Technology drives deeper

One of the constants in the oil and gas industry is technology advancement. Even in an abysmally poor revenue year, money continues to go to technology development. And the results of this targeted investment are changing the landscape in offshore operations.

Mooring milestones
There have been several interesting developments in mooring systems this year. One is the introduction of the Inter-M Swivel, InterMoor’s multipurpose mooring swivel, which can join chains of the same or dissimilar sizes, allowing for 360-degree rotational freedom under tension. Because this tool does not require kenters or joining shackles, it can connect directly into studless or common studlink chain.

Meanwhile, Viking Moorings has introduced a product it calls the “fibre in a bag” solution, what Viking describes as a complete fiber rope storage system that allows the fiber rope to be stored safely on the seabed until mobilization. Viking developed this solution in partnership with DNV.

The benefits to operators include simplified pre-laid mooring operations with the ability to store the fiber rope and buoy underwater. The “fibre in a bag” solution protects the seafloor infrastructure and eliminates the need to protect buoys at the surface. The kit allows for efficient and flexible onboard handling and storage with no requirements for specialized tooling or external cranes.

Traditionally in pre-mooring applications, the anchor chain on the seabed is grappled to connect the chain to a buoy in advance of the rig’s arrival. Grappling often disturbs the seabed surface. It also often requires a guard boat to prevent collisions between the buoys and other marine traffic. And the fiber rope insert that follows the ground chain cannot be pre-laid, since any movement of the insert can cause the fiber to come in contact with corals, debris, or other seabed particles that can damage the fiber.

Perdido is the deepest spar production facility in the world, and it marks the first commercial production from the Lower Tertiary in the GoM. (Image courtesy of Shell)

The system is designed to be stored alongside a remotely operated Spin Buoy (developed in partnership with Norwegian company Spin AS) that can be brought to the surface for connection using a coded acoustic signal, negating the need for conventional buoys on the surface and reducing the need for grappling.

Another of Viking’s key partners, Italy-based Redaelli, has built the world’s largest wire closing machine, able to produce wire at up to 550 metric tons and 175 mm diameter with a breaking strength of 2,400 metric tons. In March 2010, Redaelli manufactured the heaviest steel wire rope in the world.

Floaters, subsea production
When it comes to floating systems, one of the biggest milestones for 2010 is Petrobras’ Cascade-Chinook floating production, storage, and offloading (FPSO) vessel, which is not only the first FPSO to work in the US Gulf of Mexico (GoM), but also is the world’s deepest moored FPSO to date, working in approximately 8,530 ft (2,600 m) water depth. The fields lie in Walker Ridge, 180 miles (300 km) south of the Louisiana coast.

There will be two subsea wells on Cascade and one subsea well on Chinook. According to Petrobras, each well will be drilled to an approximate depth of 27,000 ft (8,230 m). Based on reservoir performance, Petrobras could expand production to additional subsea wells on each field. Phase II of the field development plan calls for 14 additional wells.

The subsea contracts were awarded to FMC Technologies, which is required to provide four horizontal subsea trees, three manifolds, control systems, and two subsea horizontal electric submersible pumping (ESP) systems that will boost production to the FPSO.

FMC has been a leader in subsea technology development and is continuing to push the limits with the development of the first subsea separation system for heavy oil in the Marlim field, which lies in 2,100 to 8,500 ft (650 to 2,600 m) water depth 70 miles (110 km) offshore Brazil in the Campos Basin. Marlim, which has been in operation since 1991, is a mature, deepwater field that has begun to produce a lot of water. The goal of the new subsea separation and pumping system – deliveries for which will begin in 2011 – is to debottleneck the floating production facility and increase production by removing the unwanted water from the production stream at the seabed. According to FMC, this system also will be the first to use water reinjection to increase reservoir pressure and boost production and the first to separate heavy oil in a subsea environment.

Statoil’s Åsgard field lies on the Halten Bank in the Norwegian Sea, about 124 miles (200 km) off mid-Norway. Åsgard ranks among the largest developments on the Norwegian Continental Shelf, embracing a total of 52 wells drilled through 16 seabed templates. (Photo by Marit Hommedal, courtesy of Statoil)

Marlim is the fifth project awarded to FMC that will use subsea separation technologies. Preceding projects include Shell’s Perdido field in the GoM and Parque das Conchas (BC-10) field offshore Brazil, Total’s Pazflor field offshore Angola, and Statoil’s Tordis field in the North Sea.

