东营三角洲—浊积扇高频层序叠加样式与岩性圈闭

High Frequency Sequence Stacking Mode of Dongying Delta-turbidite Fans and Lithological Trap

东营三角洲砂体及与之伴生的各类浊积扇体是东营凹陷沙河街组三段重要的储油砂体。以高分辨率层序地层学理论为指导,分析基准面旋回变化对三角洲发育演化的控制作用,将三角洲发育过程中的高频层序叠加样式划分为3种类型。通过分析短期基准面的升降变化对与三角洲有关的岩性圈闭形成与分布的影响,指出短期基准面上升期形成的坡移浊积扇圈闭厚度大,分布广,储集物性好,是三角洲发育区岩性油藏勘探的主要目标。该类扇体的分布主要受基准面旋回变化、同生断裂及沉积古地貌等因素所控制,垂向上主要位于中期基准面由下降到上升的转换位置,平面上主要分布于同生断层下降盘及其之间的古地貌低洼处。

Dongying deltas sand body and its associated turbidite fans are the main reservoirs of Shahejie Three Formation in Dongying Sag. Based on the high resolution sequence stratigraphical theory, this paper analyzed the variety of base level cycles and its control on the development and evolvement of Dongying delta. Its high frequency sequence stacking mode is divided into three types. This paper also studied the variety of short term base level cycles and its effect on the form and distribution of turbidite fans which are related to Dongying delta, and indicate that the slopemoving turbidity fan which consisted of the main reservoirs were formed during rising stage of the base level. The distribution of slop-moving turbidity fan is mainly controlled by the variety of base level cycles as well depositional faults and depositional palaeogeomorphology. Vertically, slop-moving turbidity fans are located on the location where the middle term base levels transformed from rising stage to falling stage. On the plane, the slop-moving fans are distribu- ted in the downthrow of depositional faults and the palaeogeomorphological lowlands between these faults.