给你个参考吧,CNKI上有这篇文章
坳陷湖盆斜坡带曲流河砂体分布与隐蔽油藏预测——以陕北宁条梁-乔沟湾地区延安组延9_1油组为例
Sandstone Distribution Pattern and the Prediction and Evaluation of Subtle Reservoirs in Meandering Channel of Slope Belts:A Case from Yan——9_1 Reservoir of Yan an Formation in Ningtiaoliang-Qiaogouwan Area of Ordos Basin
可知,延安组研9地层应该是
Yan-9 oil reservoir of Yan an Formation