Norway-listed offshore driller Seadrill, once the crown jewel in the business empire of shipping tycoon John Fredriksen, said the oil industry may be turning a corner as it posted second-quarter earnings above forecasts on Thursday.

At the height of the oil price boom, the company was the world's largest offshore driller by market capitalisation, but it has been struggling as oil firms slash costs to counter a 57-percent decline in crude prices since mid-2014.

Seadrill's share price has fallen by 90 percent over the past two years, against a 1.5 percent rise for the Oslo benchmark index over the same period.

But the cycle may be turning, Seadrill said on Thursday, joining other industry suppliers that have recently pointed to signs of recovery in demand from oil companies.

"Oil prices stabilized in the $40-50 range during the quarter and there is a growing belief that we are at or near the bottom of this downcycle," Seadrill said in a statement.

Seadrill's earnings before interest, tax, depreciation and amortisation (EBITDA) fell to $557 million in the second quarter, against $651 million a year ago and expectations for $512 million in a Reuters poll of analysts.

Its share were up 0.28 percent at 0739 GMT, outperforming an Oslo benchmark index down 0.76 percent.

Seadrill repeated that it expected to conclude the refinancing process of its $10 billion debt by the end of the year. (Reporting by Ole Petter Skonnord