Experimental Research On Formation Of Ice In Porous Medium

It is well known that every country throughout the word is exploring and developing thenew energy sources due to the non-equivalence between the demands of human beings andthe reserves of conventional fuel energy like oil and natural gas. Vast financial and materialresources are employed to investigate the natural gas hydrate, which is drawn internationalattention as a new unconventional energy sources, and substantial achievement are eventuallyaccomplished. The researches on natural gas hydrate are currently focused on the geophysicalproperties of natural gas hydrate reservoir. However, it is difficult for researchers to conductan experimental study on in situ gas hydrate samples obtained by coring drilling due to thespecial storage conditions of natural gas hydrates, and synthesizing natural gas hydratesamples in laboratory is consequently used as the common methodology for investigatingnatural gas hydrates. Nevertheless, the existed methods for forming natural gas hydrate,especially the formation of natural gas hydrate in porous media, lead to a non-uniformdistribution for hydrate in artificially synthesized gas hydrate samples, and it will result in apoor reliability for obtaining the geophysical parameters of natural gas hydrate reservoir. Inaddition, three micromechanical models of the gas hydrate formation in reservoir, known as:hydrate is part of the pore fluid, hydrate becomes the part of solid frame, and hydrate cementsgrains evenly, were proposed by Dr. Christine Ecker in his thesis in1998, and themathematical expression represented the relationship between elastic wave velocity and gashydrate saturation in those three models were established, which was extensively acceptedand cited in academic research, but it was never be minutely reported about the research ongas hydrate existed in the pore fluid. In order to solve the problem of the non-uniformdistribution of hydrates in artificially synthesized gas hydrate samples and obtain the sampleswith gas hydrate in the pore fluid, a method for forming ice particles in porous media by theuse of microwave heating was proposed, which could provide a preliminary procedure for theformation of artificially synthesized samples with gas hydrate in the pore fluid.A parametric adjustable apparatus for travelling heating with magnetrons was independently designed according to the requirement for microwave heating apparatus while forming iceparticles in porous media, and numerical simulations of the electromagnetic field distributionin samples with6,7,8and9magnetrons were respectively conducted with High FrequencyStructural Simulation (HFSS) in this paper. Experiments on the temperature distribution in thesamples were conducted while various numbers of magnetrons are working together forheating natural gas hydrate samples. It is concluded that the electromagnetic field intensityand the temperature in the center of the measured samples are higher than that outside of thesample while working with the designed heating apparatus according to numericalsimulations and experimental results. Furthermore, it can also be concluded that the electricfield and temperature inside the samples can be changed by adjusting the distance between thewaveguide port and the sample tube.The preparation for samples with ice particles in pore space was eventually conducted bythe use of the independently designed, parametric adjustable heating apparatus withmagnetrons in this paper. As a consequence, samples with evenly distributed ice particles inpore space were finally obtained, which could make a great contribution to the formation ofgas hydrates in the pore fluid.