Umatilla River Basin Anadromus Fish Habitat Enhancement Project : 1994 Annual Report. (open access)

Umatilla River Basin Anadromus Fish Habitat Enhancement Project : 1994 Annual Report.

The Umatilla Basin Anadromous Fish Habitat Enhancement Project is funded under the Northwest Power Planning Council's Columbia River Basin Fish and Wildlife Program, Section 7.6-7.8 and targets the improvement of water quality and restoration of riparian areas, holding, spawning and rearing habitats of steelhead, spring and fall chinook and coho salmon. The project focused on implementing cooperative instream and riparian habitat improvements on private lands on the Umatilla Indian Reservation (hereafter referred to as Reservation) from April 1, 1988 to March 31, 1992. These efforts resulted in enhancement of the lower l/4 mile of Boston Canyon Creek, the lower 4 river miles of Meacham Creek and 3.2 river miles of the Umatilla River in the vicinity of Gibbon, Oregon. In 1993, the project shifted emphasis to a comprehensive watershed approach, consistent with other basin efforts, and began to identify upland and riparian watershed-wide causative factors impacting fisheries habitat and natural fisheries production capabilities throughout the Umatilla River Watershed. During the 1994-95 project period, a one river mile demonstration project was implemented on two privately owned properties on Wildhorse Creek. This was the first watershed improvement project to be implemented by the Confederated Tribes of the Umatilla Indian Reservation (CTUIR) off …
Date: May 1, 1994
Creator: Shaw, R. Todd
Object Type: Report
System: The UNT Digital Library
Discovery of the Most Distant Supernovae and the Quest for Omega (open access)

Discovery of the Most Distant Supernovae and the Quest for Omega

A search for cosmological supernovae has discovered a number of a type la supernovae. In particular, one at z = 0.458 is the most distant supernova yet observed. There is strong evidence from measurements of nearby type Ia supernovae that they can be considered as 'standard candles'. We plan to use these supernovae to measure the deceleration in the general expansion of the universe. The aim of our experiment is to try and observe and measure about 30 such distant supernovae in order to obtain a measurement of the deceleration parameter q{sub 0} which is related to {Omega}. Here {Omega} is the ratio of the density of the universe to the critical density, and we expect a measurement with an accuracy of about 30%.
Date: May 1, 1994
Creator: Goldhaber, G.; Boyle, B.; Bunclark, P.; Carter, D.; Ellis, R.; Gabi, S. et al.
Object Type: Article
System: The UNT Digital Library
UEDGE and DEGAS modeling of the DIII-D scrape-off layer plasma. Revision 1 (open access)

UEDGE and DEGAS modeling of the DIII-D scrape-off layer plasma. Revision 1

This paper presents work to develop benchmarked theoretical models of scrape-off-layer (SOL) characteristics in diverted tokamaks by comparing shot simulations using the UEDGE plasma fluid and DEGAS neutral transport codes to measurements of the DIII-D SOL plasma. The experimental data include the radial profiles of n{sub e} T{sub e}, and T{sub i}, the divertor exhaust power, the intensity of H{sub {alpha}} emission, and profiles of the radiated power. A very simple model of the anomalous perpendicular transport rates produces consistency between the calculated and measured radial profiles of the divertor power, and of the midplane densities and temperatures. Experimentally, the measured exhaust power is now 80--90% of the input power. The simulated peak power on the outer leg of the divertor floor is now within 20% of the measured power. Various sensitivities of these comparisons to model assumptions are described. Finally, these benchmarked models have been used to examine the effects of various baffle configurations for the Radiative Divertor Upgrade in DIII-D.
Date: May 1, 1994
Creator: Fenstermacher, M. E.; Porter, G. D.; Rensink, M. E.; Rognlien, T. D.; Allen, S. L.; Hill, D. N. et al.
Object Type: Article
System: The UNT Digital Library
A Simple, Closed-Form Expression for the X-Ray Reflectivity From Superlattices With Cumulative Roughness (open access)

A Simple, Closed-Form Expression for the X-Ray Reflectivity From Superlattices With Cumulative Roughness

The authors present a simple closed-form expression for the reflectivity from a multilayer which includes the effects of absorption, refraction, surface and substrate reflections but neglects dynamical effects. This expression reproduces the exact dynamical calculation except for the regions near the critical angle and for intense Bragg reflections. The expression is generalized to include cumulative interface roughness which follows a t{sup 1/2} power-law growth.
Date: May 1, 1994
Creator: Kelly, D. M.; Santa-Maria, J.; Schuller, I. K. & Fullerton, E. E.
Object Type: Report
System: The UNT Digital Library
Committee on Interagency Radiation Research and Policy Coordination (CIRRPC) (open access)

