Experimental Study On The Basic Properties Of Hydrate Deposits

As a new mineral resource,natural gas hydrate(NGH)has been widely recognized as the most promising renewable energy source in twenty-first Century because of its abundant reserves and clean combustion.In nature,it mainly exists in the form of sediment in the frozen soil or the seabed.It is possible to solve the problem of NGH exploitation by means of mechanical method to excavate the NGH crushing particle.Geophysical prospecting and mechanical method need to set up an adequate understanding of the basic physical properties of NGH sediments.Therefore,this paper mainly studies the physical properties of hydrate sediments.This paper adopts SHW-? gas hydrate rock specimen acoustic electric mechanical testing device,carried out a series of basic properties of gas hydrate sediments experiments.We get properties of hydrates from the same number of sand with different pore saturation;the same pore saturation with different types of hydrates;different particle size of sand.The research mainly includes three part.A series of different NGH sediment pore saturation synthesis experiments have been carried out by using the same mesh sand and experimnental device,the reliability of the formula and the influence of pore saturation on the properties of NGH sediment are compared and analyzed.Natural gas and tetrahydrofuran hydrate sediment were synthesized using this device,contrast experiments were carried out using SDS(twelve alkyl sulfate)solution and deionized water at the same saturation.NGH sediment synthesis experiments of different kinds and different sand were carried out by using device,the influence of different size sand and different kinds of sand on hydrate sediment properties under different pore saturation is analyzed and compared.Under the current experimental conditions,the results show that:The wave velocity of shear and longitudinal wave,dynamic mechanical parameters increase with the increase of pore saturation,the cementation of core increases with the increase of saturation.The difference of wave velocity between deionized water and SDS solution for NGH sediments was very small,and the shear modulus and Poisson's ratio of dynamic mechanical parameters have a significant difference,the rest have a small difference;the wave velocity and dynamic mechanical parameters of tetrahydrofuran hydrate sediments have certain differences;the SDS solution has little influence on the compression properties of tetrahydrofuran hydrate sediments,has some influence on the compression properties of NGH sediments.The higher the pore saturation of the same sand,the faster the velocity of sound propagation;the same type of sand with different particle size,the higher the number(particle size reduction),the faster the speed of wave propagation;different types of sand and sand on the acoustic velocity of mesh.The young's modulus,bulk modulus and shear modulus increase with quartz sand particle mesh increase.The ability to resist the compression of NGH sediments(the cementation of sediments)increases with the number of sand,but decreased with the decrease of pore saturation;different kinds of compression properties show similar with the close sand mesh;for the different type of sand,the higher hardness the sand is,the stronger the cementation of the sediments is,from the view of the dynamic mechanical parameters.