Novel Application of the Flotation Technique To Measure the Wettability Changes by Ionically Modified Water for Improved Oil Recovery in Carbonates

Abstract

The accurate determination of the wetting condition of carbonate reservoirs is a prerequisite for the selection of any enhanced oil recovery (EOR) fluid. Most carbonate formations are initially oil-wet to intermediate-wet at reservoir conditions. In order to correctly chose an EOR fluid to alter the wettability, we need to understand the initial wetting conditions and design an ionically modified water (advanced water) to alter wettability and improve oil recovery. If a reservoir has already been reached to the optimum wetting conditions by injecting formation water or any other fluid, then there is no need for ionically modified water. A number of methods have been devised to identify the wetting conditions including contact angle measurements, spontaneous imbibition, and chromatographic separation, etc. But contact angle measurement requires surfaces that lack natural surface roughness, spontaneous imbibition tests take months, and chromatographic separation is feasible only for core flooding in sulfate...