Committee on Interagency Radiation Research and Policy Coordination (CIRRPC)

Enclosed are proceedings of the workshop on Internal Dosimetry held on Atlanta, Georgia in April 1992. The recommendations from the Workshop were considered by the CIRRPC Subpanel on Occupational Radiation Protection Research in identifying those areas to be undertaken by individual Federal Agencies or in cooperative efforts. This document presents summaries of the following sessions: A.1 Applications and limitations of ICRP and other metabolic models, A.2 Applications and implementation of proposed ICRP lung model, A.3 Estimates of intake from repetitive bioassay data, A.4 Chelation models for plutonium urinalysis data, B.1 Transuranium/uranium registry data, B.2 Autopsy tissue analysis, B.3 Bioassay / Whole body counting, B.4 Data base formatting and availability, C.1 An overview of calculational techniques in use today, C.2 The perfect code, C.3 Dose calculations based on individuals instead of averages, C.4 From macro dosimetry to micro dosimetry.
Date: May 10, 1994
Creator: unknown
Object Type: Article
System: The UNT Digital Library
Hanford Tank Farm interim storage phase probabilistic risk assessment outline (open access)

Hanford Tank Farm interim storage phase probabilistic risk assessment outline

This report is the second in a series examining the risks for the high level waste (HLW) storage facilities at the Hanford Site. The first phase of the HTF PSA effort addressed risks from Tank 101-SY, only. Tank 101-SY was selected as the initial focus of the PSA because of its propensity to periodically release (burp) a mixture of flammable and toxic gases. This report expands the evaluation of Tank 101-SY to all 177 storage tanks. The 177 tanks are arranged into 18 farms and contain the HLW accumulated over 50 years of weapons material production work. A centerpiece of the remediation activity is the effort toward developing a permanent method for disposing of the HLW tank`s highly radioactive contents. One approach to risk based prioritization is to perform a PSA for the whole HLW tank farm complex to identify the highest risk tanks so that remediation planners and managers will have a more rational basis for allocating limited funds to the more critical areas. Section 3 presents the qualitative identification of generic initiators that could threaten to produce releases from one or more tanks. In section 4 a detailed accident sequence model is developed for each initiating event group. …
Date: May 19, 1994
Creator: unknown
Object Type: Report
System: The UNT Digital Library
WAG 2 remedial investigation and site investigation site-specific work plan/health and safety checklist for the sediment transport modeling task (open access)

WAG 2 remedial investigation and site investigation site-specific work plan/health and safety checklist for the sediment transport modeling task

This site-specific Work Plan/Health and Safety Checklist (WP/HSC) is a supplement to the general health and safety plan (HASP) for Waste Area Grouping (WAG) 2 remedial investigation and site investigation (WAG 2 RI&SI) activities [Health and Safety Plan for the Remedial Investigation and Site Investigation of Waste Area Grouping 2 at the Oak Ridge National Laboratory, Oak Ridge, Tennessee (ORNL/ER-169)] and provides specific details and requirements for the WAG 2 RI&SI Sediment Transport Modeling Task. This WP/HSC identifies specific site operations, site hazards, and any recommendations by Oak Ridge National Laboratory (ORNL) health and safety organizations [i.e., Industrial Hygiene (IH), Health Physics (HP), and/or Industrial Safety] that would contribute to the safe completion of the WAG 2 RI&SI. Together, the general HASP for the WAG 2 RI&SI (ORNL/ER-169) and the completed site-specific WP/HSC meet the health and safety planning requirements specified by 29 CFR 1910.120 and the ORNL Hazardous Waste Operations and Emergency Response (HAZWOPER) Program Manual. In addition to the health and safety information provided in the general HASP for the WAG 2 RI&SI, details concerning the site-specific task are elaborated in this site-specific WP/HSC, and both documents, as well as all pertinent procedures referenced therein, will be reviewed …
Date: May 1, 1994
Creator: Holt, V. L. & Baron, L. A.
Object Type: Report
System: The UNT Digital Library
Test report for remote vs. contact Raman spectroscopy (open access)

