The main conclusions are as follows: 1.The sandstones of Yanchang Formation in the south of Ordos basin mainly composed of lithic feldspathic sandstone and feldspathic sandstone.

• 主要取得以下成果和认识:1.；延长组砂岩储层主要为细粒的岩屑质长石砂岩和长石砂岩；总体上成份成熟度较低、结构成熟度中等。