Figure 2.

Density difference map between water and CO₂. The figure shows the density difference between water and CO₂ as a function of pressure (up to 60 MPa) and temperature (up to 800°C). Positive (in blue) values indicate that CO₂ has a lower density than water, which leads to CO₂ buoyancy, and negative (in red) values indicate that CO₂ has a higher density than water, leading to sinking potential in the reservoir. The downhole conditions of IDDP‐2 are temperature of 500°C and pressure of 34 MPa, which would lead to CO₂ sinking potential. The dotted black lines indicate the p–T conditions of a hydrostatic water column for a variety of geothermal gradients and the solid black lines are isodepth for the same case. The trajectories on the left‐hand side indicate CO₂ injection conditions at the reservoir for several wellhead temperatures and for a wellhead pressure of 10 MPa. The yellow line connects the downhole conditions (buoyant) of a hypothetical injection at IDDP2 with the CO₂ conditions (sinking) within the reservoir far from the injection well.