Abstract:

Upper Paleozoic strata of Ordos Basin can be divided into three medium-term cycles and eleven short-termcycles based on base-level cycle. The three medium-term cycles, namely MSC1, MSC2, and MSC3 from top to bottom,correspond respectively with Shihezi, Shanxi, Benxi and Taiyuan Formations-Fan-delta, epicontinental sea, delta,allavial fan and river channel deposit systems are identified in the target sections of the study regions. The earier stratawere epicontinetal sea deposits formed on peneplain, when the seawater receded in Permian, nonmarin basin began to form. It is predicted that the reservoirs are distribute widely within the three cycles of MSC1, MSC2 and MSC3. Yi24-E9-Yil4, Yi22-Yi6-Yil3 and Yil5-Zhaotan 1 and Yi9 well areas are favourable regions for reservoir development,While QijihLang-Tabamiao-Shan 196 well areas are the most favorable regions for oil and gas prospecting.

Key words: Base-1evel cycle, sedimentary system, reservoir prediction, Ordos Basin, Upper Paleozoic, sequence stratigraphy