Assessment of undiscovered oil resources in the Bakken and Three Forks Formations, Williston Basin Province, Montana, North Dakota, and South Dakota, 2013

Abstract

Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered volumes of 7.4 billion barrels of oil, 6.7 trillion cubic feet of associated/dissolved natural gas, and 0.53 billion barrels of natural gas liquids in the Bakken and Three Forks Formations in the Williston Basin Province of Montana, North Dakota, and South Dakota. is defined by the postulated maximum extent of petroleum fluids within the Bakken and Three Forks Formations. The Devonian and Mississippian Bakken Formation consists of four members in ascending order: (1) the Pronghorn Member (formerly known as "Sanish sand") (LeFever and others, 2011), (2) lower shale member, (3) middle member, and (4) upper shale member. The sandstones and siltstones of the Pronghorn Member represent the first transgressive unit of the Bakken Formation and are limited in extent. The maximum thickness of the Pronghorn is 58 feet (LeFever and others, 2011). The upper and lower shale members are the primary source rocks for the Bakken TPS, with present-day total organic carbon (TOC) values from <1 weight percent to 35 weight percent (Lillis, 2013). The shale members are present in parts of Montana and North Dakota and extend into the Canadian provinces of Saskatchewan and Manitoba, though the Canadian provinces were not assessed. The lower shale member reaches a maximum thickness of 56 feet along the east flank of the Nesson anticline (fig. 1). The middle member of the Figure 1. Map showing the Williston Basin Province, Bakken Total Petroleum System (TPS), and the Bakken Formation Assessment Units (AUs). Major structural features are also shown. Inset map shows location of the Bakken TPS (pink).

Quality and Age of Shallow Groundwater in the Bakken Formation Production Area, Williston Basin, Montana and North Dakota

“…The Devonian and Mississippian Bakken Formation and Devonian Three Forks Formation in the Williston Basin Province of Montana, North Dakota, and South Dakota contain the largest known unconventional oil resource in the United States (Gaswirth et al ; Gaswirth and Marra ). Horizontal drilling and hydraulic fracturing technologies have made extraction of that oil economically feasible, resulting in extensive drilling and production activities in the area.…”

“…Horizontal drilling and hydraulic fracturing technologies have made extraction of that oil economically feasible, resulting in extensive drilling and production activities in the area. Since 2008, more than 5000 oil and gas wells have been drilled in the Bakken Formation in Montana and North Dakota (Gaswirth and Marra ). Although development of conventional oil and gas resources in the basin has been ongoing since about the early 1950s (Gerhard et al ), the recent rapid and widespread development of unconventional oil and gas resources has raised concerns about the potential effects of energy development on groundwater quality in the Bakken Formation production area.…”

Conventional Oil—The Forgotten Part of the Water‐Energy Nexus

“…Brine leakage into shallow aquifers from conventional oil wells, brine injection wells, and/or surface storage facilities and pipelines, has contaminated over 31 km 2 of groundwater in and near the East Poplar Oil Field in northeastern Montana (Thamke and Smith ). It is notable that this contamination has been attributed to conventional oil development in formations overlying the unconventional Bakken Shale oil play (Gaswirth et al ).…”

Impacts of Bakken Shale Oil Development on Regional Water Uses and Supply

“…The Bakken and Three Forks Formations in the Williston Basin Province of Montana, North Dakota, and South Dakota, the largest known unconventional oil reserves in the U.S. (Gaswirth et al ., ; Gaswirth and Marra, ), are located in a semiarid region (Carter et al ., ). In western North Dakota, the first Bakken horizontal well was drilled in 2004 and, since 2008, the so‐called “Bakken crude” started to dominate oil production from other plays in North Dakota as shown in Figure .…”