Wettability of quartz surface as observed by NMR transverse relaxation time (T₂)

Injection of optimized water composition (smart water) is an advanced water flooding method for Enhanced Oil Recovery (EOR). Low saline waterflooding has been proved successful in sandstone reservoir. However, there is still controversy on the mechanism of smart water flooding. We studied the wettability property of quartz surface by using Nuclear Magnetic Resonance (NMR) method. The principle of this method is that protons in water relax faster when it comes close to solid surface. We observed that quart is highly water wet. A layer of water (bound water) forms on the quartz surface when they are mixed. The amount of bound water increases polynomially with increased surface area. Addition of some ions in water based solutions increases the amount of bound water for same amount of surface area. We studied the affect of Ca2+, Mg2+ and Na+ ions and observed that Mg2+ ion produces the maximum amount of bound water while Ca2+ ion produces the least. The result obtained from this study could be used to decide optimized water composition for waterflooding in sandstone reservoirs.