The drilling rig floor is slick with grease and oil in Watford City, N.D., Dec. 17, 2013.
The drilling rig floor is slick with grease and oil in Watford City, N.D., Dec. 17, 2013. Minneapolis Star Tribune/MCT
The drilling rig floor is slick with grease and oil in Watford City, N.D., Dec. 17, 2013. Minneapolis Star Tribune/MCT