Test report for remote vs. contact Raman spectroscopy

This report details the evaluation of two methods of spatially characterizing the chemical composition of tank core samples using Raman spectroscopy. One method involves a spatially-scanned fiber optic probe. The fiber optic probe must be in contact with a sample to interrogate its chemical composition. The second method utilizes a line-of-sight technique involving a remote imaging spectrometer that can perform characterization over an entire surface. Measurements using the imaging technique are done remotely, requiring no contact with the sample surface. The scope of this document studies the effects of laser power, distance from each type of probe to the sample surface, and interferences unique to the two methods. This report also documents the results of comparative studies of sensitivity to ferrocyanide, a key contaminant of concern in the underground storage tanks at DOE`s Hanford site. The effect of other factors on signal intensity such as moisture content is explored. The results from the two methods are compared, and a recommendation for a Raman hot cell core scanning system is presented based on the test results. This work is part of a joint effort involving several DOE laboratories for the design and development of Raman spectroscopy systems for tank waste characterization …
Date: May 1, 1994
Creator: Kyle, K. R.
Object Type: Report
System: The UNT Digital Library
PCFB Repowering Project 80 MW plant description (open access)

PCFB Repowering Project 80 MW plant description

This report documents the design of a 80 MW Pressurized Circulating Fluidized Bed (PCFB) boiler for the repowering of Unit 1 at the Des Moines Energy Center. Objective is to demonstrate that PCFB combined-cycle technology is cost effective and environmentally superior compared to traditional pulverized coal burning facilities.
Date: May 1, 1994
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Linear-size nonobtuse triangulation of polygons (open access)

Linear-size nonobtuse triangulation of polygons

We give an algorithm for triangulating n-vertex polygonal regions (with holes) so that no angle in the final triangulation measures more than {pi}/2. The number of triangles in the triangulation is only 0(n), improving a previous bound of 0(n{sup 2}), and the worst-case running time is 0(n log{sup 2} n). The basic technique used in the algorithm, recursive subdivision by disks, is new and may have wider application in mesh generation. We also report on an implementation of our algorithm.
Date: May 1, 1994
Creator: Bern, M.; Mitchell, S. & Ruppert, J.
Object Type: Article
System: The UNT Digital Library
Structural performance of a Multipurpose Canister shell for HLNW under normal handling conditions (open access)

Structural performance of a Multipurpose Canister shell for HLNW under normal handling conditions

A Multipurpose Canister (MPC) is analyzed for critical stresses that occur during normal handling conditions and accidental scenarios. Linear and Non-linear Finite Element Analysis is performed and the stresses at various critical locations in the MPC and its weldments are studied extensively. Progressive failure analysis of the MPC`s groove and fillet welds, is presented. The structural response of the MPC to dynamic lifting loads, to loads resulting from an accidental slippage of a crane cable carrying the MPC, and from the impact between two canisters, is evaluated. Nonlinear structural analysis is used in the evaluation of the local buckling and the ultimate failure phenomena in the shell when the steel is in the strain hardening state during impact. Results make a case for increasing the thickness of the shell and all the welds.
Date: May 1, 1994
Creator: Ladkany, S. G. & Rajagopalan, R.
Object Type: Article
System: The UNT Digital Library
Catalysis and co-catalysis of bond cleavages in coal and coal analogs. Final report, August 1, 1990--January 31, 1994 (open access)

Catalysis and co-catalysis of bond cleavages in coal and coal analogs. Final report, August 1, 1990--January 31, 1994

In work prior to the inception of this project, the authors observed that mixtures of phenolic materials and polyalkoxyaromatic molecules were appreciably more effective in catalyzing the decompositions of di-2-naphthyl ether and of di-1-naphthyl sulfide in tetralin solutions at 450{degrees}C than were the phenols by themselves, even though the polyalkoxyaromatic molecules, in the absence of phenolic co- catalysts, show essentially no catalytic activity. This was of appreciable interest in coal research because dinapthyl ether and dinapthyl sulfide have been employed as model compounds for coals in studies aimed at cleaving ether and sulfide bonds similar to those in coals. The authors proposed (R. K. Sharma, K. P. Raman, and B. Miller) that the mixed catalysts used in these studies catalyze cleavages of ether and sulfide bonds by means of a mechanism involving electron transfer from the polyalkoxyaromatics to the substrates, which are activated as electron acceptors by hydrogen bonding to phenols. Since phenols themselves are electron donors, they also proposed that the well known effects of phenols in catalyzing the conversion of coals are due to similar electron transfer mechanisms.
Date: May 1, 1994
Creator: Miller, B.
Object Type: Report
System: The UNT Digital Library
Fluid dynamics of pressurized, entrained coal gasifiers. Second quarterly technical progress report, January 1, 1994--March 31, 1994 (open access)

