The Silurian in the eastern Tarim Basin is a set of marine clastic sediments and only the Lower Silurian is preserved now, which is distributed in a eastern-western long and narrow belt.The belt lies south of the Well Tienan 2 and Well Weima 1, north of the Well A’nan 1. Fan delta sedimentary system is mainly developed. The Lower Sandstone Member reservoir is characterized by lithic sandstones and the main type of reservoir porosity is residual primary intergranular pore. Compaction is the important factor affecting the reservoir petrophysics. In the Lower Sandstone Member reservoir, the petrophysics of medium-grained sandstones is relatively favorable and their porosity is usually larger than 10%, and thus they constitute the main pay zone of the member. Diagenesis in the later period partly improved the petrophysics of some strata. After a long geologic evolution, the favorable reservoir intervals in the Lower Sandstone Member are preserved and may contain commercial quantities of petroleum.