Baker Hughes BKR, +0.08% on Friday reported that the number of active U.S. rigs drilling for oil rose by four to 454 this week. That followed increases in each of the previous two weeks, including a climb of six oil rigs last week, Baker Hughes data show. The total active U.S. rig count, which includes those drilling for natural gas, climbed by six to stand at 556, according to Baker Hughes. December West Texas Intermediate crude CLZ21, -0.91% continued to trade lower, down 89 cents, or 1.1%, at $80.70 a barrel on the New York Mercantile Exchange.