Developing Troll phase three
03/07/2018 Operator Equinor and partners have submitted their Plan for Development and Operation (PDO) for the third development stage of the Troll field in the North Sea.
Production on Troll is expected to continue until around 2060. Troll consists of a large gas cap with a relatively thin underlying oil zone. The field covers an area of 710 square kilometres and contains gas and oil in three slanted fault blocks. These are Troll east, Troll west gas province and Troll west oil province.
The development of Troll consists of three phases. The first was gas production from Troll east (approved in 1986 and updated in 1990). The second was oil production from the Troll west provinces (approved for the first time in 1992, followed by multiple approved additions and amendments). And the third phase – for which an amended PDO has now been submitted – comprises the gas cap in Troll west. Production is scheduled to start in the first half of 2021.
The Troll field is located about 80 kilometres west of Bergen. Water depth over the field is between 300 and 340 metres. Production start-up took place in 1995. Following approximately 23 years of production, Troll has delivered about 900 million standard cubic metres of oil equivalents (oil and gas corresponding to 5,6 billion barrels). Remaining reserves are estimated at approximately 870 million cubic metres (5,4 billion barrels).
The Troll field is a gas giant that delivered 36,7 billion standard cubic metres in 2017. At the same time, Troll has been the largest oil producer on the Norwegian shelf for several years. The oil is produced from a thin oil zone and the licensees have been at the forefront of using advanced technology for (horizontal) wells and completion. This also resulted in the licensees on Troll receiving the Norwegian Petroleum Directorate’s first IOR prize in 1998.
- There are still considerable remaining oil and gas resources to recover from Troll, and the Norwegian Petroleum Directorate is therefore still concerned with the balance in the extraction of oil and gas, says Arvid Østhus (see photo), assistant director for Development and operations in the northern North Sea in the Norwegian Petroleum Directorate.
Equinor’s sketch of the development solution for Troll phase three.