• Correcting Oil-Water Relative Permeability Data For Capillary End Effect In Displacement Experiments

      Qadeer, Suhail (1988)
      By neglecting the effect of capillary forces, the relative permeabilities calculated by the method of Johnson, Bossler, and Neumann or Jones and Roszelle from low rate displacement experiments are in error.<p> In this study, steady state and displacement experiments were carried out. A history matching package along with a fully implicit numerical simulator and a Welge type model were developed and the displacement data were analyzed by history matching to quantify these errors. A modified centrifuge drainage bucket was used to obtain drainage and imbibition capillary pressure data.<p> The results show that in the case of drainage the non-wetting phase end point relative permeabilities and saturation exponents increase with an increase in rate. However the saturation exponent for the wetting phase decreases with rate. The wetting phase end point relative permeability stayed more or less constant with rate. In the case of imbibition these parameters did not indicate any meaningful rate dependent trend. <p>
    • Adaptation of engineering education in emerging technological revolution: a review

      Agbaraji, Casmir I. (2000-05)
      The future of engineering education has been a subject of concern in past years. There is no doubt that changes are needed to keep abreast with the new tools of technology and business, and to attract students. The planning of curricula should be governed by the definition of an engineer as the creator for public goods and by the demands of the industry. The tools that were available for engineering education in the past, those that are being presently used, and the techniques that dominate in the twenty-first century are analyzed. The problems associated with the new engineering education are discussed. The areas of engineering education that need improvement are highlighted. The current role of engineers in organization is analyzed. Engineering education will be challenged as never before, to shape the nature and quality of life in the twenty-first century. Engineering education will be at the forefront to meet these challenges.
    • Simulation based dimensionless waterflood performance curves for predicting recovery

      Dunn, Michael David (2000-08)
      Predicting waterflood recovery with simulation based dimensionless performance curves has advantages over the more traditional approaches in certain applications. This work discusses the advantages of the type curve approach in moderately mature fields where high resolution history matches are required. The method also has advantages when uncertainty analyses is important. The dimensionless type curve methodology can be applied to many different fields. A case study of a large, complex field is presented to show how the curves are created and how they can be applied. In this field, a study of the geology and stratigraphy indicated that reservoir continuity, permeability variance, and effects of faulting were the most important drivers of recovery efficiency. Simulations were performed on 45 datasets to describe waterflood performance over the range of variation. A spreadsheet program was created to predict recovery of any description, based on interpolations of the simulation results. The dimensionless curves can be used to predict full-field performance, as the basis of an integrated evaluation tool and/or for comparing actual performance to predicted performance. Using correlations to predict recoveries allows for ease of sensitivity analyses, and ease of application by casual users in an organization.
    • Experimental and economic evaluation of GTL fluid flow properties and effect on TAPS

      Ramakrishnan, Hariharan (2000-12)
      In this study, procedures are outlined to recondition and sample crude oil from high-pressure Welker cylinders. Standard laboratory procedures are developed to determine viscosity and density properties of crude oil, GTL and their mixtures. The steps needed to ensure Quality Assurance and Project Plan (QAPjp) is given in detail. A calibration macro is written to automate viscometer calibration calculations. A preliminary economic model is developed to evaluate GTL transportation options. Viscosity and density are measured for various samples at different temperatures. The reproducibility of the results is found to be within 5%. Batching is more preferable then blending for the parameter values considered in the economic model. In brief, GTL option appears to be a feasible way of utilizing Alaskan North Slope (ANS) gas resources and increasing the lifetime of TAPS, if suitable advancement in GTL conversion technology results in a substantial reduction in capital investment.
    • Evaluation of the modes of transporting GTL products through the Trans-Alaska Pipeline System (TAPS)

      Akwukwaegbu, Chinedu Franklyn (2001-05)
      Gas-to-liquids (GTL) conversion technology, where natural gas is chemically converted to transportable hydrocarbon liquid products, is an emerging technology that will undoubtedly reach commercialization within the next decade. Two GTL transportation modes, that could be used to exploit vast Alaska Natural Gas resources in the form of stable liquid through the Trans-Alaska Pipeline System (TAPS), are evaluated either as single slugs (batches) or commingled (mixed) with Crude Oil. In this study, thee pertinent energy equations are solved for both batch and commingled flow modes. The solutions of these equations are analytically presented for determining among other parameters, the pressure gradient and pertinent slug length required for batching. The application of the determined hydraulic parameters will aid in the analysis and economic evaluation of the GTL transportation modes through the Trans-Alaska Pipeline System (TAPS).
    • Geologic description and reservoir modeling of a Jurassic aged, low permeability, light oil reservoir, northern coastal plain, Alaska

