By Rania El Gamal
RIYADH (Reuters) - Top oil exporter Saudi Arabia announced a slight rise in its crude oil reserves on Wednesday after they were independently audited, providing more detail about the size of deposits shrouded in secrecy for decades.
Saudi Arabia's reserves of easily recoverable oil have long been the world's largest but few details were public. The external audit was started as part of preparations for the initial public offering of state oil company Aramco.
The Saudi Energy Ministry said in a statement carried by state news agency SPA that Saudi Arabia's proven oil and gas reserves stood at around 268.5 billion barrels of oil and 325.1 trillion standard cubic feet of gas as of the end of 2017.
"The results point out that the kingdom's reserves of oil and gas are bigger than what we have been announcing," Saudi Energy Minister Khalid al-Falih told a news conference in Riyadh.
The news conference took place hours later than initially scheduled and SPA corrected its initial announcement of the reserves figures.
The audit will dispel scepticism in the oil industry about the size of Saudi reserves and provide assurance for potential Aramco investors, should the IPO which has been delayed eventually go ahead.
For almost 30 years - despite rising production, large swings in oil prices and improved technology - Riyadh had annually reported the same number for reserves at around 261 billion barrels, according to a statistical review by BP.
Saudi Arabia confirmed for the first time that Dallas-based consultants DeGolyer and MacNaughton carried out the audit.
Plans for the Aramco IPO were shelved last year for the forseeable future, sources told Reuters. Saudi Arabia says the share sale will "certainly" still happen when conditions are right.
(Writing by Alexander Cornwell and Alex Lawler, editing by Louise Heavens and Susan Fenton)