Limits and grading evaluation criteria of tight oil reservoirs in typical continental basins of China

ZHOU Nengwu,LU Shuangfang,WANG Min,HUANG Wenbiao,XIAO Dianshi,JIAO Chenxue,WANG Jingming,TIAN Weichao,ZHOU Lei,CHEN Fangwen,LIU Wei,WANG Zhixuan

Table 1 Theoretical lower limit of the physical properties of tight oil reservoirs in typical continental basins in China.

Basin System Formation Lithology Formation pressure/ MPa Surface tension[33]/ (mN·m-1) Wetting angle/ (°) Water film thickness/ nm Porosity/ % Permeability/ 10-3 μm2 North Songliao Basin Upper Cretaceous Qingshankou Formation Siltstone 18-22 14.5 40 18 3.00 0.012 00 South Songliao Basin Lower Cretaceous Quantou Formation Fine- medium sandstone 20-22 13.7 25 19 3.40 0.015 00 Bohai Bay Paleogene Kongdian-Shahejie Formation Glutenite 26-35 8.6 27 10 3.29 0.011 00 North Jiangsu Paleogene Funing Formation Siltstone 28-35 8.1 23 9 1.66 0.002 40 Ordos Triassic Yanchang Formation Sandstone 18-22 14.5 30[34] 19 4.00 0.020 00 Junggar Permian Lucaogou Formation Mixed rock 37-45 3.0 85 5 1.00 0.000 12