济阳坳陷页岩油储层孔隙结构与渗流特征  

Pore structure and percolation characteristics in shale oil reservoir of Jiyang Depression

作　　者：刘丽 闵令元[1] 孙志刚[1] 裴磊 顾辉亮 LIU Li;MIN Lingyuan;SUN Zhigang;PEI Lei;GU Huiliang(Exploration and Development Research Institute,Shengli Oilfield Company,SINOPEC,Dongying City,Shandong Province,257015,China)

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015

出　　处：《油气地质与采收率》2021年第1期106-114,共9页Petroleum Geology and Recovery Efficiency

基　　金：中国石化页岩油气勘探开发重点实验室课题“济阳坳陷页岩油赋存特征及可动机理研究”(KL20041)。

摘　　要：微观孔隙结构是控制渗流特征的内在因素,渗流特征是微观孔隙结构的外在表现。借助高压压汞测试技术,获取表征页岩油储层孔喉大小、分布及连通性的微观孔隙结构参数,分析不同尺度孔喉对渗流能力的贡献程度。基于稳定流法,建立页岩油单相渗流曲线,分析岩石渗透率、地层原油黏度对渗流规律的影响。研究结果表明,济阳坳陷页岩油储层孔隙结构具有强非均质性特征,孔喉以亚微米-纳米级为主,纳米级孔喉连通的孔隙体积占比最大,参与渗流的主要为微米级孔喉(层理缝)和亚微米级孔喉。亚微米-纳米级孔喉是页岩油储层产生非线性渗流和启动压力梯度的主要原因,启动压力梯度随着流度的减小而增大,二者之间呈幂函数关系。建立页岩油储层极限泄油半径预测公式,可根据储层渗透率、地层原油黏度预测一定生产压差下页岩油可流动的最远距离,为井距设计或压裂裂缝间距优化提供参数依据。The microscopic pore structure is an internal factor controlling percolation characteristics,and percolation char⁃acteristics are the external manifestation of the microscopic pore structure.Through the technique of mercury injection cap⁃illary pressure,the microscopic pore structure parameters characterizing pore throat size,distribution,and connectivity were obtained.The contributions of pore throats on different scales to the percolation capacity of the shale oil reservoir were analyzed.The single-phase percolation curve of shale oil was established with the steady flow method to analyze the influ⁃ence of rock permeability and in-place oil viscosity on the law of percolation in shale oil reservoirs.The results show that the pore structure of the shale oil reservoir in Jiyang Depression characterized by significant heterogeneity is mainly com⁃posed of submicron and nanometer pore throats.In terms of volume,most pores are connected by nanometer pore throats,but percolation is transported mainly through micron(bedding fractures)and submicron pore throats.Nonlinear percolation and starting pressure gradient in shale oil reservoir can be attributable mainly to submicron and nanometer pore throats.The relationship between the starting pressure gradient rises as fluidity falls,which can be expressed by a power function.The formula estimating maximum drainage radius of the shale oil reservoir is established to predict the longest flow distance according to rock permeability and in-place oil viscosity under a certain production pressure difference,which provides a parameter basis for well spacing design or fracture spacing optimization.

关 键 词：页岩油 亚微米-纳米级孔喉 强非均质性 非线性渗流 启动压力梯度 极限泄油半径 

分 类 号：TE122.2[石油与天然气工程—油气勘探]