PROGRESS IN EXPERIMENTAL RESEARCH ON RESISTIVITY EVOLUTION OF HYDRATE BEARING SEDIMENTS

Electrical resistivity is extremely sensitive to the composition and microstructure of hydrate-bearing sediments, and is often applied as a key parameter reflecting the evolution of physical properties during the formation and decomposition of hydrates. However, due to the complexity of influencing factors, the variation of resistivity with the formation and decomposition of CH₄ hydrate is still unclear. Based on the research progress of resistivity experiment of hydrate-bearing sediments, the evolution of resistivity in the hydrate forming process in different systems, such as pure water, saline water and unsaturated water, is studied in this paper. The results show that in the sediments saturated by pure water, the hydrate develops gradually from contact mode to cementation mode; in the systems filled by saturated brine, hydrate occurs in a suspension mode and Ostwald maturation occurs; in the sediments with unsaturated water, hydrate occurrence changes from suspension mode to cementation mode. Based on the above analysis, a model of hydrate formation process is proposed by the authors, and the future development trend of experimental research on electrical characteristics is discussed. It is confident that the results have certain reference significance for hydrate electrical research.