Evaluation methods and results of oil shale resources in southeastern Ordos Basin

Ordos Basin is rich in oil shale resources and has a series of oil drilling data. However, the investigation and evaluation of oil shale resources are still inadequate due to limited useful oil content data, which makes it difficult to predict oil shale resources properly. According to such drilling data in Tongchuan area as logging and oil content in combination with ΔlogR methodology, the oil content log interpretation model has been established, which can identify oil shale layer and interpret and calculate oil content much more precisely. Moreover, on the basis of oil content and oil shale thickness given by plenty of oil drilling data, the quantity of oil shale resources of Chang 7 of Triassic Yanchang Formation in the study area of 1.3×104km2 is evaluated, and the oil shale distribution area is estimated to be 1.08×104km2. Besides, the quantity of oil shale prospective resources is estimated to be 3866×108t while that of the counterpart of carbonization oil shale is 179×108t, which indicates the great potential to form superlarge oil shale resources. The results achieved by the authors provide significant evidence for the exploration of oil shale in this area.