Oil-bearing potential, mobility evaluation and significance of shale oil in Chang 7 shale system in the Ordos Basin: A case study of well H317

Taking the Chang 7 shale system of Yanchang Formation in Ordos Basin as the research target and based on the statistics of a large number of geological samples, the authors established the oil generation and expulsion model. The movable threshold (hydrocarbon expulsion threshold) of the Chang 7 shale system was considered to be 70 mg/g TOC, and the evaluation template of shale oil in Chang 7 shale system was established, which included oil-bearing potential and mobility. In the evaluation template, the shale oil in this area was divided into three categories:effective resources, potential resources and ineffective resources. Based on the actual geological application examples of well H317, the different lithologies were systematically classified using the evaluation template. Sandstone, silty mudstone and some massive mudstone in the Chang 7 shale system of well H317 are probably the effective resources and favorable targets for shale oil exploration and development. Although the oil-bearing capacity of black shale is good, the composition is heavy and that will cause the fluidity to be not as good as the other kinds of lithologies mentioned previously. However, by using engineering techniques such as situ mining, it may become a potential target for shale oil exploration in this area.