• Experimental investigation of the influence of various nanoparticles on water-based mud

      Dhiman, Paritosh (2016-12)
      In the oil and gas industry, drilling fluids play an important role in the success of drilling operations. Hence, it is vital to predict accurately and maintain drilling fluid properties. Drilling fluids have multitude of functions, including but not limited to balancing the formation pressure, transporting cuttings, lubricating the bit, minimizing formation damage and maintaining well stability. Efficient completion of any drilling operation is governed by the selection of the proper drilling fluid. Growing hydrocarbon demand is driving the industry to explore unconventional resources such as shale formations and deep water and ultra-deep water areas where high temperature high pressure (HTHP) conditions persist. Generally, oil-based muds have been widely used in HTHP operations, as they can withstand high temperatures while offering high lubricity, but they are expensive and have an environmental impact. Water-based muds offer a cost-effective and environment-friendly option, but they have limited HTHP application, as they tend to break down, resulting in increased fluid loss and viscosity reduction. Also, upon exposure to high temperatures, they also face the issue of gelation and degradation of weighing materials and additives. Due to these issues with both oil-based muds and water-based muds, new drilling fluids are formulated regularly and the existing systems are tailored to curtail drilling operation costs. Most recently, nanoparticles have been recognized as an effective additive to improve the performance of drilling fluids, having the potential to overcome the limitations of current drilling fluid systems in challenging conditions. In this study, experiments have been conducted to investigate the impact of different nanoparticles on various drilling fluid properties, including rheology, filtration, and lubricity, considering a wide range of influence factors, such as nanoparticle concentration, particle size, nanoparticle type, temperature, and aging. The effect of nanoparticle concentrations (0.01 wt% ~ 1wt%) on drilling fluid properties has been first investigated using SiO₂ nanoparticles with and without coating. Then the effect of nanoparticle size (5 nm ~ 50 nm) on drilling fluid properties has been examined using TiO₂ nanoparticles. Subsequently, the impact of nanoparticle type, including four different nanoparticles, on drilling fluid properties has been tested. Moreover, the effects of temperature and aging on the nanoparticle-based drilling fluid properties have been investigated.
    • Experimental investigation on the transportation of commingled blends of gas-to-liquid (GTL) products and Alaskan heavy crude oil through the Trans-Alaska Pipeline System (TAPS)

      Igbokwe, Chidiebere G. C.; Dandekar, Abhijit Y.; Chukwu, Godwin A.; Patil, Shirish L.; Khataniar, Santanu (2006-08)
      Heavy oil deposits in the West Sak and Ugnu formations are currently considered as potential resources to address the issue of declining oil production on Alaska's North Slope (ANS). Similarly, an estimated proven and recoverable ANS gas reserve of 38 trillion cubic feet (TCF) can be converted to high premium Gas-to-Liquid products which may be commingled with Alaskan heavy oil products. These commingled blends of GTL and Alaska heavy oil can be transported through the Trans Alaska Pipeline System (TAPS). The primary operational issues that could affect the transportation of these fluids through TAPS are: pump ability of the heavy oil, cold restart following a prolonged shut down, and solid deposition in the pipeline. Since TAPS was originally designed to carry light to medium, low viscosity crude oil, transporting heavy or viscous oil may cause problems with the overall hydraulics. In this study, ANS crude oil was distilled and the heavy fraction cuts (~18° API gravity) were commingled with ANS crude oil and GTL samples for evaluation. Density and viscosity results showed that addition of GTL significantly reduced heavy oil viscosity to present TAPS conditions. However, solid deposition was observed to be a potential problem.
    • Experimental Investigations Of Fluid Dynamic And Thermal Performance Of Nanofluids

