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Monitoring DNAPL pumping using integrated geophysical techniques

Description: The removal of DNAPL during pumping was monitored. At Hill AFB in Utah, a free-product DNAPL plume (predominantly TCE, with some TCA, PCE, methylene chloride) is pooled in water-wet soil on a thick clay aquitard. Groundwater pumping at Operable Unit 2 began in 1994; to date, nearly 30,000 gal DNAPL have been recovered. From Sept. 1994 through Sept. 1995, changes in the basin during DNAPL pumping were monitored using fiber optic chemical sensors, neutron logs, and electrical resistance tomography (ERT). The first two sensor types verify the presence of DNAPL in vicinity of 3 boreholes which form a cross section from the perimeter of the basin to its center. Cross borehole ERT images the changes in formation electrical properties due to removal of DNAPL, extending the understanding of DNAPL removal between the boreholes. During pumping, electrical resistivities decreased; we suggest these decreases are directly caused by the reduction in DNAPL. During ground water pumping, water with relatively low resistivity replaces some of the DNAPL pockets as the highly insulating DNAPL is removed. Results suggest that, as DNAPL is pumped from a nearby well, product slowly drains along the top of an aquitard and into the pump well, where it collects.
Date: January 1, 1997
Creator: Newmark, R.L.
Partner: UNT Libraries Government Documents Department

Dumping pump and treat: rapid cleanups using thermal technology

Description: Underground spills of volatile hydrocarbons are often difficult to clean up, especially if the contaminants are present in or below the water table as a separate liquid-organic phase. Excavating and treating the contaminated soil may not be practical or even possible if the affected zone is relatively deep. Merely pumping groundwater has proven to be ineffective because huge amounts of water must be flushed through the contaminated area to clean it; even then the contaminants may not be completely removed. Due to the low solubility of most common contaminants, such pump and treat systems can be expected to take decades to centuries to actually clean a site. Today, many sites are required to pump and treat contaminated groundwater even though there is no expectation that the site will be cleaned. In these cases, the pumps simply control the spread of the contaminant, while requiring a continuous flow of money, paperwork, and management attention. Although pump and treat systems are relatively inexpensive to operate, they represent along term cost. Most importantly, they rarely remove enough contaminant to change the property`s status. Although a pump and treat system can offer compliance in a regulatory sense, it doesn`t solve the site`s liability problem. Thermal methods promise to solve this dilemma by actually cleaning a property in a short time period, thus limiting the period of liability. This may involve cleaning a site to closure during the initial contaminant-removal phase, or removal of the majority of the contaminant so that natural processes such as bioremediation can return the site to pristine condition over a period of years, without further owner intervention. Today`s regulatory environment encourages this approach through efforts such as the brownfields initiatives. In either case, this requires a strong commitment on the part of the site owner. Most if not all the ...
Date: March 11, 1997
Creator: Newmark, R.L. & Aines, R.D.
Partner: UNT Libraries Government Documents Department

Preliminary report on shallow research drilling in the Salton Sea region

Description: During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The central thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09/degree/C/m) to extreme (0.83/degree/C/m) in only 2.4 km. The heat flow in the central part of the anomaly is greater than 600 mW/m/sup 2/ and in some areas exceeds 1200 mW/m/sup 2/. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes.
Date: January 14, 1988
Creator: Newmark, R.L.; Kasameyer, P.W. & Younker, L.W.
Partner: UNT Libraries Government Documents Department

Electrical resistance tomography using steel cased boreholes as long electrodes

Description: Electrical resistance tomography (ERT) using multiple electrodes installed in boreholes has been shown to be useful for both site characterization and process monitoring. In some cases, however, installing multiple downhole electrodes is too costly (e.g., deep targets) or risky (e.g., contaminated sites). For these cases we have examined the possibility of using the steel casings of existing boreholes as electrodes. Several possibilities can be considered. The first case we investigated uses an array of steel casings as electrodes. This results in very few data and thus requires additional constraints to limit the domain of possible inverse solutions. Simulations indicate that the spatial resolution and sensitivity are understandably low but it is possible to coarsely map the lateral extent of subsurface processes such as steam floods. The second case uses an array of traditional point borehole electrodes combined with long-conductor electrodes (steel casings). Although this arrangement provides more data, in many cases it results in poor reconstructions of test targets. Results indicate that this method may hold promise for low resolution imaging where steel casings can be used as electrodes but the merits depend strongly on details of each application. Field tests using these configurations are currently being conducted.
Date: July 20, 1999
Creator: Daily, W; Newmark, R L & Ramirez, A
Partner: UNT Libraries Government Documents Department

Drilling investigations of crustal rifting processes in the Salton Trough, California

Description: The paper describes the results of CSDP activities in the Salton Sea Geothermal Field (SSGF), concentrating on a shallow heat-flow survey, but also considering preliminary results from the Salton Sea Scientific Drilling Program (SSSDP). Whether the heat input rate to localized systems is high enough to account for the overall thermal budget of the Salton Trough is examined. (ACR)
Date: January 1, 1986
Creator: Kasameyer, P.W.; Younker, L.W.; Newmark, R.L. & Duba, A.G.
Partner: UNT Libraries Government Documents Department

Drilling investigations of crustal rifting processes in the Salton Trough, California. Revision 1

