渤海湾盆地饶阳凹陷流体包裹体特征及浅层油气成藏改造过程OA

To investigate the influence of Cenozoic tectonic activity on shallow hydrocarbon accumulation and trans-formation in Raoyang Sag of Bohai Bay Basin,fluid-inclusion analysis and test are conducted.Combined with burial history and fault-caprock sealing evaluation,hydrocarbon accumulation and tectonic transformation processes are revealed by analyzing the differences in fluid-inclusion characteristics in shallow reservoirs.The results show that,although 2 major late-Cenozoic tectonic events caused local anomalies in fluid-inclusion signatures,3 stages of hy-drocarbon charging were still identified in shallow reservoirs,corresponding to fluid-inclusion fluorescence colours of yellow(80～90 ℃),yellow-white to yellow-green(90～120 ℃)and blue-green(120～140 ℃).Dongying Formation exhibits continuous charging during stages Ⅰ,Ⅱ and Ⅲ,while Guantao Formation reservoirs are mainly charged during stage Ⅱ,lacking low-maturity(stage I)and mature(stage Ⅲ)hydrocarbon charging.Hydrocarbon in Don-gying Formation accumulated mainly via Paleogene-Neogene active oil-source faults that connected the underlying Shahejie Formation source rocks,undergoing 2 significant transformation events.Guantao Formation reservoirs orig-inated from leakage and re-accumulation of Dongying Formation hydrocarbons at 12 Ma.Reservoir distribution is mainly controlled by fault-sealing zones where top fault-caprock thickness of Dongying Formation is less than 62 m.The research provides theoretical support for achieving breakthroughs in full-sequence hydrocarbon exploration throughout Jizhong Depression.