Before 2013, the Three Forks Formation in the Williston Basin was generally thought to be unproductive. Then the U.S. Geological Survey (USGS) released its 2013 assessment. The Three Forks was missing from the agency’s 2008 assessment. But new drilling helped the USGS understand the reservoir and its resource potential.

The USGS upped its Three Forks estimates from essentially nothing to 3.73 billion barrels (Bbbl) of oil.

Now, the Williston Basin is up for a new physical after U.S. Senator John Hoeven (R-ND) pressed USGS director Suzette M. Kimball in late October to update the 2013 assessment. The next target, Hoeven told Hart Energy, is the Tyler Formation.

Hoeven said industry advancements in directional drilling and hydraulic fracturing have greatly expanded access to resources in the Williston. But his request also was driven by the industry’s development of the Tyler Formation.

“They’re just developing the Tyler Formation. The Tyler formation is a newer development and [the assessment] will provide us more information,” Hoeven said.

The Tyler Formation has produced more than 84 million barrels (MMbbl) of oil from 285 wells, peaking with daily production of 3.3 MMbbl in 1976. However, it has been relatively unexplored by horizontal drilling.

North Dakota officials said that Marathon Oil Corp. (MRO) drilled four Tyler wells in Slope County in 2014. Two have been plugged and abandoned, one was dry and the last permit was canceled.

While the Tyler may be an economical play at $100 oil for now, any additional information the USGS can provide through an assessment would be beneficial, state officials said.

As with the Three Forks, the Williston is not to be underestimated.

Hoeven said a new assessment could again show a significant increase in resources.

“I think that’s good from a long-term standpoint, as far as not only attracting investment to continue to produce oil and gas in the Williston Basin. It’s also important for us as we continue to work to make sure we have the infrastructure and other amenities to maintain good quality of life.”

Tyler Hitch

The Tyler has been a beguiling play, with a range of operators testing it.

Operators have most recently targeted Slope County, N.D.

Marathon Oil, which has drilled in the Tyler for several years, reported completion of the Powell 31-27th in January. Production was 18 barrels per day (bbl/d) of oil and 45 bbl/d of water in January, according to the North Dakota Industrial Commission.

In 2013, when most attention was focused on the Bakken and Three Forks, North Dakota Geological Survey (NDGS) geologist Stephan H. Nordeng told Hart Energy that the formation is an extensive, organic-rich Pennsylvanian unit ranging from 286 to 325 million years old.

A Time-Temperature Index (TTI) map of the Tyler Formation, constructed from modern geothermal heat flow measurements and stratigraphic interval thickness data shows that oil production from the Tyler Formation is from rocks that are mature enough to generate oil.

“It contains organic-rich intervals consisting of kerogen in excellent quality, oil-prone source rocks,” Nordeng said.

Parts of the formation with non-sandstone areas may be oil saturated, NDGS said in a 2012 report.

“Most of the area where the Tyler Formation contains thermally mature source rocks does not contain much sandstone,” the NDGS said. “Defining unconventional, non-sandstone reservoir intervals within the Tyler section would be important.”

“The success of Upton Resources’ horizontal Tyler wells appears to be a function of how consistently the horizontal laterals were able to stay within the targeted sandstone interval,” the NDGS said.

Prospecting

The USGS’ last estimates for the Bakken and Three Forks changed the perception by investors of the Williston Basin and doubled its resources. Hoeven was also behind the push for that assessment.

He believes that in time, the Tyler could have the same effect on investment that the Bakken and Three Forks had.

In a September 2014 presentation, Lynn Helms, director of the North Dakota Industrial Commission’s department of mineral resources, outline job growth for the formation through 2050. With the price of oil then relatively strong, Helms modeled production, gathering, fracking and drilling jobs. His presentation shows they would routinely top 1,500 by 2020.

Charts showed that rigs and wells would also increase, with roughly seven operating by 2020.

In May 2011, Hoeven persuaded then U.S. Interior Department Secretary Ken Salazar to initiate a new USGS study of the Williston. Hoeven wanted to create private-sector investment in infrastructure such as housing and retail.

By the time the report was released, the Williston Basin was already a powerhouse. North Dakota employment grew by 27.4% from 2008-2013, the highest rate in the nation, according to a February report by the International Monetary Fund.

After the 2013 USGS report, Hoeven said investment in infrastructure soared “directly related to transport of oil, but also roads and housing and retail establishments. It was very important.”

With lower energy prices, Hoeven said North Dakota can catch up to growth and develop a strategy to further reduces costs.

“An update of the resource through USGS is part of that planning,” he said. “This is going to be a long-term play.”

Darren Barbee can be reached at dbarbee@hartenergy.com.

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