Statoil is making subsea history as well with advances in subsea compression. According to Margareth Øvrum, executive vice president for Technology & New Energy, “Compressing gas on subsea installations represents a considerable technological leap for the industry.” Statoil is taking this leap on the Åsgard field.

Moving compression to the seabed and closer to the well increases efficiency and improves production rates, substantially extending the producing life of the field.

Preparations for seabed compression have come furthest on Åsgard, where the Midgard and Mikkel gas deposits are tied back to the Åsgard B platform. Statoil also is investing in similar projects elsewhere.

In October 2010, Shell announced it would continue to invest in BC-10 offshore Brazil, developing the fourth field in the BC-10 block. BC-10 was the first full-field development to separate and pump oil and gas from the seabed. Today, production from the first phase of BC-10 is above expectations.

The second Shell field to employ this technology was the Perdido development.

The seabed booster systems installed on Perdido minimize design complexity and offer higher efficiency and pressure boost capacity than alternative artificial lift methods, with flow rates up to 150,000 b/d and boost pressures in excess of 5,000 psi.

In May 2010, Baker Hughes installed Centrilift XP enhanced run-life ESP systems in two vertical subsea boosting stations on Perdido, setting a depth record for ESP installation in 8,000 ft (2,438 m) of water. The unique Perdido system has direct vertical access for installing and retrieving the ESP systems.

The Perdido vertical booster stations handle production from three subsea satellite fields (Great White, Silvertip, and Tobago) tied back to the spar host facility. The booster stations are directly beneath the spar and are connected to the platform via top tensioned risers.

Perdido was a unique development in a number of ways and achieved several significant “firsts.” It is the first application of full host subsea separation and boosting in the GoM, boasting a system that removes about 2,000 psi of back pressure from the wells. Perdido has the first spar wet-tree direct vertical access wells in water more than 1.2 miles (2 km) deep. And it marks the first commercial production from the Lower Tertiary in the GoM. Perdido is the deepest spar production facility in the world.

Another first – one that has been overlooked all too often – is that the Perdido project, which came onstream on March 31, 2010, was carried out start to finish with no lost time incidents. That amounts to more than 10.5 million safely worked man hours.

Changing operational safety
Indisputably, the overawing event of 2010, was the sinking of the Deepwater Horizon, which left 11 men dead and resulted in the worst oil spill the US has ever seen. In the wake of this event, the industry was challenged to find a new way forward. The American Petroleum Institute (API) attacked that problem head on, announcing less than two weeks after the incident the formation of two task forces to address both short- and long-term issues related to offshore equipment and offshore operating practices.

In the short term, the task forces worked with the SWAT teams assembled by BP to help ensure that all response efforts were coordinated. The longer term goal of the task forces is to share lessons learned from the review of the Deepwater Horizon incident and update API standards on an ongoing basis.

Guy Luquette, president of Chevron North America E&P and API Upstream Committee chairman, explained at the Bureau of Ocean Energy Management, Regulation, and Enforcement (BOEMRE) forum on Sept. 7, that the task forces had two goals: to identify risks and eliminate them and to improve environmental performance.

The ultimate goal, Luquette said, is “to restore public confidence” in the oil and gas industry and in the regulatory industry.

Luquette was joined that day by John Peters of Chevron, chairman of the Offshore Operating Procedures Task Force; Alan Summers of Diamond Offshore Drilling, chairman of the Offshore Equipment Task Force; Charlie Williams of Shell, chairman of the Subsea Well Control and Containment Task Force; and Jay Collins of Oceaneering and Keith Robson of Marathon Oil, who co-chair the Oil Spill Response Task Force.

Each of the Task Force leaders outlined the goals and objectives of his group, explained the extent to which progress has been made to date, and presented plans for continued improvement. That objective will be met cooperatively, Keith Robson said. “We need to collaborate and coordinate better. That is absolutely the way to go.”

Although the task forces have their work cut out for them if they are to achieve all of their goals, Luquette believes there already has been substantial progress. “We are much more ready to get back to work,” he said, “and we are committed to making further progress.”