UPDATE 1-Barometer of shale oil industry's health warns agony to get worse
February 03, 2016 at 18:15 PM EST
HOUSTON, Feb 3 (Reuters) - The latest blow to the energy industry's collective psyche has been inflicted by National Oilwell Varco Inc, with the giant oilfield equipment maker warning the pace of drilling and fracking will only slow further as 2016 drags on.