Penn West had long-term debt of C$1.86 billion as of March 31, or $1.44 billion at current exchange rates.

The company said it was in talks with lenders on amending its financial covenants, which if successful would reduce the risk of default.

Penn West said it would try to raise money by selling more assets and would seek funding from investors.

The Calgary-based company, like other oil and gas companies, is suffering from a near-60 percent slump in global crude prices since mid-2014.

The plunge has pushed at least 28 publicly traded North American oil and gas producers to seek bankruptcy protection since early 2015, according to a Reuters review of regulatory filings.

Penn West, which reported a smaller first-quarter loss on Monday due to lower expenses, said total production fell 18.9 percent to 77,010 barrels of oil equivalent per day in the three months ended March 31.

The company slashed its budget by as much as 90 percent in January. It also cut about 35 percent of its workforce in September and stopped paying dividend from the next month in an effort to reign in spending.

Penn West's Canada-listed and U.S.-traded shares were up about 1 percent in early trading.

Up to Friday's close, the Toronto shares had fallen about 59 percent in the past year and 10.3 percent since the start of the year.

(Reporting by Arathy S Nair in Bengaluru; Editing by Maju Samuel)