Study Of Sandbody Internal Architecture In The Layer-recombination Pilot Area Of North2East

With the continuous deepening of oil field development, most of continental oil fieldshave entered into high or special high water-cut stage in China. But on conditions of today'stechniques, the average oil recovery reaches about35%, which means there are still a lot ofoil left in the ground. Due to the impact of reservoir heterogeneity, the distribution ofremaining oil is highly fragmented, resulting in the potential tapping more and more difficult.Therefore, to find out the reservoir characteristics underground is greatly significant toenhance oil recovery. The study mainly selects seven sedimentary units of the northeast pilotarea No.2sequence in reorganization test area of Saertu reservoir and Putaohua reservoir.Under the guidance of the outcrops, sedimentary theory and depositional model, wo haveestablished a stratigraphic framework, studied the sedimentary microfacies, internalarchitecture of different sand body and reservoir heterogeneity of the study area.The major target formations are meandering channel deposits and underwaterdistributary channel deposits. It has different sand body internal architecture because ofdifferent depositional environment. Based on the core analysis and description, geology andlogging data, the paper combines the depositional setting of the study area with the results ofprevious studies,then uses the principle of "cycles contrast, hierarchical control" to divide thesand body into single sand body in vertical, meanwhile, it establishes sedimentary microfaciestypes and typical logging phase mode of the study area, then wo identified single-wellmicrofacies to the wells which are not cored, and finally gets rational plane combinations.With "relatively deep method of top sand body" and single channel identification method, itaccomplishes the identification of the abandoned channel and division of the single channel inthe study area. On this basis, according to the characteristics of meandering river depositionand straight-type river sedimentary, the study focuses on the two different channel sandinternal architectures of different origin, determines the locations of the meandering river barpoint as well as the lateral accretion layer, lateral accretion body size and distribution features,and establishes the internal mezzanine distribution pattern of the straight-type channel. Finally,on the basis of each small layer of sand body distribution and sedimentary facies distribution,the permeability values and the mezzanine analysis, it gives a comprehensive evaluation ofthe target formation heterogeneity characteristics in the study area.