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Productivity and Injectivity of Horizontal Wells

Description: A general wellbore flow model is presented to incorporate not only frictional, accelerational and gravitational pressure drops, but also the pressure drop caused by inflow. Influence of inflow or outflow on the wellbore pressure drop is analyzed. New friction factor correlations accounting for both inflow and outflow are also developed. The greatest source of uncertainty is reservoir description and how it is used in simulators. Integration of data through geostatistical techniques leads to multiple descriptions that all honor available data. The reality is never known. The only way to reduce this uncertainty is to use more data from geological studies, formation evaluation, high resolution seismic, well tests and production history to constrain stochastic images. Even with a perfect knowledge about reservoir geology, current models cannot do routine simulations at a fine enough scale. Furthermore, we normally don't know what scale is fine enough. Upscaling introduces errors and masks some of the physical phenomenon that we are trying to model. The scale at which upscaling is robust is not known and it is probably smaller in most cases than the scale actually used for predicting performance. Uncertainties in the well index can cause errors in predictions that are of the same magnitude as those caused by reservoir heterogeneities. Simplified semi-analytical models for cresting behavior and productivity predictions can be very misleading.
Date: April 29, 1997
Creator: Aziz, Khalid; Arababi, Sepehr & Hewett, Thomas A.
Partner: UNT Libraries Government Documents Department

Basin Analysis of Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain

Description: Part 3 (Petroleum System Modeling of the Jurassic Smackover Formation) objectives are to provide an analysis of the Smackover petroleum system in Years 4 and 5 of the project and to transfer effectively the research results to producers through workshops and topical reports. Work Accomplished (Year 5): Task 1 - Basin Flow - Basin flow modeling has been completed and the topical report has been submitted to the U.S. DOE for review. Task 2 - Petroleum Source Rocks - Work on the characterization of Smackover petroleum source rocks has been integrated into the basin flow model. The information on the source rocks is being prepared for inclusion in the final report. Task 3 - Petroleum Reservoirs - Work on the characterization of Smackover petroleum reservoirs continues. The cores to be described have been identified and many of the cores for the eastern and western parts of the basin have been described. Task 4 - Reservoir Diagenesis - Work on reservoir diagenesis continues. Samples from the cores selected for the reservoir characterization are being used for this task. Task 5 - Underdeveloped Reservoirs - Two underdeveloped Smackover reservoirs have been identified. They are the microbial reef and shoal reservoirs. Work Planned (Year 5): Task 1 - Basin Flow - This task has been completed and the topical report has been submitted to the U.S. DOE. Task 2 - Petroleum Source Rocks - Petroleum source rock information will continue to be prepared for the final report. Task 3 - Petroleum Reservoirs - Characterization of petroleum reservoirs will continue through core studies. Task 4 - Reservoir Diagenesis - Characterization of reservoir diagenesis will continue through petrographic analysis. Task 5 - Underdeveloped Reservoirs - Study of Smackover underdeveloped reservoirs will continue with focus on the microbial reef and shoal reservoirs.
Date: March 1, 2001
Creator: Mancini, Ernest
Partner: UNT Libraries Government Documents Department

Basin Analysis of the Mississippi Interior Salt Basin and Petroleum System Modeling of the Jurassic Smackover Formation, Eastern Gulf Coastal Plain

Description: Part 3 (Petroleum System Modeling of the Jurassic Smackover Formation) objectives are to provide an analysis of the Smackover petroleum system in Years 4 and 5 of the project and to transfer effectively the research results to producers through workshops and topical reports. Work Accomplished (Year 5): Task 1 - Basin Flow - Basin flow modeling has been completed and the modeling results are being interpreted for report writing (Table 1). Task 2 - Petroleum Source Rocks - Work on the characterization of Smackover petroleum source rocks has been integrated into the basin flow model. Task 3 - Petroleum Reservoirs - Work on the characterization of Smackover petroleum reservoirs continues. The cores to be described have been identified and many of the cores for the eastern part of the basin have been described. Task 4 - Reservoir Diagenesis - Work on reservoir diagenesis has been initiated. Samples from the cores selected for the reservoir characterization are being used for this task. Work Planned (Year 5): Task 1 - Basin Flow - The report on basin flow will be completed. Task 2 - Petroleum Source Rocks - Petroleum source rock data will be reviewed in light of the basin flow model results. Task 3 - Petroleum Reservoirs - Characterization of petroleum reservoirs will continue through core studies. Task 4 - Reservoir Diagenesis - Characterization of reservoir diagenesis will continue through petrographic analysis.
Date: December 31, 2000
Creator: Mancini, Ernest
Partner: UNT Libraries Government Documents Department

