Gross revenue fell 24.5 percent to C$584 million ($510.3 million) in the third quarter ended Sept. 30 as production fell 25 percent to 100,839 barrels of oil equivalent per day (boepd).

The Calgary-based company has been selling assets to focus on its Cardium field in Alberta.

Penn West said on Wednesday that average selling prices for light oil and natural gas liquids fell 5.3 percent to $87.49 per barrel in the quarter, while average prices for heavy oil fell 14 percent to $72.38 per barrel.

The company's U.S.-listed shares, which hit a 52-week low of $4.05 on Tuesday, were down 2.5 percent in premarket trading on the New York Stock Exchange.

Penn West reiterated its 2014 production forecast of 101,000-106,000 boepd, and said it expected 2015 production to average 95,000 to 105,000 boepd.

Penn West posted a net loss of C$15 million, or 3 Canadian cents per share, compared with a profit of C$34 million, or 7 Canadian cents a year earlier.

The company's funds flow, an important measure of its ability to pay for new projects and drilling, fell 22 percent to C$231 million, or 47 Canadian cents per share, from C$296 million, or 61 Canadian cents.

Penn West said on Oct. 23 that it would sell non-core assets in south central Alberta for about $355 million.

The company said in September it was working to improve internal controls after a series of accounting errors misclassified nearly C$300 million in expenses.

(Reporting By Scott Haggett and Darshana Sankararaman in Bangalore; Editing by Sriraj Kalluvila and Ted Kerr)