      Kulkarni, Devdatta Prakash; Das, Debendra K. (2007)
      The goal of this research was to investigate the fluid dynamic and thermal performance of various nanofluids. Nanofluids are dispersions of metallic nanometer size particles (<100 nm) into the base fluids. The choice of base fluid is an ethylene or propylene glycol and water mixture in cold regions. Initially the rheological characterization of copper oxide (CuO) nanofluids in water and in propylene glycol was performed. Results revealed that higher concentrations of CuO nanoparticles (5 to 15%) in water exhibited time-independent pseudoplastic and shear-thinning behavior. Lower concentrations (1 to 6%) of CuO nanofluids in propylene glycol revealed that these nanofluids behaved as Newtonian fluids. Both nanofluids showed that viscosity decreased exponentially with increase in temperature. Subsequent correlations for viscosities as a function of volume concentration and temperature were developed. Effects of different thermophysical properties on the Prandtl number of CuO, silicon dioxide (SiO2) and aluminum oxide (A12O 3) nanofluids were investigated. Results showed that the Prandtl number increased with increasing volume concentrations, which in turn increased the heat transfer coefficients of the nanofluids. Various nanofluids were compared for their heat transfer rates based on the Mouromtseff number, which is a Figure of Merit for heat transfer fluids. From this analysis, the optimal concentrations of nanoparticles in base fluids were found for CuO-water nanofluids. Experiments were performed to investigate the convective heat transfer enhancement and pressure loss of CuO, SiO2 and A12O 3 nanofluids in the turbulent regime. The increases in heat transfer coefficient by nanofluids for various volume concentrations compared to the base fluid were determined. Pressure loss was observed to increase with nanoparticle volume concentration. It was observed that an increase in particle diameter increased the heat transfer coefficient. Calculations showed that application of nanofluids in heat exchangers in buildings could result in volumetric flow reduction, reduction in the mass flow rate and size, and pumping power savings. Experiments on a diesel electric generator with nanofluids showed a reduction of cogeneration efficiency due to the decrease in specific heat compared to the base fluids. However, it was found that the efficiency of the waste heat recovery heat exchanger increased for nanofluids.
    • Experimental Study Of Adsorbed Cation Effects On The Frost Susceptibility Of Natural Soils

      Darrow, Margaret Marie; Huang, Scott; Shur, Yuri (2007)
      Frost heaving is ubiquitous throughout cold regions, causing damage to building foundations, roads, airfields, railways, utilities, and pipelines. Out of the voluminous body of research conducted over the last 80 years, few studies investigated the mineral surface effects on frost heaving. These previous studies were conducted nearly 50 years ago with rudimentary equipment and on homogeneous and artificial soils that have limited applicability to actual field conditions. The purpose of the research presented here is to investigate the adsorbed cation effects on the frost susceptibility of natural soils through experimental testing. A comprehensive suite of laboratory experiments was conducted on five natural heterogeneous soils, including the preparation of divalent and monovalent cation-treated samples. Experimental testing included measurements of engineering index properties, chemical properties, clay content and mineralogy, soil-moisture characteristic curves, unfrozen water content, zeta potential, and frost heave testing. Frost heave tests were conducted using a state-of-the-art laboratory system that demonstrates high repeatability. Soil-moisture characteristic---soil freezing characteristic (SMC-SFC) relations were developed for the five natural soils over an unprecedented range of measurements and using a new approach, which can be related to the Clausius-Clapeyron equation. The SMC-SFC relations yield a new variable, eta, which describes the water retention properties of soil at increasing matric potentials and decreasing temperatures. The five untreated soils demonstrated significantly different frost heave ratios, ranging from 0.7 percent to 49.2 percent. Statistical analysis indicates that the frost susceptibility of the five untreated soils is most dependent on adsorbed cations, eta, amount of microaggregates smaller than 2 mum, and clay content. For the entire body of untreated and cation-treated samples, statistical analysis indicates that the frost susceptibility is most dependent on adsorbed cations, unfrozen water content, and amount of smectite, kaolinite, and chlorite present in the soil. The results from each cation treatment indicate that the frost susceptibility of (1) Ca2+-saturated soil is most dependent on zeta potential and unfrozen water content; (2) Mg2+-saturated soil is most dependent on zeta potential and amount of chlorite; and (3) Na +-saturated soil is most dependent on zeta potential, unfrozen water content, and amount of chlorite.
    • Experimental study of multiphase flow of viscous oil, gas and sand in horizontal pipes

