CO2-sensitive and self-enhanced foams for mobility control during CO2 injection for improved oil recovery and geo-storage

Foam is of practical interest in many industrial processes, and can be used for blocking gas channeling and mobility control during the process of CO2 storage and improved oil recovery (IOR). It is important to develop new kinds of foam agents, which can tolerate high temperature and salinity under complex reservoir conditions. It is also desirable to develop chemicals that have CO2-sensitivity for selective channeling blocking. CO2-sensitivity is referred to that injected chemical can be converted into effective foam agent in formation water with CO2 presence. In this paper, an organic amine, octadecyl dipropylene triamine, was studied in terms of chemical mechanisms for foam generation and CO2-sensitivity. The chemical can be converted into a Gemini surfactant like agent to generate CO2 foams in-situ. The effects of important influencing factors on foaming performance at reservoir conditions were evaluated, including CO2 purity, chemical concentration, temperature, pressure and water salinity. The results indicated that the amine chemical has good CO2-sensitivity for generation of CO2 foams and has exhibited extraordinary features with high temperature and salinity tolerance. CO2 flooding assisted by this type of chemical will broaden the scope of reservoirs that can be candidates for CO2 IOR and geo-storage. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.