• 2-D bed sediment transport modeling of a reach on the Sagavanirktok River, Alaska

      Ladines, Isaac A.; Toniolo, Horacio; Barnes, David; Schnabel, Bill (2019-05)
      Conducting a 2-D sediment transport modeling study on the Sagavanirktok River has offered great insight to bed sediment movement. During the summer of 2017, sediment excavation of two parallel trenches began in the Sagavanirktok River, in an effort to raise the road elevation of the Dalton Highway to remediate against future floods. To predict the time in which the trenches refill with upstream sediment a 2-D numerical model was used. Three scenarios: (1) a normal cumulative volumetric flow, (2) a max discharge event, and (3) a max cumulative volumetric flow, were coupled with three sediment transport equations: Parker, Wilcock-Crowe and Meyer Peter and Müller for a total of 9 simulations. Results indicated that scenario (1) predicted the longest time to fill, ranging from 1-6 years followed by scenario (2), an even shorter time, and scenario (3) showing sustained high flows have the capability to nearly refill the trenches in one year. Because the nature of this research is predictive, limitations exist as a function of assumptions made and the numerical model. Therefore, caution should be taken in analyzing the results. However, it is important to note that this is the first time estimates have been calculated for an extraction site to be refilled on the Sagavanirktok River. Such a model could be transformed into a tool to project filling of future material sites. Ultimately, this could expedite the permitting process, eliminating the need to move to a new site by returning to a site that has been refilled from upstream sediment.
    • 3-D modeling of interaction between a hydraulic fracture and multiple natural fractures using finite element analysis

      Talukder, Debashish; Awoleke, Obadare; Ahmadi, Mohabbat; Hanks, Catherine (2019-05)
      A three-layered, 3-D geo-mechanical model was developed using Finite Element Analysis (FEA) software (ABAQUS) to simulate single stage hydraulic fracturing treatment in a synthetic fractured model based on available shale information from literature. The main objectives of this study were- (i) to investigate the interaction between a hydraulic fracture (HF) orthogonally intersecting two parallel natural fractures (NF) and (ii) to identify significant parameters and their 2-factor interactions that affect HF propagation in the presence of multiple NFs. Based on literature review, an initial set of 20 parameters (a combination of geologic and drilling parameters) was selected. Those parameters were believed to affect the hydraulic fracture propagation in a naturally fractured model. Experiments were conducted in two stages. First-order order numerical experiments were conducted under the Plackett-Burman experimental design. Central Composite Design (CCD) was used to check curvature and to take care of non-linearity existing in the dataset. A stepwise sensitivity analysis and parametric study were conducted to identify significant parameters and their interactions. When the HF interacted with NFs, there were three possible outcomes- the HF either got arrested, dilated or crossed the NF. The overall hydraulic fracture geometry depended on the type of interaction behavior occurring at the intersection. The NF leakoff coefficient was the most significant factor in the 1st order experiments that affected the HF propagation in the presence of multiple NFs. CCD results suggested that NF strength at the bottom shale layer and injection fluid viscosity significantly influenced the HF opening in the presence of the natural fractures. The most significant two-factor interaction was the interaction between stress contrast and Young's modulus of the overburden shale (Ytop). This study will help understand the interaction behavior between a HF and two pre-existing NFs. The parametric study will provide a valuable insight for hydraulic fracturing treatment in a naturally fractured formation.
    • A Methodology For Intelligent Honeypot Deployment And Active Engagement Of Attackers

