Spatial and temporal evolution of the Sinian and its implications on petroleum exploration in the Sichuan Basin, China

In recent years, there have been significant discoveries of hydrocarbon resources with commercial value in the Dengying Formation of the central Sichuan Basin. However, the impact of tectonic evolution on hydrocarbon accumulation has not been appropriately documented. In this study, we employed multiple methods, including seismic interpretation, balanced cross-section restoration, deformation quantification, erosion calculation, and paleo-highs/lows reconstruction, to investigate the tectonic kinematics, erosion distribution, paleo-highs/lows evolution of the Sichuan Basin. The quantification of deformation reveals that the Sichuan Basin has experienced a complicated tectonic evolution, with two rounds of transition from tension to contraction since the Sinian. In the Late Ordovician, contraction caused by the Caledonian Orogeny resulted in a foreland basin being developed in the Sichuan Basin. Since the Late Triassic, the Sichuan Basin has experienced intense contraction, resulting in the development of its current structural pattern. By integrating the erosion distribution, the reconstructed paleo-highs/lows maps of Sinian strata indicate the development of inherited paleo-uplifts in the central and southwestern Sichuan Basin from the Early Cambrian to the present. The evolution of paleo-highs/lows plays a critical control on the hydrocarbon accumulation of the Weiyuan and Anyue gas fields, indicating there could be high potential for hydrocarbon exploration in areas with high slope gradients in the paleo-uplifts.