Carbon storage safety

Nov. 18, 2021

When Dr. Ganesh Dasari was a doctoral candidate at Cambridge University, he didn’t know his passion for civil engineering would steer him toward becoming a leading expert in carbon storage technologies.

Today, he is part of a team of geoscientists and engineers at ExxonMobil identifying ways to safely store carbon dioxide (CO₂) deep underground. The technologies they’re developing today could shape the future of large-scale carbon capture and storage (CCS) projects around the world.

Dr. Dasari and the team are busy finding safe and secure geologic locations to store captured CO₂ in the US, Europe, and Asia – including locations to support ExxonMobil’s planned CCS projects in Texas and Louisiana. They’re developing a safe process to inject CO₂ thousands of feet under the earth’s surface into these carefully selected geological formations where it can be permanently stored. Once underground, the CO₂ is held in place by a thick seal rock and gradually transforms into solid minerals.

By capturing CO₂ emissions before they reach the atmosphere, CCS can play a big role in reducing emissions, particularly from heavy industries like steel and cement.

We spoke with Dr. Dasari to better understand how CO₂ storage sites are carefully and rigorously selected. As a leader in locating potential CO₂ storage sites for our carbon capture and storage projects, Dr. Dasari is an authority on safety considerations in carbon storage planning.

Depth

"Any formation chosen for CO₂storage will typically be at least a half mile underground. This is far enough beneath the surface to prevent interaction with the water table, which is in the top 500 feet.”

Pressure

"The CO₂will be pressurized to increase its density by 300 to 500 times so a large amount of CO₂can be stored in a relatively small area."

Integrity

“A three-tier system of technologies will monitor sites for leaks at different levels: atmosphere, near-surface and sub-surface.”

Seal

"The injected CO₂will be held in place by thick, impermeable seal rocks, which are similar to the rocks that have kept oil and gas underground for millions of years.”

Time

“Over thousands of years, CO₂will start to mineralize into the rock formation. Over tens of thousands of years, it will begin to transform from a gas to a solid.”