Study On Genesis And Distribution Pattern Of Reservior In Upper Es₄ South Slope Of Dongying Depression

There are good formation conditions of subtle reservoir in upper the 4th member of Shahejie Formation of Dongying depression, since of 1965 when reservoir was found ,there are new reservoir discovery , subtle reservoir exploration increasing become important research field. Under the guide of Vail sequence stratigraphic theory, and through the combination of geological data, seismic data, well logging data, drilling cores and other related analyzed data and experimental technique, in upper the 4rh member of Shahejie Formation of Dongying depression, there is established the sequence stratigraphy framework which included 2 third-orde sequences in the limit of T7, sequence 1 which is correspond to ChunShang of upper the 4th member of Shahejie Formation of Dongying depression , include 6 sand groups (Cs6, Cs5, Cs4, Cs3, Cs2, Cs1) from bottom to top of the formation being studied, and sequence 2 which is correspond to Chunxia and Chunxiaxia of upper the 4th member of Shahejie Formation of Dongying depression , include 3 sand groups (Cxx, Cx2, Cx1) from bottom to top of the formation being studied. In comprehensively consideration of the coring , geologging , electriclogging and seismic data, the author sets up the depositional systems of region being studied , such as: river-delta-slumping turbidite fan (deepsea fan)system , beach and dam systerm, beach shallow lake and half deep-deep lake system. It states systematically the depositional systems and their feature .At the same time ,the source of research region have been studied and there were two source systerm(south and north ) . The sand body under the control of the northern source is characteristic of fan delta ,inshore subsea apron and sublacustrine fan; and the sand body under the control of the southern source is characteristic of meandering river delta and slumping turbidite fan .And It analyses the periodicity and cyclicity evolution of depositional model in vertical and plain section , discusses the control factors of depositional system distribution, such as : conformation , source, palaeogeomorphology, variation of lake level,variation of base-level , dynamic condition, palaeoclimate ,and so on . The conformation, source and palaeogeomorphology are more important than the others in research region. These all can taken as a basis for prospecting and study of the next step in this region.