Characteristics and main controlling factors of reservoirs in the fourth member of Sinian Dengying Formation in Yuanba and its peripheral area, northeastern Sichuan Basin, SW China

JIN Mindong,LI Bisong,ZHU Xiang,DAI Lincheng,JIANG Zhili,WU Hao,LI Hui,YANG Peiyun

Fig. 8. Lithology and karstification profile of the top of the fourth member of Dengying Formation in Guchengxiang Profile, Wangchang county. (a) Layer 5, terrigenous detrital gravels and particles of coarse sand grade in the irony weathered crust; (b) Layer 4, 1 m thick asphalt layer with rich dissolved pores and caves; (c) Layer 3, siliceous dolomite with no reservoir; (d) layer 1, clotted dolomite with abundant dissolved pores and caves.