Combining NMR and RCP to Characterize Full-range Pore Structure in Tight Glutenite Reservoirs

In order to quantitatively evaluate the full range of the conventional pore and treelike pore and to gain insight into the heterogeneous pore structure and its effect on macroscopic properties, a combination of nuclear magnetic resonance (NMR) and rate-controlled mercury porosimetry (RCP) was performed on tight glutenites from Baikouquan Formation in the Junggar Basin of China. Through comparing the shape of P1 in T2 distribution with the shape of throat distribution derived from RCP, we determined the full-range pore size distribution of tight glutenites. The result shows that there is a wide range of pore size distribution from 0.05 to 200 p:m in tight glutenites. Based on fractal theory and characteristics of mercury intrusion curves, the size distributions of the conventional pore and the treelike pore were obtained. Combined with centrifugation experiments, it can be concluded that the movable fluid is primarily distributed in the conventional pores. Furthermore, the proportion of the conventional pore has a positive effect on the permeability and movable fluid saturation of tight glutenite, while the increase of the proportion of the treelike pore and mixed pore will seriously damage the permeability and mobility of tight glutenite.