Fluid dynamics of pressurized, entrained coal gasifiers. Second quarterly technical progress report, January 1, 1994--March 31, 1994

Pressurized, entrained gasification is a promising new technology for the clean and efficient combustion of coal. Its principle is to operate a coal gasifier at a high inlet gas velocity to increase the inflow of reactants, and at an elevated pressure to raise the overall efficiency of the process. Unfortunately, because of the extraordinary difficulties involved in performing measurements in hot, pressurized, high-velocity pilot plants, its fluid dynamics are largely unknown. Thus the designer cannot predict with certainty crucial phenomena like erosion, heat transfer and solid capture. In this context, we are conducting a study of the fluid dynamics of Pressurized Entrained Coal Gasifiers (PECGs). The idea is to simulate the flows in generic industrial PECGs using dimensional similitude. To this end, we employ a unique entrained gas-solid flow facility with the flexibility to recycle -- rather than discard -- gases other than air. By matching five dimensionless parameters, suspensions in mixtures of helium, carbon dioxide and sulfur hexafluoride simulate the effects of pressure and scale-up on the fluid dynamics of PECGs. Because it operates under cold, atmospheric conditions, the laboratory facility is ideal for detailed measurements. In the second quarter of this project, we have continued our comparisons of …
Date: May 1, 1994
Creator: Louge, M. Y.
Object Type: Report
System: The UNT Digital Library
Catalyst and Process Development for Synthesis Gas Conversion to Isobutylene. Quarterly Report, October 1, 1993--December 31, 1993 (open access)

Catalyst and Process Development for Synthesis Gas Conversion to Isobutylene. Quarterly Report, October 1, 1993--December 31, 1993

The objectives of this project are to develop a new catalyst; the kinetics for this catalyst; reactor models for trickle bed, slurry and fixed bed reactors; and to simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for conversion of a hydrogen lean synthesis gas to isobutylene. A hydrogen-lean synthesis gas with a ratio of H{sub 2}/CO of 0.5 to 1.0 is produced from the gasification of coal, lignite, or biomass. Isobutylene is a key reactant in the synthesis of methyl tertiary butyl ether (MTBE) and of isooctanes. MTBE and isooctanes are high octane fuels used to blend with low octane gasolines to raise the octane number required for modern automobiles. The production of these two key octane boosters is limited by the supply of isobutylene. MTBE, when used as an octane enhancer, also decreases the amount of pollutants emitted from the exhaust of an automobile engine.
Date: May 1, 1994
Creator: Anthony, R. G. & Akgerman, A.
Object Type: Report
System: The UNT Digital Library
Environmental radiation monitoring plan for depleted uranium and beryllium areas, Yuma Proving Ground (open access)

Environmental radiation monitoring plan for depleted uranium and beryllium areas, Yuma Proving Ground

This Environmental Radiation Monitoring Plan (ERM) discusses sampling soils, vegetation, and biota for depleted uranium (DU) and beryllium (Be) at Yuma Proving Ground (YPG). The existing ERM plan was used and modified to more adequately assess the potential of DU and Be migration through the YPG ecosystem. The potential pathways for DU and Be migration are discussed and include soil to vegetation, soil to animals, vegetation to animals, animals to animals, and animals to man. Sample collection will show DU deposition and will be used to estimate DU migration. The number of samples from each area varies and depends on if the firing range of interest is currently used for DU testing (GP 17A) or if the range is not used currently for DU testing (GP 20). Twenty to thirty-five individual mammals or lizards will be sampled from each transect. Air samples and samples of dust in the air fall will be collected in three locations in the active ranges. Thirty to forty-five sediment samples will be collected from different locations in the arroys near the impact areas. DU and Be sampling in the Hard Impact and Soft Impact areas changed only slightly from the existing ERM. The modifications are …
Date: May 11, 1994
Creator: Ebinger, Michael H. & Hansen, Wayne R.
Object Type: Report
System: The UNT Digital Library
Flow visualization for Lagrangian particle methods (open access)

