Off-Shore Drilling Enhanced by Advances in Deep-Water Technology

When land-based oil & gas processing is not an option, or when existing fields no longer have enough pressure to release their reserves, oil & gas companies look to undersea technology to help them extract every drop of oil and molecule of natural gas they can.

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Advances in subsea power distribution, gas compression and digital oil field management are increasing safety, improving energy efficiency and increasing operational performance. 

Jean-Luc Eschbach, integrated offshore solutions director for Schneider Electric’s (www.schneiderelectric.com) infrastructure business says processors can increase the recovery of fluids by 30 percent and get it out much faster using the latest technology.  This is being shown to reduce the operating costs of a subsea reservoir with a typical 25-year lifespan by up to 40 percent.

At the Off-shore Technology conference in spring 2012, Eschbach showed Schneider Electric’s deep-water power distribution solutions and described how equipment reliability is increasingly the profitability and long-term success of subsea oil & gas operations. (A free whitepaper on the “Impact of Subsea Processing Power Distribution” is available at www.Sereply.com by entering key code f823v).

Subsea high and low voltage switchgear is a key enabling component for subsea process units. Eschbach said locating the switchgear module on the seafloor avoids having to provide any topside facilities and reduces the operating expense as well as the cost of the power lines. But the harsh and challenging conditions of a subsea environment can be tough on the equipment and present some unique challenges.

The power need is huge—50 to 70 MW at 36kV rating—and “you want to be able to operate everything on the seafloor from the shore,” said Eschbach. That can mean on-shore PLCs must be able to keep full control of the operations from distances up to 100 miles away. Remote operators can isolate a fault, remove power from faulty devices, re-route power in the system and more, precisely and reliably.

MTTF of 25 years
Technology advances are delivering expected equipment life of 30 years and mean time to failure (MTTF) ratings of more than 25 years, said Eschbach. Operators can also make use of new technology like video vibration monitoring, digital oil field management software and integrated physical-security solutions. 

And while these systems are highly automated, not all responses are automatic. “That control is not happening automatically,” stresses Eschbach. “Similar what you find in the space industry, you don’t want it be automatic. You want full control. Understanding that is actually a strong point of Schneider Electric,” he adds. “Our systems operate in the space industry, the nuclear industry and on military submarines, so we know about the importance of precise and reliable control.” 

Schneider Electric’s subsea offerings include maintenance-free high-voltage and low-voltage subsea power distribution and control systems with redundant telecom connections to topside and onshore facilities, as well as fully engineered solution from grid to loads for all operating conditions.

Åsgard field
Schneider Electric is working with Aker Solutions to design and implement the seabed controls power and distribution unit (CPDU) for the subsea gas compression station of Åsgard. Operated by Statoil and located off the coast of Norway in water depths ranging from 240 to 310 meters, this is the world’s first operational project for subsea gas compression and one of he largest developments on the Norwegian continental shelf with a a total of 52 wells. Åsgard is scheduled to begin production in 2014.

Compression enhances the production rate as natural gas pressure in a reservoir declines. Subsea compression on Åsgard is expected to improve recovery from the Mikkel and Midgard fields by 278 million barrels of oil equivalent, said Eschbach.

“This application will open up new territories for oil & gas production and processing and enable the development of deep offshore fields, as well as fields in challenging areas like hurricane-prone or arctic waters,” he said.

Schneider Electric’s proposed solution reportedly met all customer specifications for electrical distribution architecture, subsea enclosure constraints and reliability standards. The project includes a series of tests to demonstrate compliance with ISO 13628-6, as well as very specific studies on availability, thermal and mechanical operational safety, and electromagnetic compatibility.

Renee Robbins Bassett, rbassett@automationworld.com, is Managing Editor of Automation World.

 

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