Offshore in depth

New subsea technology is developing at warp speed, to the extent that it’s almost impossible to keep up with all the latest. The push to develop almost all of the new technology under research emanates from the goal of a complete subsea system— production, separation and transport.

This column covers notable developments, some still on the drawing board and some reaching field application. If you happen to be aware of something new that would benefit our readers, please send me an email at the address at the bottom of this page.

Subsea power, separation and transport. Among subsea technology research projects being pursued by Total, several stand out. Total is addressing the challenge of transporting oil subsea over long distances. In Total’s estimation, heating long-distance transport lines will be the key to success, along with electric power transmission.

With electric trace heating, electric heating wires are wound between the two pipes of an insulated pipe-in-pipe line. Total says that it is the first to test this technology on a subsea gas pipeline linking the Islay gas development, in the UK North Sea, to the subsea gas-gathering network that Total already has deployed over the area. In this case, one section of the production loop is equipped with electric trace heating, pointing to a future solution for long-distance transport in the deep offshore.

In another approach, Total is developing the use of composite fabric. Energized Composite Solutions (ECS) technology capitalizes on the properties of a composite fabric coating to heat the lines. This “in-house” innovation is now undergoing a qualification program, and Total says it has demonstrated a number of advantages over electric trace heating wires. These advantages include the fabric’s lighter weight and flexibility, which enable it to conform to any geometry; a more even distribution of heat; simplified repair; and low vulnerability to localized damage, thanks to the many interconnections between the heating filaments.

Liquid-liquid separation is another step that Total sees as decisive in maximizing the recovery of mature oil fields. The quantity of produced water inevitably increases over a field’s life.

The purpose of subsea liquid-liquid separation, Total says, is to remove water from the hydrocarbons, rather than bring it up to the FPSO. In line with this concept, Total is studying a configuration that couples a liquid-liquid separation step with reinjection of the water into the reservoir.

In the future, the seawater injected into the reservoirs to enhance oil recovery will be treated on the seafloor, as well. Total is working on SPRINGS (Subsea Processing and Injection Gear for Seawater), and says it is the first seawater sulfate removal system designed for seafloor installation. With a treatment and injection capacity of 5,000 bwpd to 50,000 bwpd, SPRINGS is designed for satellite oil fields more than 10 km from an FPSO.

Total says SPRINGS can also be deployed to optimize the production of existing fields without requiring any major revamp of the FPSO facilities. The nanofiltration membranes selected for the system have been qualified for a depth of 3,000 m, a first in the deep offshore industry. An industrial trial is tentatively planned for 2015.

Settlement on Mars. Francesco Falco, general manager of Oil & Gas for GE’s Power Conversion business, said it well recently. “If the technological advances of the past 30 years in oil and gas were as breathtaking as putting man on the Moon, then the ones we face today will be like building a permanent settlement on Mars.”

Subsea processing, Falco says in a recent blog, could increase field reserves by 20% to 30%. He sees four main applications for subsea processing:

• Boosting—increasing oil recovery through full wellstream boosting
• Seawater injection—increasing oil recovery through waterflooding
• Separation—debottlenecking, creating incremental capacity
• Gas compression—enabling gas production and improving economics in mature fields.

“Imagine that by tomorrow, we will have fully functioning production platforms sitting on the bottom of the ocean, at depths of 2,000 m or more. What will be the cost?

Subsea processing is driven by economics and increased oil recovery. I think it will be the solution, not only for some extreme areas like the Arctic—since it enables access to stranded assets—but also for most of the future offshore discoveries.”

Subsea engineering graduate program. Located in the global oil and gas capital of Houston, and in partnership with the world’s leading energy engineering companies, the University of Houston has launched what it says is the world’s first subsea engineering graduate program. According to the university, the program formalizes an engineering science-based education that provides the scientific and technical skills necessary to create the first generation of trained subsea engineering specialists.

Each subsea engineering course has its lecture content distributed as one-third basic engineering sciences, one-third engineering practices in subsea engineering (i.e., translating the engineering sciences into engineering design methods, including following regulated engineering standards) and one-third knowledge synthesis (enabled through a major design project).

Each course also requires a written project report, a technical presentation and the use of subsea engineering software. The program is headed by Matthew A. Franchek, Ph.D., founding director of Subsea Engineering, Department of Mechanical Engineering. We’ll have more information on the program in next month’s column.