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. 4. Reservoir space types of the fourth member of Dengying Formation in northeastern Sichuan Basin. (a) Fine-crystalline dolomite, intercrystalline (dissolved) pores, Profile Hujiaba, Layer 160, plane-polarized light; (b) clotted dolomite, intragranular dissolved pores, Profile Hujiaba, Layer 138, plane-polarized light; (c) microbe-bond framework dolomite, with dissolved pores and caves, Profile Hujiaba, Layer 99, plane-polarized light; (d) stromatolite dolomite, with dissolved caves along bedding, and cracks connected with caves, Profile Hujiaba, Layer 140, plane-polarized light; (e) high angle fractures connected with dissolved caves, Well Tx1, 2190.31 m, core photo; (f) microbe-bond dolarenite, crack filled partially by dolostone, Well Ms1, 8106.50 m, plane-polarized light.