Aker Solutions has reached a major milestone in delivering the 100th subsea tree to the world's largest subsea field development - Statoil's Troll.
A subsea tree is a key technology enabling oil and gas production directly from a subsea well to a processing facility. The tree is essentially an advanced set of valves and is used together with associated technologies to control the well flow. The subsea tree is an integral part of a subsea production system.
The Troll field is located in the northern part of the North Sea, approximately 65 kilometres west of Kollsnes, near Bergen in Norway. The field contains 40 per cent of the total gas reserves on the Norwegian continental shelf and is also one of the largest oil fields on the continental shelf.
"Aker Solutions has a proud history of subsea design, manufacturing and installation of subsea production systems and the delivery of Troll subsea tree number 100 is a testimony to our capabilities," says Mads Andersen, Executive Vice President of Aker Solutions and head of the subsea business.
The vision of embarking on a large subsea project began in 1991 when Kvaerner Energy, now known as Aker Solutions, started developing a subsea tree. In July 1996, they were awarded a major contract for the delivery of 65 subsea trees for the Troll project which opened up for the opportunity to be a major player in the subsea production system market. The delivery to Norsk Hydro, now Statoil, started in the spring of 1997.
The contract award and deliveries for the Troll project have helped to shape and develop Aker Solutions' subsea business. Today, the company is one of the major suppliers of subsea production systems in the world and the Tranby technology and manufacturing centre outside Oslo, which is the main production site for subsea trees in Norway, has grown to employ over 500 people. In total, the subsea business in Aker Solutions employs more than 4300 people globally.
Aker Solutions continues to develop their technology to solve the challenges of deeper water, higher pressures and temperatures, longer step-outs and increased oil recovery demands.
"Aker Solutions is constantly breaking new technology frontiers to find solutions for more demanding fields. At the same time, we are developing smarter, more robust and adaptable technologies to standardise our existing portfolio of subsea production systems," says Andersen.
Shell was initially the operator of Troll when the first block was awarded in 1979. A large gas field with underlying oil was discovered in the same year and the field was then declared commercial in 1983. During the same year, the three neighbouring blocks were awarded to Statoil, Norsk Hydro and Saga Petroleum.
Shell's block contained 32% of the Troll field's reserves while the remaining 68% were discovered in the other three blocks. In 1985, the two licenses were merged and Troll was developed as a field. Statoil became the operator for Troll Gas in 1996, while Norsk Hydro began production from Troll Oil in the autumn of 1995.
Of the 100 trees delivered to Statoil, 99 of them are oil producing trees and one of them is a water injection tree. Thirty-two of the subsea trees are connected to the Troll B platform and the rest are connected to the Troll C platform.