Geological storage of carbon dioxide by injection of carbonated water in an Iranian oil reservoir: A case study

• Carbonated water injection can improve oil recovery and lower GHG emissions.
• This study evaluates CWI as a GHG control method.
• This study evaluates CWI and an enhanced oil recovery method.
• An Iranian oil reservoir is selected for implementation of production.

The remarkable consequence of carbonated water injection (CWI) is not only in lowering a green-house gas that is otherwise released into the atmosphere, but in its notable ability in increasing oil recovery from hydrocarbon reservoirs. This type of carbon dioxide (CO2) sequestration method requires amounts of CO2 that can be recovered from sources available near hydrocarbon fields. Thus cost of transportation, storage, pressurizing (obtained CO2 from such sources is already high pressured) and compression (hydrostatic pressure of water in injection well makes injection easier) is lowered. Furthermore, carbonated water forms carbonic acid that reacts with rocks and improves permeability (i.e. injectibility) while CO2 dissolves in oil, causes oil expansion, lowers oil viscosity and improves recovery.In this work, different production scenarios have been studied in one of Iran's southern reservoirs. CWI has been evaluated against natural depletion and water injection based on its performance in enhancing production and ability to safely sequestrate CO2. Finally, experimental CWI in core scale reported in literature has been implemented to determine dominant forces in CWI and dependency of CWI performance on viscosity of crude oil samples and injection flow rates.