      Hecker, Christopher R.; Nance, Kara; Hay, Brian (2012)
      The internet has brought about tremendous changes in the way we see the world, allowing us to communicate at the speed of light, and dramatically changing the face of business forever. Organizations are able to share their business strategies and sensitive or proprietary information across the globe in order to create a sense of cohesiveness. This ability to share information across the vastness of the internet also allows attackers to exploit these different avenues to steal intellectual property or gather information vital to the national security of an entire nation. As technology advances to include more devices accessing an organization's network and as more business is handled via the internet, attackers' opportunities increase daily. Honeypots were created in response to this cyber warfare. Honeypots provide a technique to gather information about attackers performing reconnaissance on a network or device without the voluminous logs obtained by the majority of intrusion detection systems. This research effort provides a methodology to dynamically generate context-appropriate honeynets. Administrators are able to modify the system to conform to the target environment and gather the information passively or through increasing degrees of active scanning. The information obtained during the process of scanning the environment aids the administrator in creating a network topology and understanding the flux of devices in the network. This research continues the effort to defend an organization's networks against the onslaught of attackers.
    • Adsorption of Cu (II) and Cd (II) by chininous polymers

      Zhang, Hong (2006-12)
      Heavy metal contamination has emerged as a major health problem worldwide. Biosorption, using biological waste products as sorbents, may provide a cost effective treatment strategy. The current study investigated several types of biomass, generated from waste crab shells, as bio-sorbents to remove cadmium and copper in a batch reaction system. Isotherm studies suggested that uptake increased with increasing number of amine groups, i.e. increasing degree of deacetylation (DDA) as measured by hydrogen nuclear magnetic resonance (¹H-NMR) as well as Fourier Transform Infra-red (FTIR) spectroscopy. Potentiometric titration was shown not to be a valid method in measuring the DDA for medium DDA range. pH was proven to be a main factor affecting the adsorption because of the considerable competition of protons for the binding sites at low pH. Cu²+ had higher affinity than Cd²⁺ to the chitinous polymer. Metal adsorption was elevated by high ionic strength because of more adsorption sites becoming accessible as a result of significant expansion of the network under high ionic strength. Sulfate as salt, added in the solution, greatly stimulated the adsorption of metal ions by reducing the repulsion force between the charged surface and the metal cations.
    • Aerodynamic heating of the student rocket project-5 sounding rocket

      Mudunuri, Venkata; Goering, Douglas; Das, Debendra K.; Hawkins, Joseph (2005-05)
      This thesis deals with the calculation of the flow properties and heat transfer around the rocket nose cone for Student Rocket Project-5 (SRP-5). Governing differential equations are presented for this purpose, giving the fundamental relations between the skin temperature and flight history. The determination of all the required parameters in the equations is discussed, and the Runge-Kutta numerical method of integration is used to obtain the solution. A model to implement the above equations to predict skin temperature for the given trajectory was built in SIMULINK®. Individual sub-systems of the SIMULINK® model are used to calculate local tree-stream values, Reynolds number, heat absorption capacity and skin friction coefficient. The SIMULINK® model was used to predict the variation of the skin temperature for the SRP-5 flight trajectory. The simulation results also show comparisons of the different subsystem outputs with data provided by the contractor for the NASA Sounding Rocket Contract (NSROC).
    • Alaska Arctic coastal plain gravel pad hydrology: impacts to dismantlement removal and restoration operations ; a study on the human - hydrology relationship in Arctic environments

