Variations in wetting behavior of mixed-wet cores resulting from probe oil solvency and exposure to synthetic oil-based mud emulsifiers

摘要: Abstract Mixed wettability (MXW) results from adsorption crude oil on rock surface which is not overlain by bulk water. Crude oil/brine/rock interactions and their effect recovery are often investigated after replacing the with a mineral oil. If displaced directly oil, extreme alteration, referred to as MXW-DF (direct flood), observed. Less change observed if an intermediate solvent, such decalin, used avoid destabilization of asphaltenes contained in oil; conditions attained this treatment MXW-F (film). The displacement test probe most common choice being either or There strong practical interest developing cores that have wetting properties comparable at reservoir conditions. main objective work compare solvency, characterized refractive index, behavior, spontaneous imbibition, MXW given parent tested oils included oils, alkanes, toluene, alpha-methylnaphthalene (AMN), modified both increased reduced base solutions emulsifiers synthetic oil-based mud (SBM) formulations. Wettability established direct alkane (MXW-DF) showed systematic increase water wetness solvency Other approaches tuning states also presented. Base formulation SBM had essentially no imbibition behavior MXW-F, whereas exposure two kinds emulsifier resulted persistently suppressed for wide range oils.