摘要
The long-term safety assessment of CO2 aquifer storage requires a deep understanding o permeability evolution during inelastic deformations in sedimentary rocks.The permeability change has been measured in the entire process from elastic,plastic,post-failure to axial stress unloading for Shirahama sandstone subjected to triaxial compressions under various confining pressures.The measurements revealed that the confining pressure plays an important role in controlling inelastic deformation behavior and the tendency of the permeability evolution.In the brittle faulting regime under a low confining pressure,significant increase in permeability accompanied by dilatancy can be observed.In brittle-ductile transition regime and ductile regime,faulting or inelastic deformation does not necessarily and significantly enhance the permeability,and the permeability during deformation is lower than their corresponding initial values.Microscopic observations revealed that the two mechanisms:(1)shear-enhanced cracking,and (2)grain crushing,are responsible for these inelastic deformation and permeability evolution tendency.The presented results suggested that storing CO2 in those sites where ductile deformation prevails may be more safe.
The long-term safety assessment of CO2 aquifer storage requires a deep understanding of permeability evolution during inelastic deformations in sedimentary rocks. The permeability change has been measured in the entire process from elastici plastic, post-failure to axial stress unloading for Shirahama sandstone subjected to triaxial compressions under various confining pressures. The measurements revealed that the confining pressure plays an important role in controlling inelastic deformation behavior and the tendency of the permeability evolution. In the brittle faulting regime under a low confining pressure, significant increase in permeability accompanied by dilatancy can be observed. In brittle-ductile transition regime and ductile regime, faulting or inelastic deformation does not necessarily and significantly enhance the permeability, and the permeability during deformation is lower than their corresponding initial values. Microscopic observations revealed that the two mechanisms: (1) shear-enhanced cracking, and (2) grain crushing, are responsible for these inelastic deformation and permeability evolution tendency. The presented results suggested that storing CO2 in those sites where ductile deformation prevails may be more safe.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2003年第6期995-1001,共7页
Chinese Journal of Rock Mechanics and Engineering
关键词
CO2
砂岩
渗透
含水层
隔离
rock mechanics, Shirahama sandstone, permeability, brittle-ductile transition, fault sealing, CO2 aquifer storage
