低渗透储层特征与测井评价方法

低渗透储层是我国目前油气勘探的主要目标之一。根据低渗透储层特征及岩石物理实验结果，对吉林油田W地区低渗透储层的成因机理进行了分析。研究结果表明，该地区的扇三角洲前缘亚相沉积的储层岩石矿物成熟度低，具有以细砂和粉细砂岩为主的储层岩性特征，这为低渗透储层的形成提供了先天条件。后经成岩压实作用及粘土矿物的充填，造成孔喉半径变小，孔隙结构复杂，孔隙空间对水的滞留能力加强，束缚水饱和度高，油层与水层电阻率差别减小，电阻率增大指数小于3。岩心实验结果分析还表明，综合物性参数可用于表征岩石孔隙结构的复杂性，且与束缚水饱和度有很好的相关性，据此建立了束缚水饱和度解释模型。在6种不同矿化度溶液下测量完全饱和溶液的岩心电导率，岩心电导率与溶液电导率的关系曲线表明，粘土矿物不存在附加导电性，阿尔奇公式仍可用于求取含水饱和度。用该模型对油田12口井资料进行了处理，结果显示其解释油水层效果与原有模型相比有明显改善。

Low permeability reservoir characteristics and log evaluation method

Low permeability reservoir is one of the main oil and gas exploration areas in China.The genetic mechanism of low permeability reservoir of Jilin Oilfield was analyzed based on its characteristic and petrophysical measurements.It is found that fan-delta front sedimentary environment,low compositional maturity,mainly fine-grain sandstone and silty sands are the pre-conditions for forming the low permeability reservoir.By diagenesis compaction and filling of clays,the formation of the reservoir is characterized by small pore throat radius,complex pore structures, rich irreducible water saturation,and small resistivity difference between oil layer and water layer.The resistivity index is smaller than three.The experiments show that integrated physical property parameter can be used to characterize the complexity of pore structure.There is a good relationship between integrated physical property parameter and irreducible water saturation,which can be used to set up an irreducible water saturation interpretation model.The rock conductivity of brine-saturated cores for six different salinity solutions was measured.The curve between rock conductivity and solution conductivity shows that there isn't additional clay conductivity.Archie's equation can still be used to compute water saturation.Log data from 12 wells in Jilin Oilfield were processed by the new model,and the result is evidently improved.