CO2 Injection and Sequestration Modelling in Deep Saline Aquifers Using Various Trapping Mechanisms

ABSTRACT: Global warming threatens and deteriorates human life and the environment. It causes the rising sea level, increasing average global air and sea surface temperatures, and widespread snow and ice melting are well-known effects of global warming. The implementation and development of Carbon Capture and Storage (CCS) technology is highly recommended and progressive to reduce and minimize the amount of greenhouse gases entering the atmosphere. Therefore, carbon dioxide (CO2) sequestration is a technique to store CO2 in an underground formation. Successful CO2 storage in underground formations depends on many factors such as efficient sealing, no escaping from the storage, and minimum corrosion to injection tubing/casing. Therefore, proper planning involving thorough study and reaction kinetics of CO2 with the underground formation is indeed necessary for proper planning. This research project demonstrates serious trapping mechanisms of CO2 under deep saline aquifers for long-term storage of CO2. In this simulation model, CO2 is injected for 1 year (starting year, 01-01-2000) using CMG-GEM simulation software and then the fate of CO2 post-injection is modeled for the next 200 years (01-01-2200). The simulation results showed a notable effect on the sequestration of CO2 in the deep saline aquifers via various trapping mechanisms. 1. INTRODUCTION Anthropogenic carbon dioxide's concentration in the climate has been rising at a concerning rate, during the past few decades. The IPCC proposes a 29,000 Gt carbon budget to limit global temperature increase to 2°C over preindustrial levels (Anderson et al., 2016). By 2100, 510Gt CO2 must be preserved globally, but only 300Mt (0.006%) is currently stored, with an efficiency rate of 40 Mt/yr. CO2 is a gas under atmospheric conditions but transforms into a supercritical fluid at pressures over 7.19 MPa and temperatures over 31.1°C, exhibiting both liquid and Gaseous properties It becomes conducive for subsurface storage, with its viscosity remaining similar to gases and density increasing like liquids, allowing more CO2 to be trapped in rock as shown in Figure 1. Carbon dioxide storage essentially involves injecting CO2 at high pressures into porous formations that are conducive for long-term storage over periods of the order 104 years. These reservoir depths allow the injected CO2 to remain in a supercritical state (Adewole and Sultan, 2019).