Characteristics and impacts on favorable reservoirs of carbonate ramp microfacies: A case study of the Middle-Lower Ordovician in Gucheng area, Tarim Basin, NW China

LIU Yini,HU Mingyi,ZHANG San,ZHANG Junlong,GAO Da,XIAO Chuantao

Fig. 4. Seismic facies characteristics of microfacies in the Ordovician in Gucheng area. (a) Dolomitic shoal and top flat, characterized by chaotic mound-like reflections with weak amplitude, and dolomitic lagoon and dolomitic flat on the west, characterized by reflections with continuous medium to strong amplitude; Well GC16; 6160 to 6268 m; (b) Inter-shoal sea microfacies, characterized by continuous sub-parallel reflections with strong amplitude, and middle-high energy shoal microfacies on both sides, characterized by chaotic mound-like reflections with weak amplitude; Well GC14; 6483 to 6586 m; (c) Low-energy shoal microfacies, characterized by chaotic mound-like reflections with weak amplitude (smaller than the medium-high energy shoal microfacies); Well GC11; 6156 to 6221 m; (d) Static mud microfacies, characterized by sub-parallel reflection with moderate to strong amplitude along the bedding; Well GC4; 6080 to 6142 m. O₂yj-Middle Ordovician Yijianfang Fm.; O₂y_1-2-Middle Ordovician Ying 1^st Member-Ying 2^nd Member; O₁y₃-Lower Ordovician Ying 3^rd Member; O₁y₄-Lower Ordovician Ying 4^th Member; O₁p-Lower Ordovician Penglaiba Fm.