Visualization the Surfactant Imbibition at Pore Scale by Using of FracturedMicromodels

摘要

Recovery in low permeability oil reservoirs is challenging because they are often high fractured and oil-wet.Microemulsion-forming surfactant solutions,which can replace oil from tight matrix by imbibition,have been verified as effective enhanced oil recovery fluids for tight reservoirs.To better understandthe mechanisms of oil recovery from oil-wet,fractured rocks using microemulsion-forming surfactants,microfluidic experiments including single channel micromodel tests and fractured micromodel imbibitiontests which could visualize the in-situ phase changes were conducted in this work.Through on our study,the priority of wettability alteration and phase change with a function salinity was clarified.Besides,theimbibition dynamics of microemulsion-forming surfactants at different salinities were provided,and furtherunderstanding about the equilibrium process of microemulsion during imbibition was obtained.Basedour studies,we suggest a moderate salinity for microemulsion-forming surfactants enhanced imbibitionrecovery.