      Newell, Jack Robert (2001-05)
      The objectives of the study include the analysis of the geologic description and reservoir modeling of a Jurassic aged, low permeability, light oil reservoir on the northern coastal plain of Alaska. The methodology of the study was to use a reservoir simulation model to evaluate the performance and cumulative recovery of the reservoir under primary depletion and a water injection process. Results of the simulation showed a primary recovery of 15.9 %OOIP of oil by solution gas drive. The results of thee simulation by a water displacement process showed that 41.9 %OOIP oil could be recovered with a production of 38.5 %HCPV of the injected water. This study has an application in determining estimates of the design paramaters for surface facilities required for the development of the field.
    • An economic appraisal of hole cleaning using hydraulic horsepower and jet impact force

      Wright, James Alfred (2001-12)
      In today's competitive business environment, reducing operating cost means dollars to the bottom line. One way that a drilling company can reduce operating cost is by optimizing energy use at the mud pumps. The mud pumps are massive pieces of equipment that are the backbone of the cutting's removal system. Optimizing the hydraulics program is one way to reduce mud pump operating cost. Big hydraulics play an important role in the drilling process. The beneficial action of the fluid's cleaning the bottom hole and the bit teeth, and carrying particles into the annulus is well-established. A variety of hydraulic optimization designs are available, however, in this study the efficiency and cost effectiveness of two methods are compared: Jet Impact force and Hydraulic Horsepower. Both methods have a fundamental objective to maximize the available hydraulics to provide optimum cleaning but Jet Impact method optimizes drilling cost better than Hydraulic Horsepower.
    • An evaluation of oilfield drilling fluid rheological properties at low shear rate ranges for hydraulic flow models

      Pan, Weizhong (2002-05)
      The hydraulic calculation requires the selection of a best fit model from some models used in petroleum industry. Especially, at low shear rate. This study is based on the data taken from ten wells to evaluate five models- Bingham plastic, Power Law, Casson, Herschel-Bulkley, and Robertson-Stiff for hydraulic optimization. In the course of optimizing, statistical method was used to evaluate all the data using linear regression and least square methods. Calculations were made to determine the rheological parameters, correlation coefficients and relative errors. Comparison was also made to the correlation coefficients and relative errors for selecting the best model for optimizing the hydraulics of specific drilling fluids. In order to verify the optimized results, the pressure losses both inside the drillpipe and the annulus and the Equivalent Circulating Density (ECD) were calculated by using these five models. Data obtained from Herschel-Bulkley model presented the most accurate results.
    • Performance considerations for horiznontal [sic] and unconventional wellbore configurations

      Deshpande, Mahesh (2002-08)
      The goal of this study was to investigate the performance of horizontal and unconventional well configurations and formulate guidelines for selecting optimum configuration. The simulation model was validated by comparing the productivity of numerical model for a horizontal well with the analytical models. The productivity of horizontal, snake wells and fishbone wellbore configurations was studied by varying four parameters, vertical position of well in the payzone, permeability anisotropy, partial completion and well length. Effect of friction loss correlations on estimation of well productivity losses was also studied. The study concludes that the ratio vertical position of well, Zw to the payzone thickness, h decreases the productivity of the wells increases. There is no significant change in performance of the wells for different configurations. As the permeability anisotropy ratio decreases the productivity decreases. The cumulative production does not decrease by half when the perforated well length is decreased by half. Also, the productivity index increases with increase in well length. Based on the results obtained we formulate guidelines for selecting well bore configurations. The results of this study can be applied to the design of horizontal and unconventional well configurations to aid reservoir management.
    • Numerical simulation study to evaluate recovery performance of miscible displacement and WAG process

