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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Correlation and Stratigraphic Analysis of the Bakken and Sappington Formations in Montana

Adiguzel, Zeynep 1986- 14 March 2013 (has links)
The Upper Devonian-Lower Mississippian (Late Fammenian-Tournaisian) Bakken Formation in the Williston Basin is one of the largest continuous oil fields in the U.S. The upper and the lower shale members are organic rich source rocks that supplied oil to the middle member, which is reservoir rock. Although the oil-producing Bakken Formation has been intensely studied in the Williston Basin, the lateral relationship between the Bakken Formation and the coeval Sappington Formation in western Montana remains cryptic. This study correlates the Sappington Formation in western Montana with the Bakken Formation in the Williston Basin in northeastern Montana. It clarifies the lateral relationship between these two units, and extent of their members across Montana and, the causes of these thickness variations. This study utilized 675 well logs (mostly gamma ray, caliper, sonic, density, neutron, resistivity logs) to make multiple E-W and N-S cross sections and isopach maps. Also, seven outcrops of the Sappington Formation in southwestern Montana and five Bakken Formation cores in the Williston Basin were tied to the subsurface data. Variations in the distribution of the Bakken/Sappington Formation were caused by eustatic changes and local epeirogenic uplifts. The Bakken/Sappington Formation is thickest in the depressions in southwestern and the northeastern Montana, the Central Montana Trough and the Williston Basin in Montana. The Bakken/Sappington Formation is thin coincident with major structural uplifts that were active during the Late Devonian, such as Yellowstone Park Uplift, Bearpaw Anticline, Scapegoat-Bannatyne Anticline and Nesson Anticline. Devonian strata are difficult to identify in the subsurface of south-central Montana making the Bakken/Sappington correlation problematic in this area. The Lower Bakken/Sappington Member thickness is 15 ft (4.6 m) in northeastern and southwestern Montana. The Lower Bakken/Sappington Member is more continuous in western Montana than the other Bakken/Sappington Members. The Middle Bakken/Sappington Member is thickest (~55 ft; 16.7 m) in the northeastern Williston Basin and in the Central Montana Trough (~50 ft; 15.2 m). The Middle Bakken/Sappington Member was less affected by the tectonics and it is present from northwestern to northeastern Montana, except in far northwestern and central Montana. The Upper Bakken Member (~5-15 ft; 1.5 m-4.6 m) is the most continuous unit in the Williston Basin, as the Bakken Members show onlapping relationship that makes the distribution of each younger member greater. However, the Upper Bakken/Sappington Member is absent west of the Central Montana Trough due to basin inversion and it is also absent in far northwestern and central Montana as a result of the erosion or nondeposition caused by the local uplifts. Transgressions were responsible for the deposition of the upper and the lower black shales in offshore marine environments, whereas the Middle Bakken/Sappington Member was deposited during regression and records multiple offshore marine to tidal environments.
2

Bakken Shale Oil Production Trends

Tran, Tan 2011 May 1900 (has links)
As the conventional reservoirs decrease in discovering, producing and reserving, unconventional reservoirs are more remarkable in terms of discovering, development and having more reserve. More fields have been discovered where Barnett Shale and Bakken Shale are the most recently unconventional reservoir examples. Shale reservoirs are typically considered self-sourcing and have very low permeability ranging from 10-100 nanodarcies. Over the past few decades, numerous research projects and developments have been studied, but it seems there is still some contention and misunderstanding surrounding shale reservoirs. One of the largest shale in the United State is the Bakken Shale play. This study will describe the primary geologic characteristics, field development history, reservoir properties,and especially production trends, over the Bakken Shale play. Data are available for over hundred wells from different companies. Most production data come from the Production Data Application (HDPI) database and in the format of monthly production for oil, water and gas. Additional 95 well data including daily production rate, completion, Pressure Volume Temperature (PVT), pressure data are given from companies who sponsor for this research study. This study finds that there are three Types of well production trends in the Bakken formation. Each decline curve characteristic has an important meaning to the production trend of the Bakken Shale play. In the Type I production trend, the reservoir pressure drops below bubble point pressure and gas releasingout of the solution. With the Type II production trend, oil flows linearly from the matrix into the fracture system, either natural fracture or hydraulic fracture. Reservoir pressure is higher than the bubble point pressure during the producing time and oil flows as a single phase throughout the production period of the well. A Type III production trend typically has scattering production data from wells with a different Type of trend. It is difficult to study this Type of behavior because of scattering data, which leads to erroneous interpretation for the analysis. These production Types, especially Types I and II will give a new type curve matches for shale oil wells above or below the bubble point.
3

Sedimentology, ichnology and sequence stratigraphy of the upper Devonian-lower Carboniferous Bakken Formation in the southeastern corner of Saskatchewan

