* Nigeria is under pressure to clean up oil sector
* Study shows $5 bln in potential revenue lost in 2002-2011
By Emma Farge
VIENNA, Dec 13 (Reuters) - Nigeria, Africa's largest oil exporter, has no plans to reform its state oil company NNPC and the way its crude oil is sold, its oil minister said on Wednesday.
"The issue of changing the way we sell our oil has been looked at by NNPC who do not feel there is a major problem with that," Diezani Alison-Madueke told reporters after an OPEC meeting in Vienna.
Nigeria's government has come under intense pressure to clean up Africa's biggest energy sector after public anger over corruption and waste of the country's oil wealth surfaced during January protests over fuel prices.
A study published by the former head of the anti-corruption agency Nuhu Ribadu showed that some $5 billion in potential revenue had been lost between 2002-2011 because state oil firm NNPC had been selling itself oil at cut-down prices.
Alison-Madueke said there were no current plans to reform the NNPC's operations.
"We will look at the entire results of the report on balance and ensure it is implemented according to the government white paper," she added.
She said on Wednesday Nigeria was producing around 2.4 million to 2.5 million barrels per day and output should remain at similar levels next year.
A major fire at a Shell facility, an Exxon spill and severe flooding cut oil output by up to a fifth in October and November, and caused lengthy delays to exports.
The minister said production had since recovered and should remain at current levels.
"I expect it at least to stabilise (next year). The problems have been flooding and bunkering and some vandalism which have disrupted pipeline services," she said.
Alison-Madueke said Nigeria still hoped to hold a marginal oil licensing round by early next year. This would be the first since a bid round five years ago which failed to attract interest from foreign oil majors.
Several targets for bid rounds set by the oil ministry have not been met in recent years and uncertainty over an over-reaching energy bill being debated in parliament could deter potential investors, industry experts say.