Three Forks Formation
The Bakken's Deeper Sibling - 7.4 Billion Barrels Combined Resource
Location
Key Reservoir Properties
Upper Devonian
Dolomite, siltstone, shale
9,000 - 11,500 ft
250 ft
4-10%
42.0° API
10,000,000 acres
4,300.0 MM bbls
Executive Summary
The Three Forks Formation represents the next frontier in Williston Basin development—a deeper unconventional target directly beneath the prolific Bakken Shale. With the Bakken in a mature phase, operators are increasingly looking to the Three Forks for future growth.
Key highlights:
- USGS Estimate: 4.3 billion barrels of oil (combined Bakken/Three Forks: 7.4 billion barrels)
- Wells Drilled: ~8,000 horizontal wells through mid-2023
- Middle Three Forks: Showing 1-2 MMbbl EUR uplift vs. adjacent units
- Major Activity: Continental Resources, ConocoPhillips, Chord Energy leading development
With 80% of Devon Energy's Grayson Mill acquisition in the Bakken and 20% in Three Forks, major operators are betting on this deeper target.
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Historical Background
Early History and Discovery
The Three Forks Formation was identified as a potential target during the early development of the Bakken play, as the formations are stratigraphically connected—the lower Bakken shale acts as a seal for the upper Three Forks reservoir.
Three Forks Development Timeline
| 2008-2010 | Initial Three Forks testing alongside Bakken development |
| 2013 | USGS releases combined Bakken/Three Forks assessment: 7.4 billion barrels |
| 2015-2020 | Upper Three Forks becomes standard completion target |
| 2020-2023 | Middle Three Forks development accelerates, ~340 wells drilled |
| 2024 | Devon's $5B Grayson Mill acquisition includes 300 Three Forks refrac candidates |
2024 Industry Activity
- Chord Energy: $4 billion Enerplus merger creates largest Williston operator (1.3 million net acres, 287,000 BOE/d)
- Devon Energy: $5 billion Grayson Mill acquisition adds 500 gross locations (20% Three Forks)
- Continental Resources: ~125 new wells planned, advancing EOR projects
- Hess: Maintaining 200,000 BOE/d for 8-10 years from Bakken/Three Forks
Geological Characteristics
Reservoir Properties
The Three Forks Formation is a Devonian-age dolomite and siltstone sequence directly underlying the Bakken Shale. It is subdivided into upper, middle, and lower benches.
Three Forks Reservoir Properties
Stratigraphic Benches
- Upper Three Forks: Most developed bench, ~8,000 wells, closest to Bakken
- Middle Three Forks: ~340 wells, showing strong EUR uplift
- Lower Three Forks: <50 wells, least developed but potential upside
Middle Three Forks Potential
A 2024 Hart Energy study of 25 DSUs in northeastern McKenzie County found that 17 units with middle Three Forks wells showed 1-2 MMbbl uplift in EUR compared to adjacent units without middle Three Forks development.
Drilling & Completion Economics
Estimated Well Costs (2024)
Completion Design
Three Forks completions are similar to Bakken, with some operators using larger frac jobs to access the tighter dolomite:
- Lateral Length: 10,000 - 15,000 ft (trending longer)
- Frac Stages: 40-60+ stages
- Proppant Loading: 2,000-3,000 lbs per lateral foot
Production Decline Characteristics
Like the Bakken above it, Three Forks wells experience steep decline:
- Year 1 Decline: 70-78% from initial production
- Year 2 Decline: 85-88% cumulative from IP
- Requires continuous drilling to maintain production
Production Decline Analysis
The Shale Decline Reality
While industry headlines tout record production, the underlying data reveals a critical truth: shale wells experience dramatic production declines that require constant drilling just to maintain output. This creates a "treadmill" effect where massive capital expenditure is needed simply to prevent production collapse.
Industry Expert Analysis
"New wells drilled in 2023 may ultimately produce roughly half of what new wells from 2019 will ultimately produce. The industry is sacrificing future production to maximize short-term output."
— Art Berman, Petroleum Geologist (40+ years experience)The Lateral Length Paradox
Since 2014, the industry has nearly tripled average lateral lengths from 5,000 ft to 14,000+ ft. While this increases initial production rates, it also accelerates decline—effectively using "wider straws" to drain reservoirs faster.
Declining Well Productivity (EUR)
Estimated Ultimate Recovery (EUR) per well has been declining since 2019. According to petroleum geologist Art Berman, Bakken EUR dropped approximately 50% from 2020 to 2023.
