Sedimentary Characteristic of the Ordovician Strata in the Area of the Middle Tarimu Basin

The area of the middle Tarimu Basin is an important oil-gas province. The Ordovician is the hydrocarbon source rock and also is one of the main series of stratum in exploration, which is characterized by wide distribution and greatly vertical-horizontal variation. The lower Ordovician is similar to Cambrian, the carbonate platform developed and the tuff and dolomite rocks are in major. The lithology division of the middle-upper Ordovician has the No.1 fault in the area of the middle Tarimu Basin as the boundary, which is divided into two strata and lithology areas. The carbonate platform and accident clastic rocks developed simultaneously in this period. The Cambrian-lower Ordovician is the widest sources rock in the areas and the middle-upper Ordovician source rock just distributed over the sub-sea terrace.