scholarly journals A Petrographic Study of the Three Forks Formation (Upper Devonian), Williston Basin, North Dakota: Based on Thin Section Analysis, XRD and SEM

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Richard Ashu
Keyword(s):  
North Dakota ◽  
Thin Section ◽  
Williston Basin ◽  
Reservoir Quality ◽  
Three Forks Formation ◽  
Three Forks ◽  
Porosity And Permeability ◽  
Thin Section Analysis ◽  
Key Aspects ◽  
Petrographic Study

Deeply buried below 8,000 ft, the Three Forks Formation in North Dakota displays a variety of interesting diagenetic characteristics including dolomitization and hematite precipitation. Samples from three lithofacies are analyzed by thin section and SEM petrography and combined bulk and clay XRD analyses. Key aspects controlling the porosity and permeability of this formation are revealed by focusing on the detail mineralogy, rock type and diagenetic mineral distribution, and overall reservoir quality. Results prove that the Three Forks mineralogy is dominated by dolomite, along with substantial hematite, monocrystalline quartz, and mica flakes with trace feldspar, calcite, and pyrite. Clays mainly consist of illite together with minor chlorite and kaolinite and are associated with the scattered clasts. The reservoir quality is controlled by intercrystalline, rare microvuggy, and microporosity types that result from diagenetic and depositional events. Three stages of the dolomitization process are identified and discussed. Our hypothesis is that dolomitization commenced soon after deposition and was pervasive as no original carbonate texture is detectable.

scholarly journals Organic compounds in produced waters from the Bakken Formation and Three Forks Formation in the Williston Basin, North Dakota

Heliyon ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. e03590
Author(s):  
Matthew S. Varonka ◽  
Tanya J. Gallegos ◽  
Anne L. Bates ◽  
Colin Doolan ◽  
William H. Orem
Keyword(s):  
North Dakota ◽  
Organic Compounds ◽  
Williston Basin ◽  
Bakken Formation ◽  
Three Forks Formation ◽  
Three Forks ◽  
Produced Waters

Completing the Second Target: Finding Optimal Completion Practices for the Three Forks Formation in the Williston Basin Using Multivariate Statistical Analysis

2015 ◽  
Author(s):  
Brandon Williams ◽  
Brian Weaver ◽  
Leen Weijers
Keyword(s):  
Statistical Analysis ◽  
North Dakota ◽  
Horizontal Wells ◽  
Production Performance ◽  
Outcome Variable ◽  
Williston Basin ◽  
The North ◽  
Three Forks Formation ◽  
Three Forks ◽  
Multiple Variables

Abstract The Three Forks Formation in the Williston Basin has started to see a large increase in activity in the past six years. This is largely due to the shallower Bakken Formation transitioning into an infill development mode and operators looking at finding incremental reserves from the Three Forks Formation below. The objective of this paper is to evaluate the geological and completion variables of Three Forks horizontal wells in the North Dakota portion of the Williston Basin, and show which factors impact production performance using multivariate statistics. A financial evaluation of the completion factors will also be presented to show which variables have the biggest impact on production. A database of available completion and geological data has been assembled from the North Dakota Industrial Commission (NDIC) website. To date there are roughly 2,400 horizontal wells targeting the Three Forks Formation on the North Dakota side of the Williston Basin. Some of the variables collected include number of fracture stages, amount and type of proppant, total volume and type of frac fluid, lateral length, max treatment pressure and rate, API oil gravity, formation thickness (from formation tops) and production. The data was subjected to multivariate nonlinear statistical analysis. This type of analysis allows for simultaneously comparing multiple variables to one outcome variable. In this case study the outcome variable is 180-day production. Using multivariate analysis in the Three Forks Formation of the Williston Basin will aid in predicting production in different parts of the basin and finding which controllable completion variables have the most significant impact on production. The output can also aid in production forecasting based on changes to treatment designs.

scholarly journals Sedimentology, petrography, and reservoir quality of the Zarga and Ghazal formations in the Keyi oilfield, Muglad Basin, Sudan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yousif M. Makeen ◽  
Xuanlong Shan ◽  
Habeeb A. Ayinla ◽  
Ekundayo Joseph Adepehin ◽  
Ndip Edwin Ayuk ◽  
...  
Keyword(s):  
Thin Section ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Coarse Grained ◽  
Reservoir Quality ◽  
Research Attention ◽  
Sequence Composition ◽  
Exploration And Production ◽  
Authigenic Mineral ◽  
Thin Section Analysis

AbstractThe Zarga and Ghazal formations constitute important reservoirs across the Muglad Basin, Sudan. Nevertheless, the sedimentology and diagenesis of these reservoir intervals have hitherto received insignificant research attention. Detailed understanding of sedimentary facies and diagenesis could enhance geological and geophysical data for better exploration and production and minimize risks. In this study, subsurface reservoir cores representing the Zarga formation (1114.70–1118.50 m and 1118.50–1125.30 m), and the Ghazal formation (91,403.30–1406.83 m) were subjected to sedimentological (lithofacies and grain size), petrographic/mineralogic (thin section, XRD, SEM), and petrophysical (porosity and permeability) analyses to describe their reservoir quality, provenance, and depositional environments. Eight (8) different lithofacies, texturally characterized as moderately to well-sorted, and medium to coarse-grained, sub-feldspathic to feldspathic arenite were distinguished in the cored intervals. Mono-crystalline quartz (19.3–26.2%) predominated over polycrystalline quartz (2.6–13.8%), feldspar (6.6–10.3%), and mica (1.4–7.6%) being the most prominent constituent of the reservoir rocks. Provenance plot indicated the sediments were from a transitional continental provenance setting. The overall vertical sequence, composition, and internal sedimentary structures of the lithofacies suggest a fluvial-to-deltaic depositional environment for the Ghazal formation, while the Zarga formation indicated a dominant deltaic setting. Kaolinite occurs mainly as authigenic mineral, while carbonates quantitatively fluctuate with an insignificant amount of quartz overgrowths in most of the analyzed cores. Integration of XRD, SEM, and thin section analysis highlights that kaolinite, chlorite, illite, and smectite are present as authigenic minerals. Pore-destroying diagenetic processes (e.g. precipitation, cementation, and compaction etc.) generally prevailed over pore-enhancing processes (e.g. dissolution). Point-counted datasets indicate a better reservoir quality for the Ghazal formation (ɸ = 27.7% to 30.7%; K = 9.65 mD to 1196.71 mD) than the Zarga formation (17.9% to 24.5%; K = 1051.09 mD to 1090.45 mD).

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

Fact Sheet ◽  
2013 ◽  
Author(s):  
Stephanie B. Gaswirth ◽  
Kristen R. Marra ◽  
Troy A. Cook ◽  
Ronald R. Charpentier ◽  
Donald L. Gautier ◽  
...  
Keyword(s):  
South Dakota ◽  
North Dakota ◽  
Williston Basin ◽  
Oil Resources ◽  
Three Forks
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