摘要
以松辽盆地南部长岭凹陷白垩系青山口组一段页岩油为例,基于密闭取心样品和二维核磁共振流体识别,定量揭示有机质对黏土结合水导电性的差异化影响,系统剖析湖相页岩导电机制与岩电关系,构建一种考虑有机质对黏土结合水导电性影响的湖相页岩油饱和度模型。研究发现,湖相页岩存在基质自由水和黏土结合水两类导电介质,通过引入结合水胶结指数(m_(sh))表征有机质对黏土结合水导电性的影响;m_(sh)与有效孔隙度呈正相关,在较多硬性骨架支撑且孔隙发育时,有机质更易充填或吸附到黏土层间,降低双电层离子交换能力,导致m_(sh)增大,黏土结合水导电能力降低。页岩电导率整体受制于黏土结合水导电能力,两类导电网络的相对贡献受有效孔隙度和m_(sh)调控,有效孔隙度和m_(sh)越大,基质自由水导电的贡献越显著。实验结果表明,考虑有机质对黏土结合水导电性影响的页岩油饱和度模型,其饱和度解释精度明显高于阿尔奇公式和Total-shale模型。
Taking the shale oil of the first member of the Cretaceous Qingshankou Formation of Changling Sag in southern Songliao Basin as an example,this paper establishes a saturation model of lacustrine shale oil considering the influence of organic matter on clay-bound water conductivity.Based on the fluid characterization results of sealed samples and two-dimensional nuclear magnetic resonance,the differential influence of organic matter on clay-bound water conductivity was quantitatively revealed,and the conductivity mechanism and rock-electrical relationships of lacustrine shale were systematically analyzed.The results show that there are two conductive networks for lacustrine shales,i.e.the matrix free water and the clay-bound water.The bound water cementation index msh was introduced to reflect the impact of organic matter on clay-bound water conductivity,and it is positively correlated with the effective porosity.When there is sufficient rigid framework support and well-developed pores,organic matter is more likely to fill or adsorb onto clay interlayers.This reduces the ion exchange capacity of the electrical double layer,leading to an increase in msh and a decrease in the conductivity of clay-bound water.The overall conductivity of shale is controlled by the clay-bound water conductivity,and the relative contributions of the mentioned two conductive networks to formation conductivity are affected by the effective porosity and msh.The larger the effective porosity and msh,the more the contribution of the matrix free water to formation conductivity.According to the experimental results,the proposed saturation model yields a significantly higher interpretation accuracy in oil saturation than the Archie model and the Total-shale model.
作者
肖佃师
李卓
王民
党微
谢潇权
韩佰凤
XIAO Dianshi;LI Zhuo;WANG Min;DANG Wei;XIE Xiaoquan;HAN Baifeng(School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China;Exploration and Development Research Institute,PetroChina Jilin Oilfield Company,Songyuan 138000,China)
出处
《石油勘探与开发》
北大核心
2025年第5期1068-1079,共12页
Petroleum Exploration and Development
基金
国家自然科学基金项目(42472217)。
关键词
有机质-黏土复合体
结合水胶结指数
饱和度模型
导电机制
湖相页岩
白垩系青山口组
页岩油
松辽盆地
organic matter-clay complex
bound water cementation index
saturation model
conductivity mechanism
lacustrine shale
Cretaceous Qingshankou Formation
shale oil
Songliao Basin
