页岩油储层“七性”关系评价研究——以苏北盆地溱潼凹陷阜宁组二段为例

Research on seven properties relationship evaluation of shale oil reservoir——A case study of the second member of Funing Formation in Qintong Sag of Subei Basin

苏北盆地溱潼凹陷阜宁组二段页岩油首次获高产稳产突破。为了提高页岩油的勘探评价认识,根据页岩油储量计算规范,对页岩油储层“七性”关系的研究是一项重要内容。从溱潼凹陷阜二段泥页岩沉积特征、岩石类型划分及矿物成分特征入手,综合应用测井资料(包括常规测井及成像测井资料)和岩心分析化验资料,通过统计分布规律及建立交会图版相关分析的方法,对岩性、物性、电性、地化特性、含油性、脆性及地应力特性进行分析评价,明确工区页岩油层“七性”关系特征。研究表明,研究区不同岩相孔隙度整体差异不大,物性受岩性控制,含黏土硅质页岩孔隙度最大,平均值为4.0%;阜二段泥页岩孔隙度与声波时差正相关,与补偿密度负相关;声波时差为230~270μs/m,补偿密度为2.44~2.62 t/m^(3)。页岩油储层段物性与电性相关性较差,深电阻率随泥质含量增大有降低趋势,随孔隙度增大有增大趋势;不同岩相含油饱和度参数整体差异不大,含油饱和度一定程度上受岩性控制,含黏土硅质页岩饱和度最大,平均值为64.4%。含油饱和度与孔隙度呈现正相关关系,含油饱和度受物性控制。

Shale oil of Fu2 Member in Subei Basin has achieved a breakthrough in high and stable output for the first time.In order to improve the understanding of shale oil exploration and evaluation,according to the calculation standard of shale oil reserves,the study of seven properties of shale reservoir is an important content.According to the sedimentary characteristics of Fu2 Member in Qintong Sag,beginning with the classification of rock types and mineral composition characteristics,comprehensive application of logging data(including conventional logging and imaging logging data),and core test and analysis data,through statistics and establishment of intersection chart,analysis and evaluation of lithology,physical properties,electrical properties,geochemical characteristics,oil-bearing properties,brittleness and in-situ stress characteristics are carried out.Seven properties relationship characteristics are clearly defined.The study shows that the porosity of different lithofacies in study area has little difference,and the physical properties are controlled by lithology.The porosity of siliceous shale containing clay is the largest,with an average valueis 4.0%;The porosity of shale in Fu2 Member is positively correlated with acoustic time difference and negatively correlated with compensation density.The acoustic time difference is 230~270μs/m,and the compensation density is 2.44~2.62 t/m^(3).The correlation between physical properties and electrical properties of shale oil reservoir is poor,and the deep resistivity tends to decrease with the increase of shale content and increase with the increase of porosity;The oil saturation parameters of different lithofacies have little difference,and the oil saturation is controlled by lithology to a certain extent.The saturation of clay-bearing siliceous shale is the largest,with an average value is 64.4%.There is a positive correlation between oil saturation and porosity,and oil saturation is controlled by physical properties.