The amount of rigs drilling for oil in the U.S. rose for the first time in seven months, triggering a slump in crude oil prices to their lowest settlement in two months. U.S. oil producers added 12 rigs last week , breaking 29 straight weeks of cuts, in response to prices that have rebound to- and stayed at $60 a barrel since late April. That convinced producers to end months of massive cutbacks that started after the U.S. shale drilling boom flooded the market and sent prices crashing. But the increase in rigs is scaring investors and analysts who have warned that oil could be on the verge of another sharp fall. Production has kept making small gains even as drilling has declined and stockpiles have hit historic levels around the world. If rigs get back to work, that could keep the market flooded with oil, a concern that […]