Mesozoic–Paleozoic Structural Characteristics and Their Controlling Effects on Oil and Gas in the Kongnan Area of Bohai Bay Basin

Abstract

The Bohai Bay Basin is a typical marginal basin with complex internal structures and abundant oil and gas resources, exhibiting unique marine geological characteristics and processes. Based on seismic profile interpretation and balanced cross-section techniques, this paper presents a comprehensive systematic study of the structural combination and tectonic evolution of the Neo-Mesozoic–Cenozoic superimposed basin in the southern Bohai Bay Basin. The research findings indicate that the area exhibits four types of structural properties, including compression, extension, strike-slip, and thrust structures, along with thirteen fundamental styles. Building upon this foundation, research has been conducted on the tectonic evolution and formation processes during the Mesozoic and Cenozoic eras. Based on the effective correlation between hydrocarbon generation and tectonic evolution phases, a three-phase model was proposed as “early anticline-controlled oil accumulation-primary reservoir formation, mid-stage fault adjustment-secondary reservoir formation, late-stage block modification-multiple phase petroleum accumulation”. Our model explains the composite reservoir system in the Neogene–Mesozoic era, characterized by multiple-stage structural oil and gas accumulation, coexistence of primary and secondary hydrocarbon, and various types of oil and gas reservoirs. This study elucidates the controlling effects of structural characteristics and evolution on oil and gas accumulation under marine geological conditions, providing a theoretical basis for the efficient development of oil and gas resources in marginal basins.

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