Aspects of CO2 Injection in Geological Formations and Its Risk Assessment

Abstract

Anthropogenic emission of greenhouse gases (GHG) in atmosphere is equivocal and the major cause of global warming, significantly impacting the global climate change. Scientists, researchers, expert organizations, and policymakers suggest that in order to combat the instabilities caused by global warming, further investigation in the direction of safe CO2 storage should be at utmost priority. To reduce GHG concentration in atmosphere, carbon capture and storage (CCS) has emerged as a promising bridge technology, by capturing CO2 from the major sources such as cement factories, fossil fuel-based production plants, etc. and subsequently storing it in subsurface. CCS technology greatly reduces CO2 concentration and restricts and protects subsequent migration by safely storing within geologic formations for millions of years. The CO2 is injected into suitable geological formations at depths below 800 m or more, and various trapping mechanisms would prevent further migration of the stored CO2 to the surface. Potential candidates for safe storage of CO2 are geological storage (in geological formations, such as un-mineable coal seams, depleted oil and gas fields, and deep saline formations), ocean storage (direct release into ocean), and industrial fixation into inorganic carbonates. This chapter provides a detailed knowledge on the sources of GHG emissions into the atmosphere and the status of CCS process worldwide emphasizing on the various trapping mechanisms of CO2 in geological formations. The storage of CO2 in geological formations is greatly affected by environmental factors, so impact of these variables is described. In order to study the impact of these variables on CO2 sequestration, a state-of-the-art modeling techniques along with the numerical methods are reviewed comprehensively.