Insights into Rock Wettability Influencing Factors: A Review

Abstract

Wetting characteristics of a hydrocarbon reservoir are generally quantified for cost-effective field development. The wetting process of rock by oil is a complex process involving reactions among compounds (rock, oil, and brine), the impact of environmental conditions (temperature, pressure, etc.), and treatment history (coring, transportation, etc.). There has not been much attention given to understanding the mechanisms causing different rock wetting states to quantify rock’s wettability. This work aims to provide an in-depth insight into rock wettability influencing factors including CO₂ & H₂. In addition, advanced computational approaches such as molecular dynamics simulation, computational fluid dynamics, and machine learning for wettability have also been reviewed to govern the undiscovered interactions and mechanisms of this complex process. The key observation is that the polarity of organic components (asphaltenes and long-chain acids) determines the oil wetness in crude oil. In addition, acidic polar organics dominate oil-wetting in carbonate rocks; basic polar organics are key in sandstone. Also, environmental factors such as water films, brine salinity, and pH influence wettability significantly.