Carbonates present complex pore systems that strongly influence the physical properties and their interrelationships.This study proposes a new approach to establish pore-type mixing-based permeability transforms by in...Carbonates present complex pore systems that strongly influence the physical properties and their interrelationships.This study proposes a new approach to establish pore-type mixing-based permeability transforms by integrating well-log and core data.We investigate the influence of pore-structure heterogeneity on permeability and velocity through the rock-frame flexibility factors(γ and γ_(μ)),derivable using standard sonic and density logs.We derive permeability transforms,with correlation coefficients,R of 0.8 to 0.9,from core measurements and pore-structure variations-dependent physical parameters,namely the porosity exponent(m),Poisson’s ratio(σ),velocity deviation log(VDL),and velocity ratio(VR).Through extrapolation using log-data,the m-and VDL-based correlations provide significantly better permeability estimates,with the highest accuracy attained with the m-based correlation,whereas the VR-andσ-based correlations lead to permeability overes-timation for high porosities.We plotted log-derived porosity vs.permeability,obtained applying the m-based correlation,to generate consistent porosity-permeability relationships,which account for pore-structure heterogeneity,by sorting the scattering points into distinct groups/trends by considering the variations of pore-structure types and abundance of a specific porosity.For the studied oilfield,three porosity-permeability relationships are identified,with correlation coefficients approaching 0.9,thus validating the approach and supporting its application in petrophysically similar reservoirs.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA14010302)the National Key Research and Development Program of China(No.2017YFC0603104)the Ministère de l’Enseignement Supérieur et de la Recherche,Agence Nigérienne des Allocations et des Bourses,ANAB-Niger(No.2015563007).
文摘Carbonates present complex pore systems that strongly influence the physical properties and their interrelationships.This study proposes a new approach to establish pore-type mixing-based permeability transforms by integrating well-log and core data.We investigate the influence of pore-structure heterogeneity on permeability and velocity through the rock-frame flexibility factors(γ and γ_(μ)),derivable using standard sonic and density logs.We derive permeability transforms,with correlation coefficients,R of 0.8 to 0.9,from core measurements and pore-structure variations-dependent physical parameters,namely the porosity exponent(m),Poisson’s ratio(σ),velocity deviation log(VDL),and velocity ratio(VR).Through extrapolation using log-data,the m-and VDL-based correlations provide significantly better permeability estimates,with the highest accuracy attained with the m-based correlation,whereas the VR-andσ-based correlations lead to permeability overes-timation for high porosities.We plotted log-derived porosity vs.permeability,obtained applying the m-based correlation,to generate consistent porosity-permeability relationships,which account for pore-structure heterogeneity,by sorting the scattering points into distinct groups/trends by considering the variations of pore-structure types and abundance of a specific porosity.For the studied oilfield,three porosity-permeability relationships are identified,with correlation coefficients approaching 0.9,thus validating the approach and supporting its application in petrophysically similar reservoirs.