      Wu, Xingru (2002-08)
      Several factors including gravity segregation, solvent types, injection methods, and production/injection well constraints are known to impact the performance of Water-Alternate-Gas (WAG) process and miscible displacement. This thesis studies well completions to optimize the miscible displacement and WAG processes through numerical simulation of a pattern model with stochastic permeability distribution. To study the impact of well placement and completions on miscible performance in heterogeneous media, we injected various solvents and examined the effect of gravity segregation, permeability distribution and anisotropy, horizontal well lengths, orientation of vertical and horizontal wells on oil recovery. Also, we conducted simulations with various WAG ratios and cycle lengths to understand the WAG processes. Performance of miscible gas flooding and WAG process are compared to that of waterflooding.
    • Rapid evaluation of the gel strength of GTL products during a prolonged trans-Alaska pipeline shutdown

      Timmcke, Michael Donovon (2002-12)
      A prolonged winter shutdown of the Trans-Alaska Pipeline (TAPS) could cause the fluid in the pipeline to form a gel with sufficient strength to prevent restart. With the economic viability of a North Slope Gas-To-Liquid (GTL) plant improving, understanding the effect the addition of GTL products to TAPS will have on the gel strength of pipeline fluids is essential to quantify the risk of such a project. This study presents the development of a fast cold ramp technique to predict the gel strength of TAPS fluids. The gel strength of various blend ratios of GTL and crude oil are determined using this fast cold ramp technique and are compared to slow cold ramp gel strength tests performed at Westport Technology Center, Houston. The study found that the gel strength of TAPS fluids may be reduced and controlled by altering the final boiling point of GTL products introduced into the pipeline system.
    • Economic evaluation of gas to liquids (GTL) product transportation through the Trans Alaska Pipeline Systems (TAPS)

      Ejiofor, Nkemakonam (2003-05)
      The Alaska North Slope is a potential candidate for the Gas to Liquid (GTL) technology. With over 38 Tcf of natural gas reserves stranded on the Alaska North Slope, the GTL technology is considered as a possible method of harnessing the abundant resources. GTL fuels are environmentally friendly (sulfur free) with better ignition and burning properties than conventional petroleum products from crude oil. Evaluating the options of transporting GTL products through the existing Trans Alaska Pipeline System (TAPS) together with crude oil either as a blend of crude oil and GTL (commingled) or as alternate slugs of each product (batching) is the main focus of this study. Economic evaluation using Rate of Return analysis to identify the most favorable mode of transportation of the GTL products was performed. Batching, using the modem tracking and sensor techniques was found to be the most economic method yielding the highest return on investment.
    • Phase behavior analysis of gas-to-liquid (GTL) products for transportation through Trans Alaska Pipeline System

      Sharma, Amit (2003-08)
      The natural gas reserves on the North Slope of Alaska can be converted to a high premium liquid product using the Gas-to-Liquids (GTL) technology. The GTL product can be transported from the North Slope of Alaska to the southern port of Alaska through the Trans Alaska Pipeline system (TAPS). In this study, experimental work done in the laboratory to determine the phase behavior and fluid properties of the GTL products and their blends with North Slope crude oil has been presented. To transport the fluid, it becomes necessary to investigate the phase behavior of the fluid at pipeline conditions. Bubble point measurements were conducted to determine, in what phase the TAPS crude oil and GTL blends will exist when being transported through TAPS. Density and viscosity measurements were done to facilitate the fluid property modeling at elevated pressure conditions. The bubble point obtained using the DB Robinson's phase behavior apparatus were used for verifying the accuracy of the Soave-Redlich-Kwong (SRK) and the Peng-Robinson (PR) Equation of State (EOS) for predicting the phase behavior of GTL, TAPS crude and their blends. The results indicate that the GTL and GTL/crude oil blends will always exist as a single-phase liquid, hence two phase problems associated with transportation of the GTL can be ignored. The PR and the SRK equation of state can be used for modeling the phase behavior of the commingled fluid through TAPS. The Peng-Robinson equation of state and the Pederson principle of corresponding state have been used for modeling the density and viscosity of the GTL and GTL/crude oil blends.
    • 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.
    • Mass transfer study on CO₂ penetration through methane hydrates using CO₂ vapor and a CO₂ nucleated micro-emulsion

