东海西湖凹陷平湖斜坡带平湖组层序地层学

The Sequence Stratigraphy of Pinghu Formation in Xihu Sag of East China Sea

运用层序地层学原理，对西湖凹陷平湖斜坡带平湖组进行了层序地层分析。平湖组处于本区层序地层划分的第Ⅱ层序内，由五个次级亚层序组成。平湖斜坡带层序的发育早期受断裂作作的控制，海平面变化的频繁周期性控制了层序的形成、发育和结束，并决定了古生物面貌、体系域发育和沉积相的基本特征。平湖斜坡带平湖组发育了低位体系域、海进体系域和高位体系域。平湖组海进体系域形成的泻湖、潮坪相暗色泥岩是本区主要的生烃源岩；高位体系域形成的潮道砂和三角洲等砂体，孔、渗条件较好，是主要的储集层。不同体系域的岩石学特征，在空间上形成了生、储、盖匹配关系，使平湖斜坡带成为西湖凹陷的一个大油气田。

篧e developed the scquence straitigraphy analyses for Pinghu Formation in Pinghu Slope,in Xihu Sag. Pinghu Formation belongs to the second sequence, which consists of 5 secondaryparasequences. The development of sequence in Pinghu Slope are controlled by early faulting.It is frequently periodic sea level changes that dominate the origination, development and ending of sequence, and also dominate the general features of paleobiological style, system trct and depositional facies.There are lowstand system tract, transgressive sysiem tract and highstand system tract in Pinghu Formation, in Pinghu Slope. The transgressive system tract comprise lagoon and tidal flat dark mudstone, which are the main sourcerock in the area. The highstand system tract comtprise tidal channel and deltaic sandstcne, which are in good porosity and permeability, become he main retervior in the area. Pinghu Slopc are promising petroliferous area due to the favorecablc match of sourcerock, reservior and caprock, which are the result of the petrographic characters of different system tract.