2015 March 1900 (has links)
The Upper Devonian-Lower Carboniferous Bakken Formation is present in the subsurface of the Williston Basin in northeastern Montana, North Dakota, southwestern Manitoba and southern Saskatchewan. In the southeastern corner of Saskatchewan, the Bakken Formation either conformably overlies the Upper Devonian Big Valley Formation or unconformably overlies the Torquay Formation, and is conformably overlain by the Lower Carboniferous Souris Valley (Lodgepole) Formation. The Bakken Formation typically includes three members: the lower and upper organic-rich black shale, and the middle calcareous/dolomitic sandstone and siltstone, which makes a “perfect” petroleum system including source rock, reservoir, and seal all within the same formation. According to detailed core analysis in the southeastern corner of Saskatchewan, the Bakken Formation is divided into eight facies, and one of which (Facies 2) is subdivided into two subfacies: Facies 1 (planar cross-stratified fine-grained sandstone); Facies 2A (wavy- to flaser-bedded very fine-grained sandstone); Facies 2B (thinly parallel-laminated very fine-grained sandstone and siltstone); Facies 3 (parallel-laminated very fine-grained sandstone and muddy siltstone); Facies 4 (sandy siltstone); Facies 5 (highly bioturbated interbedded very fine-grained sandstone and siltstone); Facies 6 (interbedded highly bioturbated sandy siltstone and micro-hummocky cross-stratified very fine-grained sandstone); Facies 7 (highly bioturbated siltstone); and Facies 8 (black shale). Our integrated sedimentologic and ichnologic study suggests that deposition of the Bakken occurred in two different paleoenvironmental settings: open marine (Facies 4 to 8) and brackish-water marginal marine (Facies 1 to 3). The open-marine facies association is characterized by the distal Cruziana Ichnofacies, whereas the brackish-water marginal-marine facies association is characterized by the depauperate Cruziana Ichnofacies. Isochore maps shows that both open-marine and marginal-marine deposits are widely distributed in this study area, also suggesting the existence of a N-S trending paleo-shoreline. The Bakken strata in this study area represent either one transgressive systems tract deposits or two transgressive systems tracts separated by a coplanar surface or amalgamated sequence boundary and transgressive surface. This surface has been identified in previous studies west-southwest of our study area, therefore assisting in high-resolution correlation of Bakken strata.
4

Estimation of Increased Traffic on Highways in Montana and North Dakota due to Oil Development and Production

Dybing, Alan Gabriel January 2012 (has links)
Advances in oil extraction technology such as hydraulic fracturing have improved capabilities to extract and produce oil in the Bakken and Three Forks shale formations located in North Dakota, Montana, Manitoba, and Saskatchewan. From 2004 to the present, there has been a significant increase in oil rigs and new oil wells in these areas, resulting in increased impacts to the local, county, state, and federal roadway network. Traditional methods of rural traffic forecasting using an established growth rate are not sufficient under the changing traffic levels. The goal of this research is to develop a traffic model that will improve segment specific traffic forecasts for use in highway design and planning. The traffic model will consist of five main components: 1) a Geographic Information Systems (GIS) network model of local, county, state and federal roads, 2) a truck costing model for use in estimating segment specific user costs, 3) a spatial oil location model to estimate future oil development areas, 4) a series of mathematical programming models to optimize a multi-region oil development area for nine individual input/output movements, and 5) an aggregation of multiple routings to segment specific traffic levels in a GIS network model.
5

Sensitivity of seismic reflections to variations in anisotropy in the Bakken Formation, Williston Basin, North Dakota

Ye, Fang, geophysicist. 25 October 2010 (has links)
The Upper Devonian–Lower Mississippian Bakken Formation in the Williston Basin is estimated to have significant amount of technically recoverable oil and gas. The objective of this study is to identify differences in the character of the seismic response to Bakken interval between locations with high and poor production rates. The predicted seismic responses of the Bakken Formation will hopefully help achieve such discrimination from surface seismic recordings. In this study, borehole data of Bakken wells from both the Cottonwood and the Sanish Field were analyzed, including density information and seismic P and S wave velocities from Sonic Scanner logs. The Bakken Formation is deeper and thicker (and somewhat more productive) in the Sanish Field and is shallower and thinner in the Cottonwood Field. The Upper and Lower Bakken shale units are similar and can be characterized by low density, low P and S wave velocities and low Vp/Vs ratios. The Sonic Scanner data suggest that the Upper and Lower Bakken shales can be treated as VTI media while the Middle Bakken may be considered as seismically isotropic. Models of seismic response for both fields were constructed, including isotropic models and models with variations in VTI, HTI, and the combination of VTI and HTI in the Bakken intervals. Full offset elastic synthetic seismograms with a vertical point source were generated to simulate the seismic responses of the various models of Bakken Formation. This sensitivity study shows pronounced differences in the seismic reflection response between isotropic and anisotropic models. P-P, P-SV and SV-SV respond differently to anisotropy. VTI anisotropy and HTI anisotropy of the Bakken have different character. In particular, types of seismic data (P-P, P-SV, and SV-SV) and the range of source-receiver offsets that are most sensitive to variations in anisotropic parameters and fluid saturation were identified. Results suggest that bed thickness, anisotropy of the Upper and Lower Bakken shales, fractures/cracks and fluid fill in the fracture/cracks all influence the seismic responses of the Bakken Formation. The paucity of data available for “poorly” producing wells limited the evaluation of the direct seismic response to productivity, but sensitivity to potentially useful parameters was established. / text
6

