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iTOUGH2 Command Reference

Description: iTOUGH2 is a program for parameter estimation, sensitivity analysis, and uncertainty propagation analysis. It is based on the TOUGH2 simulator for non-isothermal multiphase flow in fractured and porous media. This report contains a detailed description of all iTOUGH2 commands.
Date: June 18, 2002
Creator: Finsterle, Stefan
Partner: UNT Libraries Government Documents Department

iTOUGH2 Sample Problems

Description: iTOUGH2 is a program for parameter estimation, sensitivity analysis, and uncertainty propagation analysis. It is based on the TOUGH2 simulator for non-isothermal multiphase flow in fractured and porous media. This report contains a collection of iTOUGH2 sample problems.
Date: June 18, 2002
Creator: Finsterle, Stefan
Partner: UNT Libraries Government Documents Department

The Use of Simulation for the Design and Analysis of Thermophotovoltaic Networks

Description: Simulation has provided valuable quantification of the fundamental behavior of thermophotovoltaic cell networks. The results of simulation studies have supported the design and fabrication of small-scale demonstration networks and are expected to guide assembly of large-scale systems. This paper describes the methodology and software simulator developed to address issues in thermophotovoltaic (TPV) networking, including failure analysis, electrical network design, and nonuniform illumination. Results from simulation studies are given illustrating their application to the design and fabrication of small-scale TPV arrays.
Date: July 20, 2004
Creator: Oppenlander, JE; Vell, JL; Gaes, WS; Siganporia, DM; Danielson, LR & Dashiell, MW
Partner: UNT Libraries Government Documents Department

The case of the missing supercomputer performance : achieving optimal performance on the 8, 192 processors of ASCI Q

Description: In this paper we describe how we improved the effective performance of ASCI Q, the world's second-fastest supercomputer, to meet our expectations. Using an arsenal of performance-analysis techniques including analytical models, custom microbenchmarks, full applications, and simulators, we succeeded in observing a serious-but previously undetectable-performance problem. We identified the source of the problem, eliminated the problem, and 'closed the loop' by demonstrating improved application performance. We present our methodology and provide insight into performance analysis that is immediately applicable to other large-scale cluster-based supercomputers.
Date: January 1, 2003
Creator: Petrini, F. (Fabrizio); Kerbyson, D. J. (Darren J.) & Pakin, S. D. (Scott D.)
Partner: UNT Libraries Government Documents Department

Spectral Measurements of Pulse Solar Simulators

Description: Spectral measurements of pulse solar simulators are used to quantify the wavelength-dependant characteristics of the light. Because every PV device has a unique spectral response, it is important to know the spectral irradiance and to periodically monitor the spectra for changes. Measurements are made at the National Renewable Energy Laboratory (NREL) using several different techniques including the NREL-developed Pulse Analysis Spectroradiometer System (PASS).
Date: November 12, 1998
Creator: Cannon, T. W.
Partner: UNT Libraries Government Documents Department

Productivity and injectivity of horizontal wells. Quarterly report, April 1, 1995--June 30, 1995

Description: The following activities have been carried out in the last three months: Work on developing a three-dimensional Voronoi grid simulator is progressing. Extensive testing of the grid generation and visualization modules of the simulator is continuing while modifications and improvements are being made to these capabilities; The recently developed semi-analytical method for calculating critical cresting rates is being extended for the case of simultaneous gas and water coning toward a horizontal well; The accuracy of available correlations and analytical models for breakthrough times of horizontal wells is being investigated through simulations of a field case; Work on developing methods for coupling between reservoir and the werbore through a network modeling approach is progressing. The current stage of the study involves evaluation of available analytical methods; The necessary modifications have been made to the rig at the Marathon facility and the high rate two-phase flow experiments are about to commence; new correlations for wall friction and interfacial friction factors have been developed for the stratified flow in horizontal and inclined pipes. After further testing this new approach will be used in our mechanistic model; and this quarterly report has been entirely devoted to the task fisted in the last item above and we only present an abridged version of the Masters report of Mr. Liang-Biao Ouyang on which it is based. The complete study will be included in the next Annual Report of the Project.
Date: August 1, 1995
Creator: Aziz, K. & Hewett, T.A.
Partner: UNT Libraries Government Documents Department

