Statoil has made the investment decision to develop the Mariner oil field in the British North Sea. The project entails investments of more than €5.3bn (over US$7bn) and is the largest new offshore development in the UK in more than a decade. Pending final approval of the field development plan by the UK authorities, Statoil expects to start production from Mariner in 2017. The field is estimated to produce for 30 years, with average production of around 55,000 bbl/d of oil over the plateau period from 2017 to 2020. The Mariner Field consists of two shallow reservoirs, the Maureen Formation and the Heimdal Sandstones of the Lista Formation, with nearly 2 billion barrels of oil in place and expected reserves of more than 250 million barrels of oil. Both formations yield heavy oil of around 12 to 14 API.
The heavy oil project will require pioneering technology in order to be developed. Since its discovery in 1981, the Mariner field has been subject to a number of development studies by different operators. Statoil became operator for Mariner in 2007, when it acquired 44.44% and operatorship for Mariner from Chevron. Statoil acquired a further 20.6667% of Mariner from Nautical Petroleum in 2010. JX Nippon Exploration and Production (28.89%) and Alba Resources (part of Cairn Energy, 6%) are partners in Mariner.