An internal OPEC+ effort to independently assess each member's sustainable production capacity - a central input for determining 2027 output quotas - has been delayed following disruptions to planned capacity-expansion projects linked to the US-Israeli war on Iran, two sources close to the process said.
OPEC+, the grouping that includes the Organization of the Petroleum Exporting Countries together with Russia and allied producers, had initiated the production capacity review for all members in late 2025. The exercise was to be completed by the end of September 2026 so that updated capacity assessments could inform negotiations over quotas for 2027. The timeline has slipped, the sources said, with one source indicating the review is now expected to wrap up by mid-November.
The producer group did not respond immediately to requests for comment, the sources said.
Production capacity estimates in flux
Officials undertaking the capacity review face heightened uncertainty because the Middle East conflict has delayed projects that were scheduled to raise output capacity in some OPEC+ countries. Those delays have made it harder to produce reliable, forward-looking estimates of how much oil each member can sustainably produce.
According to the sources, not all members have submitted the data needed to complete the review. The absence of full data sets increases uncertainty around the independent assessment that the review is meant to produce. That assessment is a key metric used in subsequent negotiations when members agree on individual production targets.
Delays to planned capacity additions could change the assumptions that underpin the review. If assessed capacity for some countries is revised downward, those producers could face pressure to accept lower quotas. Conversely, producers whose assessed capacity has increased would be expected to press for higher allocations.
Political stakes and recent membership moves
The political sensitivity of capacity estimates is underscored by recent membership developments. The United Arab Emirates, which had lobbied for a larger quota to reflect rising production capacity, left the alliance in May. Iraq is also seeking a higher quota and has considered leaving OPEC, according to sources speaking in June.
The delay to the capacity review adds an extra layer of complexity to an already delicate negotiation framework in which capacity assessments directly influence how much each member is permitted to produce.
What remains uncertain
At present, the precise extent to which delayed projects will alter capacity estimates is unclear, as is the full list of members that have not supplied necessary data. The review's revised timeline to mid-November reflects these outstanding information gaps and the ripple effects of regional disruptions on the technical work required to complete the assessment.