Crude oil mobility and its controlling factors in tight sand reservoirs in northern Songliao Basin, East China

FENG Jun,ZHANG Bowei,FENG Zihui,WANG Yachun,ZHANG Juhe,FU Xiaofei,SUN Yonghe,HUO Qiuli,SHAO Hongmei,ZENG Huasen,QU Bin,CHI Huanyuan

Table 3 Classification standard of tight sandstone reservoir in northern Songliao Basin.

Reservoir type Lithology Starting pressure gradient/(MPa?m-1) Movable oil rate/% Movable fluid saturation/% Porosity/ % Permeability/ 10-3 μm2 Average pore throat radius/nm Ⅰ Fine sandstone, siltstone 0.3-0.6 More than 30 More than 40 8-12 0.10-1.00 100-300 Ⅱ Siltstone, mud-bearing siltstone, argillaceous siltstone 0.6-1.0 5-30 10-40 5-8 0.03-0.10 50-100 Ⅲ Calcium-bearing siltstone, argillaceous siltstone More than 1.0 Less than5 Less than 10 Less than 5 Less than 0.03 Less than 50