Statoil Shrinks Drilling Technology

Statoil has launched a new subsea concept called Cap-X designed to increase the efficiency of horizontal drilling in shallow reservoirs.

Cap-X is a combination of existing and new technology. It is a quarter of the size of today’s subsea templates and enables more operations from vessels instead of rigs. Additionally, the main structure of the technology can be produced in shorter time by a larger number of suppliers, with potential for local production.

The development of Cap-X was initiated in 2013 to increase commerciality of potential resources in the Barents Sea.

"Once again we aim to drive subsea technology development on the Norwegian continental shelf together with our industry partners. The potential for increased efficiency and reduced costs can make this the next standard within subsea templates," says Margareth Øvrum executive vice president for technology, projects and drilling at Statoil.

"With Cap-X, Statoil is one step closer to a “plug and play” solution on the seabed."

Half of Statoil’s production comes from our 500 subsea wells.

Subsea Production

First Generation: 1986-1990

Is this possible? Subsea production was tested on the Norwegian continental shelf (NCS) as early as the 1970s. Statoil decided to focus on subsea production during its first development project and its first ever operated well was a subsea well at Gullfaks in 1986. For the first projects the question was largely whether it was possible to move the well system from the platform deck to the seabed. Tommeliten was the first field to use a template structure, i.e. a template accommodating several wells.

Second Generation: 1991-1995

Simplification: After having seen that production systems can be reliably operated on the seabed, the engineers started looking for simpler and more cost-effective solutions. Small-size reservoirs discovered around the Statfjord field did not alone justify a complete development including a platform, and they were located too far from the platforms to allow wells to be drilled from the platform legs. Cheaper subsea concepts connected directly to the platform were therefore used for producing this oil. Similar projects were implemented around Sleipner, Heidrun and Norne.

Third Generation: 1996-2002

Lower cost developments in deeper waters: This generation was an enabler for using floating production systems in deeper water on the NCS. Yme, Lufeng, Åsgard and Troll oil are examples of fields that came on stream during this period. Lufeng in China was Statoil’s first international operatorship. At this field the company also applied pumps for the first time to lift the oil from the seabed to the production vessel. This was the first step towards the subsea factory. The second step was the Troll pilot project where the produced water was removed from the wellstream on the seabed and re-injected.

Fourth Generation: 2003-2007

Crossing new frontiers: The formerly "impossible" development projects were now made possible. The era of easy oil was over, and the fields that were discovered involved enormous development challenges. Gas was discovered on the Kristin field, but the reservoir pressure and temperature were higher than in any other developed field on the NCS. At Ormen Lange and Snøhvit the distance was the greatest challenge. Statoil decided to use subsea-to-shore solutions for these fields, and with long pipelines bringing the gas to land rather than to a platform. The Tordis subsea separation, boosting and injection system was developed and installed to pursue the ambition of a subsea factory. This system removes water and increases the oil pressure by pumping and re-injecting the water.

Fifth Generation: 2007-2014

Standardization and increased recovery: So far, one objection to subsea wells has been that the same volume could not be produced from such wells compared to traditional wells connected to a production system on a platform. Thanks to new smart wells, it is possible to obtain more information from the reservoirs and perform efficient well interventions which have almost eliminated this gap. The Tyrihans field, which came on stream in 2009, is an example of such a field. Tyrihans also installed a system for injecting seawater into the reservoir by using pumps on the seabed. This generation of subsea technology has formed the basis for Statoil's development of a standard subsea catalogue and a new range of successful fast-track subsea tie-backs.

Sixth Generation: 2015-

The first vital decisions for the sixth generation have been taken in the seabed gas compression projects for Gullfaks and Åsgard. These project technologies will pioneer an important part of future subsea factories. This period is also expected to be dominated by deeper waters, longer step-out distances and the start of Arctic challenges. The Aasta Hansteen development is expected to lead the way into deeper waters, and subsea will play an important role in the development of the new Barents Sea discoveries like Skrugard and Havis.