| The Ordovician reservoir has a good potential for oil and gas exploration in Yubei area, Tarim Basin. Based on the cores, thin sections, imaging logging, physical property data, and geochemical data, the karst reservoirs of Lower -Middle Ordovician in Yubei area have obvious features of "stratification from upper to lower and differentiation from east to west". Longitudinally, there are three sets of reservoirs: the upper section of Yingshan Formation, mainly fracture type; the lower section of Yingshan Formation, mainly fracture-vug type; and the Penglaiba Formation, mainly vug type. Horizontally, the reservoirs developed in the eastern fault zone, mainly fracture type, while it is relatively poor in the central and western regions. According to the palaeo-geomorphology and fracture evolution, the Ordovician reservoir can be divided into two genetic types: weathering crust karst reservoir, mainly distributed in the high parts of palaeo-structures, and fault-controlled karst reservoir, mainly distributed along larger scale fractures. The model of Ordovician reservoir is established in Yubei area, by which the central platform of Yubei could be the next favorable play. |
