Evaluation of relative permeability using the multi-flow method in carbonate rocks with highly heterogeneity considering the preservation of wettability through a mild cleaning process

This study presents a mild cleaning procedure developed for carbonate rocks from the BrazilianPre-salt, whose representative facies were used in relative oil/water permeability tests. Traditionally, corecleaning for flow property characterization is performed using solvents such as toluene and methanol,primarily to eliminate contaminants introduced during coring operations. While alternative procedures forwettability restoration have been proposed mostly applied to outcrop rocks these methods often showlimited effectiveness when used on actual reservoir samples, particularly regarding preserving initialwettability. This limitation underscores the need for improved methodologies to generate reliable data inreservoir characterization workflows. The proposed mild cleaning method aims to preserve the wettingproperties of carbonates reservoir samples during relative permeability measurements. The procedure’seffectiveness was evaluated by analyzing the effluents collected during fluid injection stages and bycomparing the relative oil permeability values at different points throughout the restoration and cleaningprocess. The results showed that, regardless of the aging method employed, the relative oil permeabilityremained consistent. This consistency is attributed to the successful preservation of wettability achievedusing the proposed cleaning approach.