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X-ray tomography of preserved samples from the Geysers scientific corehole

Description: Approximately 800 ft. of continuous core was recovered from borehole SB-15 D (on unit 15, near the site of the abandoned Geysers Resort) during a recently completed drilling operation. Sections of this core were collected at 50 ft intervals for subsequent examination as drilling proceeded. Five foot sections were not removed at the drill site, but were sealed in the innermost sleeve of a triple tube coring system to minimize drying and disturbance of the core. All cores remained sealed and were radiographed within 72 hours of drilling: the five foot core from near 1400 ft. was scanned within 18 hours of drilling. A third generation x-ray scanner, which uses high energy radiation to penetrate the aluminum sleeve and 3.5 inch cores, was used to make preliminary radiographs and to collect multiple views of the sample as the core is rotated in front of the beam. True three dimensional tomographs are then reconstructed from the data. The images have a spatial resolution of approximately 140 micrometers and can resolve contrast differences of 0.2%. The tomographs clearly show differences in lithology with depth in the reservoir. Partially filled fractures, vein selvage and vuggy porosity are all evident in parts of the core. A principle goal is to determine the fluid content of the reservoir. Important questions to investigate include water loss during core recovery, infiltration of drilling fluid, and the heterogeneous distribution of pore fluid. Images show that radial gradients in x-ray attenuation commonly occur in jacketed cores. Regions of excess attenuation extend about halfway into the 3.5 in. core, and are probably caused by mud invasion induced by capillarity of the small scale porosity of the graywacke matrix. X-ray measurements will be coordinated with other independent measurements of fluid content underway in separate studies, particularly NMR spectroscopy of frozen `pressure ...
Date: January 23, 1995
Creator: Bonner, B.P.; Roberts, J.J.; Schneberk, D.J.; Marsh, A.; Ruddle, C. & Updike, E.
Partner: UNT Libraries Government Documents Department

Computer model for calculating gamma-ray pulse-height spectra for logging applications

Description: A generalized computer model has been devised to simulate the emission, transport, and detection of natural gamma radiation from various logging environments. The model yields high-resolution gamma-ray pulse-height spectra that can be used to correct both gross gamma and spectral gamma-ray logs. The technique can help provide corrections to airborne and surface radiometric survey logs for the effects of varying altitude, formation composition, and overburden. Applied to borehole logging, the model can yield estimates of the effects of varying borehole fluid and casing attenuations, as well as varying formation porosity and saturation.
Date: January 1, 1981
Creator: Evans, M.L.
Partner: UNT Libraries Government Documents Department

HWVP soil baseline summary report

Description: The roughly 0.5-km{sup 2} (0.2-mi{sup 2}) Hanford Waste Vitrification Plant (WHVP) site is located in the Pasco Basin in south-central Washington State at the US Department of Energy`s Hanford Site. The HWVP site is planned for use as a waste treatment facility for treating the high-activity fraction of waste currently stored in underground storage tanks on the Hanford Site. In order to determine the pre-construction chemical properties of the proposed construction site soils and to enable the HWVP to segregate these, as necessary, from any impact of HWVP operations, a soil baseline sampling plan was written and implemented. The report describes the baseline sampling plan.
Date: July 7, 1993
Creator: Wasemiller, M. A.
Partner: UNT Libraries Government Documents Department

Tank selection for Light Duty Utility Arm (LDUA) system hot testing in a single shell tank

Description: The purpose of this report is to recommend a single shell tank in which to hot test the Light Duty Utility Arm (LDUA) for the Tank Waste Remediation System (TWRS) in Fiscal Year 1996. The LDUA is designed to utilize a 12 inch riser. During hot testing, the LDUA will deploy two end effectors (a High Resolution Stereoscopic Video Camera System and a Still/Stereo Photography System mounted on the end of the arm`s tool interface plate). In addition, three other systems (an Overview Video System, an Overview Stereo Video System, and a Topographic Mapping System) will be independently deployed and tested through 4 inch risers.
Date: January 31, 1995
Creator: Bhatia, P. K.
Partner: UNT Libraries Government Documents Department

