where does the CO2 go once injected in the reservoir and what prevents it from escaping over time?

The pores of the reservoir into which the CO2 is injected are initially filled with salty water (brine), which is unfit for drinking or agricultural purposes. The injected CO2, being lighter than the water, rises until it encounters the overlying impermeable rock layer or ‘caprock’. The CO2 becomes trapped and accumulates beneath the caprock (Structural trapping). Some CO2 is trapped in the tiny pore spaces (Residual trapping), some is dissolved in the brine making it heavier and tends to move downwards (Dissolution trapping) and after 1000s of years in dissolution, a small proportion can precipitate through chemical reactions with the native reservoir rock and fluids (Mineral trapping). SRDM

ULTimateCO2 research aims to discover how the SRDM trapping mechanisms evolve over time: e.g. predictions by 3D modelling of the behaviour of the CO2 in terms of migration flow path and mechanisms; studying analogues in the field to better understand the reservoir properties and the long-term consequences of the presence of CO2; lab experiments to consider what effects the other substances injected along with the CO2 (impurities) have on chemical reactivity.

Dernière mise à jour le 12.05.2014