苏北盆地张家垛油田阜宁组三段发育4种岩相：黑色泥岩相，生物扰动粉砂岩相、泥质纹层＋生物钻孔粉-细砂岩相及平行层理细砂岩相。剖面结构主要为向上变粗的反韵律，其次是向上变粗复变细的复合韵律，几乎不见正韵律。根据岩石相、剖面结构、测井相及粒度累计曲线，认为阜宁组三段为浅湖滩坝沉积。根据沉积特征和砂体展布规律，将储层进一步划分为坝砂和滩砂，并提出该地区的滩坝沉积模式。坝砂由于泥质含量低、储层物性好，油气充满度高；而滩砂泥质纹层理发育，非均质性弱。由于主要充填在平行层理细砂岩相和泥质纹层＋生物钻孔粉砂岩相中，充注程度差别大。%Four types of lithofacies are identified in the 3rd member of Funing Formation in Zhangjiaduo oilfield ,the Su-bei Basin,including dark mudstone,bioturbated siltstone,siltstone-fine sandstone lithofacies with argillaceous laminates and burrow as well as fine sandstone with parallel bedding .Upward-coarsening reverse rhythm is the main section struc-ture,followed by first upward-coarsening and then upward-thinning composite rhythm ,while positive rhythm is very rare . All the features of lithofacies ,section structure ,logging facies and cumulative grading curve show that the 3rd member of Funing Fm is typical shallow lake beach-bar facies.According to the sedimentary characteristics and spatial distributions , the reservoirs are further divided into sandstone of bar microfacies and sandstone of beach microfacies .A beach-bar sedi-mentary model is proposed .The sandstone reservoirs of bar microfacies are high in hydrocarbon fullness , due to its low shale content and high porosity .In contrast ,the sandstone reservoirs of beach microfacies show great variance in hydrocar-bon fullness as argillaceous laminations are well developed ,heterogeneity is week ,and hydrocarbons mainly fill in the fine sandstone lithofacies with parallel bedding and argillaceous laminates +burrow fine sandstone lithofacies .
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