Determination of Wettability and Its Effect on Waterflood Performance in Limestone Medium

Wettability measurement methods, the effect of wettability on fluid distribution, and fluid flow in porous media were discussed, and the influence of rock wettability on the relative permeability and recovery of oil by waterflooding were investigated. Experimental studies were conducted on a total of 23 core plugs from two different limestone formations. Synthetic brine (NaCl solution) and mineral oil, which has a viscosity ratio of ∼10, were used as the test fluids. Core samples, saturated with synthetic brine, were flushed with mineral oil to establish the initial conditions, and the wettability of the samples was measured by the Amott−Harvey method. Test results showed that the wettability of the samples ranged from strongly water-wet to intermediately wet. Wettability measurements were repeated and showed that the Amott−Harvey wettability indices were reproducible. The effects of aging time, brine salinity, and saturation procedure on wettability were examined. Long-time aging in mineral oil altered t...