Experimental Test of the Sweet-Parker Model of Magnetic Reconnection

Description: We report a quantitative experimental test of the Sweet-Parker model of magnetic reconnection in a controlled laboratory plasma. It is found that the observed reconnection rate cannot be explained by the Sweet-Parker model unless the model is generalized to incorporate compressibility, downstream pressure, and the effective resistivity. The latter is significantly enhanced over its classical values in the collisionless limit.
Date: September 1, 1997
Creator: Hsu, Scott; Ji, Hantao; Kulsrud, Russell & Yamada, Masaaki
Partner: UNT Libraries Government Documents Department

Modeling electrodeposition for LIGA microdevice fabrication

Description: To better understand and to help optimize the electroforming portion of the LIGA process, we have developed one and two-dimensional numerical models describing electrode-position of metal into high aspect-ratio molds. The one-dimensional model addresses dissociation, diffusion, electromigration, and deposition of multiple ion species. The two-dimensional model is limited to a single species, but includes transport induced by forced flow of electrolyte outside the mold and by buoyancy associated with metal ion depletion within the mold. To guide model development and to validate these models, we have also conducted a series of laboratory experiments using a sulfamate bath to deposit nickel in cylindrical molds having aspect ratios up to twenty-five. The experimental results indicate that current densities well in excess of the diffusion-limited currents may still yield metal deposits of acceptable morphology. However, the numerical models demonstrate that such large ion fluxes cannot be sustained by convection within the mold resulting from flow across the mold top. Instead, calculations suggest that the observed enhancement of transport probably results from natural convection within the molds, and that buoyancy-driven flows may be critical to metal ion transport even in micron-scale features having very large aspect ratios. Taking advantage of this enhanced ion transport may allow order-of-magnitude reductions in electroforming times for LIGA microdevice fabrication. 42 refs., 14 figs., 1 tab.
Date: February 1, 1998
Creator: Griffiths, S.K.; Nilson, R.H. & Bradshaw, R.W.
Partner: UNT Libraries Government Documents Department

An elastic-perfectly plastic flow model for finite element analysis of perforated materials

Description: This paper describes the formulation of an elastic-perfectly plastic flow theory applicable to equivalent solid [EQS] modeling of perforated materials. An equilateral triangular array of circular penetrations is considered. The usual assumptions regarding geometry and loading conditions applicable to the development of elastic constants for EQS modeling of perforated plates are considered to apply here. An elastic-perfectly plastic [EPP] EQS model is developed for a collapse surface that includes fourth-order stress terms. The fourth order yield function has been shown to be appropriate for plates with a triangular array of circular holes. A complete flow model is formulated using the consistent tangent modulus approach based on the fourth order yield function.
Date: February 1, 1999
Creator: Jones, D.P.; Gordon, J.L.; Hutula, D.N.; Banas, D. & Newman, J.B.
Partner: UNT Libraries Government Documents Department

Metastable states and intermittent switching of small populations of confined point vortices

Description: We have found that small populations of point vortices confined in a box exhibit a variety of new and interesting metastable collective motions, ranging from rigid body rotation to complete chaos. These motions are induced by simulated heating and cooling of the vortices; they do not appear in adiabatic systems. By judicious choice of vortex circulations, heating and cooling rates, and box size, we have produced systems that switch intermittently between several metastable states, that oscillate quasi-periodically, and that show a variety of interesting collective behaviors that in some cases are suggestive of biological organisms.
Date: July 1, 1995
Creator: Schmieder, R.W.
Partner: UNT Libraries Government Documents Department

Elliptical vortices in shear: Hamiltonian moment formulation and Melnikov analysis