      Miller, Ori; Barnes, David L.; Stuefer, Svetlana L.; Shur, Yuri (2019-08)
      To guard against thawing permafrost and associated thaw subsidence, the oil facilities in the Arctic are constructed on gravel pads placed on top of the existing arctic tundra, however the impacts of this infrastructure to the sensitive hydrology are not fully understood. Production in some of the older fields is on the decline; however oil exploration in the Arctic Coastal Plain is resulting in the discovery and development of new reserves. In the coming years, old sites will need to be decommissioned as production transitions to new sites. New facilities will also need to be designed and constructed. Oil companies in Alaska have historically conducted operations under leases issued through the Alaska Department of Natural Resources. The leases stipulate that once resource extraction operations are completed, the facilities must be decommissioned and the sites restored, however they are often vague in their requirements and are variable in their specifics from lease to lease. As the oil companies transition to the new sites, decisions must be made regarding what should be done with vacated gravel pads. The construction of gravel pads essentially destroys underlying arctic tundra. In undisturbed areas in the Arctic, the tundra itself creates an insulating layer that limits the seasonal thaw depth to around 0.5 m. Removal of this layer causes thaw depths to greatly increase impacting the stability of the ground and the hydrology of the surrounding area. Because of this impact, other possible restoration techniques are being considered, such as vegetating and leaving the pads in place. Water movement is one of the major driving factors in the arctic contributing to permafrost degradation. Groundwater carries with it heat, which is transferred to the soil as the groundwater moves. Therefore, hydrology plays a major role in the stability of the arctic environment. This is especially relevant in areas where gravel pads exist. Gravel pads are anthropogenic structures that have significant water storage potential. Because of the unique conditions in the Arctic, pore-water flow through these gravel pads is not yet well understood. The purpose of this study is to develop a more complete scientific understanding of the driving forces behind pad pore-water movement. This study expands on fieldwork from a prior hydrological field study conducted by others. The prior study is expanded through this work by developing an associated groundwater model to the gravel pad from the field study to examine the flow through it and the controlling factors for this flow. The study site used for this project is located in Prudhoe Bay and is the pad constructed for the very first production well in Prudhoe Bay in 1968. This study demonstrates that it is the topography of the silt layer beneath the gravel pads that is the most significant factor controlling pad pore-water movement. The results from the modeling study will assist engineers and environmental scientists in better understanding the groundwater flow. This understanding will aid in the decommissioning and restoration process and help inform decision making in regards to the future of the existing pads. The results may also be used to inform the development of new infrastructure such that any new pads which are built may be constructed with their relationship to the local hydrology more in mind.
    • Altering the thermal regime of soils below heated buildings in the continuous and discontinuous permafrost zones of Alaska

      Perreault, Paul Vincent; Shur, Yuri; Hulsey, J. Leroy; Barnes, David; Ahn, Il Sang (2016-05)
      This research investigates the impacts of thermal insulation on the thermal regime of soils below heated buildings in seasonally and perennially frozen soils. The research provides practical answers (A) for designing frost‐protected shallow foundations in unfrozen soils of the discontinuous permafrost zone in Alaska and (B) shows that applying seasonal thermal insulation can reduce the risk of permafrost thawing under buildings with open crawl spaces, even in warming climatic conditions. At seasonal frost sites, this research extends frost‐protected shallow foundation applications by providing design suggestions that account for colder Interior Alaska’s air freezing indices down to 4 400 °C∙d (8,000 °F∙d). This research includes field studies at six Fairbanks sites, mathematical analyses, and finite element modeling. An appendix includes frost‐protected shallow foundation design recommendations. Pivotal findings include the discovery of more pronounced impacts from horizontal frost heaving forces than are likely in warmer climates. At permafrost sites, this research investigates the application of manufactured thermal insulation to buildings with open crawl spaces as a method to preserve soils in the frozen state. This research reports the findings from using insulation to reduce permafrost temperature, and increase the bearing capacity of permafrost soils. Findings include the differing thermal results of applying insulation on the ground surface in an open crawl space either permanently (i.e., left in place), or seasonally (i.e., applied in warm months and removed in cold months). Research includes fieldwork in Fairbanks, and finite element analyses for Fairbanks, Kotzebue, and Barrow. Pivotal findings show that seasonal thermal insulation effectively cools the permafrost. By contrast, Fairbanks, Kotzebue, and Barrow investigations show that permanently applied thermal insulation decreases the active layer, while also increasing (not decreasing) the permafrost temperature. Using seasonal thermal insulation, in a controlled manner, satisfactorily alters the thermal regime of soils below heated buildings and provides additional foundation alternatives for arctic buildings.
    • An Evalulation Of Variables Affecting Gold Extraction At A Mineral Processing Plant Operated In A Sub-Arctic Environment