Solutions of test problems for disposal of CO2 in saline aquifers

Description: This report presents detailed results for three flow problems involving CO2 migration in saline aquifers, that had been posed as part of an international code intercomparison study. Selected data for PVT properties of aqueous mixtures involving CO2 are given, and the dynamics of immiscible displacement of an aqueous phase by supercritical CO2 is discussed. Simulations were conducted with a version of the TOUGH2 general purpose reservoir simulator that includes a special property package for supercritical CO2. The results can serve as benchmarks for debugging numerical simulation models.
Date: March 5, 2003
Creator: Pruess, Karsten & Garcia, Julio
Partner: UNT Libraries Government Documents Department

iTOUGH2: From parameter estimation to model structure identification

Description: iTOUGH2 provides inverse modeling capabilities for the TOUGH2 family of nonisothermal multiphase flow simulators. It can be used for a formalized sensitivity analysis, parameter estimation by automatic model calibration, and uncertainty propagation analyses. While iTOUGH2 has been successfully applied for the estimation of a variety of parameters based on different data types, it is recognized that errors in the conceptual model have a great impact on both the estimated parameters and the subsequent model predictions. Identification of the most suitable model structure is therefore one of the most important and most difficult tasks. Within the iTOUGH2 framework, model identification can be partly addressed through appropriate parameterization of alternative conceptual-model elements. In addition, statistical measures are provided that help rank the performance of different conceptual models. We present a number of features added to the code that allow for a better parameterization of conceptual model elements, specifically heterogeneity. We discuss how these new features can be used to support the identification of key model structure elements and their impact on model predictions.
Date: May 12, 2003
Creator: Finsterle, Stefan
Partner: UNT Libraries Government Documents Department

Evaluation of leading scalar and vector architectures for scientific computations

Description: The growing gap between sustained and peak performance for scientific applications is a well-known problem in high performance computing. The recent development of parallel vector systems offers the potential to reduce this gap for many computational science codes and deliver a substantial increase in computing capabilities. This project examines the performance of the cacheless vector Earth Simulator (ES) and compares it to superscalar cache-based IBM Power3 system. Results demonstrate that the ES is significantly faster than the Power3 architecture, highlighting the tremendous potential advantage of the ES for numerical simulation. However, vectorization of a particle-in-cell application (GTC) greatly increased the memory footprint preventing loop-level parallelism and limiting scalability potential.
Date: April 20, 2004
Creator: Simon, Horst D.; Oliker, Leonid; Canning, Andrew; Carter, Jonathan; Ethier, Stephane & Shalf, John
Partner: UNT Libraries Government Documents Department

Productivity and Injectivity of Horizontal Wells

Description: The generation of suitable simulation grids for heterogeneous media and specific discretization issues that arise. Streamlines and equipotentials are used to define our base grids. Since streamlines are concentrated in high velocity regions they provide a natural means of clustering fine grid cells in crucial flow regions. For complex configurations and particularly for strongly heterogeneous regions the resulting grid cells can become very distorted due to extremely high curvatures. Two types of cell centered formulation are examined together with a cell vertex-point distributed scheme. Important distinctions are found for highly distorted cells. The new grids are tested for accuracy in terms of critical breakthrough parameters and it is shown that a much higher level of grid resolution is required by conventional simulators in order to achieve results that are comparable with those computed on relatively coarse streamline-potential grids.
Date: November 16, 1999
Creator: Aziz, Khalid; Hewett, Thomas A.; Arbabi, Sepehr & Smith, Marilyn
Partner: UNT Libraries Government Documents Department

Development of an Improved Permeability Modification Simulator

Description: This report describes the development of an improved permeability modification simulator performed jointly by BDM Petroleum Technologies and Schlumberger Dowell under a cooperative research and development agreement (CRADA) with the US Department of Energy. The improved simulator was developed by modifying NIPER's PC-GEL permeability modification simulator to include a radial model, a thermal energy equation, a wellbore simulator, and a fully implicit time-stepping option. The temperature-dependent gelation kinetics of a delayed gel system (DGS) is also included in the simulator.
Date: March 9, 1999
Creator: Gao, H.W. & Elphnick, J.
Partner: UNT Libraries Government Documents Department

Reservoir Characterization of Upper Devonian Gordon Sandstone, Jacksonburg, Stringtown Oil Field, Northwestern West Virginia