Flow visualization for Lagrangian particle methods

In particle methods, each particle represents a finite region over which there is a distribution of the field quantity of interest. The field value at any point is calculated by summing the distribution functions for all the particles. This summation procedure does not require the use of any connectivities to generate continuous fields. Various AVS modules and networks have been developed that enable us to visualize the results from particle methods. This will be demonstrated by visualizing a numerical simulation of a rising, chaotic bubble. In this fluid dynamics simulation, each particle represents a region with a specified vorticity distribution.
Date: May 1, 1994
Creator: Glass, M. W. & Kempka, S. N.
Object Type: Article
System: The UNT Digital Library
Critical-state flux-density profiles in type-II superconducting thin-film strips and disks (open access)

Critical-state flux-density profiles in type-II superconducting thin-film strips and disks

When a weak magnetic field is applied to a superconducting strip or disk of thickness d (of the order of the penetration depth {lambda}) much less than its width or radius, induced super-currents flow so as to prevent magnetic flux from penetrating the superconductor (except within {lambda} of the edge). A stronger field causes vortices to enter, and the profiles of the macroscopic flux density B are determined by critical-state equations describing bulk pinning. Near the sample edge, where the vortices are, the magnitude of the current density J is J{sub c}. In vortex-free regions of the sample, the magnitude of J is less than J{sub c} but is not zero. The profiles of B can be calculated analytically by assuming that J, averaged over the film thickness, is given by the difference between the values of the tangential component of B at the top and bottom surfaces of the film. This paper examines the basis for this assumption, which is equivalent to assuming that the current density is determined solely by the curvature of H, rather than by the gradient of its magnitude. It is shown that this is a good approximation for thin-film strips and disks.
Date: May 1, 1994
Creator: Clem, J. R.
Object Type: Article
System: The UNT Digital Library
Technical evaluation of software for gamma-ray logging system (open access)

Technical evaluation of software for gamma-ray logging system

This report contains results of a technical review of software, identified as LGCALC, that processes data collected by a high-resolution gamma-ray borehole logging system. The software presently operates within Westinghouse Hanford Company, Department of Geosciences, to process data collected by the Radionuclide Logging System. The software has been reviewed for its suitability for processing data to be collected by new high-resolution gamma-ray logging trucks scheduled to begin operational tests within Westinghouse Tank Waste Remediation Systems during 1994. Examination of the program code and hands-on operational tests have shown that this software is suitable for its intended use of processing high-resolution gamma-ray data obtained from borehole logging. Most of the code requires no changes, but in a few limited cases, suggestions have been made to correct errors or improve operation. Section 4 describes these changes. The technical review has confirmed the appropriateness, correctness, completeness, and coding accuracy of algorithms used to process spectral gamma-ray data, leading to a calculation of subsurface radionuclide contaminants. Running the program with test data from calibration models has confirmed that the program operates correctly. Comparisons with hand calculations have shown the correctness of the output from the program, based on known input data. Section 3 describes …
Date: May 1, 1994
Creator: Stromswold, D. C.
Object Type: Report
System: The UNT Digital Library
Meta-Transport Library, A protocol base class library. Release 1.1 (open access)

Meta-Transport Library, A protocol base class library. Release 1.1

This User`s Guide describes the installation and use of the Meta- Transport Library protocol base classes. This software package includes the full source code for the implementation, as well as man pages and appropriate documents. The fully built MTL is a C++ library file that is linked into derived protocol code.
Date: May 10, 1994
Creator: Strayer, T.
Object Type: Report
System: The UNT Digital Library
Analytical procedures for waste minimization and pollution prevention (open access)

Analytical procedures for waste minimization and pollution prevention

Procedures exist for waste characterization, but waste minimization and pollution prevention have not usually played a role in development of these procedures. The US Department of Energy (DOE) expects to require several million characterizations over a 30-year period to accomplish the Department`s goals in environmental restoration and waste management. The waste generated by the analytical procedures used for characterizations is a significant source of new DOE waste. We have begun investigating ways to reduce these secondary wastes, focusing on three areas: microanalysis using flow injection; reduction of solvent volume required for dissolution of waste samples for radiochemical analysis; and alternative samples preparation for analysis of organic constituents in waste samples. Preliminary results are reported.
Date: May 1, 1994
Creator: Green, D. W.; Smith, L. L.; Crain, J. S.; Boparai, A. S. & Schilling, J. B.
Object Type: Article
System: The UNT Digital Library
Dynamic stability of maglev systems (open access)

