The main gasbearing reservoir in Block 120 of Sulige gas field is Shanl and HeB.In orderto identify the sandbody distribution in this block,we studied the sedimentary microfacies based onsedimentology,paleogeography,and petrography and logging geology.It is suggested that the facies ofShanl segment belongs to precipitation facies of meandering river,while He8 segment belongs to braided river.The best reservoir sandstone is located in the river channel;In the period of Shan13,thesandstone which is good for gasoil reservoir is better than Shanl and Shan.With obvious struclure features of braided deposition profile,He8 developed a lot of channel subfacies and its propertyfor oil&gas reservoir is far better than Shanl;From the timing,Shan is meandering river sedimentarywhile He8 is braided river sedimentary,with the thickness of sandbody and the proportion of sand increasing.From graphic division,thicker sandbody in this zone located from north to south,which isrelatively consistent with sedimentary facies distribution.Sand body thickness,development scale andsand body space distribution are subject to the cloth of sedimentary facies control.