Looking for oil beneath the ocean is a needle-in-a-haystack challenge, but bacteria that consume hydrocarbons can help identify promising places to drill.
The Scotian Slope, a 160,000-square-kilometre swath of seabed south of Nova Scotia, is an attractive but challenging area for oil exploration. The energy industry has invested $37 billion in offshore development in Atlantic Canada over the past two decades, but little is known about what lies beneath the Scotian Slope, which makes the search for drilling locations a long and expensive process.
Thanks to a partnership between the Nova Scotia Department of Energy and the University of Calgary’s Geomicrobiology Group, however, exploration companies could be steered in the right direction by some tiny helpers. A teaspoon of sediment from the ocean floor contains about a billion bacteria. Some of these bacteria consume hydrocarbons; they can indicate the presence of sub-surface oil and help identify promising places to drill test wells.
“We’re using genomics to do a ‘census’ of the microorganisms in seabed sediment samples,” says Geomicrobiology Group leader Dr. Casey Hubert. “The DNA tells us the composition of that population. A high proportion of specialized hydrocarbon-degrading bacteria could indicate an oil reservoir below. If the genomic, geophysical, chemical and seismic data all line up, it might be a hot spot for petroleum.”
Field work for this project began last summer aboard the CCGS Hudson. Core samples were taken at water depths reaching 2,500 metres. Some were analyzed in a lab on the Hudson; others were sent to the University of Calgary. One of the goals of this summer’s field season, says Dr. Hubert, is to attempt more of the genomics while at sea, so the ship can quickly return to a specific location if results are interesting.
In addition to looking for aerobic and anaerobic bacteria (which need and don’t need oxygen to grow, respectively), Hubert is also interested in thermophilic bacteria, believed to flow upwards with hydrocarbons toward the ocean floor. These thermophiles prefer high temperatures and are dormant until sediment samples are heated, indicating the potential for warm oil reservoirs far below the seabed. The team hopes that layering together information on all three types of bacteria will offer a more comprehensive picture.
“This is cutting-edge research that requires a lot of integration,” says Adam MacDonald, a petroleum geophysicist with the Nova Scotia Department of Energy. “I’m optimistic it will help. Everybody is trying to zero in on the target but we have an enormous geographical area, so we can use genomics to reduce the risk.”