Abstract:

Microstructure of pores and fissures is an important factor which influences the rock physical parameters such as acoustic velocity, permeability. These physical parameters are the important foundation for the gas hydrate accumulation and exploration in permafrost. The rock core samples recovered from Juhugeng district in Qinghai Province were studied in this paper. The pores and fissures of these samples were detected by the micro-focus computer tomography (micro CT). The results show that fissures widely exist in mudstone in good connectivity with the widths between 100 to 200 μm. However, pores are distributed dispersedly and there are poorly connected throats in sandstone with volumes of most pores lower than 0.1 mm³. The porosities of cores are estimated to be 2.36%-2.89% (sandstone samples) and 1.04%-3.64% (mudstone samples) respectively by the method of counting the voxel of 3D gray images.

Key words: micro CT, natural gas hydrate, Juhugeng drilling area, rock, micro structure