Oil prices have increased amid a boom in US supply due to shale oil and the resumption of output in the Gulf of Mexico after Hurricane Barry despite tensions in the Middle East.

Prices continued to face pressure as the second-quarter economic growth in China slowed to 6.2% from a year earlier, the slowest pace in more than two decades.

Brent crude futures increased by 21 cents to $66.69 a barrel, while West Texas Intermediate crude futures rose by 19 cents to $59.77 a barrel, Reuters reported.

Oil companies in the US began restoring part of the 74% of production that was stopped at Gulf of Mexico platforms before the onset of Hurricane Barry.

Saxo Bank commodity strategist Ole Hansen was quoted by Reuters as saying: “Crude oil is having a quiet day today after giving back some of last week’s gains. US output from the Gulf looks set to increase and … Barry failed to hit refinery assets along the coast.”

Even though workers started returning to over 280 production platforms that were evacuated, it could take several days for the resumption of full production.

PVM analyst Tamas Varga said: “You could almost hear the big sigh of relief from oil producers and refiners in the region as the storm passed without causing significant damage.”

Commerzbank analysts said that the storm is expected to result in a noticeable decline in US crude oil stocks this week.

Following a boom in shale oil production, the US has become the world’s biggest crude producer, ahead of Russia and Saudi Arabia.

The US Energy Information Administration said that the output from seven major shale formations is expected to increase by 49,000 barrels per day (bpd) in August, to a record 8.55 million bpd.

Meanwhile, the tension between the US and Iran over the nuclear programme has scared the market, as deterioration in the situation could have the potential to increase oil prices.