      Hollow, John T.; Lin, Hsing Kuang (2006)
      The Fort Knox Mine, located 25 miles northeast of Fairbanks, Alaska, is operated in a sub-Antic environment. Since process slurry temperatures cycle seasonally with air temperature, the mine presents a unique opportunity to measure the impact of slurry temperature on process performance under full scale plant, conditions. This thesis analyzes an energy balance approach to model the seasonal variations in slurry temperature throughout the Fort Knox mill. The mill utilizes both gravity concentration and cyanidation for gold recovery. Models were developed to accurately predict the impact of slurry temperature on cyanide leach, carbon adsorption and cyanide destruction kinetics. The energy balance model, combined with the kinetics models, was used to accurately predict the gold recovery and subsequently to justify the installation of a tailings wash thickener to recovery heat from the mill tailings. A substantial portion of this thesis is dedicated to the development of these models, analysis of the post expansion plant performance, and summarizing project economics. Gold in the Fort Knox deposit is generally less than 100 microns in size and contained in quartz veins and along shears within the host granite, at an average gold grade of 0.8 g/metric ton. In April 2001, the mill began processing ore from a satellite ore deposit, the True North Mine, as a blend with Fort Knox ore. The gold grade in the True North deposit averages 1.5 g/metric ton and can be associated with pyrite, arsenopyrite and stibnite. An unexpected drop in gold recovery resulted from processing the blended ore and was the subject of an extensive laboratory evaluation. Laboratory results suggested that the leach kinetics of the coarse gold particles were significantly impacted, when the blended ore was processed, and that the impact could be reduced, or eliminated, with the addition of lead nitrate. Subsequently, a lead nitrate addition scheme was implemented at the Fort Knox mill. A portion of this thesis is dedicated to a review of the laboratory program, an evaluation of the environmental impacts and a summary of plant performance, when utilizing lead nitrate at the Fort Knox Mine.
    • An investigation of digital forensic concepts in an international environment: the U.S., South Africa, and Namibia

      Phillips, Amelia; Nance, Kara; Bhatt, Uma; Hay, Brian; Genetti, Jon; Blurton, David (2013-08)
      Digital forensic investigations are growing in number not only in the United States but in nations around the world. The activities of multinational corporations and cybercrime cross jurisdictional boundaries on a daily basis. This investigation sets out to perform a qualitative analysis of the requirements needed for acceptance of digital evidence in multiple jurisdictions and the qualifications of digital forensic examiners by focusing on three case studies. The countries chosen are the United States, South Africa and Namibia. The research lays the foundation by examining existing international laws and treaties, and then uses the three case studies to address constitutional issues, civil and criminal law as they pertain to digital evidence. By ascertaining where the similarities and differences lie, a grounded theory approach is used to provide digital forensic examiners, legal staff and investigators a basis that can be used to approach digital cases that come from or must be presented in foreign jurisdictions. As more countries struggle to establish their digital laws regarding investigations, the resulting approach will serve as a guide and reference.
    • Analysis of a chemically-bonded phosphate ceramic as an alternative oilfield cementing system for Arctic regions

      Banerjee, Sudiptya; Patil, Shirish L.; Chukwu, Godwin A.; Khataniar, Santanu; Chen, Gang (2005-08)
      Traditional Portland cement has been used in the oilfield industry for over a hundred years in the United States. However, under the harsh cold of arctic conditions, cement has failed to provide the minimum standards of strength and safety required in the petroleum industry. Though there has been significant research to correct this shortcoming, no ideal solution has been found to improve the arctic performance of Portland cement. A chemically-bonded phosphate ceramic, known generically as Ceramicrete, has been developed which appears attractive as a cement replacement in arctic well construction. This material contains no Portland cement and does not have its limitations under cold conditions. It uses the same equipment in terms of storage and production as the Portland cement. In this research, Ceramicrete was vigorously tested according to industry-specifications in order to compare its material behavior against that of Portland cement as a viable alternative under arctic oilfield conditions.
    • Analysis of a chemically-bonded phosphate ceramic as an alternative oilfield cementing system for Arctic regions

