Drilling contractor Hercules Offshore Inc. said it filed for Chapter 11 bankruptcy as demand from oil and gas producers and explorers drops due to weak prices.

Hercules, which announced last month that it would file for creditor protection, said on Aug. 13 it expected its prepackaged reorganization to conclude in 45-60 days.

Under the restructuring plan, more than $1.2 billion of Hercules' senior notes will be converted to 96.9% of new equity. Existing shareholders, who Hercules said are "out of the money" by $500 million, will get the remaining 3.1%.

The Houston-based company will also get $450 million of debt financing from some noteholders.

The financing will allow the company to pay for a new high-specification rig, Hercules Highlander, that is under construction in Singapore, Hercules said.

Hercules has a fleet of 27 jackup rigs, including the one under construction.