Description: The equations of motion for interacting, elliptical vortices in a background shear flow are derived using a Hamiltonian moment formulation. The equations reduce to the 6th order system of Melander et al. [J. Fluid Mech. 167, 95 (1986)] when a pair of vortices is considered and shear is neglected. The equations for a pair of identical vortices axe analyzed with a number of methods, with particular emphasis on the basic interactions and on the implications for vortex merger. The splitting distance between the stable and unstable manifolds connecting the hyperbolic fixed points of the intercentroidal motion-the separatrix splitting-is estimated with a Melnikov analysis. This analysis differs from the standard time-periodic Melnikov analysis on two counts: (a) the ``periodic`` perturbation arises from a second degree of freedom in the system which is not wholly independent of the first degree of freedom, the intercentroidal motion; (b) this perturbation has a faster time scale than the intercentroidal motion. The resulting Melnikov integral appears to be exponentially small in the perturbation as the latter goes to zero. Numerical simulations, notably Poincare sections, provide a global view of the dynamics and indicate that there are two modes of merger. The effect of the shear on chaotic motion and on chaotic scattering is also discussed.
Date: July 1, 1995
Creator: Ngan, K.; Meacham, S. & Morrison, P.J.
Partner: UNT Libraries Government Documents Department

NONLINEAR DYNAMICAL SYSTEMS - Final report

Description: This document is the final report on the work completed on DE-FG02-95ER25238 since the start of the second renewal period: Jan 1, 2001. It supplements the annual reports submitted in 2001 and 2002. In the renewal proposal I envisaged work in three main areas: Analytical and topological tools for studying flows and maps Low dimensional models of fluid flow Models of animal locomotion and I describe the progess made on each project.
Date: December 31, 2005
Creator: Holmes, Philip
Partner: UNT Libraries Government Documents Department

Numerical Methods for a Porous Medium Equation

Description: The degenerate parabolic equation has been used to model the flow of gas through a porous medium. Error estimates for continuous and discrete time finite element procedures to approximate the solution of this equation are proved and a new regularity result is described.
Date: August 1978
Creator: Rose, M. E.
Partner: UNT Libraries Government Documents Department

Using DUSTRAN to Simulate Fog-Oil Dispersion and Its Impacts on Local Insect Populations at Ft. Hood: Final Report

Description: Smokes and obscurants (S&O) are important screening agents used during military training exercises on many military installations. Although the use of S&O is subject to environmental laws, the fate and effects of S&O on natural habitats are not well documented. One particular concern is the impact S&O may have on local insect populations, which can be important components of terrestrial food chains of endangered species. Fog-oil (FO) is an S&O that is of particular concern. An important part of assessing potential ecosystem impacts is the ability to predict downwind FO concentrations. This report documents the use of the comprehensive atmospheric dispersion modeling system DUST TRANsport (DUSTRAN) to simulate the downwind transport and diffusion of a hypothetical FO release on the U.S. Army installation at Ft. Hood, TX.
Date: December 29, 2006
Creator: Rishel, Jeremy P.; Chapman, Elaine G.; Rutz, Frederick C. & Allwine, K Jerry
Partner: UNT Libraries Government Documents Department

Water Imbibition into Rock as Affected by Sample Shape, Pore, Conductivity, and Antecedent Water Content

Description: Infiltration is often presumed to follow Philip's equation, I = st{sup 1/2}, where I is cumulative infiltration, s is sorptivity, and t is time. This form of the equation is appropriate for short times, and/or for negligible gravitational effects. For a uniform soil, this equation describes a plot of log(mass imbibed) versus log(time), with a slope (imbibition exponent) of 1/2. The equation has also been applied to low-porosity rocks, where the extremely small pores render gravitational forces negligible. Experiments recently performed on a wide variety of rocks produced imbibition exponents from 0.2 to 0.5. Many rock types showed initial imbibition proceeding as I {approx} t{sup 1/4}, then later switched to ''normal'' (t{sup 1/2}) behavior. The distance to the wetting front that corresponds to this cross-over behavior was found to be related to the sample shape: tall thin samples are more likely to exhibit the exponent 1/4, and to cross over to 1/2-type behavior later, while short, squat samples are less likely to display the 1/4-type behavior at all. Additionally, the exponents are sensitive to antecedent water content, with initially wetter samples having smaller values. In this study, we present the experimental data, and provide a consistent and physically-based explanation using percolation theory. The analogy between imbibition and diffusion is used to model imbibition into samples with low pore connectivity, with the exponents and their crossover behavior emerging from a random walk process. All laboratory phenomena--different exponents, crossover behavior, and effects of sample shape and antecedent water content--are reproduced by the model, with similar patterns across experiment and simulation. We conclude both that diffusion is a useful and powerful conceptual model for understanding imbibition, and also that imbibition experiments, being simpler than diffusion measurements, can be used to examine diffusive behavior in rock.
Date: August 29, 2005
Creator: Ewing, R.P.
Partner: UNT Libraries Government Documents Department

