But the industrialized world's energy watchdog said it remained uncertain whether the April 20 explosion on the Deepwater Horizon rig--which resulted in 11 deaths and an environmental disaster as oil gushed from BP's leaking Macondo well--would lead to specific regulatory changes, either in the region or in other oil-producing countries.

"There are a lot of question marks about whether it is going to be a game-changer for the industry or not," David Fyfe, head of the IEA's oil markets division, told a press conference launching the agency's latest annual report, which examines the prospects for oil and gas markets over the five years to 2015.

The report, entitled Medium-term oil and gas markets 2010, said that a delay of between one and two years for all planned new deepwater oilfield projects implied that US Gulf of Mexico production could be 100-300,000 b/d lower than projected by 2015.

If other producers were to introduce changes to existing regulatory procedures, an additional volume of 550,000 b/d could be affected, it said.

But the agency stressed that its numbers for the possible drop in projected Gulf of Mexico output were "purely for illustration," and made the point that because regulatory procedures and operating conditions differed from country to country, "extrapolating any potential delays in the Gulf to other deepwater regions has limited analytical value."

Nevertheless, it said, "Canada, the UK, Norway, Brazil and China are all examining existing procedures in light of the disaster. A further 550,000 b/d of expected 2009-15 production growth from deepwater Brazil, Angola and Nigeria could be at risk, albeit there are no current indications that permitting in these countries is likely to be affected."

REASONABLE MEASURE

IEA executive director Nobuo Tanaka, who told Platts last Friday that global oil supplies faced a possible cut of almost 1 million b/d by 2015 if oil producing countries introduced new drilling curbs as a result of the spill, told the press conference that the moratorium on deepwater drilling in the US Gulf of Mexico was "a reasonable measure" but called for a balanced reaction to the spill in terms of new regulations and procedures.

"The reaction must be balanced," Tanaka said.

The US introduced a six-month moratorium on deepwater drilling after the Macondo spill and there has been speculation the ban could be extended for a further six months. But a federal judge ruled Tuesday that the six-month moratorium, which came into effect on May 30, was too wide-ranging and did not reflect the risks of deepwater drilling there.

The administration of President Barack Obama said it would immediately appeal the ruling.

--Stuart Elliott, stuart_elliott@platts.com