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. 7. Features of piebald karst system and half-dissociation belt in the fourth member of Dengying Formation in the northeastern Sichuan Basin. (a) Piebald karst system, Profile Hujiaba, Layer 134, outcrop photo; (b) piebald karst system, Profile Yangba in Nanjiang county, Layer 303, outcrop photo; (c) piebald karst system, Well Ms1, 8079 m, plane-polarized light; (d) karst cave filled by carbonate sand and breccia, Profile Hujiaba, Layer 151, outcrop photo; (e) half-dissociation belt (fragile halo), Profile Hujiaba, Layer 121, plane-polarized light; (f) half-dissociation belt (fragile halo), Profile Hujiaba, Layer 153, plane-polarized light.