      Hulsurkar, Panav; Awoleke, Obadare; Ahmadi, Mohabbat; Patil, Shirish (2017-05)
      The oil and gas industry relies on multiphase flow models and correlations to predict the behavior of fluids through wells and pipelines. Significant amount of research has been performed on the multiphase flow of different types of liquids with gases to extend the applicability of existing models to field-specific fluid conditions. Heavy oil and gas flow research commenced in the past decade and new correlations have been developed that define their flow behavior/regimes. This study aims to plant a foot in the quite deficient area of multiphase flow research that focuses on a sufficiently common situation faced by many heavy oil producing fields: the presence of sand in wells and pipelines. This study will be the first recorded attempt to understand the multiphase flow of heavy oil, gas, and sand. A 1.5" diameter multiphase flow loop facility capable of handling solids was designed and constructed for the study. Data logging instruments were calibrated and installed to be able to withstand the erosive effects of sand. The flow loop was leak and pressure tested with water and air. Three oils of 150, 196 and 218 cP viscosities were utilized to gather 49 single phase liquid, 227 two-phase liquid- air and 87 three-phase liquid, air and solid multiphase flow data points which included differential and absolute pressures, fluid flow rates, temperatures, liquid and composite liquid- solid hold- up data and photo and videotaping of the observed flow regimes. Validation of the setup was performed using single phase flow of oil and two-phase flow of oil and air. Sand was added in three different concentrations to the 218 cP oil and three-phase oil, gas and sand multiphase flow tests were performed. Flow patterns were identified and flow pattern maps were created using acquired data. No change was observed on flow pattern transitions by changing oil viscosities. Liquid hold- up and differential pressures were compared to observe the effect of changing oil viscosity and the presence of sand in varying concentrations on the two-phase flow of oil and gas and the three-phase flow of oil, gas and sand respectively. An increase in differential pressures was observed with increasing viscosities and the addition of sand. No changes in hold-up were seen with changing oil viscosities rather flow patterns impacted liquid hold-up significantly. The slug flow pattern was analyzed. Composite liquid-solid hold-up in slug flow were physically measured and predicted. Liquid slug lengths were predicted and compared with observed lengths using photo and videography techniques. Differential pressures and liquid hold-up were compared with existing multiphase flow models in the PIPESIM multiphase flow simulator to test model predictions against observed flow data. The dependence of differential pressure gradients and liquid hold-up on dimensionless variables was realized by performing normalized linear regressions to identify the most significant dimensionless groups and the results were given a mathematical form by proposing correlations for differential pressure and hold-up predictions. To the best of our knowledge, this study is the first attempt at systematically measuring pressure drop and liquid hold up during the three-phase flow of oil, gas and sand.
    • Experimental study of solid deposition and vapor pressure in gas-to-liquid and crude oil mixtures for trasportation through the Trans Alaska Pipeline System

      Amadi, Samuel Uche (2003-08)
      Chemical conversion of Alaska North Slope (ANS) gas to liquid and subsequently transporting it through the Trans Alaska Pipeline System (TAPS) is a means of bringing the ANS gas to the market. However, transporting the gas-to-liquid (GTL) product with ANS crude oil through the Trans Alaska Pipeline System (TAPS) may pose some operational challenges. The major issue of concern relates to the asphaltene and wax deposition problems in the pipeline, as well as the vapor pressure of GTL and GTL/crude oil blends. In this study, experiments were carried out to determine the degree to which GTL is a flocculant of asphaltene. The stability/instability of the ANS crude to asphaltene deposition, as well as the wax appearance temperature of various cuts of GTL and GTL/crude oil blends were also determined. The results show that GTL is a possible flocculant of asphaltene, however, ANS is stable to asphaltene deposition. The results also show that GTL has a high wax appearance temperature, which raises a concern under arctic conditions. The Reid vapor pressure test results from this study show no consistent trend. This is because the GTL samples used have been flashed already as a result of sample withdrawal from the container by previous researchers. Thus the sample did not meet both the ASTM and IP requirements for Reid vapor test.
    • Experimental Study of Various Techniques to Protect Ice-Rich Cut Slopes

      Li, Lin; McHattie, Robert; Xhang, Xiong; Zhang, Mingchu (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2014)
    • Experimental Study of Various Techniques to Protect Ice-Rich Cut Slopes

