沾化凹陷沙四段油气成藏动力学研究

THE RESEARCH OF DYNAMICS ACCUMU LATION IN THE 4^(th) MEMBER OF SHAHEJIE FORMATION,ZHANHUA DEPRESSION

沾化凹陷古近系沙河街组四段是济阳坳陷内重要的油气产层,但其油气成藏动力学研究仍处于起步阶段。从实测静温数据出发,分析了沾化凹陷现今温度场的分布特征;利用实测与计算的地层流体压力数据,对沾化凹陷沙四段现今压力场的纵、横向分布特征进行了剖析,阐述了沙四段油气分布与纵向压力场的耦合关系,指出岩性与异常压力的双重封堵是油气成藏的关键因素。应用盆地模拟技术,对沾化凹陷典型井古温压场的形成与演化进行了模拟。研究表明,古温压场演化过程与沾化凹陷整体的构造升降有关,古地温场决定烃源岩的热演化,古压力场决定烃源岩的生排烃与油气的运移聚集。以沾化凹陷构造的形成与演化为主线,恢复了沙四段油气的成藏动力学过程。

The 4th Member of Shahejie Formation of Paleogene has been an important oil producing formation in ZhanHua depression.The involved research in dynamics accumulation of the hydrocarbon is,however,in the initial stage yet.Based on the observed temperatures,the paper analyzed the characteristics of the present temperature system on its distribution of the 4th Member of Shahejie Formation.With the pressure data measured and calculated,the paper generalized the characteristics of present pressure system on its longitudinal and plane distribution,interpreted the coupled relationship between the distribution of oil-gas and the pressure system within this formation,and finally concluded that the sealing both by lithology and abnormal pressure is the key factor to oil-gas accumulation.By the techniques of basin modeling,the process of paleo-temperature-pressure systems' formation and evolution of typical wells could be reconstructed in Zhanhua depression.What the research revealed as the following: the evolution process of pale temperature-pressure system is related to the tectonic movement;the paleo-temperature system has influences on thermal evolution of the oil source rock;the paleo-pressure systems decide migration and accumulation of hydrocaobon.Taking structural evolution of Zhanhua depression as the main clues,the dynamics process of oil-gas accumulation in 4th Member of Shahejie formation is rebuilded.