Sedimentary Facies And Reservoir Characteristics Of The Third Member Of Shahejie Formation In Gubei Subsidence

Gubei sag is a level4negative tectonic units which is located in northeastern Zhanhua sag in Giyang depression. Hydrocarbon source rock in the study area is thick and buried deep, and exist submarine fan, low fan and turbidite fan and many other types of favorable reservoir. It has a greater potential in hydrocarbon exploration and development.Es3is the main hydrocarbon source rock and the principal oil-bearing series. We have made a few preliminary research results, in current it is in a critical transition. But there are still some deficiencies:imperfect understanding of sedimentary features; detail distribution features of the reservoir are not enough; physical properties of it are not clear and so on. So this paper mainly research depositional system and reservoir distribution which restrict the exploration and development of oil and gas in Es3.This paper identifies three types of sedimentary facies including the fan delta, nearshore subaqueous fan and slump turbidite fan, which are result from the various types of phase signs and logging data. Carry out all types of sedimentary facies analysis, reveals vertical and horizontal distribution of the various sedimentary facies in the study area. The results show that there exist multiple source system, the phase of different types of source system is different, and the same source system is not only consistent, but also with the variability of reservoir scale and force.According to core analysis and test data analysis, this paper digests and absorbs achievements of predecessors, and has research on reservoir characteristics which are guided by sedimentology, sequence stratigraphy and reservoir geology. Study results were as follows: size and distribution of reservoir is controlled by provenance system, sand body distribution along the valley; rock types of the single and various types of pore, Ⅱ type of reservoir in majority; physical properties of it is controlled by the layer thickness, depth and sedimentary microfacies.Through these studies, the sedimentary facies and reservoir characteristics of Es3are recognized; it offers a scientific basis for further exploration and development.