Dynamic stability of maglev systems

Because dynamic instabilities are not acceptable in any commercial maglev system, it is important to consider dynamic instability in the development of all maglev systems. This study considers the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.
Date: May 1, 1994
Creator: Cai, Y.; Chen, S. S.; Mulcahy, T. M. & Rote, D. M.
Object Type: Report
System: The UNT Digital Library
Characterization of a putative S-locus encoded receptor protein kinase and its role in self-incompatibility. Progress report (open access)

Characterization of a putative S-locus encoded receptor protein kinase and its role in self-incompatibility. Progress report

The major results of our research effort include the determination of the S-Receptor Kinase (SRK) gene structure, the demonstration of S-haplotype-associated SRK polymorphisms and possible co-evolution of SRK and SLG, the characterization of the temporal and spatial expression patterns of SRK, and the demonstration that SRK has intrinsic serine/threonine kinase activity. Our results have indicated that SLG originated from an SRK-like gene by a gene duplication event and suggested a possible molecular basis for leaky S haplotypes. The data have allowed us to develop a model of self-incompatibility based on the interaction of SRK and SLG and the activation of SRK in response to self-pollination. More generally, the information that we have obtained is potentially relevant to understanding mechanisms of signalling inplants. Thus, the interaction of membrane-based receptor protein kinases with secreted forms of their extracellular domains may represent a generalized mechanism by which receptors signal across the plant cell wall.
Date: May 1, 1994
Creator: Nasrallah, J. B.
Object Type: Report
System: The UNT Digital Library
Pretreatment of neutralized cladding removal waste sludge: Results of the second design basis experiment (open access)

Pretreatment of neutralized cladding removal waste sludge: Results of the second design basis experiment

For several years, the Pacific Northwest Laboratory (PNL) has been investigating methods to pretreat Hanford neutralized cladding removal waste (NCRW) sludge. In the past, Zircaloy-clad metallic U fuel was chemically decladded using the Zirflex process; NCRW sludge was formed when the decladding solution was neutralized for storage in carbon-steel tanks. This sludge, which is currently stored in Tanks 103-AW and 105-AW on the Hanford Site, primarily consists of insoluble Zr hydroxides and/or oxides and NaF. Significant quantities of Al, La, U, as well as other insoluble minor constituents are present in the sludge, along with sodium and potassium nitrates, nitrites, and hydroxides in the interstitial liquid. The sludge contains about 2,000 nCi of transuranic (TRU) material per gram of dry sludge, and mixed fission products. Therefore, the sludge must be handled as high-level waste (HLW). The NCRW sludge must be pretreated before treatment (e.g., vitrification) and disposal, so that the overall cost of disposal can be minimized. The NCRW pretreatment flowsheet was designed to achieve the following objectives: (a) to separate Am and Pu from the major sludge constituents (Na, Zr). (b) to separate Am and Pu from U. (c) to concentrate Am and Pu in a small volume for …
Date: May 1, 1994
Creator: Lumetta, G. J.
Object Type: Report
System: The UNT Digital Library
Lightweight CO{sub 2}-resistant cements for geothermal well completions (open access)

Lightweight CO{sub 2}-resistant cements for geothermal well completions

Alkali metal catalyzed reactions between CO{sub 2}-containing brines and portland cement-based well cements can result in rapid strength reductions, increased permeability and casing corrosion, reduced well life, increased costs, and environmental concerns. Materials formed by acid-base reactions between calcium aluminate compounds and phosphate-containing solutions yield high strength, low permeability and CO{sub 2}-resistant cements when cured in hydrothermal environments. The cementing formulations are pumpable for several hours at temperatures up to 150C, thereby making their use for well completions technically feasible. When this cementing matrix was exposed in an autoclave containing Na{sub 2}CO{sub 3}-saturated brine for 120 days, < 0.4 wt% CaCO{sub 3} was produced. A conventional portland cement-based well completion material will form {approx} 10 wt% CaCO{sub 3} after only 7 days exposure. Addition of hollow aluminosilicate microspheres to the uncured matrix constituents yields slurries with densities as low as {approx} 1.2 g/cc which cure to produce materials with properties meeting the criteria for well cementing. Laboratory characterization is nearing completion, engineering scale-up is underway, and plans for field testing in a variety of geothermal fluids are being made.
Date: May 1, 1994
Creator: Kukacka, L. E. & Sugama, T.
Object Type: Article
System: The UNT Digital Library