      Li, Lin; McHattie, Robert; Zhang, Xiong; Zhang, Mingchu (Alaska University Transportation Center, 2014-08)
      Cut slopes are usually required to achieve roadway design grades in the ice-rich permafrost areas in Alaska. However, excavation and exposure of a cut slope destroy the existing thermal balance and result in degradation of ice-rich permafrost. Environmentally acceptable, legal, and economically viable solutions for ice-rich slope protection are still rare. Three potential thermal-erosion mitigation techniques were investigated. Four test sections (Section A: 1 ft wood chips, Section B: coconut blanket, Section C: coconut blanket + Tecco-mesh, and Section D: 1 ft crushed rock as a control section) were constructed at the Dalton Highway 9 Mile Hill during the period of April 17 through April 27, 2013. Temperature and moisture sensors were installed to monitor four test sections and evaluate the effectiveness of the different mitigation techniques. Also, a weather station was built to record climatic information at the test site by April 30, 2013. The filed monitoring period ended on November 11, 2014. No obvious erosion was observed in Sections A and B due to less ice content when compared with Sections C and D which failed one and a half months after construction. The performance of four techniques was discussed in detail.
    • Experimental Study on an Electrical Deicing Technology Utilizing Carbon Fiber Tape

      Yang, Zhaohui “Joey”; Yang, Ting; Song, Gangbing; Singla, Mithun (Alaska University Transportation Center, 2012)
    • An experimental study on the interaction of coaxial and co-rotating vortex rings

      Satti, Jagannadha Reddy (2012-05)
      The study investigated the role of formation time, Reynolds Number, and non-dimensional frequency number, the three most significant parameters in the dynamics of vortex rings, in the interaction between co-axial and co-rotating vortex rings and in the ring behaviors of merging and leapfrogging. To generate and investigate vortex rings with the required characteristics, two laminar vortex rings were generated consecutively from a piston-cylinder apparatus such that the rings propagated in the same direction and that the spatial separation between them decreased until they began merging. Using digital particle image velocimetry to measure the flow fields as well as the trajectory and circulation of the individual rings, a series of experiments were conducted at three formation times, with the experiments at each formation time repeated at different Reynolds Numbers, and the experiments at each Reynolds Number in turn repeated at different non-dimensional frequency numbers. The results indicate that at low Reynolds Numbers, the total circulation in the flow is relatively constant before and after the rings merge. However, at high Reynolds Numbers, the total circulation begins rapidly decreasing upon the contact of two vortex ring cores, indicating a transition to a turbulent vortex ring during merging, before stabilizing at a lower level, indicating that the merged ring has transitioned back to a laminar vortex ring after shedding some circulation.
    • Experiments on the interactions between a rigid plate and vortices

      Milke, Shaun; Peterson, Rorik; Peng, Jifeng; Xiang, Yujiang (2015-08)
      This study provides a quantitative analysis, and subsequent comparison, of flow field behavior under varied experimental parameters for vortex production by, and vortex ring interaction with, a rigid plate. The relationship between the experimental parameters: flapping amplitude and average rotational speed, and flow field characteristics: vorticity, circulation, total kinetic energy, and vortex trajectory, were examined for the cantilevered plate. The relationships between the parameter of plate inclination and the flow field characteristics of vorticity, circulation, and vortex trajectory, were examined for the inclined plate. All experiments involved a particle image velocimetry (PIV) analysis followed by processing of the data to produce quantified flow field data. The cantilevered plate experiments revealed that a flapping cantilevered plate produces two primary vortices: a tip vortex and a plate hugging vortex, and in some cases a stopping vortex above the tip. It was determined that the maximum magnitudes attained, the accumulation rate, and the dissipation rate of both circulation and kinetic energy are speed dependent. However, rate of accumulation and dissipation of either quantity does not vary with total flapping amplitude. It was concluded that flapping amplitude does not influence the shape of vortex trajectory or the trajectory angle relative to the horizontal, though the total distance traveled along the vortex trajectory is dependent on flapping amplitude. In the case of the inclined plate, it was concluded that the levels of vorticity, particularly in the lower part of the vortex ring, and the formation of additional vortices in the flow field are dependent on plate inclination and thus, the degree of asymmetry of the interaction. During the die off phase the circulation of the upper part of the vortex ring is inversely proportional to plate angle, while circulation of the lower part of the vortex ring is proportional to plate inclination. The relationship between plate inclination and vertical displacement of the two parts of the ring was found to be based on the degree of asymmetry.
    • Exploration and estimation of gravel resource potential in southeast Chukchi Sea continental shelf off Kivalina, Alaska

