关键词: &ldquo, 拖曳&rdquo, 生排烃, 油气运移, 烃源岩, 辽东湾坳陷, 郯庐断裂带, 走滑断层

Abstract: The Tan-Lu fault zone is an important active fault zone in the Bohai Sea area, which controls the conditions of regional oil
and gas accumulation. Based on a case study in the Liaozhong sag of the Liaodong Bay Depression, the geometrical and evolutionary
characteristics of the Tan-Lu fault were studied by using 3D seismic data and the balanced section technique. Based on the results, the
influence of the strike-slip activity of the Tan-Lu fault on the development, distribution, evolution, generation and expulsion of source
rock was addressed. Results show that the tectonic evolution of the Liaodong Bay depression in the Cenozoic is divided into five stages
and three cycles. The strike-slip activity of the Tan-Lu fault staggers the source rocks developed in the early and synchronous stages,
changes the spatial distribution of source rock and hydrocarbon generation potential, and makes it beneficial to form reducing
environments and develop source rocks with higher hydrocarbon generation potential. The strike-slip activity increases the geothermal
gradient and the geothermal heat flow near the fault zone, which is conducive to reducing the hydrocarbon generation threshold.
Different parts of the Tan-Lu fault vary in activities in periods, and they act as close or open channels for hydrocarbon migration. The
Tan-Lu fault strike-slip activity from the late Dongying and early Minghuazhen stages to the present has a good matching with the main
hydrocarbon generation and accumulation periods. It is suggested that the strike-slip activity of the Tan-Lu fault forms a
“towed-pattern” of the hydrocarbon generation and expulsion. As a result, the traps with relatively poor source rock conditions may
also have exploration value, which broadens the ideas of oil and gas exploration.

Key words: “towed-pattern”of the hydrocarbon generation and expulsion, hydrocarbon migration, source rock, Liaodong Bay depression;
Tan-Lu fault zone, strike-slip fault