Investigation of the Key Parameters Affecting Wettability of a Brazilian Pre-Salt Crude Oil and Brine on Pure Minerals Through Statistical Analysis

Abstract

Wettability is a fundamental property that defines the fluid’s distribution in oil reservoirs. Assessing wettability is required to model flow in porous media. Nevertheless, it involves complex intermolecular and surface forces. Contact angle measurement is a quantitative method to determine wettability. However, rock samples must be prepared to assure results representative of reservoir conditions. This work applies statistical analysis to investigate the relevance of variables involved in sample preparation (aging time, solvent used to remove the excess oil from the surface) and mineral type on the wettability of oil and brine from a Pre-Salt field on pure minerals. Since there is limited experimental wettability data at Pre-Salt conditions, this work aims to assist filling this gap. The results showed aging time and mineral type as the most important parameters for analysis. Furthermore, authors found that greater aging time in oil and point of zero charge of the mineral lead to a more oil-wet behavior.