Abstract:
The Tongchuan-Yan’an area, the southeastern of Ordos Basin, is one of the richest oil shale resources areas in China. Triassic Yanchang Formation is considered as the greatest potential resource layer for oil shale exploration. In order to understand the deposit characteristics, grade quality and exploration prospect and to provide a reference for further exploration of oil shale in Chang 7 Member of Yanchang Formation in the study area, according to comprehensive data interpretation of geological survey, geological drilling, well logging and sample analysis, the prospective resource estimation reveals that the oil shale is large in thickness and high in oil content, and it has a concentrated and stable distribution, which is considered as medium-grade and sulfur-rich oil shale. Sedimentary environment has an important effect on the thickness and oil content of oil shale. The transition belt between semi-deep lake and shallow lake, and the lake-bay environment are the most favorable facies for the formation of oil shale. It is proposed that the amount of oil shale resource of Chang 7 with the depth below 500 meters has reached 1 346.46×10
8 t, while the counterpart of carbonized oil shale has reached 63.70×10
8 t. The resource potential of the study area is enormous, and implies the prospect of large and super-large oil shale deposits.