Reservoir simulation and optimization of CO₂ huff-and-puff operations in the Bakken Shale

Sanchez Rivera, Daniel 10 October 2014 (has links)
A numerical reservoir model was created to optimize CO₂ Huff-and-Puff operations in the Bakken Shale. Huff-and-Puff is an enhanced oil recovery treatment in which a well alternates between injection, soaking, and production. Injecting CO₂ into the formation and allowing it to “soak” re-pressurizes the reservoir and improves oil mobility, boosting production from the well. A compositional reservoir simulator was used to study the various design components of the Huff-and-Puff process in order to identify the parameters with the largest impact on recovery and understand the reservoir’s response to cyclical CO₂ injection. It was found that starting Huff-and-Puff too early in the life of the well diminishes its effectiveness, and that shorter soaking periods are preferable over longer waiting times. Huff-and-Puff works best in reservoirs with highly-conductive natural fracture networks, which allow CO₂ to migrate deep into the formation and mix with the reservoir fluids. The discretization of the computational domain has a large impact on the simulation results, with coarser gridding corresponding to larger projected recoveries. Doubling the number of hydraulic fractures per stage results in considerably greater CO₂ injection requirements without proportionally larger incremental recovery factors. Incremental recovery from CO₂ Huff-and-Puff appears to be insufficient to make the process commercially feasible under current economic conditions. However, re-injecting mixtures of CO₂ and produced hydrocarbon gases was proven to be technically and economically viable, which could significantly improve profit margins of Huff-and-Puff operations. A substantial portion of this project involved studying alternative numerical methods for modeling hydraulically-fractured reservoir models. A domain decomposition technique known as mortar coupling was used to model the reservoir system as two individually-solved subdomains: fracture and matrix. A mortar-based numerical reservoir simulator was developed and its results compared to a tradition full-domain finite difference model for the Cinco-Ley et al. (1978) finite-conductivity vertical fracture problem. Despite some numerical issues, mortar coupling closely matched Cinco-Ley et al.'s (1978) solution and has potential applications in complex problems where decoupling the fracture-matrix system might be advantageous. / text
7

Sedimentology, ichnology, and stratigraphic architecture of the upper Devonian-lower Mississippian Bakken Formation, west-central Saskatchewan

2015 June 1900 (has links)
The Upper Devonian-Lower Mississippian Bakken Formation has recently become a prolific producer of light gravity oil in southeastern Saskatchewan since the advent of horizontal drilling and multi-stage hydraulic fracture technologies, which has resulted in an increase in geological studies within the area. However, the Bakken Formation of west-central Saskatchewan has been producing heavy oil since the 1950s, and has comparatively received much less attention than its southeastern counterpart. The Bakken Formation is the youngest member of the Three Forks Group and unconformably overlies the Big Valley Formation. In west-central Saskatchewan, the Bakken Formation can be conformably overlain by the Mississippian carbonates of the Madison Group or unconformably overlain by the Lower Cretaceous Mannville Group. A tripartite subdivision is applied to the Bakken Formation, with a mixed clastic/carbonate Middle Member deposited between Lower and Upper Black Shale Members. Based on detailed core description, eight facies have been defined for the Bakken Formation of west-central Saskatchewan: Facies 1 (Lower and Upper Black Shale members), Facies 2 (bioturbated siltstone/sandstone), Facies 3 (wave-rippled sandstone), Facies 4 (bioclastic grainstone), Facies 5 (interbedded mudstone, siltstone, and very fine-grained sandstone), Facies 6 (very fine- to fine-grained sandstone), Facies 7 (bioturbated siltstone/sandstone), and Facies 8 (massive and brecciated siltstone). Deposition of the Bakken Formation in west-central Saskatchewan occurred under either open-marine or marginal-marine conditions. Facies association 1 (open-marine interval), which is made up of F1 through F4, is characterized by the distal Cruziana Ichnofacies. It was deposited within a wave-dominated shallow-marine depositional environment. Facies association 2 (marginal-marine interval), which is comprised of F5 through F8, shows scarce biogenic structures, most likely as a result of brackish-water conditions. Geological mapping (structure surface and isopach) of the facies and facies associations has aided in illustrating their lateral distribution. However, mapping of the overlying Mississippian carbonates and sub-Mesozoic unconformity shows that post-Mississippian erosion was a controlling factor in the distribution and preservation of Bakken Formation deposits, which creates uncertainty when interpreting geological maps and stratigraphic cross-sections. Although post-Mississippian erosion causes problems when reconstructing the depositional history and stratigraphic architecture of the Bakken Formation, it illustrates the importance of not performing stratigraphic studies within a vacuum, only focusing on the formation of interest. Rather, underlying and overlying units must be studied to see whether or not the unit of interest’s deposition and distribution has been affected by pre- and post-depositional events.

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