contact angles can potentially be modified by the presence and properties of water films on mineral surfaces the thickness of water film is controlled by mineral surface properties and pore water chemistry surface tension between sc co 2 and aqueous solution can potentially be affected by solution chemistry and possible organic compound dissolution into either the supercritical phase or the aqueous solution which may modify the interfacial properties between the two liquids as indicated in equation 7 the macroscopic effective surface tension u03c3 is scale dependent which makes it difficult to characterize for an actual system in general chemical reactions will be enhanced by the formation of sc co 2 ganglia due to an increase in specific surface area of sc co 2 the key parameters identified here may then evolve with time for example dissolution of organics e g oil residues from mineral surfaces can change the wetting properties of the surface and therefore the liquid mineral contact angle mineral dissolution and precipitation may change the pore structure of the storage media for example secondary mineral precipitation may enhance capillary trapping by reducing porosity or pore throat size specifically as minerals dissolve and new minerals precipitate the pore surface properties e g surface roughness and chemical identity will also change evaluating the importance of these effects on long term co 2 trapping.