The number of active US oil rigs continues to climb, with more additions likely as crude prices hover around $50. Drillers added three oil rigs in the week to Oct 7, bringing the total to 428, the most since February, but still below the 605 rigs seen a year ago, according to the energy services firm Baker Hughes. The 15-week streak of gains was the third longest since 1987. The oil rig count reached a six-year low of 316 in May but drillers have added 112 rigs since a price rally in June that pushed crude briefly above $50.