Carboniferous Akshak Group's Sedimentary Facies And Depositional Environmental Analysis In Yili Area

Yili Basin lies to the west of Junggar Basin and the north of Tarim Basin, while in the Late Paleozoic it was also a part of the Chu river -Saleisuyi Basin. Though all of these basins nearby in the Carboniferous - Permian strata have been explored with huge reserves of oil and gas, the exploration of hydrocarbon in Yili Basin which has the similar strata are not available. Furthermore, there are also different opinions in terms of the Carboniferous tectonic setting in Yili Basin, i.e., Rift Valley environment or Island-arc environment. All above uncertaintiesare due to relatively inadequate studies on the basic geological research in Yili Basin and its complex tectonic background.In this paper, we obtained substantial measured field profile as our first-hand information, and did detailed studies on Carboniferous strata in Yili Basin. On the basis of above works, the sedimentary phases and their micro-phases from Akeshake formation in early Carboniferous are divided .The paleogeographic characteristics of its structure and the sequence stratigraphy, as well as the geologic features of petroleum are analyzed. It is proposed that Carboniferous strato in Yili Basin may reflect rift tectonic background, and the entire Akeshake formation shows its depositional model into the sea. As to petroleum geology, Carboniferous source rocks from Yili have experienced several times maturation. However, considering the structural influence, oil and gas may be failure to be reserved, so it suggests the future exploration should be focused on the study of structural traps.