辽东湾海域JZ25地区流体包裹体与油气运移

An analysis on fluid inclusions and hydrocarbon migration in JZ 25 area of Liaodong Bay waters

应用流体包裹体均一温度法对渤海辽东湾海域JZ25地区油气充注史进行研究,结果表明该地区经历两期油气充注:第一期发生于石英次生加大作用之前,以液态烃相包裹体为主,但丰度低、成熟度低;第二期发生于石英次生加大作用之后,有机包裹体主要分布于沿切割石英碎屑颗粒及其次生加大边的微裂缝面或长石颗粒的溶蚀孔隙中,且丰度高,是JZ25油气藏的主要形成时期,距今约23～21Ma。在此基础上,进一步对研究区古近系沙河街组三段烃源岩的超压系统、油气运移通道进行分析,并建立了储层-断层共控的油气运移模式,为JZ25地区高丰度的亿吨级油气藏的发现提供重要依据。

A study of hydrocarbon charge history was carried out in JZ25 area, Liaodong Bay waters, by using homogenization temperature of fluid inclusions. The resuhs indicate that the area had experienced two stages of hydrocarbon charge. The first one happened during the period prior to a secondary outgrowth of quartz and mainly in form of liquid-hydrocarbon inclusions of low abundance and low maturity. The second stage happened during the period after the secondary outgrowth of quart and organic inclusions of high abundance were mainly distributed along the micro-fi＇actures that cut through quartz grains and their outgrowth rims or in the dissolution pores of feldspar grains. Hydrocarbon reservoirs in JZ25 area is considered to be formed mainly during the second stage,which is 23 -21 Ma from nowadays. An analysis of excess pressure system and hydrocarbon pathway of source rocks in third member of the Shahejie Formation in the study area was then performed based on the above understanding. A model illustrating hydrocarbon migration controlled by both reservoirs and faults was also established and served as an important guidance for the exploration of large-scale hydrocarbon reservoirs in JZ25 area.