Sequence Stratigraphy Study of the Upper Paleozoic of the Suligemiao Oil and Gas-bearing Area,North Ordos Basin

Based on the study of the tectonic evolution, the assemblage of vertical lithology, the character of logs, and the theory of sequence stratigraphy, the sequence stratigraphy in upper Paleozoic of Suligemiao oil and gas-bearing is studied in this paper. Divide the upper Paleozoic into 5 sequence sets, and Jinci to Shihezi Formation is subdivided into 14 sequences, which formed in epicontinental sea, deltaic and fluvial sedimentary environments. The sequence stratigraphy framework of this area has been set up. The map of sandbody distribution is drawn according to system tract. The development and distribution of the sandbody are discussed in the lowstand system tract of sequence 8 and 9. By the sandstone mapping in the unit of system tract, the distribution of sandstone is shown distinctly. The formation and distribution of sand reservoir is controlled by the sedimentary environment, which is gathered in the lowstand systems tract.