GPS satellites have become the new lodestar for lost drivers and modern navigators, but things are not always so simple if you live in South America. An atmospheric kink caused by the interplay of solar flares and Earth’s magnetic field called ionospheric scintillation can scramble satellite signals and leave travelers at sea. Literally.
It’s one thing if you make a wrong turn in a car, but quite another if you are drilling an oil well 7,000 feet below the surface of the sea and many miles from shore. That’s why GE developed a crack navigation system for a fleet of new Petrobras drillships and semi-submersible rigs drilling wells some 180 miles off the coast of Brazil, in some of the world’s deepest oil deposits underneath more than four miles of water, rock, and salt sediment.
“When you are drilling, you need to stay where you are,” says Paul English, marine vertical leader at GE’s Power Conversion business. “Coming off the wellhead because you’ve lost position could be a very expensive and very risky process.”
Like a digital brain, the system connects to a hardware body wired for big data and the Industrial Internet, and designed by GE and partners to steer the ships and rigs on the high seas. The full system will soon serve on 22 Petrobras vessels. The total value of the new contract exceeds $600 million.
English says that the navigation system, which GE calls dynamic positioning (DP), is “triple-redundant” and can keep a ship within three to five meter radius on the heaving seas. The DP is listening to three different GPS signals as well two acoustics systems catching pings from ultrasonic beacons anchored on the seabed. “There are five references coming in at any time,” says English. “It’s checking the quality of data and feeding it into a pooling function, looking for error. If one signal gets out of bounds, the system kicks it out.”
The DP system then applies sophisticated mathematical modeling software that blends the location information with wind speed and ocean current strength data, and calculates commands for the hardware body.
GE and partners have developed a system of “intelligent” thrusters, propeller motors, electricity generators and other equipment that listen to information from the DP brain and keep the vessels in the right place.
The system allows the crew to monitor the ship on multiple screens and on “ruggedized” iPads. “When the ship drifts near the boundary of where we want to be, the operator receives a loss of position alarm,” English says. “The chief engineer on the bridge, the guy down in the engine room, and the worker by the thruster can all see the current situation on the mobile screes. The can move around, check equipment, and exchange pictures and video.”
A recent report from the American Meteorological Society said that during peaks in the 11-year solar activity cycle, and one is scheduled to arrive this year, Brazil and other equatorial regions “will experience intense scintillation on the order of 100 days per year.” But Petrobras workers and sailors won’t have the sun in their eyes.
