dissociation in the hydrate production process and is very beneficial to the scientific research and future field monitoring of hydrate production which gets more and more attention.

The invention belongs to the technical field of geotechnical engineering, and provides a modeling method of a sediment multi-field coupling model taking hydrate decomposition into account. According to the modeling method, on the basis of a pore-medium mechanical basic theory, in combination with the mechanical characteristics, flow characteristics and heat-transfer characteristics of hydrate sediment, control equations and constitutive equations of physical and mechanical behaviors of the hydrate sediment are given. By the adoption of a PDE module in COMSOLM ultiphysics software, the control equation discretization of temperature, pressure and saturation degrees is achieved, an outer material interface in a structural mechanical module is adopted, and a hydrate-sediment critical-state constitutive model based on a thermodynamics method is embedded. Meanwhile, a return mapping algorithm of a backward euler integral format is adopted, C++ language is adopted to write a model program, and numerical simulation and analysis, taking the hydrate decomposition process into account, of the physical and mechanical behaviors of the sediment are achieved.

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.

The invention provides an experimental method and an experimental device for measuring sand produced by hydrate dissociation and seepage. The experimental method comprises the following steps: filling a sample tube with an experimental material to simulate a hydrate sediment layer; placing the sample tube in an environment with the pressure of 8-30MPa and at a temperature of 0-10 DEG C; filling the sample tube with methane gas and water to simulate hydrate dissociation and production; simulating hydrate dissociation and seepage through a filter screen, wherein a water-sand-gas mixture in the sample tube passes through the filter screen and then methane gas and a mixture of water and part of sand flow out; and enabling the methane gas to flow upwards through a flow meter to obtain the volume of the methane gas, and enabling the water and sand mixture to flow downwards through a nuclear magnetic resonance measurement module to obtain the volume of sand. The experimental method and the experimental device can be used for measuring the temperature and pressure, the sand production rate, the gas output and the water flow during hydrate dissociation and seepage in real time, thereby providing a scientific basis and a technical support for predicting sand produced by hydrate production and making control measures.

The invention discloses a triaxial test device for natural gas hydrate deposits, which belongs to the field of testing the mechanical properties of natural gas hydrate deposits. The device includes a triaxial test device host, a temperature control system, a pore pressure control system, a confining pressure control system and a computer data acquisition and control system. The host of the triaxial test device adopts a double pressure chamber structure, which can accurately measure the change of sediments during the decomposition of natural gas hydrate; the load sensor is installed inside the pressure chamber to improve the accuracy of the strength data; The pore gas and pore water of the sample are pre-cooled to reduce the decomposition of natural gas hydrate in the saturated water process, and also improve the accuracy of temperature control; the sample installation process is connected by quick joints, which is convenient and fast. The device can simulate the decomposition process of natural gas hydrate under production conditions, realize high-precision temperature control, and accurately measure strength and volume change. It is of great significance to understand the mechanical properties of natural gas hydrate deposits and evaluate the stability of reservoirs.

The present invention discloses a process for the dissociation of natural gas hydrates comprises injecting additives or hydrate dissociation promoters into the system at the hydrate dissociation temperatures ranging from 283-293 K in conjunction with or without first depressurizing the system to pressures (50%-75%) below the hydrate equilibrium pressure and such leading to the recovery of methane or natural gases.

The invention discloses a gas separation method and a separation system based on porous materials, relates to the technical field of mixed gas separation, and can solve the problems of discontinuous separation process, low separation coefficient, slow reaction speed and the like in the existing hydrate separation process. The gas separation method based on the porous material is to provide a wet reaction channel filled with a porous material, and the pore size of the porous material is nano-scale; the pretreated mixed gas is passed into the reaction channel, and the gas to be separated in the mixed gas is separated from the reaction channel. The water / aqueous solution in the porous material undergoes a hydration reaction to form hydrates, and the remaining gas is discharged, and the water content in the reaction channel is kept within a preset range; the hydrates in the reaction channel are decomposed to obtain the purified gas to be separated. At the same time, a separation system using the above method is proposed. The gas separation method based on the porous material provided by the invention can maximize the gas-water contact area, increase the hydrate formation rate, and simultaneously increase the gas separation coefficient.