      Limaye, Nilesh; Patil, Shirish L.; Chen, Gang; Khataniar, Santanu; Chukwu, Godwin A. (2007-12)
      Novel chemically bonded phosphate ceramic borehole sealant, i.e. Ceramicrete, has many advantages over conventionally used permafrost cement at Alaska North Slope (ANS). However, in normal field practices when Ceramicrete is mixed with water in blenders, it has a chance of being contaminated with leftover Portland cement. In order to identify the effect of Portland cement contamination, recent tests have been conducted at BJ services in Tomball, TX as well as at the University of Alaska Fairbanks with Ceramicrete formulations proposed by the Argonne National Laboratory. The tests conducted at BJ Services with proposed Ceramicrete formulations and Portland cement contamination have shown significant drawbacks which has caused these formulations to be rejected. However, the newly developed Ceramicrete formulation at the University of Alaska Fairbanks has shown positive results with Portland cement contamination as well as without Portland cement contamination for its effective use in oil well cementing operations at ANS.
    • Analysis of a generic flip chip under shock and vibration

      Kasturi, Uday Bhaskar; Chen, Cheng-fu; Butcher, Eric; Lin, Chuen-Sen (2004-12)
      A flip chip package, underfilled or non-underfilled, was analyzed under mechanical shock and/or vibration at the device and board levels, respectively. For the tests at the device level, the maximum stress developed at the corner-most solder joint. The horizontal drop orientation, with the chip facing up, produced the worst scenario for solder joint lifetime prediction. The underfilled package is better than non-underfilled under the excitation of mechanical shock and vibration. Parametric studies of the underfill material strength suggested that the higher the elastic modulus, the better it carried the mechanical shock. However, practically the upper bound of the elastic modulus is limited to avoid die cracking due to thermal mismatch of material expansion. The combined loading of thermal residual stress and mechanical shock was also conducted to study their influence on the solder lifetime prediction. It was found that the thermal pre-stressed condition plays a key role for the von Mises stress excursion, but has almost no influence on the shock-induced normal stress. The phenomenon appears similarly in the board level testing, but with worse reliability in solders due to the higher stresses induced.
    • Analysis of an oscillating plate coupled with fluid

      Nash, Michael J.; Peng, Jifeng; Sheng, Gang; Lin, Chuen-Sen (2013-12)
      The mechanical vibration of an oscillating cantilever plate is studied to determine the interaction of a plate coupled with air and with water. Experimental data was collected and analyzed using multiple methods including Fast Fourier Transform, wavelet analysis, and the Hilbert-Huang Transform (HHT) to characterize the behavior of the plate. The HHT is able to process nonlinear and nonstationary signals and provides more meaningful information compared to the traditionally used Fourier transform for similar applications. The HHT was found to be appropriate and more descriptive for the analysis of coupled fluid-structure systems. Digital Particle Image Velocimetry (DPIV) was also used to analyze the circulation and energy transferred to the fluid.
    • Analysis of unfrozen water in cation-treated, fine-grained soils using the pulse nuclear magnetic resonance (P-NMR) method

      Kruse, Aaron M.; Darrow, Margaret M.; Metz, Paul A.; Trainor, Thomas P. (2016-12)
      Unfrozen water within frozen soils is a key component that determines a soil's thermophysical response to changing physical and environmental conditions. This research focuses on the use of pulse nuclear magnetic resonance (P-NMR) for measuring unfrozen water content within frozen soils. The research is divided into two components: 1) improvements made to the P-NMR testing method, including refinements in the laboratory set up and testing procedure, and experimental validation of the normalization method; and 2) determination of unfrozen water content of fine-grained, cation-treated samples at various sub-freezing temperatures using the improved P-NMR methodology. Previous P-NMR testing used the first return data from the free induction decay signal intensity to calculate unfrozen water content; however, this approach may overestimate unfrozen water due to inclusion of ice content. This research used the normalization method for calculating unfrozen water, which proved to be repeatable with excellent agreement between P-NMR-derived unfrozen water and physical gravimetric water content data. Cation treatments of five standard clays and one heterogeneous soil were prepared to determine how the physicochemical structure of clays, including the adsorbed cations, controls the amount of unfrozen water. Results indicated that cation treatments have negligible effect on the unfrozen water content of kaolinite, and minimal effect on illite, chlorite, and the heterogeneous soil. Conversely, soils that are partially or completely composed of smectite demonstrated the largest unfrozen water content when treated with Na⁺ cations, and a marked reduction with the K⁺ treatment. Using the results of the standard clay testing, the unfrozen water content for the natural, heterogeneous soil was estimated, which matched measured values within 4%. This suggests that the unfrozen water content of a heterogeneous soil with a known mineralogy may be approximated from a database of measured standard clay unfrozen water contents of standard clays.
    • Application of design of experiments for well pattern optimization in Umiat oil field: a natural petroleum reserve of Alaska case study

