AVO gradient intercept plot. Circles represent the conditions under a 15 MPa pore pressure, 5% CO₂ saturation, and 0.2 porosity. Stars represent the conditions under a 15 MPa pore pressure and 20% CO₂ saturation. Triangles represent the conditions under an 8 MPa pore pressure and 20% CO₂ saturation. The red, blue, green, and orange colours represent porosities of 0.2, 0.21, 0.22, and 0.23, respectively.