Potential of Low Salinity Brines in Altering Wettability and Improving Oil Recovery from Liquid Rich Shale by Spontaneous Imbibition

摘要

Low salinity brines were tested to be effective at altering wettability in sandstone and carbonate reservoirs while their impact on shale has not been examined so far.Such studies could help analyze the effectiveness of monovalent and divalent salts which could further be used to formulate affordable injection fluids that economically recover additional oil compared to coneventional injection fluids.This paper aims to investigate the effect of concentration of brines of monovalent sodium and divalent calcium on altering the wettability and oil-water IFT in liquid rich shale with heterogeneous lithological composition that includes carbonate,quartz and clays.Contact angle,IFT and zeta potential tests were conducted to analyze rock-brine and oil-brine interactions while spontaneous imbibtion was conducted at an optimum salinity derived from wettability tests.Computed Tomography was used to study fluid penetration into rock matrix and its effect on the resultant oil recovery.