The search for new oil in UK waters is facing its "biggest challenge in 50 years", according to a report.
Exploration "slumped" in 2011 and has not yet recovered, according to industry body Oil & Gas UK.
Its activity survey for 2014 said that only 15 exploration wells were drilled in 2013, continuing a steep downward trend since 2008 when 44 such wells were drilled.
Oil & Gas UK said last year's level, on top of "poor" and "very disappointing" figures for 2012 and 2011, meant that the last three years have seen the lowest rate of exploration activity in the history of the UK Continental Shelf (UKCS).
Loading article content
This year, 25 exploration wells are planned, still below the number drilled six years ago and "too low to recover even a fraction of the potential resources", the report said.
The study's warning that "the clock is ticking" for the industry came despite relatively healthy figures for investment and production.
Capital expenditure of about £13 billion is forecast for this year, the second highest year for investment on record, with spending likely to remain above £10 billion next year.