Computation of porosity and water content from geophysical logs, Yucca Mountain, Nevada

Description: Neutron and density logs acquired in boreholes at Yucca Mountain, Nevada are used to determine porosity and water content as a function of depth. Computation of porosity requires an estimate of grain density, which is provided by core data, mineralogical data, or is inferred from rock type where neither core nor mineralogy are available. The porosity estimate is merged with mineralogical data acquired by X-ray diffraction to compute the volumetric fractions of major mineral groups. The resulting depth-based portrayal of bulk rock composition is equivalent to a whole rock analysis of mineralogy and porosity. Water content is computed from epithermal and thermal neutron logs. In the unsaturated zone, the density log is required along with a neutron log. Water content can also be computed from dielectric logs, which were acquired in only a fraction of the boreholes, whereas neutron logs were acquired in all boreholes. Mineralogical data are used to compute a structural (or bound) water estimate, which is subtracted from the total water estimate from the neutron-density combination. Structural water can be subtracted only from intervals where mineralogical analyses are available; otherwise only total water can be reported. The algorithms and procedures are applied to logs acquired during 1979 to 1984 at Yucca Mountain. Examples illustrate the results. Comparison between computed porosity and core measurements shows systematic differences ranging from 0.005 to 0.04. These values are consistent with a sensitivity analysis using uncertainty parameters for good logging conditions. Water content from core measurements is available in only one borehole, yielding a difference between computed and core-based water content of 0.006.
Date: December 31, 1996
Creator: Nelson, P. H.
Partner: UNT Libraries Government Documents Department

The efficiency calibration and development of environmental correction factors for an in situ high-resolution gamma spectroscopy well logging system

Description: A Gamma Spectroscopy Logging System (GSLS) has been developed to study sub-surface radionuclide contamination. Absolute efficiency calibration of the GSLS was performed using simple cylindrical borehole geometry. The calibration source incorporated naturally occurring radioactive material (NORM) that emitted photons ranging from 186-keV to 2,614-keV. More complex borehole geometries were modeled using commercially available shielding software. A linear relationship was found between increasing source thickness and relative photon fluence rates at the detector. Examination of varying porosity and moisture content showed that as porosity increases, relative photon fluence rates increase linearly for all energies. Attenuation effects due to iron, water, PVC, and concrete cylindrical shields were found to agree with previous studies. Regression analyses produced energy-dependent equations for efficiency corrections applicable to spectral gamma-ray well logs collected under non-standard borehole conditions.
Date: May 1, 1996
Creator: Giles, J.R.
Partner: UNT Libraries Government Documents Department

Slimhole drilling and directional drilling for on-site inspections under a Comprehensive Test Ban: An initial assessment

Description: On Site-Inspection (OSI), under the Comprehensive Test Ban being negotiated in the Conference on Disarmament in Geneva, may include drilling at the site of a suspected clandestine underground nuclear explosion to recover radioactive samples. It is in the interest of the drilling party to operate as light and compact a system as possible because it is likely that the drilling equipment will first be airlifted to the country being inspected, and then will be carried by air or surface to the inspection site. It will be necessary for the inspection party to have the capability for more than vertical drilling since there may not be a drilling site available vertically above the suspected nuclear cavity location. This means having, the ability to perform directional drilling and to obtain accurate positioning of the drilling tool. Consequently, several directions may be explored from a single surface drilling pad. If the target depth is expected to be at or less than 600 m (2000 ft), slant drilling may be required to a length well in excess of 600 m. Clearly, the operation must be designed with health and safety features to prevent radioactive exposure if the drilling encounters a nuclear source region. The DOE/LLNL community has developed a strong expertise in this regard. In this initial assessment we focus on the portability and directionality of drilling systems.
Date: July 1, 1995
Creator: Heuze, F.E.
Partner: UNT Libraries Government Documents Department