Description: This report gives results of efforts to determine electrofacies from logs; measure permeability in outcrop to study very fine-scale trends; find the correlation between permeability measured by the minipermeameter and in core plugs, define porosity-permeability flow units; and run the BOAST III reservoir simulator using the flow units defined for the Gordon reservoir.
Date: May 21, 2002
Creator: Ameri, S.; Aminian, K.; Avary, K.L.; Bilgesu, H.I.; Hohn, M.E.; McDowell, R.R. et al.
Partner: UNT Libraries Government Documents Department

Wellbore Models GWELL, GWNACL, and HOLA User's Guide

Description: This report describes three multi-component, multi-feedzone geothermal wellbore simulators developed. These simulators reproduce the measured flowing temperature and pressure profiles in flowing wells and determine the relative contribution, fluid properties (e.g. enthalpy, temperature) and fluid composition (e.g. CO{sub 2}, NaCl) of each feedzone for a given discharge condition. The three related wellbore simulators that will be discussed here are HOLA, GWELL and GWNACL. HOLA is a multi-feedzone geothermal wellbore simulator for pure water, modified after the wellbore simulator developed by Bjornsson, 1987 and can now handle deviated wells. The other two simulators GWELL (see also Aunzo, 1990) and GWNACL are modified versions of HOLA that can handle H{sub 2}O-CO{sub 2} and H{sub 2}O-NaCl systems, respectively. These simulators can handle both single and two-phase flows in vertical and inclined pipes and calculate the flowing temperature and pressure profiles in the well. The simulators solve numerically the differential equations that describe the steady-state energy, mass and momentum flow in a pipe. The codes allow for multiple feedzones, variable grid spacing and well radius. These codes were developed using FORTRAN language on the UNIX system.
Date: October 1, 1991
Creator: Aunzo, Z.P.; Bjornsson, G. & Bodvarsson, G.S.
Partner: UNT Libraries Government Documents Department

A New Parameter to Assess Hydromechanical Effect in Single-hole Hydraulic Testing and Grouting

Description: Grouting or filling of the open voids in fractured rock is done by introducing a fluid, a grout, through boreholes under pressure. The grout may be either a Newtonian fluid or a Bingham fluid. The penetration of the grout and the resulting pressure profile may give rise to hydromechanical effects, which depends on factors such as the fracture aperture, pressure at the borehole and the rheological properties of the grout. In this paper, we postulate that a new parameter, {angstrom}, which is the integral of the fluid pressure change in the fracture plane, is an appropriate measure to describe the change in fracture aperture volume due to a change in effective stress. In many cases, analytic expressions are available to calculate pressure profiles for relevant input data and the {angstrom} parameter. The approach is verified against a fully coupled hydromechanical simulator for the case of a Newtonian fluid. Results of the verification exercise show that the new approach is reasonable and that the {angstrom}-parameter is a good measure for the fracture volume change: i.e., the larger the {angstrom}-parameter, the larger the fracture volume change, in an almost linear fashion. To demonstrate the application of the approach, short duration hydraulic tests and constant pressure grouting are studied. Concluded is that using analytic expressions for penetration lengths and pressure profiles to calculate the {angstrom} parameter provides a possibility to describe a complex situation and compare, discuss and weigh the impact of hydromechanical couplings for different alternatives. Further, the analyses identify an effect of high-pressure grouting, where uncontrolled grouting of larger fractures and insufficient (or less-than-expected) sealing of finer fractures is a potential result.
Date: September 1, 2007
Creator: Rutqvist, Jonny; Fransson, A.; Tsang, C.-F.; Rutqvist, J. & Gustafson, G.
Partner: UNT Libraries Government Documents Department

On fluid flow in a heterogeneous medium under nonisothermal conditions

Description: An asymptotic technique, valid in the presence of smoothly-varying heterogeneity, provides explicit expressions for the velocity of a propagating pressure and temperature disturbance. The governing equations contain nonlinear terms due to the presence of temperature-dependent coefficients and due to the advection of fluids with differing temperatures. Two cases give well-defined expressions in terms of the parameters of the porous medium: the uncoupled propagation of a pressure disturbance and the propagation of a fully coupled temperature and pressure disturbance. The velocity of the coupled disturbance or front, depends upon the medium parameters and upon the change in temperature and pressure across the front. For uncoupled flow, the semi-analytic expression for the front velocity reduces to that associated with a linear diffusion equation. A comparison of the asymptotic travel time estimates with calculations from a numerical simulator indicates reasonably good agreement for both uncoupled and coupled disturbances.
Date: November 1, 2010
Creator: D.W., Vasco
Partner: UNT Libraries Government Documents Department

