Sedimentary microfacies in Chang 6 oil-bearing bed of Yanchang formation in the north area of Ganguyi Oilfield

Aim Researched into the sedimentary microfacies and the distribution of depositional microfacies of the Chang 6 oil-bearing bed of Yanchang Formation in the north area of Ganguyi Oilfield,to improve a foundation of Palaeogeography for oil-gas.Methods Used geology,physical geology(log) and other techniques,analyze sediment system of Chang 6 oil-bearing bed in study area.Results Fractionize seven types of sedimentary microfacies,and explain its space distribution characters.Conclusion The agradation in this area belongs to delta sediment system,including the distributary channel,the natural barrier,the distributary mouth bar,the distant sand bar;the inter-distributary deposits,the front sands sheet and so on.The distributary channel is mostly from north-east to south-west,and the oil-gas is abundant in the distributary channel of the front-delta.