      Gurav, Yojana Shivaji; Dandekar, Abhijit; Patil, Shirish; Khataniar, Santanu; Clough, James; Patwardhan, Samarth (2020-05)
      Umiat field, located in Alaska North Slope poses unique development challenges because of its remote location and permafrost within the reservoir. This hinders the field development, and further leads to a potential low expected oil recovery despite latest estimates of oil in-place volume of 1550 million barrels. The objective of this work is to assess various possible well patterns of the Umiat field development and perform a detailed parametric study to maximize oil recovery and minimize well costs using statistical methods. Design of Experiments (DoE) is implemented to design simulation runs for characterizing system behavior using the effect of certain critical parameters, such as well type, horizontal well length, well pattern geometry, and injection/production constraints on oil recovery. After carrying out simulation runs using a commercially available simulation software, well cost is estimated for each simulation case. Response Surface methodology (RSM) is used for optimization of well pattern parameters. The parameters, their interactions and response are modeled into a mathematical equation to maximize oil recovery and minimize well cost. Economics plays a key role in deciding the best well pattern for any field during the field development phase. Hence, while solving the optimization problem, well costs have been incorporated in the analysis. Thus, based on the results of the study performed on selected parameters, using interdependence of the above mentioned methodologies, optimum combinations of variables for maximizing oil recovery and minimizing well cost will be obtained. Additionally, reservoir level optimization assists in providing a much needed platform for solving the integrated production optimization problem involving parameters relevant at different levels, such as reservoir, wells and field. As a result, this optimum well pattern methodology will help ensure optimum oil recovery in the otherwise economically unattractive field and can provide significant insights into developing the field more efficiently. Computational algorithms are gaining popularity for solving optimization problems, as opposed to manual simulations. DoE is effective, simple to use and saves computational time, when compared to algorithms. Although, DoE has been used widely in the oil industry, its application in domains like well pattern optimization is novel. This research presents a case study for the application of DoE and RSM to well optimization in a real existing field, considering all possible scenarios and variables. As a result, increase in estimated oil recovery is achieved within economical constraints through well pattern optimization.
    • Application of wicking fabric to reduce damage in Alaskan pavements

      Presler, Wendy A.; Zhang, Xiong; Liu, Juanyu; Shur, Yuri; Connor, Billy (2016-05)
      Beaver Slide is located near kilometer 177.8 (mile 110.5) on the Dalton Highway. The road is sloped downhill when heading north. The road gradient is approximately 11%, and the road prism is on a side hill. Each year, soft spots usually appear in the pavement structure in late April and remain all summer. These soft spots have been called “frost boils”. The “frost boils” have resulted in extremely unsafe driving conditions and frequent accident occurrences. Conventional repair methods have not worked. A newly developed geosynthetic wicking fabric was installed in the road structure in August 2010. The fabric has a high specific surface area (consequently high wettability and high capillary action) and high directional permittivity. Test results over the initial two year period proved the effectiveness of the wicking fabric to mitigate “frost boils” and the subsequent road softening issue. Data collected during the past four years were analyzed to evaluate the long-term performance of the wicking fabric. A scanning electron microscope (SEM) was used to explore the interaction between the wicking fabric and in situ soils, and to determine the condition of the fabric five years after installation.
    • Approximate bayesian computation for probabilistic decline curve analysis in unconventional reservoirs