Circuit simulation: some humbling thoughts

Description: A short, very personal note on circuit simulation is presented. It does neither include theoretical background on circuit simulation, nor offers an overview of available software, but just gives some general remarks for a discussion on circuit simulator needs in context to the design and development of accelerator beam instrumentation circuits and systems.
Date: January 1, 2006
Creator: Wendt, Manfred & /Fermilab
Partner: UNT Libraries Government Documents Department

Production of Natural Gas and Fluid Flow in Tight Sand Reservoirs

Description: This document reports progress of this research effort in identifying possible relationships and defining dependencies between macroscopic reservoir parameters strongly affected by microscopic flow dynamics and production well performance in tight gas sand reservoirs. Based on a critical review of the available literature, a better understanding of the main weaknesses of the current state of the art of modeling and simulation for tight sand reservoirs has been reached. Progress has been made in the development and implementation of a simple reservoir simulator that is still able to overcome some of the deficiencies detected. The simulator will be used to quantify the impact of microscopic phenomena in the macroscopic behavior of tight sand gas reservoirs. Phenomena such as, Knudsen diffusion, electro-kinetic effects, ordinary diffusion mechanisms and water vaporization are being considered as part of this study. To date, the adequate modeling of gas slippage in porous media has been determined to be of great relevance in order to explain unexpected fluid flow behavior in tight sand reservoirs.
Date: June 30, 2005
Creator: Bravo, Maria Cecilia & Gurfinkel, Mariano
Partner: UNT Libraries Government Documents Department

Second Generation Advanced Reburning for High Efficiency NOx Control

Description: This project is designed to develop a family of novel NO{sub x} control technologies, called Second Generation Advanced Reburning (SGAR) which has the potential to achieve 90+% NO{sub x} control in coal-fired boilers at a significantly lower cost than SCR. The thirteenth reporting period in Phase II (October 1-December 31, 2000) included SGAR tests in which coal was used as the reburning fuel. All test work was conducted at GE-EER's 1.0 MMBtu/hr Boiler Simulator Facility. Three test series were performed including AR-Lean, AR-Rich, and reburning + SNCR. Tests demonstrated that over 90% NO{sub x} reduction could be achieved with utilization of coal as a reburning fuel in SGAR. The most effective SGAR variant is reburning + SNCR followed by AR-Lean and AR-Rich.
Date: December 31, 2000
Creator: Zamansky, Vladimir M.; Maly, Pete M. & Lissianski, Vitali V.
Partner: UNT Libraries Government Documents Department

A NEW GENERATION CHEMICAL FLOODING SIMULATOR

Description: The premise of this research is that a general-purpose reservoir simulator for several improved oil recovery processes can and should be developed so that high-resolution simulations of a variety of very large and difficult problems can be achieved using state-of-the-art computing and computers. Such a simulator is not currently available to the industry. The goal of this proposed research is to develop a new-generation chemical flooding simulator that is capable of efficiently and accurately simulating oil reservoirs with at least a million gridblocks in less than one day on massively parallel computers. Task 1 is the formulation and development of solution scheme, Task 2 is the implementation of the chemical module, and Task 3 is validation and application. We have made significant progress on all three tasks and we are on schedule on both technical and budget. In this report, we will detail our progress on Tasks 1 through 3 for the first six months of the project.
Date: March 1, 2002
Creator: Pope, Gary A.; Sepehrnoori, Kamy & Delshad, Mojdeh
Partner: UNT Libraries Government Documents Department

A NEW GENERATION CHEMICAL FLOODING SIMULATOR

Description: The premise of this research is that a general-purpose reservoir simulator for several improved oil recovery processes can and should be developed so that high-resolution simulations of a variety of very large and difficult problems can be achieved using state-of-the-art computing and computers. Such a simulator is not currently available to the industry. The goal of this proposed research is to develop a new-generation chemical flooding simulator that is capable of efficiently and accurately simulating oil reservoirs with at least a million gridblocks in less than one day on massively parallel computers. Task 1 is the formulation and development of solution scheme, Task 2 is the implementation of the chemical module, and Task 3 is validation and application.
Date: September 30, 2002
Creator: Pope, Gary A.; Sepehrnoori, Kamy & Delshad, Mojdeh
Partner: UNT Libraries Government Documents Department