In this Dec. 19, 2014, file photo, oil pump jacks work in unison in Williston, N.D.
In this Dec. 19, 2014, file photo, oil pump jacks work in unison in Williston, N.D. Eric Gay AP
In this Dec. 19, 2014, file photo, oil pump jacks work in unison in Williston, N.D. Eric Gay AP