Effect of temperature on convective-reactive transport of CO2 in geological formations

Abstract

Geological CO₂ sequestration (GCS) remains the main promising solution to mitigate global warming. Understating the fate of CO₂ behavior is crucial for securing its containment in the reservoir and predicting the impact of dissolved CO₂ on the host formation. Most modeling-based studies in the literature investigated the convective-reactive transport of CO₂ by assuming isothermal conditions. The effect of temperature on the convective-reactive transport of CO₂ is still poorly understood, particularly at the field scale. The objective of this study is to provide an in-depth understanding of CO₂-related reactive thermohaline convection (RTHC) processes at field scale. Thus, a new numerical model based on advanced finite element formulations is developed. The new model incorporates an accurate time integration scheme with error control.  Numerical experiments confirm high accuracy and efficiency of the newly developed model. The effect of temperature on CO₂ transport is investigated for a field case in the Viking reservoir in the North Sea. Results show that including the temperature effect intensifies the fingering processes and, consequently, CO₂ dissolution. Neglecting the thermal convection processes and the impact of temperature on the dissolution rate can significantly impact the model predictions. A sensitivity analysis is developed to understand the effect of parameters governing the dissolution rate on the fingering phenomenon and the total CO₂ flux.