Key Investment Considerations
Decline Risks
- Hyperbolic Decline: 65-75% production loss in year 1 (vs 5-6% for conventional)
- Child Well Problem: 85% of new wells produce less than expected
- Inventory Exhaustion: Tier 1 acreage running out within 3-5 years
- Treadmill Economics: Continuous drilling required just to maintain output
Counter-Perspectives
- Technology continues improving operational efficiency
- Infill drilling potential may extend productive life
- Multi-zone development can maximize recovery
- Higher commodity prices improve economics on marginal wells
Decline Analysis Data Sources
- IEA - International Energy Agency, "The Implications of Oil and Gas Field Decline Rates" (2024)
- EIA - U.S. Energy Information Administration, Production Decline Curve Analysis
- SPE/JPT - Society of Petroleum Engineers, "Shale Wells Producing More Early On, Then Declining Faster Than Ever"
- Art Berman - Petroleum Geologist, artberman.com - Shale decline analysis
- David Hughes - Geoscientist, Post Carbon Institute - Shale production studies
- Goehring & Rozencwajg - Natural Resource Investors, Permian Basin analysis
- Novi Labs - Delaware Basin and shale well performance data
Remaining Potential & Future Opportunities
Development Potential
With an estimated 4.3 billion barrels of technically recoverable oil (USGS), the Three Forks offers significant remaining potential, particularly in the middle and lower benches.
Potential Opportunities
- Middle Three Forks: 1-2 MMbbl EUR uplift demonstrated
- Lower Three Forks: Minimally tested, potential upside
- Refrac Potential: 300+ candidates in Devon's acquisition
- Stacked Development: Bakken + Three Forks multi-zone
Key Risks
- Steep Decline: 70-78% first-year production loss
- Basin Maturity: Bakken in late-stage development
- Child Well Interference: Potential with stacked development
- EUR Degradation: Bakken showing declining well productivity
Investment Considerations
The Three Forks represents extension of Bakken inventory:
- Bakken Leverage: Same infrastructure, similar operations
- Incremental Returns: Middle Three Forks adds to DSU value
- Operator Quality: Major operators with track records active
- Decline Reality: Same steep decline as all tight oil plays
Conclusion
The Three Forks Formation represents a significant extension of Williston Basin tight oil inventory, offering operators additional targets beneath the maturing Bakken play.
Kingdom Exploration Assessment
Strengths
- USGS: 4.3 billion barrels recoverable
- Middle Three Forks: 1-2 MMbbl EUR uplift
- Premium crude: 42° API
- Major operator commitment (Devon, Chord, Continental)
- Existing Bakken infrastructure
Challenges
- Steep decline: 70-78% year-1 loss
- Bakken EUR declining by vintage
- Deeper = higher cost than Bakken
- Child well interference risk
- Basin in mature development phase
For operators already established in the Williston Basin, the Three Forks provides valuable inventory extension. The middle Three Forks in particular shows promise for incremental EUR improvement. However, investors should understand that the fundamental tight oil decline characteristics apply equally to Three Forks wells.
Data Sources & References
- USGS - Williston Basin Bakken and Three Forks Formations Assessment (2013, updated)
- Hart Energy - "Middle Three Forks Bench Holds Vast Untapped Oil Potential" (2024)
- Enverus Intelligence Research - Williston Basin operator analysis, Three Forks well data
- Devon Energy - Grayson Mill acquisition investor presentation
- Chord Energy - Enerplus merger and Williston Basin strategy
- Continental Resources - Williston Basin development updates
- North Dakota Department of Mineral Resources - Three Forks well and production data
- EIA - Drilling Productivity Report, Bakken region
- Pruitt, Sean - Owner, Kingdom Exploration. Research compilation and analysis.
Important Disclaimer
This geological review is provided for educational and informational purposes only. The author, Sean Pruitt, is not a licensed geologist. Information presented here has been compiled from publicly available sources including USGS reports, state geological surveys, academic publications, and industry data. Reservoir properties and production data represent ranges observed across productive areas and may vary significantly by location. Kingdom Exploration makes no representations or warranties regarding the accuracy, completeness, or reliability of this information for any specific purpose. This content does not constitute investment advice, geological consulting, or professional engineering recommendations. Investors and operators should conduct their own due diligence and consult qualified licensed professionals including petroleum geologists, reservoir engineers, and financial advisors before making any investment or operational decisions.
