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By Anna Driver and Ernest Scheyder
Nov 4 (Reuters) - A handful of U.S. shale oil producers are pushing up their production forecasts, saying efficiency gains from drilling in prime rock are helping them eke out more crude in the middle of the worst price crash in six years.
The slightly bolder outlooks this week from Oasis Petroleum Inc, Devon Energy Corp, Pioneer Natural Resources Co and Diamondback Energy Inc show that the confident swagger that typified the U.S. shale boom's early days has yet to be fully tempered by the more than 50 percent drop in oil prices since last year.
Though the consensus view is that rig productivity in U.S. shale basins is stalling to portend a drop in national output as companies struggle to pump more with less, some firms appear to still be finding new ways to drill wells faster and frack them more intensively at a lower price.
"Over time, we continue to think we'll need less rigs than we're even saying now," Pioneer Chief Executive Officer Scott Sheffield told investors on Thursday.
Shares of Oasis, Devon and Pioneer rose more than 2 percent after their respective forecasts were announced. Shares of Oasis and Devon have lost about a quarter of their value this year, while those of Pioneer have held mostly steady.
Sheffield said Pioneer, which is adding rigs, expects to grow production 11 percent this year, up from a previous view of 10 percent. The company also confirmed it would grow 15 percent per year through 2018 thanks in part to cost cuts and tweaked technology. It produced 211,000 barrels of oil equivalent per day (boepd) in the third quarter.
Some of the flatlining of U.S. rig productivity has come as producers experiment with lower cost techniques for fracking, which involves injecting liquids and sand at high pressure into wells to coax oil from rock.
Pioneer said some of its well performance in the Eagle Ford shale of Texas was hurt recently when it tried to complete wells with lower fluid concentrations. In the future, it said wells would be fracked with more fluid and more sand so as to boost production.
At Oasis, executives now expect the company to produce 49,700 to 50,100 boepd, up from a previous estimate of 49,000 to 50,000 boepd.
Oasis Chief Executive Thomas Nusz cited the company's use of ceramics and other techniques to boost production, and touted a drop of more than 50 percent in capital spending and other costs.
And at Devon, Chief Executive Dave Hager raised the company's full-year production growth outlook for the second time this year.
"We are delivering this incremental production growth with significantly lower costs," Hager said in a statement, adding he expects Devon to cut about $1 billion from its budget by year end.
Diamondback raised the lower end of the range for its production guidance to 31,000 boepd from 30,000 boepd while saying it would come in at the low end of its expected capital spending of $400 million to $450 million. The top end for production stayed at 32,000 boepd.
"We continue to deliver robust well results ... while lowering both well costs and total expenses," stated Diamondback CEO Travis Stice. (Reporting by Ernest Scheyder in New York and Anna Driver in Houston; Editing by Terry Wade and Lisa Shumaker)