Three - Redhill Cenozoic Sedimentary Facies Of Favorable Reservoir Facies Prediction,

The Mesozoic and Cenozoic is widely distributed and well outcropped in the Santai-Hongshan region, north margin of the Qaidam Basin. On the base of all kinds of qualitative and quantitative data of stratigraphy and petrology of outcrop and well sections, according to the single factor analysis and comprehensive mapping method, the maps of single factors and sedimentary facies of the Mesozoic and Cenozoic were compiled. A lot of study on sedimentary facies of the Qaidam Basin have been made, but they are all qualitative and lack quantitative data in defining the units of sedimentary facies. The feature of this study that the map of sedimentary facies compiled are quantitative data and that every facies is defined on the basis of quantitative data of single factors. This is the first time to apply this method in studying sedimentary facies of the Qaidam Basin. There are five types sedimentary facies in this region, including alluvial fan, braided river, flood plain, braided river delta and lake. The braided river is further divided into gravel braided river and sandy braided river, the upstream and downstream are also defined. The reservoir in this region mainly is sandstone, the main diagenesis is squeezing, cementing and solution. The diagenesis stage is during the early B diagenesis stage to late B diagenesis stage. The most space of reservoir is original porosity and only minority is secondary porosity. Combining the characteristic of reservoir development and studying of the sedimentary facies, the reservoir physical properties are dominated by sedimentary facies, distribution channel and channel mouth bar are most favorite environment for reservoir forming, and next is sand brain river, the worst is alluvial fan. Base on the distribution of the sedimentary facie. The author forecast the most favorable area for every research unit.