Adsorption of EOR Polymers and Surfactants on Carbonate Minerals

Abstract

Polymer and Surfactants are widely used to improve the oil recovery from a reservoir. One of the main issues with injection of these chemicals is their adsorption over reservoir rock surfaces. The first part of this study focuses on understanding the adsorption characteristics of a newly proposed polymer “Schizophyllan” for application in high temperature (120°C) and high salinity (250 g/l) carbonate reservoirs which are typical in Middle East. In the static adsorption experiments, the effect of parameters like mineral type, salinity, background ions, and temperature on adsorption was investigated. We find that adsorption density over minerals decreases with salinity and temperature. The adsorption of the polymer is higher on carbonate rocks compared to silica and kaolin. Dynamic adsorption using the core flow experiments is also studied. The adsorption in the presence of oil is low compared to the adsorption when there was no oil in the core. The change in viscosity of polymer as a result of flowing through the core has also been reported. In the second part we study the adsorption of a switchable surfactant (Neutral to Cationic) which is a promising candidate for CO2 foam for mobility control. The adsorption shows a significant reduction with an increase in salinity and temperature. This is a promising result for further selection of this surfactant for the field applications.