Comparison Wettability Alteration of Different Rock Types, Using Nanofluid

During depletion of gas condensate reservoir, bottom hole pressure falls below dew point pressure and condensate starts to form around well bore. These phenomena reduce gas production significantly. Altering the wettability of gas-liquid system from liquid wetting to intermediate gas wetting is a permanent strategy for removing condensate and achieving high gas recovery. In this paper, Performance of modified silica nanofluid on wettability alteration of carbonate rock types from Iranian gas reservoir is investigated. Carbonate rock types are characterized based on porosity, permeability and rock mineralogy. EDAX analysis and acid test are used to recognize calcite and dolomite as dominate carbonate minerals. Contact angle experiments are conducted before and after wettability alteration to determine surface wetting behaviour due to nanofluid adsorption. In addition, core flooding experiments are conducted on high permeable rock types to investigate effect of nanoparticles on fluid flow at core scale. It is inferred from contact angle results that higher contact angle is achieved for carbonate rock types which have more calcite respect to dolomite. EDAX analysis also showed more adsorption silica and fluorine on these rock types. Core flood experiments demonstrated Enhancement in recovery factor due to improvement gas and condensate relative permeability after surface treatment.