      White, Aaron N. (2003-12)
      Gas hydrates are solid inclusion compounds that are made up of ice and large amounts of guest gas molecules. Due to their abundance in nature and the ability to entrap large amounts of natural gas, progress towards tapping this energy resource is on the forefront of research. Much research on the kinetics of formation and decomposition needs to be completed. This study was comprised of the identification of CH₄ and CO₂ through their characteristic Peak Raman shifts, the determination of the mass transfer rates of CO₂ through pre-formed methane hydrate, and an experimental injectant using a dissociated CO₂ micro-emulsion to help destabilize the CH₄ hydrate zone. Identification experiments showed that characteristic peak locations were instrument dependent and that O-H stretch analysis could help in the determination of the phase gas was in. Mass transfer rates were obtained for CO₂ penetration through methane hydrates by a headspace swap in an associated free gas zone. Experimental temperatures of the hydrate zone were 0, 2.5, and 4.5°C. Results indicate that CO₂ can penetrate into CH₄ hydrate zone by dissociating the CH4 from a hydrate phase and stabilizing the mixed CO₂-CH₄ hydrates. The process is slow in the magnitude of 10⁻⁸ meters per second.
    • Production modeling and economic evaluation of a potential gas hydrate pilot production program on the North Slope of Alaska

      Howe, Stephen John; Patil, Shirish L.; Reynolds, Douglas B.; Ogbe, David O.; Chukwu, Godwin A. (2004-05)
      Methane hydrates consist of a water ice lattice with methane gas molecules contained in the lattice cavities. When dissociated into its constituent water and methane, one volume of hydrate contains approximately 138 volumes of methane gas. On the North Slope area of Alaska, it is estimated that accumulations containing between 300 and 5000 trillion cubic feet of gas. The feasibility of a pilot production project was computed to determine the production potential of the hydrate accumulation and its economic return. The production of gas from a 1 mile by 4 mile reservoir block containing hydrate underlain by an accumulation of free gas was simulated and the resulting production profile inputted into an economic model. As the mechanism for the production of hydrates differs from conventional hydrocarbons, an existing thermal hydrocarbon computer simulation program was adapted. Results of the simulations indicate that depressurization of the free gas zone reduces the pressure at the gas-hydrate interface below that necessary for hydrate stability and causes the hydrate to dissociate into methane gas and water. Analysis found that, in most situations, a development project would be profitable, though the results are highly leveraged to the transportation cost and gas sales price.
    • Determination of methane hydrate stability zones in the Prudhoe Bay, Kuparuk River, and Milne Point units on the North Slope of Alaska

      Westervelt, Jason V. (2004-05)
      Estimates range from approximately 37 to 44 trillion cubic feet of in-place gas in methane hydrate from within the Eileen Trend of the Prudhoe Bay (PBU), Kuparuk River (KRU), and Milne Point (MPU) Units on the North Slope of Alaska (Collett, 1993). This study was based on measuring pressure and temperature conditions for hydrate dissociation. The results showed that the depth of the hydrate stability zone (HSZ) ranges from 585 to 780 meters. The results from this study also show that the HSZ in the Alaska North Slope (ANS) is thinning westward. This study also showed that the effect of formation brines typically found on the North Slope only affects the depth of the hydrate stability zone by 30 to 45 meters when a porous media is not present. Experiments carried out on a porous media sample provided by the Anadarko Corporation showed that the formation brines only affect the depth of the hydrate stability zone by 10 to 15 meters. Geothermal gradients, gas composition, and the type of porous media play the biggest role in the thickness of the HSZ. These variables are also the most important when determining the depth to the HSZ.
    • Optimization of oilfield power distribution through installation of underground transmission lines applied to the Alaskan North Slope

      Mielke, Robert (2004-05)
      An analytical model is developed to evaluate economic feasibility of installing new underground segments to the power transmission system maintained and operated by Greater Prudhoe Bay Central Power Station. Installation of underground segments is considered for intersections of power lines and roadways. Old materials and equipment are abandoned in favor of new technological infrastructure additions to transmission systems. This installation is progressive in its approach; it aims to eliminate superfluous oilfield operations via implementation of technological innovation. Results indicate that installation of underground segments of transmission line is an economically feasible project. Installation sites are chosen that optimize the economics of this investment. Project impact to power reliability, idle rig time, and streamlined rig operations far outweighs the investment associated with this project. Additionally, this project's effect on Prudhoe Bay oil production shows great potential for additional power line burial projects. Hence, it is hoped that this research be considered a pilot project, that future power line burial projects be considered for implementation, and that economic modeling of future projects be accomplished via revision of this work to include comparison of actual vs. predicted economics of this pilot project.