The work of marine seismic survey companies is becoming more and more critical as the world's recoverable oil and gas reserves continue to be a concern. The search for new carbon deposits ranges farther and farther offshore, and deeper and deeper beneath the surface, often in harsh, inhospitable climates. According to most estimates, seismic activity is expected to grow 10 percent this year with business picking up in the Gulf of Mexico and the Arctic continuing to be a hot exploration frontier.
"There are an estimated 380 billion barrels of undiscovered oil and gas north of the Arctic Circle that remain to be found, of which 84 percent is expected to occur in offshore areas," says Peter Zickerman, Executive Vice President and Head of Strategic Investments for seismic explorer Polarcus in Dubai. "Until the world finds alternative energy sources, the quest to find new oil reserves and maximize extraction from existing fields remains paramount."
Places like the Gulf of Mexico and Northwest Europe, which have been explored several times over, require companies to constantly fine-tune their data-gathering techniques to find hydrocarbons through deeper and more complex geology. "Planning starts with geological objectives," explains Zickerman, "and the right plan provides the geological solution, not just the technology itself, and that's been our breakthrough."
The growth of unconventional exploration is having a huge impact on the oil and gas industry on land and at sea. These unconventional reserves, characterized by tight shale rock, are challenging for producers and have only recently become economically viable with the advent of horizontal drilling and hydraulic fracturing.
MicroSeismic, Inc.'s Mike Mueller, Vice President of Analysis, said, "There are tremendous unconventional oil and gas resources being developed onshore all over North America and internationally. Offshore unconventional resources are also plentiful but present an additional development challenge in that they tend to be in very deep water."
The unconventional geologic opportunity is called the Lower Tertiary or Paleogene Trend (largely sandstone), characterized by tight reservoirs which have to be stimulated by injecting fluids and propellants in order to open up oil and gas flow – the fracing process. In an offshore drilling scenario, vertical wells could be drilled in 5,000 feet of water through 20,000 feet of sediment and salt and into a pre-salt interval, where stimulating in the pre-salt could begin.
"Early exploration in the Paleogene Trend in the Gulf of Mexico indicates it may contain more oil in one place than has been discovered in all other Gulf of Mexico exploration and production activities to date," says Mueller. "And operators active in the Paleogene will need multistage hydraulic fracturing to complete wells and achieve production rates that make the fields economical in the face of increasing exploration and development costs that are in the tens of billions of dollars. In this emerging market, operators are turning to hydraulic frac monitoring to protect their investment and provide feedback on the effectiveness of their frac programs."
MicroSeismic pioneered a method of monitoring using an array of cables containing geophones, which establishes a large two-dimensional listening device. The passive seismic data gathered 24/7 is critical to measuring pressure and stress changes and borehole failures, which can be transmitted back to an onshore office for analysis. The results are made securely available to clients anywhere in as little as five minutes. "In the hydraulic fracturing monitoring market, the systems MicroSeismic deploys are distinct from the legacy downhole technology and can be implemented offshore with existing seismic acquisition technology," Mueller explained. The company has been testing the technology in an offshore installation for BP in Norway for the past 10 years.
In the post-Macondo era, Mueller advocates passive seismic technology as new areas of exploration and development open up and new environmental regulations take hold. "The unconventional revolution is a game-changing, 25-to-50-year process. In the U.S., the need for oil import volumes is going down. We're reversing a trend that has been in place for 30 years or more. It's astonishing." And it all begins with a seismic survey.