U.S. energy firms added oil rigs for a third week in a row for the first time since June, keeping the rig count at its highest in over three years, as declining productivity in some shale fields force companies to drill more to keep output growing. Drillers added two oil rigs in the week to Oct. 26, bringing the total count to 875, the highest level since March 2015, General Electric Co’s Baker Hughes energy services firm said in its closely followed report on Friday. For the month, the rig count rose 12 in October, the biggest monthly increase since drillers added 34 rigs in May. That was also the first time the count increased for four months in a […]