By Stephanie Kelly

NEW YORK (Reuters) -Oil prices gained for a fifth straight day on Monday, with Brent at its highest since October 2018 and heading for $80, as investors fretted about tighter supplies because of rising demand in parts of the world.

Brent crude was up $1.38, or 1.8%, to $79.47 a barrel by 11:10 a.m. EDT (1510 GMT), having posted three straight weeks of gains. U.S. crude futures rose $1.35, or 1.8%, to $75.33 a barrel, its highest since July, after rising for a fifth straight week.

Goldman Sachs raised by $10 its year-end forecast for Brent crude to $90 per barrel. Global supplies have tightened due to the fast recovery of fuel demand from the outbreak of the Delta variant of the coronavirus and Hurricane Ida’s hit to U.S. production.

“While we have long held a bullish oil view, the current global supply-demand deficit is larger than we expected, with the recovery in global demand from the Delta impact even faster than our above-consensus forecast and with global supply remaining short of our below consensus forecasts,” Goldman said.

Caught short by the demand rebound, members of the Organization of the Petroleum Exporting Countries and their allies, known as OPEC+, have had difficulty raising output as underinvestment or maintenance delays persist from the pandemic.

“The rise of oil prices is continuing beyond what even most bullish traders would dream just months ago, and Brent hurtling towards the threshold of $80 per barrel is reflective of the extraordinarily tight crude market,” said Louise Dickson, senior oil markets analyst at Rystad Energy.

“U.S. supply constraints will continue to provide upside to oil prices, as Ida-related outages will still affect U.S. supply in the first quarter of 2022.”

Global oil demand is expected to reach pre-pandemic levels by early next year as the economy recovers, although spare refining capacity could weigh on the outlook, producers and traders said at an industry conference.

Global demand is seen rising to 100 million barrels per day (bpd) by end-2021 or in the first quarter of 2022, Hess Corp President Greg Hill said. The world consumed 99.7 million bpd of oil in 2019, according to the IEA, before the COVID-19 pandemic hammered economic activities and fuel demand.

In India, oil imports hit a three-month peak in August, rebounding from nearly one-year lows touched in July, as refiners in the second-biggest importer of crude stocked up in anticipation of higher demand.

(Reporting by Stephanie Kelly; additional reporting by Noah Browning and Aaron Sheldrick; Editing by Louise Heavens and David Evans)

By Stephanie Kelly

NEW YORK (Reuters) -Oil prices gained for a fifth straight day on Monday, with Brent at its highest since October 2018 and heading for $80, as investors fretted about tighter supplies because of rising demand in parts of the world.

Brent crude was up $1.38, or 1.8%, to $79.47 a barrel by 11:10 a.m. EDT (1510 GMT), having posted three straight weeks of gains. U.S. crude futures rose $1.35, or 1.8%, to $75.33 a barrel, its highest since July, after rising for a fifth straight week.

Goldman Sachs raised by $10 its year-end forecast for Brent crude to $90 per barrel. Global supplies have tightened due to the fast recovery of fuel demand from the outbreak of the Delta variant of the coronavirus and Hurricane Ida’s hit to U.S. production.

“While we have long held a bullish oil view, the current global supply-demand deficit is larger than we expected, with the recovery in global demand from the Delta impact even faster than our above-consensus forecast and with global supply remaining short of our below consensus forecasts,” Goldman said.

Caught short by the demand rebound, members of the Organization of the Petroleum Exporting Countries and their allies, known as OPEC+, have had difficulty raising output as underinvestment or maintenance delays persist from the pandemic.

“The rise of oil prices is continuing beyond what even most bullish traders would dream just months ago, and Brent hurtling towards the threshold of $80 per barrel is reflective of the extraordinarily tight crude market,” said Louise Dickson, senior oil markets analyst at Rystad Energy.

“U.S. supply constraints will continue to provide upside to oil prices, as Ida-related outages will still affect U.S. supply in the first quarter of 2022.”

Global oil demand is expected to reach pre-pandemic levels by early next year as the economy recovers, although spare refining capacity could weigh on the outlook, producers and traders said at an industry conference.

Global demand is seen rising to 100 million barrels per day (bpd) by end-2021 or in the first quarter of 2022, Hess Corp President Greg Hill said. The world consumed 99.7 million bpd of oil in 2019, according to the IEA, before the COVID-19 pandemic hammered economic activities and fuel demand.

In India, oil imports hit a three-month peak in August, rebounding from nearly one-year lows touched in July, as refiners in the second-biggest importer of crude stocked up in anticipation of higher demand.

(Reporting by Stephanie Kelly; additional reporting by Noah Browning and Aaron Sheldrick; Editing by Louise Heavens and David Evans)