      D'Souza, Abhijith T. (2005-12)
      Frequent storm surges in the Alaskan arctic result in washovers and high erosion of barrier islands. The village council of Kivalina has resolved to relocate from its present location on a barrier island in Northwest arctic Alaska to an adjacent onshore site. The relocation plan envisages excavation of upper 4 meter of the 25 km² onshore permafrost ground and construction of a foundation pad. The objective of this research is to estimate the gravel resource potential in the continental shelf off Kivalina. In this context seismic surveys and sediment sampling were conducted. The seismic surveys were of limited use as they failed to resolve the upper 1-2 m of the seafloor. The lithostratigraphy indicated dominance of the 2.4-3.4 mm size fraction in the region north of Kivalina. The geostatistical analysis indicated an omnidirectional variogram fit to the data with ordinary kriging producing the best kriging estimate of the gravel resource potential. At least 20 x 10⁶ m³ of gravel above the 90 % cut-off is present in the upper 0.5 m of the seafloor. The regional Pleistocene glaciation has affected the lateral variations in gravel abundance in the nearshore southeast Chukchi Sea.
    • Factors affecting costs of mining in Alaska

      Lambert, C.; Taylor, D. (University of Alaska Mineral Industry Research Laboratory, 1982)
      The basic factors which affect the cost of mining in Alaska are discussed herein. Contrary to popular opinion, cold weather is not the major factor. This problem has, for the most part, been solved through experience in Eastern Canada and later efforts in British Columbia and the Yukon. Remoteness and isolation and its effect upon personnel, inventory and services of all kinds are among the more difficult with which to anticipate and cope. Considerable creativity is required to solve these problems, which differ somewhat with the type and location of mineral deposit, and will quite likely require solutions at variance with the current attitudes and practices of the company involved. In Alaska, electric power, transportation and land tenure pose difficulties of a type not experienced when existing mines in Canada were developed.
    • Factors Affecting Water Management on the North Slope of Alaska

      Greenwood, Julian K.; Murphy, R. Sage (University of Alaska, Institute of Water Resources, 1972-02)
      The North Slope of Alaska is undergoing sudden development following the recent discovery of large oil and gas reserves in the area. The water resources of the region should be carefully managed both to ensure adequate supplies of usable water at reasonable cost, and to guard against excessive deterioration of water quality. The likely effects on the environment of man's activities are investigated and found to be poorly understood at the present time. Research priorities are suggested to supply rapid answers to questions of immediate importance. The applicability of a regional management concept to the North Slope waters is considered and the concept is recommended as part of a broad land and water planning philosophy which would emphasize regional control over state and federal control. The use of economic incentives rather than standards for the control of water quality is not recommended at the present time.
    • Fairbanks North Star Borough Rural Roads Upgrade Inventory and Cost Estimation Software

      Lee, Ming (Alaska University Transportation Center, Fairbanks Northstar Borough, 2013)
    • Fast Determination of Soil Behavior in the Capillary Zone Using Simple Laboratory Tests

      Xhang, Xiong; Li, Lin; Lytton, Robert L. (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2012)
    • Fatigue behavior of conventional and rubberized asphalt mixes

