The Oil and Gas Authority published a new decommissioning strategy in which it warns that bills could spiral if action is not taken to improve commercial practices.
The OGA has set a target to reduce the expected costs of decommissioning by £20.7bn by 2022, from the £59.7bn total expected in 2017.
The regulator highlighted the problems caused by lack of collaboration in the North Sea, in which many firms have stakes in fields. These have been compounded by the swings in oil and gas prices triggered by the coronavirus crisis, which have made it harder for firms to develop long-term decommissioning strategies.
The strategy report found the expected cost of decommissioning assets included in the 2017 forecast had fallen to £48bn in 2020. When assets developed since 2017 were included the estimated cost increased to £51bn.
Royal Dutch Shell revealed last month that it was repaid $99 m by the UK Government last year. The costs of decommissioning the huge Brent field more than offset the profits the company made on its North Sea output.