UK 2P Reserves Drop to 2.5 Bboe Following Zero 2025 Exploration Drilling, NSTA Reports
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UK proven and probable (2P) oil and gas reserves dropped by 0.4 billion barrels of oil equivalent (Bboe) year-over-year to 2.5 Bboe by the end of 2025, according to new estimates from the North Sea Transition Authority (NSTA).
This reduction was primarily driven by 2025 production totaling roughly 380 million barrels of oil equivalent (MMboe) that was not offset by new resource additions. Zero exploration wells were drilled on the UK Continental Shelf (UKCS) in 2025, and no new field development plans (FDPs) received consent, though one FDP addendum was approved. Active fields generated a net 40 MMboe through in-field operations, performance upgrades, and deferred field shutdowns—offsetting some downward revisions and early field retirements to achieve a +10% underlying reserves replacement ratio.
Conversely, central estimates for contingent resources expanded by 0.3 Bboe to 6.5 Bboe. This growth stems from operators advancing nine proposed developments and updating existing field assessments, despite downgrades to certain sanctioned projects. The 6.5 Bboe contingent resource total breaks down into:
* **Unlicensed marginal discoveries:** 2.1 Bboe
* **Proposed new developments:** 1.6 Bboe
* **Producing fields:** 1.5 Bboe
* **Licensed marginal discoveries:** 1.3 Bboe
Estimates for mean licensed prospective resources in mapped leads and prospects decreased from 1.5 Bboe to 1.2 Bboe, alongside an additional 3.6 Bboe in unlicensed mapped areas. Unmapped play prospects hold an estimated mean of 11.2 Bboe in unlicensed resources.
Overall, UKCS oil-equivalent reserves and discovered resources maintain a split of approximately 70% oil and 30% gas. Total cumulative production from the UKCS reached 48.1 Bboe by year-end 2025.
The NSTA emphasized that operators continue to categorize developments impacted by the Court of Session judgment—which quashed prior consents—as reserves. Licensees can continue development activities on these sites, though oil and gas extraction remains prohibited pending formal consent decisions. All compiled reserve and resource figures rely on unaudited data submitted by operators.