      Paryani, Mohit; Ahmadi, Mohabbat; Hanks, Catherine; Awoleke, Obadare (2015-12)
      Predicting the production rate and ultimate production of shale resource plays is critical in order to determine if development is economical. In the absence of production from the Shublik Shale, Alaska, Arps' decline model and other newly proposed decline models were used to analyze production data from oil producing wells in the Eagle Ford Shale, Texas. It was found that shales violated assumptions used in Arps' model for conventional hydrocarbon accumulations. Newly proposed models fit the past production data to varying degrees, with the Logistic Growth Analysis (LGA) and Power Law Exponential (PLE) models making the most conservative predictions and those of Duong's model falling in between LGA and PLE. Using a regression coefficient cutoff of 95%, we see that the LGA model fits the production data (both rate and cumulative) from 81 of the 100 wells analyzed. Arps' hyperbolic and the LGA equation provided the most optimistic and pessimistic reserve estimates, respectively. The second part of this study investigates how the choice of residual function affects the estimation of model parameters and consequent remaining well life and reserves. Results suggest that using logarithmic rate residuals maximized the likelihood of Arps' equation having bounded estimates of reserves. We saw that approximately 75% of the well histories that were fitted using the logarithmic rate residual had hyperbolic b-values < 1, as opposed to 40% using the least squares error function--an 87.5% increase. This is because they allow the most recent production data to be weighted more heavily, thereby ensuring that the fitted parameters reflect the current flow regime in the drainage area of the wells. In the third part of this work, in order to quantify the uncertainty associated with Decline Curve Analysis (DCA) models, a methodology was developed that integrated DCA models with an approximate Bayesian probabilistic method based on rejection sampling. The proposed Bayesian model was tested by history matching the simulation results with the observed production data of 100 gas wells from the Barnett Shale and 21 oil wells from the Eagle Ford Shale. For example, in Karnes County, the ABC P90-P50-P10 average interval per well was 170-184-204 MSTB, while the true average cumulative production per well was 183 MSTB. The ABC methodology coupled with any deterministic DCA model will help in long-term planning of operations necessary for optimal/effective field development.
    • Assessing the fate of crude oil in Arctic coastline sediments: effect of exposure time and sediment structure

      Iverson, Anna Christine; Schiewer, Silke; Perkins, Robert; Barnes, David (2015-08)
      The research presented in this thesis will allow for a better understanding of how crude oil interacts with the shoreline. Offshore oil production along Alaska's arctic coast is expected to increase in coming years. While this is likely to create large economic benefits for the state, crude oil spills may occur. An oil spill may reach the shoreline, where it could create adverse short and long-term ecological effects. Mass transfer processes, affected by sediment characteristics, play an important role in determining the fate of crude oil along shorelines. Crude oil viscosity and diffusion are strongly temperature dependent. Nutrients, commonly added to stimulate bioremediation, may be washed out with waves and tides. It is therefore necessary to study how factors such as the beach matrix, nutrient addition and temperature affect hydrocarbon distribution. Laboratory experiments were implemented to help better understand how the soil composition and tidal action will affect the oil's movement through the shoreline sediments. Experiments were conducted for two different sediment types (sandy-gravel versus pebble) obtained from Barrow, AK and two different temperatures (20° and 3° Celsius). A microcosm study using a PVC pipe set-up was used to simulate the transport of oil through the sediment profile. Data obtained from this study show that the amount of pooling and its location was dependent on sediment structure. In sandy gravel sediment, Total petroleum hydrocarbons (TPH) persisted 6 inches below the surface, indicating pooling does occur. In pebble sediment, TPH persisted at the top and bottom of the column, but only for the first few days, indicating the pooling would not be a long term problem. Both sediments had higher CO₂ production at higher temperatures, with the highest respiration, i.e. more biodegradation, found in sandy-gravel. While CO₂ releases were slightly higher in sediments with the addition of fertilizer, overall the application of fertilizer did not have a significant impact on the fate of crude oil in shoreline sediments.
    • Assessing the potential of Salix alaxensis for the rhizoremediation of diesel contaminated soil