Application of nodal S/sub N/ methods to radiation transport in nuclear well logging

Description: Results of testing a three-dimensional nodal discrete method on problems of interest in well logging are presented. Tests on an (x-y-z) benchmark logging problem show that the linear surface nodal method performs significantly better than the conventional linear diamond scheme. For the problems studied, the nodal method requires ten-fold less mesh and two-fold fewer discrete directions than the linear diamond method. The latter method also exhibits a large sensitivity to the number of discrete directions used. Tests on an actual eccentered, cylindrical geometry logging problem show that the rectangular geometry approximation of the (x-y-z) nodal method can be used to adequately represent the curved bondaries of the problem.
Date: January 1, 1987
Creator: Badruzzaman, A. & Chiaramonte, J.
Partner: UNT Libraries Government Documents Department

Calibration of a neutron log in partially saturated media IV: effects of sonde-wall gap

Description: A gap between a neutron sonde and the wall of a borehole can have a significant effect on the observed count rate. This effect was determined experimentally to be linear with gaps as large as 2.5 cm. The count rate is given by N/sub N/ = K/sub 0/ + K/sub 1/g where K/sub 0/ is the count rate that would be observed at zero gap, and g is the gap. The parameters K/sub 0/ and K/sub 1/ are dependent on both water (ie. hydrogen) content and bulk density. In many situations failure to correct the count rate for this gap effect can result in a significant degradation in the accuracy of the water content calculated from the count rate. In a dry borehole, K/sub 1/ is small at zero formation water content, and increases with formation water content. In a water-filled borehole, K/sub 1/ is large at zero formation water content, and tends to decrease with increasing formation water content, becoming zero, as of course it must, if the formation is pure water. The absolute value of K/sub 1/ increases with increasing density. A representation was determined for K/sub 0/ and K/sub 1/ from experimental data. This representation can be used to adjust the count rate at a given gap to equal its zero-gap value. The accuracy of the zero gap equation can then be recovered.
Date: March 8, 1984
Creator: Axelrod, M.C. & Hearst, J.R.
Partner: UNT Libraries Government Documents Department

An efficient simulation model for nuclear geophysical measurements

Description: Nuclear measurements that provide data related to geophysical parameters have been used for many years in well-logging, surface surveys, and laboratory core studies. The measurement process can be considered in two parts: (1) the transport of nuclear radiation from source to detector; and (2) the interaction of the transported radiation with the detector. For certain measurement problems, the radiation transport of step is not strongly affected by the presence of the detector in step 2. For such problems a simulation approach that decouples radiation transport from detection suggests itself. Many nuclear geophysical measurements can be modeled in this way. This method was first utilized to simulate aerial radiometric surveys and borehole logs for potassium, uranium, and thorium. A one-dimensional deterministic technique was used to model the gamma-ray transport from ground sources and the stoichastic Monte Carlo technique to model the detector response. The results of the two separate simulations are convolved to model a given source and detector combination. The method is an efficient way to model combinations of various radiation transport geometries with differing detector types and sizes. This simulation approach has been extended in the present work to include two-dimensional geometries. The two-dimensional model applies exactly to centralized well-logging tools and in an approximate form for many eccentered measurements. The model is now being used to simulate neutron porosity and gamma-gamma density measurements.
Date: January 1, 1987
Creator: Wilson, R.D.; Cook, T.K. & Dean, S.H.
Partner: UNT Libraries Government Documents Department

