The hydrate formation and reformation reduce mining efficiency and safety during natural gas hydrate exploration and natural gas pipeline transportation. In this paper, the methane hydrate formation and reformation in partially water saturated consolidated porous media were studied by low field MRI. The results show that the change of water content was ununiform both in time and space. The water content reduction rate displayed as fast-slow-fast-slow periodic rhythm; Hydrate formed prior in the bigger pores due to the bigger contact area between water and gas and lower pore water saturation; The formed hydrate made the pore structure inside of porous media more complicated; The rate of hydrate reformation was faster than that of hydrate formation because the residual hydrate microcrystalline structure after decomposition provided the place of dendrites nucleated and grew. This research can give some implications for delivering natural gas safely and studying natural gas hydrate reservoirs.
Keywords methane hydrate, formation, reformation, low-field MRI