苏里格气田西区S47区块石盒子组八段沉积微相

Detailed Sedimentary Facies of the 8th Member of Shihezi Formation in the Block S47 in Western Sulige Gas Field

鄂尔多斯盆地苏里格气田是我国陆上产能最大的气田,其主力产气层——二叠纪石盒子群八段岩性致密,储层的分布主要受沉积微相控制。但S47区块作为苏里格气田西区一个重要的新区,有关沉积微相的认识仍存在分歧。在岩心观察、钻井资料及样品分析的基础上,重点研究了S47区块盒8段沉积微相,认为该区盒8段属辫状河三角洲前缘沉积,并识别出水下分流河道、河口坝、席状砂、水下天然堤、分流间湾等5种微相;最有利的储集砂体主要为水下分流河道叠置砂体,其次为河口坝砂体。沉积微相及其展布特征的新认识为该区储层预测、水平井整体开发提供了地质理论依据。

Sulige gas field in Ordos basin is the largest terrestrial gas production field in China .As a typical tight sandstone gas pool , distribution of reservoirs of the main gas -producing strata in Sulige gas field---the 8th mem-ber of Shihezi formation in Permian system （P2h8 for short）, is mainly controlled by detailed sedimentary facies .But disagreements about detailed sedimentary facies still exist in the Block S 47---an important new region in the west-ern part of Sulige gas field .Detailed sedimentary facies of P 2h8 in the Block S47 were studied on the basis of drilling core observation , analysis of well logs and samples .It is considered that the strata of P 2h8 in the Block S47 was de-posited in braided delta front , which can be further sub -divided into subaqueous distributary channel , estuary bar , sand sheet , subaqueous levee and interdistributary bay etc .5 detailed sedimentary facies .The most favorable reser-voir is subaqueous distributary channel overlaid sand bodies and estuary bar sand bodies secondarily .New under-standings on detailed sedimentary facies and distribution features provide theoretical foundations for reservoir predic -tion and integrated exploitation by horizontal wells in the Block S 47.