While oil production in North Dakota could more than quadruple by 2025 to more than 2 million b/d, natural gas could do even better, gaining by nearly six times over current production to 3.1 Bcf/d, according to an analysis commissioned by the state's Pipeline Authority and performed by Bentek Energy LLC.
The natural gas-to-oil production ratio in the basins gets larger with age. "The reservoir engineering review indicates that the Bakken and Three Forks oil decline curves are steeper than the associated gas decline curves," Bentek said in its 129-page report. "The primary driver is the falling reservoir pressure in the Bakken and Three Forks formations. As the pressure in the reservoir declines and reaches its bubble point pressure, the natural gas that is dissolved in the oil will escape, allowing it to be captured in the gas stream."
A similar rising gas-to-oil ratio (GOR) has been observed in the Montana portion of the Williston Basin, according to the report.
In addition to its base case, Bentek provided low and high case scenarios, which predicted 2025 gross gas production of 2.01 Bcf/d and 3.8 Bcf/d, respectively. This compares with the 536 MMcf/d produced in 2011. It would "push the basin into a more leading role in supplying the U.S. natural gas market." The analysis also suggested that natural gas liquids content may rise as reservoir pressure falls, but the analysis of a subset of wellhead data was "inconclusive."
The North Dakota Pipeline Authority requested the analysis to determine if adequate natural gas pipeline infrastructure exists in the state, Bentek said.
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