Geological characteristics and potential evaluation of typical interlayer shale oil in the Ordos Basin: A case study of the Chang 7 Member of Well Ning228

Abstract

The Chang 7 Member of the Ordos Basin has favorable shale oil resource potentiality. The exploration and development of sandstone interlayer shale oil in the Chang 7 Member has made substantial breakthroughs. The exploration and development potential of shale oil is huge, and will be a significant oil and gas alternative resource in the Changqing Oilfield in the future, but its related geological fundamental research is relatively weak. Based on the observation, description and systematic sampling of the centimeter-level core of the full core section of Chang 7 Member in Well Ning228, a series of experimental test analyses and identification outcomes indicated that Chang 7 Member primarily developed four rock types: Black shale, dark mudstone, siltstone and tuff. The overall conditions of source rocks in the Chang 7 member are superior, the organic carbon content of shale is high, and the hydrocarbon generation potential is large. The organic matter types are mainly type Ⅰ and type Ⅱ, which are in the low mature-mature stage, and the black shale has higher organic matter abundance. The main reservoir spaces of the Chang 7 Member are primary pores and secondary pores. Mud shale primarily develops organic pores and inorganic pores. Fine sandstone mainly develops residual intergranular pores, intragranular pores and intergranular pores. Tuff mainly develops intergranular pores and mineral intragranular pores. The overall oil-bearing property of the Chang 7 Member is good, but the mobility difference is large. The fluid mobility in sandstone and tuff is good, and the mobility inshale is poor. In short, fine anatomical analysis of typical interlayer shale oil provides favorable guidance for promoting the large-scale development of shale oil in the Ordos Basin