Carbonated water injection: an efficient EOR approach. A review of fundamentals and prospects

Abstract Carbonated water injection (CWI) might be an efficient alternate to CO2 injection technique. In CWI, CO2 exists as a dissolved phase and not as a free phase; thus, it eliminates some challenges encountered in CO2 injection such as poor sweep efficiency and gravity segregation. In CWI, the density and viscosity of water become higher than normal due to the CO2 dissolution, thereby reducing the gravity segregation and channeling effect. This article is a comprehensive review on how carbonated water flooding has evolved over the time and captured salient features on the mechanisms involved in its role in enhanced oil recovery. The aspects reviewed in this article include a brief comparison of conventional CO2 injection and carbonated water injection and the benefits thereof. Solubility of CO2 in water, brine and oil phases is discussed in detail with valid correlations. A brief history of the development of CWI in the laboratory and field information is captured from 1905s to the present followed by the possible mechanisms and principle of CWI reported by various authors. This article also captured the latest findings on the beneficial effect of hybridizing CWI with smart water technologies.