西湖凹陷平湖斜坡带始新统平湖组层序地层

HIGH RESOLUTION SEQUENCE STRATIGRAPHY OF THE EOCENE PINGHU FORMATION,PINGHU SLOPE,XIHU SAG

运用高分辨率层序地层学的理论和技术,以钻井、测井、地震资料为基础,对西湖凹陷平湖斜坡带始新统平湖组进行了层序地层研究。研究区向上"变深"的非对称型短期旋回层序最为发育,反映了研究区在平湖组沉积时期处于距物源区较近或物源供给较充分的环境下;中期旋回以发育上升半旋回沉积厚度大于下降半旋回的不对称型旋回为主,层序分界面两侧为有利砂体发育的部位;在不同级次基准面旋回层序划分的基础上,建立了以中期旋回为时间—地层对比单元的钻(测)井高分辨率层序地层格架。

The high resolution sequence stratigraphy of the Eocene Pinghu Formation is studied with the data from well logs, isographs, seismic interpretations and regional sedimentary background. The short-term base-level cycles are characterized by asymmetric and deepening-upward stacking patterns, which indicate that the depositional environment of the Pinghu Formation is close to the provenance; the mid-term base-level cycles are mainly the asymmetric patterns dominated by ascending half cycles; the sands are mainly deposited above and below the sequence interface. Upon the analysis of different base-level cycles, a high resolution sequence stratigraphic framework was established.