      Saboundjian, Stephan K.; Raad, Lutfi; Lee, Jonah H.; Hulsey, J. Leroy; Succarieh, Mohamed; Gislason, Gary (1999)
      One of the main distress modes of flexible pavements is the fatigue cracking of the asphalt concrete surface layer. The addition of crumb-rubber modifier (CRM), obtained from scrap tires, to asphalt-aggregate mixtures has shown promise in enhancing their fatigue behavior. In this study, conventional unmodified and CRM modified asphalt-aggregate mixtures are evaluated in terms of their fatigue behavior. Controlled-strain flexural beam fatigue tests are conducted in the laboratory over a wide range of temperatures. Experimental results are compared in terms of flexural, tensile and compressive stiffnesses, phase angle, fatigue life and cumulative dissipated energy. Results showed that CRM mixes are more flexible than unmodified mixes, and that mix fatigue resistance is enhanced by the addition of CRM. Furthermore, a method of converting controlled-strain test data into equivalent controlled-stress behavior is presented. Experimental results revealed the existence of two types of controlled-strain stiffness-ratio variations. For each type of variation, an equivalent controlled-stress stiffness-ratio variation with cycles is derived. Using the predicted variations, fatigue lives for both modes of loading are determined. Predictions showed that, at a given temperature, controlled-stress mode of loading yields, as expected, shorter fatigue lives than its controlled-strain counterpart. An implicit validation of the proposed conversions revealed that fatigue equation parameters K and n for the different mixes fit within the range of values obtained from the literature for controlled-stress conditions. In addition, a fatigue life model, applicable to the haversine pattern of loading used in this study, is presented. The model takes into account the cumulative dissipated energy to failure, mode-of-loading, and initial phase angle, strain and stiffness of the mix. Analogy with the traditional strain-based fatigue equation revealed that K is a temperature-dependent parameter, whereas n and m are independent of mix temperature. A decrease in K is associated with an increase in temperature. The newly developed model is then used to predict fatigue lives of conventional and CRM mixes in typical pavement structures. For this purpose, a finite element-based mechanistic analysis is used. Results revealed the enhanced fatigue resistance of CRM mixes in comparison to unmodified conventional mixes.
    • Feasibility Study of Electric Cars in Cold Regions

      Zhang, Jing; Golub, Michael (Alaska University Transportation Center, 2009)
    • Feasibility study of in-situ heat generation for oil reservoirs underlying the permafrost

      Kargarpour, Mohammad Ali; Ahmadi, Mohabbat; Awoleke, Obadare; Hanks, Catherine (2017-05)
      Development of a heavy oil reservoir is a challenging issue in the oil industry. One of the major issues in heavy oil recovery is its high viscosity; so, using heating methods for producing oil have been developed and employed from the early 1950s. The existing relatively thick permafrost layer which overlays the heavy oil reservoirs of the North Slope of Alaska creates additional complexities for development of these heavy oil reservoirs. Applying any heating oil recovery process in regular way to these heavy oil Alaskan reservoirs would potentially jeopardize the permafrost layer. A down-hole heat generation system has been developed that uses a chemical and a special catalyst to generate heat. The effluent of this system would be steam and nitrogen. The system can be installed in a well string and at the bottom of the injector well. This thesis investigates the feasibility of employing this system for development of the heavy oil reservoirs that underlie the permafrost. The results of this study can be used for any steam injection process which uses any device for down-hole steam generation. The STARS module of the CMG reservoir simulation package is used for this study. In the model, live oil with a viscosity of about 30,000 cp is used. By examining several models with vertical and horizontal wells, a 3-D model with two horizontal injector and producer wells is ultimately constructed for final runs. Different sensitivities are run to find out the optimum operational parameters. Based on the results, a lateral well length of 800 ft in the middle of a reservoir with length of a 1250 ft is selected as a base case. Areal grid block size of 10 ft × 10 ft with the layer thickness of 10 ft in a reservoir with thickness of 50 ft is employed. To minimize the down-hole well bore temperature of the producer, just the last 50 ft (out of 800 ft of lateral length) at the toe of the well is opened to flow. Three different steam injection processes are examined: Steam Assisted Gravity Drainage (SAGD), Cyclic SAGD (CSAGD) and Cyclic Steam Stimulation (CSS). Simulation results reveal that the producer well bore temperature in optimum cases for SAGD, CSAGD and CSS is more than 140 ˚F, 110 ˚F and 100 ˚F, respectively. Also, the 10-year simulation period oil recoveries for optimum cases of SAGD, CSAGD and CSS are about 35%, 18% and 12%, respectively. On the other hand, results show applying any steam injection recovery method (SAGD, CSAGD or CSS) can only be recommended when the thickness of the overlying Sagavanirktok sand formation (which separates the permafrost from the heavy oil reservoir) is equal or more than 300 ft. The results also show that the addition of nitrogen has negative effect on the oil recovery. Based on the results, it is recommended to employ SAGD or CSAGD, but employ a system to cool the producer well-string to avoid melting the permafrost. A simple system of cooling the producer well-string is suggested.
    • Feasibility Study of RFID Technology for Construction Load Tracking

      Henrie, Morgan; Ronchetti, Mike (Alaska University Transportation Center, Alaska Department of Transportation and Public Facilities, 2010)