CO2 Sequestration
1. At the laboratory-scale investigation, how do we justify, the selection of suitable geological formations for storing CO2 - associated with the field-scale investigation that includes
(a) a relatively larger aquifer/reservoir permeability that will allow injection of CO2 with a relatively higher injection rate;
(b) a relatively larger reservoir/aquifer porosity that would allow, a relatively larger volume of CO2 storage;
(c) an impermeable cap rock with a relatively high capillary entry pressure;
(d) a geological formation that would necessarily impede the upward movement of CO2 and subsequently arresting the possible escapement of CO2 into the atmosphere?
2. In a real field scenario, we require a minimum depth of 800 m in order to ensure that the injected CO2 is in supercritical state. However, by just maintaining CO2 density range (200 – 900 kg/m3) and CO2 viscosity range (4e-05 – 7e-05 Pa-s) with temperature exceeding 31 degrees C and pressure exceeding 7.4 MPa, CO2 will automatically be in a supercritical state thermodynamically at the laboratory-scale.
Thus, in the absence of a complex porous medium with its associated depth factor at the laboratory-scale, would it remain feasible to upscale the laboratory-scale observations to a real field scenario towards CO2 sequestration?
Does laboratory-scale investigation on CO2 capture and sequestration also include (a) the costs; (b) the regulatory factors; (c) the legal logistical frameworks - associated with capture, transport and monitoring of CO2?
What is the fraction of the total anthropogenic release of CO2 (roughly 40 billion tonnes per annum globally) that has been sequestrated so far globally?
3. With varying spatial as well as temporal scales - associated with the structural, residual, solubility and mineralization trapping, how would it remain feasible to track the trapping mechanisms - associated with the injection and storage of CO2 at the laboratory-scale?
4. To what extent, we had been successful in reducing anthropogenic greenhouse gases, particularly, CO2’s share in total emissions: (a) between 2015 – 2020 (5 years following Paris agreement); and (b) between 2021 – 2022 (last couple of years); which is conceived to be one of main drivers of climate change in terms of global temperature rise?
5. To what extent, the major sources of atmospheric CO2 keep reducing – following the Paris agreement in 2015 – resulting from the consumption of fossil fuels by (a) industrial activities; (b) electricity generation; and (c) transportation sector?
All the above three sources of atmospheric CO2 remain to be in descending trend from 2015?
6. Albeit the abundant availability and a relatively lower cost of fossil fuels, whether the use of fossil fuels remains to be steadily vanishing and keep losing its place from the position of world’s most important and primary source of energy?
Currently, it is 45Mt per annum, from 35 facilities (IEA, 2022, https://www.iea.org/fuels-and-technologies/carbon-capture-utilisation-and-storage)