前陆盆地层序地层格架内的油气勘探

前陆盆地层序地层学是将层序地层学理论应用于构造活动区盆地分析的一个特例。应用层序地层学理论作指导来研究前陆盆地沉积地层时不仅要考虑全球海平面的变化,而且要重视构造作用的影响。前陆盆地构造活动不仅影响可容空间,还表现在对盆地基底构造作用的影响。前陆盆地的层序界面主要为构造作用或构造与湖平面变化叠加作用的结果。本文通过在层序地层格架内分析前陆盆地不同结构单元生储盖组合关系及油气成藏特征,认为前陆褶皱冲断带为前陆盆地中油气主要富集区,前渊蚴陷带为主要的生烃和运移中心,前缘隆起带油气勘探须考虑后期构造作用对油气藏的改造。

Hydrocarbon Exploration in Sequence Stratigraphy Framework in Foreland Basin

The sequence stratigraphy of foreland basins may be a special examples of applying the sequence stratigraphic theories to the basin analysis of tectonically active areas.The study on sedimentary stratum of the foreland basins under the guidance of the sequence stratigraphic theories,not only should consider the changes of global sea level,but also should pay more attention to the effects of tectonism.Tectonism of foreland basins affects accommodation,and also affects the tectonism of base.Sequence boundaries of foreland basins are mainly of the result by tectonism or combined effects of tectonism and lacustrine level changes.Through analysising the source-reservoir-caprock assemblage relationship and hydrocarbon accumulation characteristics of different structural elements in sequence stratigraphic framework,it is concluded that foreland thrust fold belt is the mainly hydrocarbon enriching section,foredeep depression belt is the mainly hydrocarbon generation and migration center,and the later tectonism rebuilding for oil and gas reservoirs must be paid more attention in the hydrocarbon exploration in frontal uplift belt.