Petroleum Geo-Services is now more than halfway through its full azimuth 3-D seismic “Triton” multiclient survey of a 390-block swath of the Keathley Canyon and Garden Banks areas of the Gulf of Mexico.
Steve Fishburn, PGS’s vice president of multiclient business development for the Gulf of Mexico, said the survey that began in late November last year is about 60 percent complete, and is expected to be finished by mid-August of this year, with the final product available in summer 2015.
However, he said preliminary data will be available in time for the central planning area’s next sale in March 2015.
There is, of course, intense interest by the industry in that region of the Gulf of Mexico following major discoveries there, like BP’s Gila discovery announced late last year, and the multibillion-barrel Tiber oil field.
Consequently, competition is fierce, as rival geoscience company CGG also is under way with its own surveys over much of the same area, using its StagSeis technique.
Naturally, Fishburn sang the praises of Triton, calling it “the premiere survey going on in the Gulf of Mexico right now. It’s taking all of the top technology that PGS has to offer.”
Pass the Salt
Fishburn explained that PGS’s five-vessel “Orion” configuration consists of two streamer vessels towing 10 streamers – each eight kilometers in length – along with three independent source vessels in a simultaneous long-offset configuration for total offsets of 16,500 meters.
It’s called the “Orion” configuration, he said, because it’s arranged exactly like the Orion constellation.
“PGS is utilizing our GeoStreamer technology, which is multi-sensored, so we have a hydrophone and a velocity sensor, and that allows us to record both the upward and downward-going wavefields, which gives us an advantage on a number of things on the imaging side,” said Gregg Parker, PGS’s regional president of multiclient for North and South America.
“The idea is that if you can imagine these five vessels are basically covering 50 square miles from the front of the source to the back of the streamer – in one snapshot, and it’s constantly moving. So, someone might term it as the largest moving object in the ocean right now. It’s quite a large area,” he continued.
“Every other line is shot in the opposite heading, and we do that in multiple directions,” Parker added.
“In addition to the acquisition configuration that Gregg talked about, we’re employing a number of different technologies, from the acquisition phase all the way to the processing phase, to provide uplift at a number of stages of the sequence – not just one or two,” Fishburn said.
The multisensor aspect, in conjunction with simultaneous shooting, is one of the main features of the Triton survey, though.
It’s that advancement, he explained, that’s enabling PGS to peer beyond the troublesome salt structures that have plagued prior efforts to image the vast petroleum resources that are believed to be waiting beneath the sea floor of the Gulf of Mexico.
“The issue is getting penetration underneath the salt and reflections coming back,” Parker said. “Because it is a 3-D structure, being able to image underneath the salt domes is the difficulty, and that’s why you have to have the full azimuth.”
“What our clients have told us is that multiple attempts on all of the existing data in the area has not yielded drillable prospects, because they’re not able to de-risk, based on all of the legacy datasets, to the point that they’re confident enough to spud a well,” Fishburn added.
He said the existing data available for the region is at least six years old, and was acquired using now-outdated technology.
“So, what you see in the Gulf of Mexico is … an evolution of technology coming out. The technology moved from narrow azimuth acquisition to wide-azimuth acquisition, to now what we’re calling full azimuth acquisition,” added Parker.
A Lot of Interest
PGS hasn’t been the only geoscience company that’s been hard at work tinkering with their seismic capabilities in recent years.
The aforementioned CGG boasts of similar salt-penetrating abilities for its full azimuth StagSeis method, and has its own surveys under way in the Keathley Canyon and Garden Banks areas, also using a five-vessel configuration.
The two companies are in direct competition with each other, but there’s hope that there’s enough interest in the area to go around.
“There’s a ton of the majors in there – Anadarko, BP, Chevron, Cobalt, Conoco. These are all the different lease-holders in this area,” Fishburn said, as he pointed to a map of all of blocks within the Triton survey.
“A large portion of this area is going to turn over in the next couple of years,” he added, “so this survey is out in front of what is going to be a big chunk of acreage of eligibility in a prolific area that’s been proven to have huge fields.”