Abstract: To elucidate the tectonic characteristics of faults in the Laoyemiao region of the Nanpu Depression and their role in the control of petroleum entrapment, the principles of tectonic analysis were used to perform an in-depth analysis of the coupling between petroleum entrapment factors and the evolution of faults. It was found in this study that fault systems in the Laoyemiao region may be broadly divided into basement and superficial faults, and the vertically developed igneous rocks constitute the ductile transfer zone of deep and shallow fault systems. The NNE and NE striking basement faults formed by forwards-extending Eocene rifts were present as multi-periodic listric fan faults, while the NEE-striking superficial fault systems formed by obliquely extended Oligocene rifts mainly occurred as horst and graben faults, and domino faults. In the Neogene layer, flower-and Y-shaped styles of deformation formed along the main fault line in the cap rocks due to the sliding deformation of deep faults, in the midst of thermal precipitation. The multi-periodic rifting of the main fault line in the Laoyemiao region was favorable for the sedimentation and maturation of source rocks, and the main fault line was also the primary channel for the vertical migration of petroleum within this region. Hence, anticlines and sloped zones are favorable areas for hydrocarbon accumulation.

Key words: fault system, tectonic styles, rollover anticlines, petroleum accumulation, Laoyemiao region