The 1st and 2nd Members of Shahejie Formation in A oilfield in Shijiutuo uplift,Bohai Bay Basin,are rare proli-fic thick reservoirs with complex lithologies.Six lithologies are identified,mainly including limy sandstones,oolitic dolo-mites,dolomitic sandstones.There are various factors challenging reservoir description of the A oilfield,including complex lithologies,poor quality of seismic data,and sparse appraisal wells,large difficulty of fan delta reservoir description,and poor understanding of reservoir spatial distribution.This paper applied a well-logging and seismic comprehensive method, i.e.‘four step’ method,using ECS logging,core and seismic data.It consists of reservoir rock typing based on sedimen-tary facies,sedimentary modeling based on paleo-geomorphy restoration,reservoir framework reconstructing based on fine isochronous stratigraphy and reservoir prediction based on facies constraints.By using this four step method,sandbodies of 5 phases are identified and mapped in the 1st and 2nd Members of Shahejie Formation.In addition,good-quality reservoirs are predicted by using seismic technique,and 9 new development wells are proposed for emplacement on theⅠ-2 sand body with typeⅠreservoirs.This‘four step’ method is very useful in estimating producible oil reserves,layer division, and well pattern optimization in similar oilfields.%渤海湾石臼坨地区A油田沙一、沙二段油藏是近年来少见的海上复杂岩性、高产厚层油藏，其储层普遍发育灰质砂岩、鲕粒白云岩、白云质砂岩等6类岩性。针对该油田储层岩性复杂、中－深层储层地震资料品质较差、评价井井距大、扇三洲储层表征难度大、储层空间分布认识不清等难点，应用元素俘获谱（ ECS）测井、岩心、分析化验和地震等资料，采用井－震联合技术路线，建立了厚层复杂岩性油藏的储层精细表征“四步法”技术体系，即：基于岩石相的储层分类评价技术、基于古地貌分析的沉积模式研究技术、精细等时沉积地层格架的构建方法和基于相控约束的储层预测方法。基于该技术体系，将沙一、沙二段储层纵向精细化为5期砂体，并识别出每期砂体的平面分布，同时预测了不同类型储层的空间展布。据此优化了钻探部署，从降低开发风险、提高投资效益考虑，有针对性地暂缓砂体尖灭位置附近的9口开发井钻探，并优选Ⅰ类储层Ⅰ－2砂层作为优先开发储层。该技术体系可为类似油田的可动用储量分析、层系划分及井网优化等提供技术支撑。
展开▼
