A water-disperible particulate system has been widely used in many mature oilfields for reservoir conformance control. This paper discusses performances of a newly formulated grafted bentonite to reduce the permeability and build up flow resistance in highly permeable water channeling zones. In this study, effects of various salinities, different injection flow rates and shear rates were investigated in the laboratory to determine permeability reduction ratio and transport properties to improve reservoir conformance problems. A flow model was set-up using sandpack flooding system where the sandpacks were saturated with brine. Experimental results obtained revealed that the grafted bentonite is easily injected and gradually built flow resistance by particles straining, physical-chemical attachment, and swelling. The permeability reduction ratio increased with increasing salinity while it decreased with increasing velocities. A significant permeability reduction ratio was observed when 0.5 pore volume of grafted bentonite dispersed in 1% NaCl brine was injected into brine saturated sandpack column. These significant results highlighted new insights for successful applications of modified bentonite to improve reservoir conformance problems.