Differences and controlling factors of composite hydrocarbon accumulations in the Tazhong uplift, Tarim Basin, NW China

JIANG Tongwen,HAN Jianfa,WU Guanghui,YU Hongfeng,SU Zhou,XIONG Chang,CHEN Jun,ZHANG Huifang

Table 1 Stratified characteristics of reservoirs in the Tazhong uplift.

Horizon Lithology Trap type Pore type Porosity/ % Permeability/ 10-3 μm2 Fluid characteristics Reservoir type Productivity Devonian- Carboniferous Sandstone and small amount of carbonate Anticline Primary 12 to 20 10 to 1 000 Conventional oil, a small amount of gas Bottom water block and edge water layered types High and stable production, high recovery rate Silurian Sandstone Lithology, fault anticline Primary 8 to 15 0.2 to 50.0 Heavy oil, small amount of conventional oil Bottom water block and edge water layered types Low and stable production, low recovery rate Ordovician Limestone, dolomite Lithologic, stratigraphic ones Secondary 3 to 8 <2 Complex Complex Large changes and low recovery rate