浅海重力流储层沉积模式新认识

New Understanding of Sedimentary Model of Gravity Flow Reservoir in Shallow Sea

D气田黄流组一段为浅海陆架背景下的海底扇沉积,沉积微相平面展布复杂,储层具有很强的非均质性。开展沉积机理研究,对于厘清海底扇沉积微相展布、预测砂体展布具有重要意义。通过压实校正恢复古地貌,基于粒度标准偏差开展了水动力分析。随后,在综合分析古物源、古地貌、古水深、古水动力等特征基础上,明确浅海重力流沉积物的搬运作用明显受到坡折带、洼陷、沟谷等地貌的控制,并建立了先成洼陷限制性重力流充填-溢出、斜坡坡折下侵蚀-充填-分流、平缓斜坡非限制性漫流3种浅海海底扇沉积模式。

Submarine fan deposition is developed under the background of shallow shelf in D Gasfiled.The distribution of sedimentary micro-facies and the heterogeneity of reservoir is complex.The study of sedimentation mechanism has important implications for clarifying micro-facies distribution and predicting sand bodies.This paper reconstructs paleo-geographic environments through compaction correction and analyzes paleo-hydrodynamics based on deviation of granulometry.Comprehensive analysis of ancient sources,paleo-geography,paleo-water depth and paleo-hydrodynamics clarifies that the handling of gravity flow sediments in the shallow water is obviously controlled by various landforms such as slope break belts,depressions,and valleys.Based on the above study,three types of shallow submarine fan sedimentation model are established:restrictive gravity flow filling-overflow model in pre-depression,gravity flow erosion-filling-shunting model under slopebreak,and non-restrictive overflow model on flat slopes.