Using bacteria to plug oil leaks
In a successful fields experiment, a team of scientists from Montana State University have plugged a leak at an oil bore site.
This is excellent news! Fractures in the rock around drilling sites can cause oil and gas to leak from well contained reservoirs into the surrounding environment. This can lead to contamination of land and aquifers as well as contributing to the greenhouse effect by the leaking of CO2 and methane.
Sealing the fractures is one of the only ways to prevent this but conventional methods aren't effective as the precursor compounds needed to close a fracture are solid and difficult to transport to the site of the broken rock.
Sounds like a job for bacteria, specifically, Sporosarcina pasteurii.
We have known for a long time that certain microbes can cause the precipitation of minerals. For example, S. pasteurii produces urease that catalyzes the hyrdrolysis of urea into ammonium and carbonate. If calcium is present, then calcium carbonate is also precipitated which is ideal for sealing fractures in rock. This process is called biomineralization.
So Adrienne Phillips and her team at MSU thought that they could use this natural process to repair fractures in real oil drill sites if they could get calcium carbonate to form over the opening. They simply had to transport all of the liquid precursors (including the bacteria) down to the point of the fracture and wait for them to produce enough calcium carbonate to seal the hole.
"It was a very successful test," said researcher Al Cunningham, professor emeritus of civil engineering in MSU's College of Engineering. "It was very well received by our industrial collaborator."
Now the researchers are trying to widen the application of this process. They want to grow biofilms that can precipitate minerals at high temperatures allowing them to plug most hard-to-reach leaks.
Fracture Sealing with Microbially-Induced Calcium Carbonate Precipitation: A Field Study
Adrienne J. Phillips, Alfred B. Cunningham, Robin Gerlach, Randy Hiebert, Chiachi Hwang, Bartholomeus P. Lomans, Joseph Westrich, Cesar Mantilla, Jim Kirksey, Richard Esposito