The Lower Shihezi Formation is a main gas producing formation,which is so complex in deposition that it is difficult to identify its stratigraphic sequences using conventional sublayer correlation.

• 下石盒子组是鄂尔多斯盆地大牛地气田的主要产气层位,沉积分布特征复杂,常规的小层对比方法难以准确识别其地层层序。