Application of alkalis, polyelectrolytes, and nanoparticles for reducing adsorption loss of novel anionic surfactant in carbonate rocks at high salinity and temperature conditions

Surfactant and alkaline/surfactant/polymer (ASP) flooding are commonly used chemical enhanced oil recovery (EOR) methods. However, they are traditionally carried out in sandstone reservoirs and not in carbonates due to high adsorption of surfactant onto carbonate rock and, therefore, economic expenses. One of the strategies to reduce surfactant adsorption is the application of adsorption inhibitors. Therefore, this work evaluates the performance of a novel nonionic-anionic surfactant composition designed for a carbonate field with high temperature (70 °C) and salinity (201 g/L). The study focuses on the adsorption behaviour of surfactant onto the rock surface through a static adsorption test using high-performance liquid chromatography (HPLC) and interfacial tension (IFT) measurements for surfactant concentrations determination. The adsorption data obtained were analyzed with equilibrium models (Langmuir, Freundlich). In order to find the chemicals able to decrease the adsorption loss, a list of alkalis, polyelectrolytes, and nanoparticles was tested for compatibility and thermal stability, pH and interfacial performance in mixture with the surfactant. Then, the effectiveness of agents that passed the screening criteria was examined. It was found that the selected adsorption inhibitors decreased the adsorption significantly and reached a value lower by one order of magnitude in comparison with the surfactant. To the best of our knowledge, this is the first work that compares the effectiveness of all types of adsorption inhibitors that are mainly applied in EOR, namely alkalis, polyelectrolytes, and nanoparticles. The outcomes of this study contribute to the future design of surfactant flooding in carbonates even in harsh reservoir conditions.