The Study On Geological Characteristics Of S₁₊₂ Resevoir In Block Leng 43,Liaohe Oilfield And Feasibility Of Steam Drive

Leng43 block is the principal development block of Lengjiapu oilfield.The object of this study is S₁₊₂reservoir.After years of development,the effect of CSS becomes less economical,This paper is based on study of geological characters and feasibility of development method conversion to enhance oil recovery.Strata division and correlation was conducted by integrally considering sedimentary sequence,sedimentary cycle and reservoir heterogeneity.The structure,micro-facies,reservoir distribution and barrier distribution of each horizon were studied.With RMS geological modeling software,a fine gridded geological model of the whole block was established and up-scaled in combination with configuration study and making full use of data such as core test,drilling and well logging of S₁₊₂of Leng43,providing a reliable 3 D geological model for later steam flooding feasibility study and sensitivity analysis.S₁₊₂+2 reservoir of Leng43 block is a monocline structure dipping and ending westward,which is complicated by faulting.Sedimentation of braided distributary and interdistributary micro facies are the major sedimentations.Both porosity and permeability of the reservoir are medium to high,and the continuity of the reservoir is favorable.The average thickness of barriers between sandstone units is4m-5m.The lithology mainly includes silty mudstone and anisometric argillaceous pebbled sandstone.This block is 1170-1400 m deep,a bottom water reservoir with a structural area of 5.2km² and thickness of oil layers ranging at 0.3-80 m,3.9m on average.The reservoir rock is primarily arenaceous rock with oil mainly accumulated in arenaceous rock and micro-conglomerate.The physical property of S₁₊₂+2 is favorable,the average porosity and average horizontal permeability of the reservoir is 22.5%and 454×10^-3μm²respectively,indicating that the reservoir is a medium to high permeability reservoir.Crude oil contained in the reservoir is conventional heavy oil to extra heavy oil with average density@20℃and viscosity@50℃of 0.9812g/cm³and 584-45280 mPa.s respectively.After the study above,steam flooding is feasible in this block,and geological parameter limits that may affect steam flooding is known,guiding reservoir engineering design and well group deployment and enhancing oil recovery.