* Platts detailed changes to Brent assessment on Friday
* Platts plan, Shell terms differ in some respects
* Early resolution hoped for to avoid market paralysis-PVM
By Alex Lawler
LONDON, March 18 (Reuters) - BP Plc and Royal DutchShell on Monday assessed changes announced by oilpricing agency Platts to the way it assesses the Brent oilmarket, and had yet to decide on any endorsement of the newterms.
The prospect of two standards has led to some concern abouta split in liquidity in the market, which could damage theBrent-Forties-Oseberg-Ekofisk (BFOE) benchmark rather than fixit.
"We have yet to see Shell's reaction, but it is hoped thatagreement can be reached soon to avoid any confusion andconsequent paralysis of BFOE trading as a result," said TamasVarga of London-based oil brokers PVM.
Platts, a unit of McGraw-Hill which provides clientswith price benchmarks in the energy market, on Friday announcedchanges to the way it assesses Brent. These differed from newtrading terms earlier detailed by Shell and backed by BP.
BP was still reviewing the Platts announcement, companyspokesman Robert Wine said on Monday. Shell said on Friday saidit would consider the Platts announcement and respond in duecourse.
Brent, based on four types of crude from the North Sea, setsthe price of billions of dollars of daily oil trade. Since theseare in dwindling supply, critics say the smaller market is proneto manipulation and can lead to higher global prices.
Platts on Friday said it would apply quality premiums forOseberg and Ekofisk crude delivered into BFOEforward contracts that help establish the Brent price from June2013.
The tweak, Platts hopes, will offer an incentive for moredeliveries of bettter-quality Oseberg and Ekofisk into BFOEcontracts, effectively increasing the supply of oil underpinningthe market. At present, Forties most often tends to be deliveredas it is of lower quality and usually the cheapest.
While the market in general appears to agree on the idea ofquality premiums and a June 2013 start, differences betweenPlatts and Shell include the size of the premium applied toOseberg crude, whether to apply one to Brent crude and how muchpast price data to use in calculating the premium.
Thomson Reuters, parent of Reuters news, competeswith Platts in providing news and information to the oil market.
BP (BP.)