Maximum likelihood borehole corrections for dual-detector density logs

Description: This report discusses Dual-detector density logs which have been used in the petroleum industry for years. The tool was designed with a second detector to allow compensation for the effect of a layer of mudcake between the tool and the formation being measured. The compensation algorithm commonly used calculates the correction to apply to the density measured by the long-spaced detector as proportional to the difference in the densities measured by the two detectors. The coefficient of proportionality is determined from experimental data taken with the tool in a fluid-filled hole of 15 to 40 cm diameter, with uniform thickness sheets of various materials simulating the mudcake. In applying this technology for the Containment program at the Department of Energy Nevada Test Site (NTS) we have discovered two problems. First, we frequently log in air-filled holes much larger than 40 cm. Second, the gap, or layer, is rarely uniform with depth or vertical position on the face of the tool. We have developed a method to determine the proper amount of correction dynamically. No experimental data on the gap effect are needed as long as the two detectors are calibrated to read the proper density when the gap is zero. The method assumes that the form of the equation used in the standard algorithm is correct, but uses the variation of the two density signals with depth to determine the appropriate value of the coefficient, assuming true density varies more slowly than the gap effects. This new, maximum likelihood, method appears to work better than the standard method in both fluid and air-filled holes where the borehole wall is rough and no mudcake is present. It cannot, however, correct for a uniform mudcake or air gap, and so complements but does not replace the standard method.
Date: October 1, 1993
Creator: Carlson, R.C.
Partner: UNT Libraries Government Documents Department

Time-dependent 3-D dterministic transport on parallel architectures using Dantsys/MPI

Description: In addition to the ability to solve the static transport equation, we have also incorporated time dependence into our parallel 3-D S{sub {ital N}} code DANTSYS/MPI. Using a semi-implicit scheme, DANTSYS/MPI is capable of performing time-dependent calculations for both fissioning and pure source driven problems. We have applied this to various types of problems such as nuclear well logging and prompt fission experiments. This paper describes the form of the time- dependent equations implemented, their solution strategies in DANTSYS/MPI including iteration acceleration, and the strategies used for time-step control. Results are presented for a model nuclear well logging calculation.
Date: December 31, 1996
Creator: Baker, R.S. & Alcouffe, R.E.
Partner: UNT Libraries Government Documents Department

AVATAR -- Automatic variance reduction in Monte Carlo calculations

Description: AVATAR{trademark} (Automatic Variance And Time of Analysis Reduction), accessed through the graphical user interface application, Justine{trademark}, is a superset of MCNP{trademark} that automatically invokes THREEDANT{trademark} for a three-dimensional deterministic adjoint calculation on a mesh independent of the Monte Carlo geometry, calculates weight windows, and runs MCNP. Computational efficiency increases by a factor of 2 to 5 for a three-detector oil well logging tool model. Human efficiency increases dramatically, since AVATAR eliminates the need for deep intuition and hours of tedious handwork.
Date: May 1, 1997
Creator: Van Riper, K.A.; Urbatsch, T.J. & Soran, P.D.
Partner: UNT Libraries Government Documents Department

Nuclear logging and geothermal log interpretation: formation temperature sonde evaluation

Description: The theory and methodology of the neutron-based technique for the determination of the formation temperature in geothermal fields are discussed. The feasibility of the method was demonstrated before start of the present development phase. The present work is intended to evaluate the response of the temperature probe in a simulated fracture porosity granite matrix at temperatures likely to be encountered in known geothermal reservoirs. An above ground borehole model has been designed and constructed. The effect of high ambient temperatures on the response of the neutron detectors in the probe mockup used in the measurements was investigated and used to correct the detector counts. An improved data analysis method has been developed to account properly for the effects of low porosity and high temperatures. Measurements, using the above ground borehole model, have shown that a linear correlation between the ratio of thermal counts from a Gd-filtered detector to counts from a bare detector and formation temperature is good at temperatures as high as 380/sup 0/F. The present results are consistent with earlier data obtained in high-porosity laboratory models at lower temperatures (T < 167/sup 0/F). Further measurements at high temperature at various porosities and formation neutron absorption cross sections would be necessary for a more extensive comparison.
Date: January 1, 1982
Creator: Ross, E.W.; Vagelatos, N.; Dickerson, J.M. & Nguyen, V.
Partner: UNT Libraries Government Documents Department

Geostatistics project of the National Uranium Resources Evaluation Program. Progress report, October 1978--March 1979

