U.S. shale oil fracking has already peaked and is in a period of sustained contraction, according to two major providers of services to the industry. That view from Halliburton Co. and Schlumberger Ltd. signals an eventual deceleration in U.S. oil production, which is currently at record highs. Slower output growth would have global ramifications, given additional American barrels are forecast to account for most of the increase in worldwide supply this year. Halliburton Chief Executive Officer Jeff Miller said Tuesday that customer spending in North America will keep falling this year. That echoes Schlumberger, which said Friday it’s continuing to shrink its business in the region to match lower demand. The oil services industry has cut thousands of jobs in the U.S. and […]