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dc.contributor.advisorSonnenberg, Stephen A.
dc.contributor.authorGutierrez, Claudia
dc.contributor.committeememberHendricks, Michael L.
dc.contributor.committeememberHumphrey, John D.
dc.date.accessioned2007-01-03T06:05:45Z
dc.date.available2015-02-01T04:18:44Z
dc.date.issued2014
dc.date.submitted2014
dc.description2014 Spring.
dc.descriptionIncludes illustrations (some color), color maps.
dc.descriptionIncludes bibliographical references (pages 135-138).
dc.description.abstractThe Three Forks Formation is an important hydrocarbon reservoir in the Williston Basin, North Dakota. High production rates associated with new drilling and completion techniques has created interest in this formation. Core data have increased an understanding of depositional environments, facies distribution, and other parameters that impact reservoir quality. Six cores were described in detail and additional 23 wells were evaluated to propose a depositional model for the Three Forks Formation. The upper Devonian Three Forks Formation was deposited on a shallow and extensive epeiric platform. During the late Devonian, an arid climate and sea level changes controlled deposition across a storm and tidal-dominated, evaporitic platform. Stacked cyclic patterns are evident in cores as well as logs, especially the gamma ray. The Three Forks Formation is a mud-dominated system composed of dolomitic siltstones, claystone, and mudstone. Dolomitic siltstones are tan-brown, while claystones and mudstones exhibit colors that range from gray-green to red. The reddish color is a product of erosion, weathering, and oxidation. Six facies were identified and described for the Three Forks Formation. Facies F and Facies E are in the lower part of the Three Forks Formation. These facies are bedded and massive dolomitic mudstone and dolomitic claystone with varying amounts of displacive anhydrite nodules and anhydritic laminations. The Lower Three Forks was deposited in arid environments. Evaporitic minerals and exposure and weathering features common in mudflats, salinas, and sabkhas are common. On the epeiric platform, The Lower Three Forks was deposited in a low energy zone that negatively impacted reservoir quality. Typical facies associations in the Middle Three Forks include Facies C and Facies A. Facies C is mud-supported breccias and Facies A is laminated dolomitic siltstone. The Middle Three Forks was deposited in proximal inner shelf environments. The Middle Three Forks marks a transition from sabkha to slightly deeper intertidal areas, with higher influence of storm and tidal processes. Upper Three Forks facies associations are Facies C, B, and A. These facies are laminated to massively bedded dolomite and interlaminated mudstone. The upper part of Three Forks has abundant dolomite and sparse to common clay (shale). The Upper Three Forks was deposited in distal inner shelf to proximal mid-shelf environments where higher depositional energies were common. This explains, in part, the low clay content, bigger dolomite crystals and detrital grain sizes, and enhanced reservoir quality in this interval. SML methodology (Stratigraphic Modified Lorentz Plots) was used to define reservoir quality. In North Dakota, a series of wells (14), with core data analysis available were plotted using this methodology to obtain slope trends for flow units. The slopes obtained in the productive intervals in the Upper Three Forks (slopes with angles of approximately 45 degrees) are also present in the Middle and Lower Three Forks. The SML methodology showed better reservoir quality in the Upper Three Forks than in the Middle and Lower Three Forks. Porosity-permeability and irreducible oil-irreducible water saturation plots were also constructed using available core data. These showed the best reservoir quality in the Upper Three Forks. Digenesis was also examined using thin section analyses from a well that cored the entire Three Forks interval (EOG Liberty 2-11H). The Lower Three Forks has significantly more calcite and anhydrite cementation, oxidation, and anhydrite. Collectively, these components have a negative effect on reservoir quality. In the Middle and the Upper part of Three Forks, dolomitization affects reservoir quality in a positive way, enhancing both porosity and permeability. Mineralogy also affects reservoir quality. An increase in calcite decreases reservoir quality while an increase in dolomite is associated with better reservoir quality and higher production in the Upper Three Forks. Three Forks production is influenced by thermal maturity of the Bakken Formation. The up-dip thermal boundary of the petroleum system ties directly to thermal maturity of the Lower Bakken Shale. In summary, the reservoir quality in Three Forks Formation depends on the interplay of factors such as depositional environment, mineralogical composition, diagenetic processes, and factors affecting petroleum generation and entrapment. These have a profound impact on porosity, permeability, and productivity.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierT 7419
dc.identifier.urihttp://hdl.handle.net/11124/294
dc.languageEnglish
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2014 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.rights.access1-year embargo
dc.subjectstratigraphic modified Lorentz plots
dc.subjectdepositional environment
dc.subjectThree Forks
dc.subjectreservoir quality
dc.subjectreservoir characterization
dc.subjectflow units
dc.subject.lcshGeology, Stratigraphic
dc.subject.lcshGeology -- Williston Basin
dc.subject.lcshFacies (Geology) -- North Dakota
dc.subject.lcshHydrocarbon reservoirs -- North Dakota
dc.subject.lcshDiagenesis -- North Dakota
dc.subject.lcshWilliston Basin
dc.titleStratigraphy and petroleum potential of the upper Three Forks Formation, North Dakota, Williston Basin, USA
dc.typeText
dcterms.embargo.expires2015-02-01
thesis.degree.disciplineGeology and Geological Engineering
thesis.degree.grantorColorado School of Mines
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)


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