Wood Pulp Digetster Wall Corrosion Investigation

Description: The modeling of the flow in a wood pulp digester is but one component of the investigation of the corrosion of digesters. This report describes the development of a Near-Wall-Model (NWM) that is intended to couple with a CFD model that determines the flow, heat, and chemical species transport and reaction within the bulk flow of a digester. Lubrication theory approximations were chosen from which to develop a model that could determine the flow conditions within a thin layer near the vessel wall using information from the interior conditions provided by a CFD calculation of the complete digester. The other conditions will be determined by coupled solutions of the wood chip, heat, and chemical species transport and chemical reactions. The NWM was to couple with a digester performance code in an iterative fashion to provide more detailed information about the conditions within the NW region. Process Simulations, Ltd (PSL) is developing the digester performance code. This more detailed (and perhaps more accurate) information from the NWM was to provide an estimate of the conditions that could aggravate the corrosion at the wall. It is intended that this combined tool (NWM-PSL) could be used to understand conditions at/near the wall in order to develop methods to reduce the corrosion. However, development and testing of the NWM flow model took longer than anticipated and the other developments (energy and species transport, chemical reactions and linking with the PSL code) were not completed. The development and testing of the NWM are described in this report. In addition, the investigation of the potential effects of a clear layer (layer reduced in concentration of wood chips) near the wall is reported in Appendix D. The existence of a clear layer was found to enhance the flow near the wall.
Date: September 18, 2003
Creator: Giles, GE
Partner: UNT Libraries Government Documents Department

Phase II Groundwater Flow Model of Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nye County, Nevada, Rev. No.: 0

Description: The Phase II Frenchman Flat groundwater flow model is a key element in the ''Federal Facility Agreement and Consent Order'' (FFACO) (1996) corrective action strategy for the Underground Test Area (UGTA) Frenchman Flat corrective action unit (CAU). The objective of this integrated process is to provide an estimate of the vertical and horizontal extent of contaminant migration for each CAU to predict contaminant boundaries. A contaminant boundary is the model-predicted perimeter that defines the extent of radionuclide-contaminated groundwater from underground testing above background conditions exceeding the ''Safe Drinking Water Act'' (SDWA) standards. The contaminant boundary will be composed of both a perimeter boundary and a lower hydrostratigraphic unit (HSU) boundary. The computer model will predict the location of this boundary within 1,000 years and must do so at a 95 percent level of confidence. Additional results showing contaminant concentrations and the location of the contaminant boundary at selected times will also be presented. These times may include the verification period, the end of the five-year proof-of-concept period, as well as other times that are of specific interest. This report documents the development and implementation of the groundwater flow model for the Frenchman Flat CAU. Specific objectives of the Phase II Frenchman Flat flow model are to: (1) Incorporate pertinent information and lessons learned from the Phase I Frenchman Flat CAU models. (2) Develop a three-dimensional (3-D), mathematical flow model that incorporates the important physical features of the flow system and honors CAU-specific data and information. (3) Simulate the steady-state groundwater flow system to determine the direction and magnitude of groundwater fluxes based on calibration to Frenchman Flat hydrogeologic data. (4) Quantify the uncertainty in the direction and magnitude of groundwater flow due to uncertainty in parameter values and alternative component conceptual models (e.g., geology, boundary flux, and recharge).
Date: May 1, 2006
Creator: McCord, John
Partner: UNT Libraries Government Documents Department

Phase I Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 99: Rainier Mesa/Shoshone Mountain, Nevada Test Site, Nye County, Nevada, Revision 1

Description: This document presents a summary and framework of the available hydrologic data and other information directly relevant to the development of the Rainier Mesa/Shoshone Mountain (RMSM) Corrective Action Unit (CAU) 99 groundwater flow models. Where appropriate, data and information documented elsewhere are briefly summarized with reference to the complete documentation.
Date: May 1, 2008
Creator: Bryant, Nathan
Partner: UNT Libraries Government Documents Department