Oil prices dropped on Monday, weighed by oversupply concerns, with U.S. crude dropping below $50 as trade volumes spiked ahead of the Oct. 20 expiry date for American futures contracts.
The Iranian vice-president's comments on Monday that his country needs to regain its market share added to bearish sentiments, but expectations of an upcoming OPEC production cut limited losses, analysts and traders said.
International benchmark Brent crude fell 44 cents to $51.51 per barrel at 2:35 p.m. ET, after hitting a session high of $52.29 a barrel.
U.S. West Texas Intermediate (WTI) was trading at $49.93 per barrel, down 42 cents from the last settlement, after hitting a sessions high of $50.58.
WTI hit a session low of $49.47, as trade volumes during the minute of 9:35 EDT (1335 GMT) soared to 12,932 barrels, the highest since Oct. 13.
Analysts said traders had accumulated a high number of long positions, and were looking to sell ahead of their contracts' expiry date as the U.S. Commodity Futures Trading Commission limits the number they can hold.
"There was a huge net speculative long position," said Kyle Cooper, analyst at ION Energy in Houston. "You do have to get out of positions."
Data from energy monitoring service Genscape showed a draw in crude stockpiles at the storage hub in Cushing, Oklahoma.
But traders said WTI was still under pressure from a report on Friday by oil services provider Baker Hughes, which showed U.S. drillers added four rigs in the week to Oct. 14.
Analysts said that while the market was supported by expectations that members of the Organization of the Petroleum Exporting Countries (OPEC) would take action to support prices late next month, oversupply continued to weigh.
OPEC agreed in September to cut supply to between 32.5 million and 33.0 million barrels per day (bpd), and expects to finalize the details of the deal at its meeting in Vienna on Nov. 30.
OPEC pumped a record 33.6 million bpd of crude oil in September, with some members signaling they plan further increases.
Iran is seeking to return its production to levels reached before it was hit by international sanctions in 2012.
Its current output is at 3.85 million bpd. Iran's oil minister on Monday would not say if that was enough for the country to join the OPEC deal.
"Record supply from OPEC year-to-date, weaker global GDP estimates, and still elevated inventories cause us to lower and flatten our oil price outlook," Bernstein Energy said in a note.