Wettability alteration with new composition of smart water: effect of silicate ion instead of sulfate ion

A new EOR method for chalk reservoirs and possibly applicable to all carbonate reservoirs is the wettability alteration with modified sea water as Smart Water. Over million of years, the chemical equilibrium of crude oil-brine-rock is established that includes all sectors of the oil reservoir. If the injected water into the oil reservoir differ with formation water in terms of composition and salinity it can disturb the established chemical equilibrium of crude oil-brine-rock system. During the process of establishing a new chemical equilibrium, wettability properties is also changed and may increase oil recovery. Smart Water injection has been proposed as a reason of wettability alteration. Sulfate ions in sea water is known as one of the most main reasons of the wettability alteration in carbonate rocks. In this study, we tried to introduce a new multivalent anion instead of sulfate and the performance of these two ions are investigated. Only the silicate ion and without presence of the potential determining ions able to change wettability significantly. But it deposited in presence of calcium and magnesium ions dramatically and this is an unpromising event but the scaling of silicate ions disappear with addition of hydrochloric acid (HCl). There is a question about the performance of this new solution. Can this solution change the wettability toward water wet or not? Contact angle measurements have shown that this solution has more ability in wettability alteration of carbonate rocks than modified sea water.

کلیدواژه ها:

smart water ، wettability ، silicate ، sulfate ، carbonate rock