High Resolution Sequence Stratigraphy In Braided River Delta Reservoir Of The Second Member Of Shahejie Formation In Jinzhou 25-1 Oilfield

The Jinzhou 25-1 oilfield is located in the central and northern segment of the Liaoxi uplift of the Bohai Bay Basin.The Sha-2 section of the main oil-bearing section is a set of braided river delta sediments.The characteristics of the sedimentary evolution of the oil field are complex,and the lateral change of the reservoir is rapid,seriously affecting the development effect.The paper comprehensively applied geology,well logging and 3D seismic data to carry out high-resolution sequence stratigraphic study of the second section of the Shahejie Formation of the Jinzhou 25-1 oilfield,explored the sedimentary evolution rules within the sequence stratigraphic framework,and predicted the spatial distribution of high-quality reservoirs for the oilfields.The formulation of development adjustment plans provides a direct geological basis.The paper comprehensively uses data such as core drilling,logging curves,and seismic profiles,and summarizes the lithological,electrical,and physical characteristics of the sequence interfaces at all levels,and combines sedimentary cycles to establish the high-resolution layer of the second section of the Shahejie Formation in Jinzhou 25-1 Oilfield.The sequence stratigraphic division scheme determines that the Sha 2 section is a three-level sequence,which can be further divided into two system domains,four parasequence groups,and eight quasihierarchical sequences;then,deposition is carried out in high-resolution sequence stratigraphic frameworks.The research on styles summarizes the basic features and identification of different types of sand bodies,reveals the distribution rules of favorable reservoir facies belts,and finally studies the distribution of effective sand bodies using the methods of seismic frequency division and attribute selection.The PSS2 and PSS3 quasi-sequence groups with high quality reservoirs mainly developed in the sequence stratigraphic framework were identified.The 10 D well area in the plane was the deposition center of the braided river lobe,and was the most favorable high-quality reservoir enrichment area.The research results of the thesis have certain geological significance for deepening geological understanding of the second section of the Shahejie Formation of the Jinzhou 25-1 Oilfield,solving the contradictions existing in the development of the oilfield,and improving the development of the oil field.