US sanctions on Iran have cut the OPEC member's crude exports further in May, adding to supply curbs resulting from an OPEC-led pact. Meanwhile, rising tension in the Middle East this week has raised concern about additional supply disruption.
Vienna-based OPEC trimmed its estimate of oil supply growth from outside the group in 2019 and said the rapid rise in production of US tight oil, another term for shale, was moderating.
Spare capacity is the extra oil a producing country can bring onstream and sustain at short notice, providing global markets with a cushion in the event of natural disaster, conflict or any other cause of an unplanned supply outage.
Brent crude oil futures were at $71.09 per barrel at 0341 GMT, 15 cents, or 0.2 percent, below their last close.
The EIA has raised its Brent crude-oil price forecast for 2019 to USD 65 a barrel, up from its earlier projected USD 63 due to the tighter global oil market.
The Organisation of the Petroleum Exporting Countries will pursue this policy 'despite current troubles in several of its member countries.'
Brent crude futures hit a session high of $73.27 per barrel and settled 76 cents, or 1.1 percent, higher at $72.80. Last week, Brent hit a six-month high above $75.
US light crude is seen averaging $60.23 per barrel this year, compared with $58.92 forecast in March.
Here's a roundup of key happenings in the commodities market.
Putin said that the deal is effective until the end of June and that he hoped Saudi Arabia will not have to raise its oil production to offset possible exports curbs from Iran due to the US sanctions.
Brent crude futures were at $74.09 per barrel at 0029 GMT, down 26 cents, or 0.4 percent, from their last close.
International benchmark Brent crude futures were up 34 cents, or 0.47 percent, at $72.06 by 1130 GMT, having hit an intraday peak of $72.27.
Brent crude oil futures were at $71.08 a barrel at 0111 GMT, down 10 cents, or 0.1 percent, from their last close. Brent ended down 0.5 percent on Monday.
Brent crude oil futures were at $71.46 a barrel at 0233 GMT, down 9 cents, or 0.1 percent, from their last close, having hit their highest since Nov. 12 on Friday at $71.87.
The producer group's supply cuts have been aimed largely at offsetting record crude production in the United States.
International Brent crude oil futures were at $71.01 per barrel at 0042 GMT, up 18 cents, or 0.3 percent, from their last close.
Venezuelan crude production has dropped below 1 million barrels per day (bpd) because of US sanctions. Iranian supply could fall further after May if, as many expect, Washington tightens its sanctions against Tehran.
International benchmark Brent futures were at $71.57 per barrel at 0056 GMT, down 16 cents, or 0.2 percent, from their last close.
Traders said, oil prices hardened amid reports of ongoing turmoil in the OPEC member country Venezuela. They also maintained a cautious outlook over recent violence in Libya, and the US sanctions on Iran which might affect further production supplies.
International benchmark Brent futures were at $70.83 per barrel at 0056 GMT, up 22 cents, or 0.3 percent, from their last close.
The investment bank said in a note dated April 8 that it now expects benchmark Brent crude prices to average $66 per barrel in 2019, compared with its previous estimate of $62.50.
International benchmark Brent futures touched their strongest level since last November at $71.34 per barrel on Tuesday, before losing ground to $70.96 per barrel by 0158 GMT, down 14 cents, or 0.2 percent, from their last close.
International benchmark Brent futures dropped 15 cents, or 0.2 percent, to $69.25 a barrel by 0455 GMT, having touched $70.03 in the previous session, the highest since Nov. 12.
International benchmark Brent futures dropped 23 cents, or 0.3 percent, to $69.17 a barrel by 0040. On Thursday, they closed 9 cents higher after touching a session high of $70.03, the highest since Nov. 12.
Brent futures were up 5 cents at $69.36 a barrel by 0224 GMT. On Wednesday, Brent dipped 6 cents, after touching $69.96, the highest since Nov. 12, when it last traded above $70.