北大港潜山滨海断层发育特征及其与上古生界二次生烃耦合成藏研究

Study on Developmental Characteristics of Coastal Fault in Beidagang Buried Hill and Its Coupling with the Upper Paleozoic Secondary Hydrocarbon Formation

断层的形成及演化对油气成藏具有十分重要的意义。为探明北大港潜山滨海断层对上古生界烃源岩生烃成藏的控制作用,基于大量地震资料及各时期的底面构造图,精细刻画了滨海断层发育特征,并结合烃源岩生烃演化过程,分析两者之间油气成藏匹配关系。研究结果表明:滨海断层东段断层发育程度最强,中段稍弱,西段最弱,东段发育大量花状组合构造,以牵引背斜成藏模式为主,中段发育多米诺式组合构造,以断块-断鼻成藏模式为主;E s 3时期断层活动性最强,活动中心位于中段,平均垂直活动速率达227.5 m/Ma,E d时期断层活动性减弱,活动中心位于东段,平均垂直活动速率最低仅为7.0 m/Ma;E d时期为北大港潜山石炭系—二叠系烃源岩二次生烃成藏关键时期,各成藏要素匹配关系极好,北大港中段为油气成藏有利区,是下一步勘探开发的重点区域。研究结果对北大港潜山石炭系—二叠系原生油气藏的深入勘探具有一定借鉴意义。

The formation and evolution of faults are greatly significant for hydrocarbon accumulation.In order to ascertain the control of the coastal faults in the Beidagang buried hills on the hydrocarbon generation and accumulation of upper Paleozoic source rocks,based on a large amount of seismic data and bottom structure drawings of various periods,the development characteristics of the coastal fault was characterized in detail.Combined with the hydrocarbon generation and evolution of the source rocks,the matching relationship was analyzed for hydrocarbon accumulation.The results of the study showed that the eastern section of the coastal fault was the most strong in development,the middle section was slightly weaker,and the western section was the weakest;the eastern section was developed with a large number of flower-like assemblages,and dominated by hydrocarbon accumulation on traction anticline;the middle section was developed with domino-type assemblages,and dominated by hydrocarbon accumulation on fault-black and fault-nose;in the E s 3 period,the fault activity was the strongest,and the center of activity was located in the middle section,with an average vertical activity rate of 227.5 m/Ma;the fault activity in the E d period was weaker,the center of activity was located in the east section,with an average vertical activity rate of 7.0 m/Ma;the E d period was the key period of secondary hydrocarbon generation and accumulation of the Carboniferous-Permian source rocks in Beidagang Buried Hill,and the accumulation elements were matched with each other.The middle section of Beidagang Buried Hill was a favorable area for hydrocarbon accumulation,as well as the key area for further exploration and development.The results of the study can be used as a reference for in-depth exploration of the Carboniferous-Permian primary oil-gas reservoirs in Beidagang Buried Hill.