STUDY OF TIGHT SANDSTONE PERMEABILITY FROM LATTICE BOLTZMANN & DIGITAL ROCK MODEL

Due to the experimental technology condition, to measure the permeability of the porous rock is still a changeling problem, especially for low or ultralow permeability porous rock. X-ray computed tomography (CT) technology, which can conveniently be used to obtain high-resolution internal structure data of the rock, is more and more widely used to predict and explore the permeability physical properties of the low or ultralow porous rock. How to determine the CT cross-section resolution is one of the key issues in the predict process, even this approach has some incomparable advantages of experimental methods, with high precision, convenient, and the field measurement. In this work, the tight sandstone sample from the Ordos Basin Triassic formation is selected and different tomography resolution data are obtained from Kochi Institute for Core Sample Research (10μm), National Synchrotron Radiation Laboratory of Chinese Academy of Sciences (5μm, 2μm) and National Institute of Metrology of China (2μm), respectively. Then, based on the D3Q27 lattice Boltzmann method & virtual digital physical technology, the permeability under coupled confining pressure (0～200MPa), pore pressure (0～65MPa) and temperature (25℃～180℃) is measured. The results show that when the tomography resolution is located at 2μ, the results are consisted with the experimental results obtained from Inc AUTOLAB 2000C rock system. The permeability anisotropy of tight sandstone under ultra-high temperature and pressure (0℃～400℃, 0～1.4GPa) is explored and this will be helpful to understand the strength decrease of asthenosphere and interaction between lithosphere and asthenosphere.