Shipments of oil by rail ticked up a little during the month of September.
The oil was shipped to East Coast refineries.
The amount of Bakken crude shipped by rail has been dropping because of pipeline infrastructure – most notably the Dakota Access Pipeline.
North Dakota Pipeline Authority director Justin Kringstad said in September oil companies were dealing with the after affects of hurricanes.
"Hurricane Maria impacted deliveries of oil to the East Coast," Kringstad said. "The PADD 1 refineries are fully geared to handle Bakken crude deliveries by rail."
Kringstad said those refineries had shifted away from that, and were taking more "water-borne" oil because of the market conditions.
"Those water-borne shipments were not able to be delivered as expected," Kringstad said. "So as a solution, there were trains leaving North Dakota and headed to the East Coast to feed those refineries."
In September, 76 percent of North Dakota oil was exported by pipeline – and 11 percent was taken by rail.
The rest of the oil was either trucked, or stayed in-state to be refined.