The middle Permian Lucaogou Fm. was dist ributed within Malang sag and the southwestern part of Tiaohu sag.It was the main source rock composed f rom carbonate rocks and dark shale.

• 三塘湖盆地中二叠统芦草沟组分布于马朗凹陷和条湖凹陷西南部边缘 ,主要由碳酸盐岩和暗色泥岩组成 ,是盆地主力生油岩。