**2.1 Stratigraphic trapping**

The stratigraphic trapping mechanism is determined by geological structure [19]. A complex geological structure is formed during the deposition of the formation, and the locations with high and low permeability determine the fluid flow within the formation. The CO2 injected into the formation will rise or move laterally until reaching a low permeable or impermeable caprock because the density of CO2 is less than that of the fluid formation. CO2 will be confined below the caprock in a supercritical, liquid, or gaseous state. Physical traps for storing CO2 are formed by lowpermeability formations or structures. The typical structural trap includes an anticline or a sealed fault, as shown in **Figure 2**.

**Figure 1.** *Relative importance of trapping mechanisms with time [13].*

*Geomechanics of Geological Carbon Sequestration DOI: http://dx.doi.org/10.5772/intechopen.105412*

**Figure 2.** *Typical structural traps (reproduced from [20]).*

**Figure 3.** *Schematic diagram of residual trapping (reproduced from [20]).*
