Crude prices are surging, and oil majors are cashing in.

But with the pain of the last downturn all too fresh in their memories, they remain wary of investing to bring more oil to market, analysts say.

From $27 per barrel in January 2016 the main international contract climbed to $57 at the end of last year.

Then in May 2018, it rose even higher to hit $80 per barrel, only to edge back down to around $75.

As their latest quarterly earnings reports showed, oil companies have seen their profits soar as a result.

But the shock collapse of oil prices amid a glut has left companies unwilling to get too comfortable.

Prices remain "extremely volatile", said the chief executive of French oil company Total, Patrick Pouyanne.

Prices were pushed up partly by a deal brokered in December 2016 between the Organization of the Petroleum Exporting Countries (OPEC) and Russia. 

They have since been brought back under control by a new deal struck in June this year, with the oil giants agreeing to open the taps.

However, supply disruptions in Libya, Venezuela and Iran have kept price volatility high. 

And an exchange of bellicose comments between US president Donald Trump and Iran's Hassan Rouhani over the weekend renewed fears on the markets.

Adding to the pressure, "there is still a Sword of Damocles hanging over the market, and that is shale oil," according to Guy Maisonnier at the French energy research institute IFPEN.

He was referring to the non-conventional source that has made the United States a major oil producer once again.

"The oil companies fear that a sharp rise in US production could change the dynamics of the market" with prices quickly sliding lower, he said.