The lower Jurassic layer of Yakela fault arch was formed during subsidence. The control on sediment of area tectonism was quite different in various periods and with various depositional features. The study on main Cretaceous reservoirs was very mature. The discovery of new area of oil and gas, and research on the earlier and thinner lower Jurassic layer became increasingly prominent. The four sand beds of target zone displayed typical depositional features. This paper succeeded to specifically elaborate these typical sedimentary features and differences from fragments, single well facies, provenance systems, plane sedimentary facies and longitudinal strata correlation. The sedimentary subfacies of lower Jurassic layer experienced facies from delta front to delta plain of braided river to shallow lake from bottom to top. Three main provenance systems behaved significantly different on supplying patterns and quantities.The Ⅲ-Ⅳsand bed is deposited with channel sandbodies of delta-front and three provenance systems are abundantly supplied. The distribution form of sedimentary facies in plane is in shaped of dumbbell that is represented by SC2 and S4 well area, in accordance with the distribution of effective reservoir. The Ⅱsand bed is swamp deposited as delta-plain and provenances reducing increasingly. TheⅠsand bed transited to shallow lake facies and the provenances was nearly interrupted. The microfacies display obvious differences. The extensive developed and better submarine distributary channel microfacies can be regarded as favorable facies. This paper attributes guides and references not only for subsequent oil/gas potential arguments, but also for researches on characteristics and development of similar oil/gas reservoir.