Description: During the period covered by this report, research was concentrated on multivariate approaches to the analysis of aerial radiometric data. Two aspects of principal components analysis were the subjects of two publications. The procedures recommended for linear discriminant analysis were revised. Progress was made in overlaying LANDSAT data with aerial radiometric data from the Lubbock quadrangle. Some preliminary results from principal components analysis of the Wind River data were obtained.
Date: January 1, 1979
Creator: Beckman, R.J.; Bement, T.R.; Campbell, K.; Howell, J.S.; Wecksung, G.W. & Whitemann, D.E.
Partner: UNT Libraries Government Documents Department

Western Gas Sands Project. Quarterly basin activities report

Description: This quarterly basin activities report is a summation of three months drilling and testing activities in the primary study areas of the WGSP; these include the Greater Green River Basin, the Northern Great Plains Province, the Piceance Basin, and the Uinta Basin. Additional low permeability sandstone areas are listed and located geographically. Activities in each primary study area are summarized under core program and dilling activity. (JRD)
Date: October 31, 1978
Partner: UNT Libraries Government Documents Department

Geophysical well logging operations and log analysis in Geothermal Well Desert Peak No. B-23-1

Description: Geothermal Well Desert Peak No. B-23-1 was logged by Dresser Atlas during April/May 1979 to a total depth of 2939 m (9642 ft). A temperature of 209/sup 0/C (408/sup 0/F) was observed on the maximum thermometer run with one of the logging tools. Borehole tools rated to a maximum temperature of 204.4/sup 0/C (400/sup 0/F) were utilized for logging except for the Densilog tool, which was from the other set of borehole instruments, rated to a still higher temperature, i.e., 260/sup 0/C (500/sup 0/F). The quality of the logs recorded and the environmental effects on the log response have been considered. The log response in the unusual lithologies of igneous and metamorphic formations encountered in this well could be correlated with the drill cutting data. An empirical, statistical log interpretation approach has made it possible to obtain meaningful information on the rocks penetrated. Various crossplots/histograms of the corrected log data have been generated on the computer. These are found to provide good resolution between the lithological units in the rock sequence. The crossplotting techniques and the statistical approach were combined with the drill cutting descriptions in order to arrive at the lithological characteristics. The results of log analysis and recommendations for logging of future wells have been included.
Date: March 1, 1980
Creator: Sethi, D.K. & Fertl, W.H.
Partner: UNT Libraries Government Documents Department

New Mexico State University geothermal production well. Technical completion report, January 1, 1978-December 31, 1979

Description: The detailed technical specifications for the production well, the lithologic sample analysis, and a suite of geophysical logs, consisting of electrical resistivity, spontaneous potential, gamma ray and neutron, are presented. (MHR)
Date: January 1, 1981
Creator: Chaturvedi, L.
Partner: UNT Libraries Government Documents Department

Low radioactivity spectral gamma calibration facility

Description: A low radioactivity calibration facility has been constructed at the Nevada Test Site (NTS). This facility has four calibration models of natural stone that are 3 ft in diameter and 6 ft long, with a 12 in. cored borehole in the center of each model and a lead-shielded run pipe below each model. These models have been analyzed by laboratory natural gamma ray spectroscopy (NGRS) and neutron activation analysis (NAA) for their K, U, and Th content. Also, 42 other elements were analyzed in the NAA. The /sup 222/Rn emanation data were collected. Calibrating the spectral gamma tool in this low radioactivity calibration facility allows the spectral gamma log to accurately aid in the recognition and mapping of subsurface stratigraphic units and alteration features associated with unusual concentrations of these radioactive elements, such as clay-rich zones.
Date: January 1, 1986
Creator: Mathews, M.A.; Bowman, H.R.; Huang, L., H.; Lavelle, M.J.; Smith, A.R.; Hearst, J.R. et al.
Partner: UNT Libraries Government Documents Department

Construction of the KUT test pits. [U, Th, K models for calibrating spectral logging systems]

