CLASSIFICATION AND EVALUATION OF SANDSTONE RESERVOIR

This paper briefly describes the pore types of sandstone reservoir which are located in some regions of China.Then, according to the pore type and pore-size distribution data, the sandstone reservoirs are classified and evaluated with repect to oil production capacity.Studies indicates that sandstone reservoir in China can roughly be divided into three categories: (i) Sandstones which mainly involves intergranular pores and dissolved corrosion pores possess good physical properties. Their capillary pressure curves show rough-skewness and well sorting, their natural production capacities are high; (ii) Sandstones which mainly involves micropores, interstitial pores and cement intercrystal pores in matrix possess poor to medium physical properties. Their capillary pressure curves show fine-skewness and poorly sorting, so they have only medium to low natural production capacities; (iii) Sandstone reservoir loses its commercial value when its radius of an essential part of pore-throat-size are smaller than 0.68 micrometre.Table of classification and evaluation is listed in this paper. Unquestionably, it gives petroleum geologists much convenience for accelerating the discovery of benifitial accumulation zone in benifitial lithofacies zones.