New Findings on Multi-stage Faults Controlling Hydrocarbon Accumulation in the Ordos Cratonic Basin, China

Abstract

Summary The Ordos Cratonic Basin is currently the largest oil and gas producing province in China. Previous studies found that faults are rarely developed within this basin. The QSM gas field is a newly discovered large gas field in the west of the Ordos Basin. Compared with other gas fields in the Ordos Basin, faults are developed in this gas field. However, the fault throws in the Permian reservoirs are small, making it difficult to manually interpret faults on seismic sections. Meanwhile, well test results show high production variation among wells, the control of faults on gas accumulation is still unclear. This study demonstrates an enhanced workflow to characterize multi-stage faults in the QSM gas field based on 3D seismic and borehole image data. The hydrocarbon accumulation in this region is mainly controlled by three stages of faults, which are nearly NS-trending formed in the Caledonian phase, NW-trending active in the Indosinian phase, and NEE-trending faults formed during the Himalayas phase. These new findings are different from the traditional understanding that faults are not developed in the Ordos Cratonic Basin and provide insights into the structurally complex gas field development in the Ordos Basin.