An overview of geological carbon dioxide storage methods and the mechanism of caprock in carbon dioxide storage

Population growth has increased the need for energy especially use of fossil fuels, which in turn is lead to increase carbon dioxide in the atmosphere, which is a type of greenhouse gas that leading to enhance global warming. This global warming can put plant and animal habitats in danger and change climate patterns, resulting in floods, droughts and severe destructive storms. One of the ways that reduces carbon dioxide in the atmosphere is geological carbon dioxide storage, which requires a porous reservoir with an impermeable sealing caprock that laying on the reservoir. The importance of caprock is to inhibit the movement of submerging carbon dioxide, saline and the other existence materials preventing leakage of these materials into the upper formations. Caprock should be able to withstand in-situ stress changes and physical and chemical properties changes. The purpose of this paper is to review geological carbon dioxide storage methods and the mechanism of caprock in carbon dioxide storage. The research method is an overview of related sources and references. According to the results of this study, the sealing pressure of the caprock should be distinguished before the injection process and during the injection process should not exceed a certain amount. Likewise, before the injection of carbon dioxide, its temperature should be proportionate to the temperature of the reservoir to avert caprock failure and it is better to take the geochemical, geomechanical, thermal and flow path properties in experimental and simulation works into consideration for a better understanding of caprock’s behavior and structure.