Liaohe Hainan Sub-sag Peripheralof Sea Characteristics Research

His paper,with the theoretical guidance of petroleum geology theories,based on seismic,drilling and logging data of western Liaohe beach,through core facies,electrofacies and seismic facies analysis,and combining regional geological background,systematically studies the structures and reservoirs of Shahejie formation in Dongying sag of Hainan in Liaohe offshore,drawing the following conclusions.Affected by buried hill and controlled by slope,structural-lithologic reservoirs are easy to form in the research area.Controlled by major fault,fault nose,fault block and fault anticline traps forms in Xianhe structural belt under the secondary fault segmentation,with the development of reservoirs,conductive to form potential zone of structural-lithologic reservoirs.Hainan sag mainly develops semi-and lacustrine-deep lacustrine and sublacustrine fan deposits.The western Bijialing slope has adequate supply of matter,with relatively small slope,therefore mainly develops braided river deltaic depositional system.Xianhe structural belt has steep terrain,with sediments mainly composed of near-source clasts,therefore mainly develops fan delta and nearshore subaqueous fan.Rock types are mainly feldspar sandstone and feldspar debris sandstone,with low compositional and textural maturity.Pore types include primary pores,secondary pores and mixed pores;the reservoirs of Shahejie are mainly middle-low-porosity reservoirs,low-permeability and super-low-permeability reservoirs;reservoirs of Ed3 and Ed2 members of Dongying formation are mainly middle-high-porosity reservoirs and middle-low-permeability reservoirs.Diagenesis types mainly include compaction,cementation,dissolution and metasomatism.The physical properties of reservoirs are controlled by original sedimentation,later diagenesis and abnormal pressure.The research area Bijialing structural Ed3,Es1,Es2 and Es3 and Xianhe structural Es3 have good reservoir seal assemblages,therefore can be favorable target areas for the formation of lithologic and structural-lithologic reservoirs.