Modelling geo-sequestration of CO2 under in-situ reservoir conditions

Abstract

The continuous increase of anthropogenic carbon dioxide emissions and the associated concerns about climate change have motivated new ideas about carbon-constrained energy production”. CO2 being a greenhouse gas is directly aiding the increasing rate of global warming. “A broad portfolio of technologies has to be implemented to mitigate this problem. Implementation of carbon capture and storage (CCS) is one of the most promising options to reduce greenhouse gases emissions.” CCS as a process can be divided into three parts : capturing pure phase CO2 from industries, followed by transportation of the CO2 to a CCS storage location and lastly injecting it into the subsurface aquifers and locking it away from the atmosphere, so that the CO2 will not affect our climate dynamics. The aim of this study is to understand the multiphase flow of CO2 and brine in a porous media and to quantify the different forms of the sequestrated CO2 through a series of numerical modelling runs. A two-phase dynamic numerical model is setup which simulates the physico-chemical interaction of CO2. with the receiving aquifer system, considering the effects of capillarity and dissolution on its plume evolution.As CO2 dynamics and its associated trapping mechanisms are greatly influenced by these model parameters , like injection pressure, capillary pressure, brine saturation, etc. hence a sensitivity analysis has also been performed to understand the impact of injection pressure on the CO2 gas saturation and migration of the CO2 plume. Furthermore, a time-dependent simulation was performed choosing optimum parameter values, to study the migration of the CO2 plume. We simulated the model for different periods of time, 10hr, 20hr, 90hr, 400hr and so on to understand its evolution over time . In the last part of this work, we have quantified the amount of geo-sequestrated CO2 trapped in different formats under in-situ reservoir conditions was quantified. Model results depict evolution of the CO2 amount trapped structurally, by capillarity, and by solubility, with progression of time. The findings of this study would be of great use for researchers to undertake the risk assessment studies associated with sequestration of CO2 during the pre and post- injection phases.