Earthshaking possibilities may limit underground CO2 storage

[irishbobcat]

Earthshaking possibilities may limit underground CO2 storage

Earthshaking possibilities may limit underground CO2 storage

Combating global warming by pumping carbon dioxide into the ground for long-term storage – known as carbon sequestration – could trigger small earthquakes that might breach the storage system, allowing the gas back into the atmosphere, according to Stanford geophysicist Mark Zoback. That hazard, combined with a need for thousands of injection sites around the globe, may keep sequestration from being as feasible on a large scale as some have hoped.



While those earthquakes are unlikely to be big enough to hurt people or property, they could still cause serious problems for the reservoirs containing the gas.

"It is not the shaking an earthquake causes at the surface that creates the hazard in this instance, it is what it does at depth," Zoback said. "It may not take a very big earthquake to damage the seal of an underground reservoir that has been pumped full of carbon dioxide."

Carbon dioxide is a major cause of a global warming. In many countries, including the United States, China and India, the majority of carbon dioxide is produced by coal-burning power plants and refineries. Keeping some of that carbon dioxide from entering the atmosphere by storing it underground could reduce the amount of warming.

The other complication, Zoback said, is that for sequestration to make a significant contribution to reducing carbon dioxide emissions, the volume of gas injected into reservoirs annually would have to be almost the same as the amount of fluid now being produced by the oil and gas industry each year. This would likely require thousands of injection sites around the world.

"Think about how many wells and pipelines and how much infrastructure has been developed to exploit oil and gas resources over the last hundred years," he said. "You need something of comparable scale and volume for carbon dioxide sequestration."