An additional 900 million barrels of oil could be extracted from the North Sea if companies can improve their operations, new estimates have suggested.
Andy Samuel, chair of the Oil and Gas Authority (OGA), said the extra oil could be a "significant prize" in the UK Continental Shelf (UKCS).
He spoke out after the OGA estimated that increasing the recovery factor (RF) - the overall proportion of oil that can realistically be extracted - could reap rewards.
Traditionally the recovery factor in the UKCS has been about 42% to 43% - meaning about 57% of all oil will remain in the ground - with this having remained roughly the same despite improvements in technology.
The OGA has set a target of raising this by 2020, and by looking at the potential that exists in a small number of fields, it estimated an additional 900 million barrels of oil could potentially be produced if the recovery factor was increased.
Mr Samuel said: "This new benchmarking analysis further underlines the significant prize remaining across the UKCS, in this case across a number of producing fields.
"The OGA will be sharing our results with operators to highlight and quantify opportunities where increasing recovery factor should lead to increased value.
"These data help us understand RF performance across the basin, prioritise our asset stewardship reviews with operators and identify new opportunities for improvement and sharing good practices."
Dave Lynch, BP's vice president of reservoir development, said: "The recovery factor benchmarking analysis produced by the OGA will be of huge value to highlight and develop the potential in existing, producing fields.
"We will be using this benchmarking work within BP to maximise economic recovery from our assets."