With the advent of breakthrough technologies, offshore oil companies are now able to see much more below the surface than ever before. For many years, their underground exploration was limited by formations deep below hiding the hydrocarbons they searched for. Now, groundbreaking seismic imaging with supercomputers allows oil companies to view 3-D imagery of reserves as deep as 6 miles beneath the earth’s surface.
Chief Geophysiscist at WesternGeco, Craig Beasley, said it’s like an ultrasound during pregnancy, but on a “planetary scale.”
The technology uses seismic surveyors that generate explosive sounds underwater, which then send signals down to the seafloor. Most surveys involve boats towing cables equipped with hydrophones to measure sound in the water. The 130 decible blasts from the air guns occur in intervals as long as 15 seconds, sending sound waves deep below the ocean and seafloor and then returning to hit the hydrophones. Teams of mathematicians, geophysicists and software engineers use the hydrophones to pick up echoes from the sound waves and then supercomputers to translate those echoes into three-dimensional images.
Before the breakthrough technologies, salt formations would disrupt the sound waves and therefore produce distorted images and leave gaps in the data. Now, companies can get better readings through various other options such as the “azimuth towed steamer” method, which creates a sharper image beyond the salt by releasing sound waves from multiple angles and combining the echo images using algorithms; or the “on-bottom” seismic imaging method, which uses sensors dropped off boats to the bottom of the seafloor where they wait and listen for sound.
The technology has brought with it a revival of investment from interested oil companies, such as BP. BP’s advisor for seismic imaging, John Etgen, said it would be like “drilling the dark” without these breakthrough technologies. Craig Beasley, chief geophysicist for Schlumberger’s WesternGeco subsidiary, said further advances in seismic technology will likely help oil companies find more oil they wouldn’t have been able to see before.
Seismic breakthroughs pave way for major oil finds, E&E News
New waves of seismic technology yield big oil finds (video), Fuel Fix