Monitoring of Wettability Behaviour During Capillary Pressure Measurements at Reservoir Conditions: An Alternative Experimental Approach

The development of an alternative method for monitoring wettability behaviour during capillary pressureexperiments under reservoir conditions was investigated. This study aimed to address the challenges ofunderstanding wettability dynamics, which significantly influence saturation, fluid distribution, and multiphase flowin porous media. By integrating data from various experimental techniques, the proposed method enables thedetermination of contact angles at different capillary pressures and saturations. Mercury injection capillary pressure(MICP) drainage cycle data, obtained under ambient conditions, was converted to representative reservoir conditionsusing porosity measurements at net reservoir stress and by adjusting the data to relevant fluid pairs, such as crudeoil/brine systems. Additionally, interfacial tension (IFT) measurements via the pendant drop method were performedunder reservoir pressure and temperature. The wettability term in the Young-Laplace capillary pressure equationwas then adjusted for each capillary pressure equilibrium step to ensure that water saturation from oil-water primarydrainage capillary pressure measurements matched the corresponding water saturation derived from the convertedmercury-air capillary pressure data, refined using IFT and modified MICP values. For validation, contact anglemeasurements were conducted between reservoir crude oil, simulated formation water, and a silica surface underreservoir pressure and temperature conditions. This validation step ensures the accuracy of the estimated contactangles obtained from the integrated experimental approach. The proposed method enhances the interpretation ofcapillary behaviour in porous media by providing valuable insights into wettability changes as a function of samplepreparation, capillary pressure versus saturation, and time during laboratory experiments, within the boundaryconditions of the Young-Laplace equation.