      Starsman, Jessica; Leigh, Mary Beth; Schiewer, Silke; Schnabel, William (2016-08)
      Alaska has over 280 remote communities that rely on diesel as their main source of heat; as a result, there have been multiple diesel spills across the state. Research has shown that plants are able to assist in the degradation of diesel through rhizoremediation, relying on the interaction between microorganisms, plant roots, and other components of the soil environment. Greater attention is now being given to the potential role of secondary plant compounds released during fine root turnover and the stimulatory effects they may have on the rhizoremediation process. For this study the native plant species, Salix alaxensis (felt leaf willow) was chosen. Fine root turnover in the sub-Arctic was mimicked through a microcosm study performed with sub-Arctic soil contaminated with weathered and fresh diesel, incubated at 4 °C and 20 °C. The effect of adding crushed willow roots was compared against addition of pure salicylic acid, a secondary plant compound found in the salicaceae family, and/or addition of fertilizer. Results showed that the addition of crushed fine willow roots with or without fertilizer increased diesel loss. Overall, greater loss and higher respiration occurred at 20 °C. The addition of salicylic acid with or without fertilizer increased soil toxicity. Toxicity may have been the result of observed phenol production and/or fungal growth. Findings show promise for the use of Salix alaxensis for the rhizoremediation of diesel contaminated soils in the sub-Arctic.
    • Assessment of contaminant concentrations and transport pathways in rural Alaska communities' solid waste and wastewater sites

      Mutter, Edda Andrea; Schnabel, William; Barnes, David; Duddleston, Khrys; Duffy, Lawrence; Hagedorn, Birgit (2014-05)
      Waste management practices currently employed in many rural Alaska communities are potentially contributing to human and environmental health impacts, and this problem may be exacerbated with the anticipated warming climate. For rural communities, factors that contribute to insufficient waste management practices include climate and environmental conditions, limitation of federal and state capital funding for construction, and the continuing financial burden associated with providing adequate operations and maintenance. As a response, federal regulatory exemptions are granted for construction and design of solid waste sites and limited state regulations are in place for wastewater discharge criteria. Due to the absence of proper site assessment and monitoring, very little is known about the fate and transport of point source pollutants arising from these wastewater and solid waste sites. Moreover, these fate and transport processes may be susceptible to changes resulting from human activity or a warming climate. Thus, this knowledge gap associated with waste-related pollutants in rural Alaska could obscure potential threats to human and environmental health by concealing impacts to freshwater systems. This research was intended to achieve a better understanding of rural Alaska waste leachate compositions by evaluating contaminant prevalence and diversity, quantifying contaminant concentration levels, and evaluating their potential migration into nearby freshwater systems. Over the course of three years, waste sites at five rural Alaska communities were sampled and tested for heavy metals, organic constituents, and microbial indicator organisms. The purpose of the analysis was to evaluate the impact of waste sites on soil, surface, and subsurface waters in the vicinity of the sites. The resulting findings are assembled into three chapters describing 1) the assessment of heavy metal leachate in rural Alaska solid waste sites, 2) the identification of new emerging organic pollutants in rural Alaska waste sites, and 3) the partitioning and transport behavior of pathogen indicator organisms in cold regions. The research outcome of E.coli and Enterococcus sp. were observed in waste impacted water and soil samples, heavy metal migration into nearby freshwaters, and pharmaceuticals, phthalates, and benzotriazole in waste impacted water samples. The research findings highlight the need to apply state regulations to remove potentially hazardous components from rural Alaska wastewater and municipal solid waste streams. Additionally, there is a need to establish effective solid waste and wastewater leachate monitoring and assessment strategies for active and closed rural Alaska waste sites.