Using laser beams to send high-speed streams of data, which has been used by the US Navy for secure submarine communications though ice, is being offered as an option for offshore oil operations. The possibilities range from using pulsed laser signals to measure ice sheets and detect oil leaks beneath it in the Arctic, to providing data links for autonomous underwater vehicles (AUVs) harvesting data from wireless seismic sensors on the bottom.
So far, the most concrete version of this idea is the simulation provided by defense contractor turned offshore oil technology company Qinitiq (pronounced kinetic). It presented its ideas about laser communication and testing at the OTC Arctic Technology Conference in Houston. The company is also working on options for communication links in deep water, where there are a lot more potential users.
These technologies are based on what it has learned from long experience developing laser communications for the military, which shares some needs with the oil exploration and production sector, said Greg Mooradian, a consultant working on developing laser communications capabilities for Qinetiq.
“No capability exists to detect and map oil accumulated under ice,” he said. The company has designed methods for gathering data on ice thickness and leaks from planes as well as from AUVs.
In a presentation at the conference, Mooradian said the simulations indicated that an airplane flying at 2,000 ft could spot oil beneath ice 8 ft thick with up to 4 inches of snow on top using a laser.
The system would be built using components used for lidar, a method combining light and radar. Qinitiq would use extremely rapid pulses of focused light for optical remote sensing, most often for measuring the contours of the land or ocean bottoms. In this case, it is able to measure the thickness of an ice sheet and also look for oil beneath.
Oil could be seen because it fluoresces when exposed to a blue-green laser. The wavelength used would not cause a similar reaction in microorganisms, which fluoresce at different wavelengths, Mooradian said.
A thick layer of ice would seem to be a formidable barrier, but submarines have long been penetrating ice with laser systems for point-to-point communications. Rather than thinking of it as a wall, “think of it as a thick cloud,” Mooradian said, adding that frozen water absorbs relatively little light.
Given the slow pace of Arctic exploration, a more likely early application of this method is in deepwater offshore E&P as an alternative to sending acoustic signals for wireless communication. On the plus side, lasers can offer higher bandwidth and are not affected by nearby noise.
Stephen Rassenfoss is the Emerging Technology Senior Editor for the Journal of Petroleum Technology.