By Florence Tan

SINGAPORE (Reuters) -Oil prices were little changed on Friday but on track for their fourth straight week of losses after tumbling about 5% to a four month-low on Thursday on worries over global demand.

futures edged up 4 cents, or 0.1%, to $77.46 a barrel at 0529 GMT. U.S. West Texas Intermediate crude (WTI) was at $72.95, up 5 cents, or 0.1%. Both have lost around a sixth of their value over the last four weeks.

"Oil prices are down slightly this year despite demand exceeding our optimistic expectations," Goldman Sachs analysts said in a note.

"Non-core OPEC supply has been much stronger than expected, partly offset by OPEC cuts."

Prompt monthly spreads for both contracts have flipped to contango, a market trend where prompt prices are lower than those in future months indicating healthy supply.

Oil's decline this week was mainly triggered by a steep rise in inventories and production sustaining at record levels, which analysts say triggered concerns of weak demand in the world's largest oil consumer amid high output.

JPMorgan commodities research said on Friday its global oil demand tracker showed demand averaged 101.6 million barrels a day (bpd) in the first half of November, running 200,000 bpd lower than its projection for the month.

Analysts said that the recent drop in prices is also likely to make Saudi Arabia extend its additional voluntary oil output cut of 1 million bpd into 2024.

"It has become clearer that the oil balance for the remainder of this year is not as tight as initially expected," ING analysts said in a note.

"As things stand, the market is still expected to return to surplus in 1Q24."

A rollover of additional Saudi supply cuts into early 2024 should help erase the expected surplus and provide some support to the market, ING said.