Bakken crude is similar to other North American light, sweet crudes and does not pose a greater risk to transport by rail than other transportation fuels, according to a study recently completed by Turner, Mason & Company for the North Dakota Petroleum Council (NDPC). The data also showed that Bakken crude is consistent throughout the basin with only minor geographic variability in gravity.
This is the third independent study to confirm that Bakken crude does not significantly differ from other crude oils and poses no greater risks than other flammable liquids authorized for rail transport.—Kari Cutting, vice president of the NDPC
Data shows that Bakken crude has:
An average API gravity of 41 degrees, similar to other light crudes;
An average vapor pressure of 11.5 to 11.8 psi, which is 61% below the vapor pressure threshold limit for liquids under the Hazardous Materials Regulations;
A flashpoint of less than 73 ˚F, which is within normal range;
An average initial boiling point near 99.6 ˚F, which is within normal range; and
An average sulfur weight of 0.14, which indicates low corrosivity.
These characteristics all fall well within specifications and design thresholds to transport crude safely using existing DOT 111 railcars. The findings also confirm that Bakken crude has been and continues to be properly classified under current regulations as a Hazard Class 3 Flammable Liquid, Packing Group I or II.
Fifteen well sites and 7 rail loading facilities covering the entire Bakken area were sampled and tested multiple times over a one-month period, ending in late April. The broad slate of tests and the more than 150 samples analyzed make this one of the most comprehensive independent studies of its kind ever conducted in the US.
In addition to the main work, two smaller studies were completed. The first compared the quality of the crude as loaded in North Dakota to the quality at discharge, more than 1,500 miles (2,414 km) away. The data indicated no significant changes in transit. The second looked at the effects of seasonality, which showed that the vapor pressure stayed within a relatively narrow range, despite widely varying seasonal temperatures.
The study also found that one of the tests DOT requires to determine the packing group for flammable liquids like crude oil is not optimal. The limitations of the test required for measuring initial boiling point can result in the same sample of crude being assigned to Packing Group I or II. The American Petroleum Institute is currently working to determine improved, more precise classification standards for assigning flammable liquid packing groups.
In addition to using the information to improve current packing and classification standards, the NDPC recommends using study results to establish a new crude oil benchmark to complement existing benchmarks like WTI and Brent.
John Auers, vice president of Turner, Mason & Company posited that a benchmark for Bakken crude makes sense. Auers added that more than 1 billion barrels of Bakken crude have been produced over the lifetime of the basin during the past 60 years, and current daily output is more than 1 million barrels, which validates the need for a Bakken (BKN) benchmark.
A benchmark will create a more accurate reference point for buyers and sellers of crude oil, and it will also compel operators to follow specific field standards in order to meet the BKN specifications.
The study was completed by Turner, Mason & Company and SGS Laboratories at a cost of approximately $400,000. A final written report of the study will be released in June.
Since 1952, the Petroleum Council has been the primary voice of the oil and gas industry in North Dakota. The Petroleum Council represents more than 500 companies involved in all aspects of the oil and gas industry, including oil and gas production, refining, pipeline, mineral leasing, consulting, legal work, and oil field service activities in North Dakota, South Dakota, and the Rocky Mountain Region.