US oil and gas group Nighthawk Energy reported strong production from some of its wells in Colorado, but said two others would need more work.Nighthawk, which controls and runs the Smoky Hill and Jolly Ranch projects in the Denver-Julesburg basin, said the recently drilled Big Sky 12-11, 13-11 and 5-11 wells together were producing more than 600 barrels a day, fuelling average gross oil production in February of 1,650 barrels a day.But Nighthawk said further completion and testing work was needed on its Telluride 13-2 and Big Sky 14-11 wells before they can enter production.Chairman Stephen Gutteridge said Nighthawk planned more drilling in the oil field containing the three producing Big Sky wells in April."Despite the anticipated slow decline in production from the older wells, our target is to increase gross production," he said. Shares in Nighthawk fell 0.25p or nearly 3% to 8.15p in early trading in London.PW