页岩渗透率测定方法及影响因素研究进展

Research progress on measurement methods and influencing factors of shale permeability

页岩渗透率及其分布关系页岩油气开发、常规油气藏储量评估、地下储气库及CO_(2)地质封存盖层封闭性、核废料地质处置与气田采出水回注安全性等能源环境领域重点课题,其渗透率特征研究具有广泛的理论与工程实践意义。为此,系统阐述了页岩渗透率测定方法与影响因素研究进展,结果表明,页岩渗透率为微达西至纳达西,通常采用稳态法和脉冲衰减法测得,影响页岩渗透率的因素包括但不限于流体类型及饱和度、矿物组成、孔隙压力、有效应力、实验温度、各向异性以及流体-页岩化学溶蚀与沉淀作用,不同条件下的流体-页岩相互作用差异及孔隙有效渗流半径变化是渗透率改变的根本原因。

Shale permeability and its distribution are vital to key projects in the energy and environment fields,such as shale oil and gas development,reserves estimate of conventional oil and gas reservoirs,sealing ability of caprock in underground gas storage and CO_(2)geological storage,geological disposal of nuclear waste,and reinjection safety of produced water from gas fields.The research on the characteristics of shale permeability is of extensive theoretical and engineering practical significance.Therefore,this study systematically summarized the research progress in the measurement methods and influencing factors of shale permeability.The analysis indicates that the shale permeability ranges from micro-darcy to nano-darcy,which is commonly measured by the steadystate method and pulse-decay method.The factors affecting shale permeability include but are not limited to the fluid type and saturation,mineral compositions,pore pressure,effective stress,experimental temperature,anisotropy,and fluid-rock chemical dissolution and precipitation interactions.The difference in fluid-rock interaction and the change in effective flow radii of pores under different conditions are the fundamental reasons for the permeability variation.