Sinian hydrocarbon accumulation conditions and exploration potential at the northwest margin of the Yangtze region, China

YANG Yu,WANG Zecheng,WEN Long,XIE Wuren,FU Xiaodong,LI Wenzheng

Fig. 6. Microscopic features of Dengying Formation reservoirs at the northwest margin of Yangtze craton region. (a) Hujiaba Profile; Deng-4 Member composed of algal dolarenite with intergranular dissolved pores, obvious early dissolution and reformation traces; pores filled with dolomites and asphalt; (b) Well Gaoshi-1; 4986.57 m; Deng-4 Member composed of karst breccia dolomite with intergranular pores; dolomicrite as protolith; (c) Well Pengtan-101; 5733.52 m; Deng-2 Member composed of algal clotted dolomite with isopachous foliated dolomitic cement in intergranular pores; (d) Well Pengtan-101; 5754.20 m; Deng-2 Member composed of algal dolarenite with moldic pores from selective fabric dissolution of rubbles; (e) Well Moxi-9; 5432.11 m; Deng-2 Member composed of algal dolarenite and algal oncolite dolomite with intragranular dissolved pores developed; (f) Wangjiawan Profile; Deng-2 Member composed of algal dolomite with algal lattice pores developed.