Organizers of an Iranian petroleum conference scheduled in London said the event was postponed because Iranian delegates were having visa issues.

CWC Group Ltd. said the National Iranian Oil Co. requested the event, which was scheduled for later this month, be postponed. Simon Hoare, the manager of the event for CWC, said in response to email questions there were some obstacles for Iranian delegates slated to attend the event in London.

"The NIOC has requested that we postpone the event due to challenges in gaining visas for the Iranian delegates who wished to attend," he said. "We are working with them to confirm the new dates as soon as possible."

Hoare confirmed this was the third time the London conference was postponed. Up until now, delays were in response to the political situation in Iran and uncertainty surrounding sanctions imposed on Iran in response to its controversial nuclear program.

Sanctions pressures eased in January when Iran was confirmed to have met the terms of a multilateral nuclear agreement reached in July. Existing U.S. sanctions make working in Iran complicated given enduring pressure on financial maneuvers with Tehran.

Iranian oil production in January averaged 2.9 million barrels per day, a 1.3 percent increase from December and the highest level reported by the Organization of Petroleum Exporting Countries since at least 2014.

Iranian President Hassan Rouhani recently wrapped up a tour of European nations, returning with commitments from energy companies like Total and Italy's Eni. Iran said it could put more barrels of oil on the market as sanctions pressures ease.

According to OPEC, oil prices are near 12-year lows in part because an already-oversupplied market is anticipating extra crude from Iran. A supply-side oil economy is hurting revenue streams for exporting nations, though Iranian officials have moved to diversify away from oil.

As part of a diversification scheme, Iran plans to offer tax breaks for exports of goods and services in an effort to expand non-oil exports. Apart from oil, Rouhani returned home with commitments from Airbus and auto company Renault.