长北气田位于鄂尔多斯盆地陕北斜坡东北部, 下二叠统山西组为一套碎屑沉积, 自上而下被划分为山1(P1s1) 和山2( P1s2) 等2 个岩性段, 其中山2 段是长北气田主力产层。在岩心描述、岩矿分析及测井资料综合研究的基础上, 确定山2 段属于海相辫状河三角洲沉积体系。在长北气田范围内, 主要发育三角洲平原亚相, 次为前缘相, 其广泛发育的分流河道砂体为油气聚集提供了有利场所。文中采用层序- 岩相古地理编图的技术方法, 详细描述了山2 段砂体的展布特征, 为储层预测和描述提供了可靠依据。

Changbei Gasfield is located in the northeast of Shanbei Slope in Ordos Basin. Shanxi Formation of Lower Permian is a series of clastic deposits, and it can be divided into two lithologic segments (P₁s₁ and P₁s₂) , between which the second member of Shanxi Formation (P₁s₂) is the principal producing formation. Based on core description, mineral analysis and well logging data, Shan 2 member is considered as marine braided river delta deposit. Delta plain subfacies developed well in Changbei Gasfield, of which the widely developed distributary channel sandbodies are favorable for the hydrocarbon accumulation. The method of sequence-lithofacies paleogeographymapping is adopted to describe the sandbody distribution characteristics of Shan 2 member, which could offer reliable reference for reservoir prediction.