LONDON, Jan 19 Oil crept higher on Friday, holding above the $ 50 a barrel tipping point

LONDON, Jan 19 (Reuters) Oil crept higher on Friday, holding above the $50 a barrel tipping point after an unexpectedly big rise in U.S. crude stocks pushed prices to a 20-month low.

U.S. crude rose five cents to $50.53 a barrel by 1008 GMT, after ending down $1.76, or 3.4 percent, at $50.48 on Thursday.

London Brent gained 32 cents to $52.07.

Since the end of last year, U.S. crude has fallen by 17 percent and is around 35 percent below last year's record high of $78.40.

Following news of a 6.8 million barrel rise in U.S. crude stocks on Thursday, U.S. crude fell below $50 for the first time since May 2005 to $49.90, but recovered slightly in late trade.

''Traders are unlikely to be satisfied with the brief dip below the $50 level last night. We suspect a bigger drop will be required,'' said Tobin Gorey, analyst at Australia's Commonwealth Bank.

Technical analysts, who predict future price direction from studying charts, said that should there be a convincing break below $50, the next key level would be around $44.50 -- the 50 percent retracement of the rally from the December 1998 low of $10.35 to last July's record.

Some commentators have said a concentration of ''put'', or sell, options around the $50 and $45 a barrel level could trigger huge liquidation.

Countering that, some producers, who have been relying on rising prices to protect their revenues, have started to buy to hedge against further declines.

In addition, long-term investors, who see commodities as an important diversifier against falls in other asset classes, increasingly see an opportunity to buy.

''There had been concern that when energy prices were very high, there appeared to be more downside risk than upside,'' said Richard Cooper of Mercer consultancy.

Further support could also come from the Organization of the Petroleum Exporting Countries, which has already agreed two output cuts totalling 1.7 million barrels per day to try to check the slide.

But so far Venezuela has stood alone among OPEC members in calling for further action.

REUTERS SBA DS1604