Types, cases and enlightenment of global geological carbon dioxide sequestration

This paper is the result of environmental geological survey engineering.

Objective Carbon sequestration has emerged as a crucial strategy in addressing a series of environmental issues, particularly climate change. For the global challenge of reducing carbon emissions, geological sequestration of CO₂ serves as a vital "backstop" technology and is considered a new paradigm for managing carbon footprints. However, there is a fragmented understanding of the concepts, scopes, technologies, challenges, and future prospects of geological carbon sequestration, lacking a systematic approach.

Methods This paper comprehensively reviews the current principles of geological carbon sequestration, providing a systematic overview of six types of storage media and application cases for each sequestration body. It also analyzes the potential risks associated with geological carbon sequestration and offers a prospective outlook.

Results The geological formations that are viable for CO₂ sequestration encompass saline aquifers, depleted oil and gas fields, unviable coal seams, basalt formations, CO₂ hydrates, and salt caverns. Each of these approaches boasts distinct advantages, with depth playing a pivotal role in preserving CO₂ density, subsequently bolstering both sequestration capacity and safety. Nevertheless, geological carbon sequestration confronts several primary obstacles: the risk of induced earthquakes, potential environmental hazards, and substantial costs.

Conclusions Deep saline aquifers and depleted oil and gas reservoirs are currently the most scalable pathways for CO₂ geological storage, while unmineable coal seams, basalt formations, CO₂ hydrate trapping, and salt cavern storage represent key future directions. Technological breakthroughs should focus on safety assessments related to faults, seismic activity, and environmental impacts, as well as the development of low-cost, high-efficiency, long-term, and multi-scenario CO₂ monitoring technologies.