Description: Models are required to calibrate spectral logging systems to differentiate between U, Th, and K (''KUT''), in order to determine the grade of low-grade U deposits. The models were constructed by excavating three pits, emplacing three form tanks (11 ft long, 4 ft dia culvert) with 4-in. dia central holes, and pouring the following zones: 3-ft concrete lower barren zone, a 5-ft ore zone, and a final 3-ft upper barren zone. The U ore zone comprised 0.33 percent U/sub 3/O/sub 8/ Climax ore, sand, cement, and water; the Th ore zone comprised monazite sands, plaster sand, cement, and water; and the K ore zone comprised feldspar, cement, and water. Form pipes were used to form the central holes. Analyses were made of samples taken from the zones. (DLC)
Date: September 1, 1976
Creator: Knapp, K. E. & Bush, W. E.
Partner: UNT Libraries Government Documents Department

Prediction of saturation using the carbon/oxygen log

Description: This project investigates the nature of Dresser-Atlas Carbon/Oxygen Log gamma ray spectra. It presents an attempt to improve the signal-to-noise ratio of the C/O and Si/Ca parameters used by Dresser-Atlas to determine oil saturation. Two techniques were developed to subtract the Compton background from the spectral data. Neither technique significantly improves the accuracy of the cased-hole prediction of oil saturation. However, it has been shown that it is possible to develop a satisfactory correlation for oil saturation on a well-by-well basis. This correlation can then be used to generate oil-in-place from the C/O and Si/Ca ratios. 17 references.
Date: September 1, 1984
Creator: Horner, S. C. & Sanyal, S. K.
Partner: UNT Libraries Government Documents Department

Simulating the Upper Barren Zone and the Ore Zone tests performed with the EMC logging tool

Description: The primary purpose of the Multispectral Nuclear Logging project is to assess the effectiveness of applying nuclear borehole-logging techniques to the Department of Energy`s (DOE) Environmental Restoration (ER) program, adapt the technology to improve these capabilities, and transfer that technology to industry. The purpose of the Monte Carlo simulations using MCNP is to predict the minimum concentration levels for environmental contaminants that could be detected by Multispectral Logging (MSL). The Monte Carlo code used for this type of simulation, MCNP, should be benchmarked against experimental data to show that the user can accurately reproduce the proper gamma-ray spectrum. Experimental data was obtained from Westinghouse-Hanford Company using the Environmental Measurements Corp. (EMC) logging tool in the Upper Barren Zone (UBZ) and Ore Zone (OZ) calibration models at Grand Junction. This paper continues the discussion of benchmarking MCNP using the UBZ and OZ data.
Date: September 1, 1994
Creator: Frankle, S. C.
Partner: UNT Libraries Government Documents Department

An aerial radiological survey of the Quad Cities Nuclear Power Station and surrounding area, Cordova, Illinois. Date of survey: May 1989

Description: An aerial radiological survey was conducted over the Quad Cities Nuclear Power Station in Cordova, Illinois, during the period May 9 through May 18, 1989. The survey was conducted at an altitude of 61 meters (200 feet) over a 65-square-kilometer (25-square-mile) area centered on the power station. The purpose of the survey was to document the terrestrial gamma environment of the Quad Cities Power Station and surrounding area and to determine any radiological impact on the area over the past twenty years. The results of the aerial survey are reported as inferred gamma radiation exposure rates at 1 meter above ground level in the form of a contour map. Outside the plant boundary, exposure rates were found to vary between 5 and 15 microroentgens per hour ({mu}R/h) and were attributed to naturally-occurring uranium, thorium, and radioactive potassium gamma emitters. The aerial data were compared to ground-based ``benchmark`` exposure rate measurements and radionuclide assay of soil samples obtained within the survey boundary. The ground-based measurements were found to be in good agreement with those inferred from the aerial measuring system.
Date: April 1, 1993
Creator: Maurer, R. J.
Partner: UNT Libraries Government Documents Department