U.S. energy companies added oil rigs for a sixth week in a row as crude prices continue to soar to multi-year highs after new sanctions on Iran are anticipated to take some supply out of the market, further supporting U.S. drilling and pushing production to record highs. Drillers added 10 oil rigs in the week to May 11, bringing the total count to 844, the highest level since March 2015, Baker Hughes, a GE company, said in its weekly report. That was the first time energy firms added rigs for six weeks in a row since early March. More than half the total oil rigs are in Permian Basin in west Texas and eastern New Mexico, the nation’s biggest shale oil field. Active units there increased by five this week to 463, the most since January 2015.