Study on the Depositional Feature and the Relation between It and Reservoir Distribution in Chang6 of Yanchang Formation, Huaziping Area, Ordos Basin

According to the lithology, structure and construction of sedimentary and logging facies, it analyzes that Chang-6 reservoir group in Huaziping area is front-delta deposition subfacies. In the paper, it divides sedimentary microfacies into the underwater distributary channel and the inter-distributary deposits. The distributary channel deposits is the main sandbody. The sandbody distributes as strip forms with upward transverse, it’s generally fine-grained feldspathic sandstone. The main reservoir space is the residual interparticle porosity and the secondary solution porosity. Through the studies of the relationship between sedimentary facies distribution and reservoir distribution, the accumulation of oil and gas are controlled by sedimentary microfacies, the distributary channel deposits is the good reservoir of Chang6 as well as the place beneficial for oil and gas accumulation.