(Reuters) – U.S. oil producer Whiting Petroleum Corp on Tuesday reported a much bigger-than-expected quarterly loss on weaker crude and natural gas prices, sending its shares down nearly 8% in after-hours trade. The results are the latest from shale companies that grappled with an 18% drop in crude oil prices during the third quarter. Pioneer Natural Resources, one of the largest U.S. shale producers, reported a 44% drop in quarterly profit, Concho Resources Inc’s adjusted earnings more than halved, while Hess Corp reported a quarterly loss. Whiting said net sales prices averaged $34.01 per barrel of oil equivalent in the quarter including hedging, 20% lower than a year earlier. The Denver-based company’s production fell to 11.4 million barrels of oil equivalent (boe) from 11.8 million boe. The company also tightened its full-year capital expenditure forecast to between $810 million and $830 million, from its previous outlook of $800 million to $840 million. Whiting reported a net loss of $19.1 million, or 21 cents per share, in the three months ended Sept. 30, compared with a profit of $121.4 million, or $1.32 per share, a year earlier. Excluding items, the company lost 38 cents per share, much bigger than the estimate for a 9 cents loss, according to Refinitiv IBES.