International oil benchmark Brent crude advanced for a sixth straight session on Tuesday, jumping above $80 per barrel for the first time since October 2018 as demand rebounds and supply remains tight.

West Texas Intermediate crude futuresU.S. crude oil benchmark climbed 1% for six consecutive days, reaching a record high of $76.28 per barrel. The gains are continuing after five weeks, with each contract up by more than half for 2021.

In a Tuesday note, Barclays analysts wrote that a “permanent supply deficit” is driving an ever tighter market. OECD inventories will likely end the year at their lowest point in years. WTI and Brent were raised to $74 and $77 respectively by the firm in their 2022 targets.

Brent traded at $80.14/barrel last week, 0.77% more than the previous day. Goldman Sachs sees the contract reaching $90 before the end of this year as the market recovers. After previously forecasting Brent as $80 at the close of 2018, Goldman Sachs raised its Sunday target to $90.

Producers implemented historical output reductions in April 2020, when the pandemic impacted worldwide demand. WTI briefly fell into negative territory. OPEC and its allied countries removed almost 10 million barrels per hour from the market. Although the group is slowly opening the taps to allow production to resume, they are holding off.

The U.S. has seen a similar situation. Wells were blocked and production was slow. They have instead focused on strengthening balances, paying down debt, and returning capital to shareholders.

The large-scale vaccination has helped to increase demand, but supply is still limited. After years of low investment in this sector, it is even more apparent.

The dramatic rise in natural gas prices is also helping oil, and could lead to utilities switching from gas to petroleum.

Natural gas futures On Tuesday, prices rose by more than 9% to $6.26 per British thermal unit. This is the highest price in at least 7 years. With inventory at historic lows heading into winter, the contract has risen more than 40%.

Ed Morse from Citi Global Head of Commodities said that the global market for natural gas is very tight, and inventories are much lower than normal in Europe and America. Prices should remain at their current high levels in winter. However, there is the possibility of price increases due to colder than normal weather.

The energy sector is by far the best S&P 500 group for September, up more than 10%. Only 1% is the increase in financials as it is second.

The Energy Select Sector SPDR Fund advanced over 1% during premarket trading on Tuesday.