Farmer Steven Jensen talks near his combine in a field on his farm near Tioga. Jensen was harvesting wheat Sept. 29th when he discovered a huge oil spill on a section of his farm. A Tesoro Logistics LP six-inch (15.24 cm) pipeline carrying crude oil from the Bakken shale play to the Stampede rail facility outside Columbuss, spilled more than 20,000 barrels of crude oil into the wheat field.