Prediction of favorable petroleum exploration areas based on the analysis of depression–fault transformation in the Linhe Depression, Hetao Basin, China

The Hetao Basin is a Meso-Cenozoic petroleum basin in the Midwestern China. The Linhe Depression has yielded significant oil discoveries in recent years, which developed from the change in understanding of the basin evolution. Based on the analysis of the regional stress field, unconformity surface characteristics, structural style, and formation filling characteristics, the tectonic environments of the Linhe Depression in different periods and their lateral differences were restored. Combined with the thermal simulation of source rocks, oil-source comparison, and the determination of the charging period, the influence of structural environment changes on resource potential was discussed. The results show that the Meso-Cenozoic tectonic environment of the Linhe Depression had undergone a process of transformation from depression type to fault type, resulting in differential superposition of source rocks, oil accumulation near the source, and oil accumulation in the relatively uplifted zone. Two favorable exploration zones and one prospective exploration zone are predicted. The determination of the Linhe Depression evolution broke through the early understanding that the tectonic environment of the Hetao Basin was always as a faulted depression, redefined the distribution of the main source rocks, and provided a theoretical basis for the expansion of the exploration scope and the determination of the next exploration direction.