Description: The results of CSDP activities in the Salton Sea Geothermal Field (SSGF) are briefly described, concentrating on a shallow heat flow survey, but also discussing preliminary results from the Salton Sea Scientific Drilling Program (SSSDP). The hypothesis that localized thermal zones are the source of all the heat in the Salton Trough is examined. (ACR)
Date: January 1, 1986
Creator: Kasameyer, P.W.; Younker, L.W.; Newmark, R.L. & Duba, A.G.
Partner: UNT Libraries Government Documents Department

Results from shallow research drilling at Inyo Domes, Long Valley Caldera, California and Salton Sea geothermal field, Salton Trough, California

Description: This report reviews the results from two shallow drilling programs recently completed as part of the United States Department of Energy Continental Scientific Drilling Program. The purpose is to provide a broad overview of the objectives and results of the projects, and to analyze these results in the context of the promise and potential of research drilling in crustal thermal regimes. The Inyo Domes drilling project has involved drilling 4 shallow research holes into the 600-year-old Inyo Domes chain, the youngest rhyolitic event in the coterminous United States and the youngest volcanic event in Long Valley Caldera, California. The purpose of the drilling at Inyo was to understand the thermal, chemical and mechanical behavior of silicic magma as it intrudes the upper crust. This behavior, which involves the response of magma to decompression and cooling, is closely related to both eruptive phenomena and the establishment of hydrothermal circulation. The Salton Sea shallow research drilling project involved drilling 19 shallow research holes into the Salton Sea geothermal field, California. The purpose of this drilling was to bound the thermal anomaly, constrain hydrothermal flow pathways, and assess the thermal budget of the field. Constraints on the thermal budget links the local hydrothermal system to the general processes of crustal rifting in the Salton Trough.
Date: September 1, 1987
Creator: Younker, L.W.; Eichelberger, J.C.; Kasameyer, P.W.; Newmark, R.L. & Vogel, T.A.
Partner: UNT Libraries Government Documents Department

Electrical resistance tomography using steel cased boreholes as electrodes

Description: Electrical resistance tomography (ERT) using multiple electrodes installed in boreholes has been shown to be useful for both site characterization and process monitoring. In some cases, however, installing multiple downhole electrodes is too costly (e.g., deep targets) or risky (e.g., contaminated sites). For these cases we have examined the possibility of using the steel casings of existing boreholes as electrodes. The first case we investigated used an array of steel casings as electrodes. This results in very few data and thus requires additional constraints to limit the domain of possible inverse solutions. Simulations indicate that the spatial resolution and sensitivity are understandably low but it is possible to coarsely map the lateral extent of subsurface processes such as steam floods. A hybrid case uses traditional point electrode arrays combined with long-conductor electrodes (steel casings). Although this arrangement provides more data, in many cases it results in poor reconstructions of test targets. Results indicate that this method may hold promise for low resolution imaging where steel casings can be used as electrodes.
Date: March 22, 1999
Creator: Newmark, R L; Daily, W & Ramirez, A
Partner: UNT Libraries Government Documents Department

Monitoring Carbon Dioxide Sequestration Using Electrical Resistance Tomography (ERT): A Minimally Invasive Method

Description: Successful geologic sequestration of carbon dioxide (CO{sub 2}), will require monitoring the CO{sub 2} injection to confirm the performance of the caprock/reservoir system, assess leaks and flow paths, and understand the geophysical and geochemical interactions between the CO{sub 2} and the geologic minerals and fluids. Electrical methods are especially well suited for monitoring processes involving fluids, as electrical properties are sensitive to the presence and nature of the formation fluids. High resolution tomographs of electrical properties are now used for site characterization and to monitor subsurface migration of fluids (i.e., leaking underground tanks, infiltration events, steam floods, contaminant movement, and to assess the integrity of engineered barriers). When electrical resistance tomography (ERT) imaging can be performed using existing well casings as long electrodes, the method is nearly transparent to reservoir operators, and reduces the need for additional drilling. Using numerical simulations and laboratory experiments, we have conducted sensitivity studies to determine the potential of ERT methods to detect and monitor the migration of CO{sub 2} in the subsurface. These studies have in turn been applied to the design and implementation of the first field casing surveys conducted in an oil field undergoing a CO{sub 2} flood.
Date: August 5, 2002
Creator: Newmark, R L; Ramirez, A L & Daily, W D
Partner: UNT Libraries Government Documents Department

Monitoring Carbon Dioxide Sequestration Using Electrical Resistance Tomography (ERT): Sensitivity Studies

Description: If geologic formations are used to sequester carbon dioxide (CO{sub 2}), monitoring the CO{sub 2} injection will be required to confirm the performance of the reservoir system, assess leaks and flow paths, and understand the geophysical and geochemical interactions between the CO{sub 2} and the geologic minerals and fluids. Electrical methods are well suited for monitoring processes involving fluids, as electrical properties are sensitive to the presence and nature of the formation fluids. High resolution tomographs of electrical properties are now possible using it 3D technique called electrical resistance tomography (ERT). Surveys are commonly conducted utilizing vertical arrays of point electrodes in a cross-well configuration. Recent field results obtained using steel well casings as electrodes are promising. When 3D ERT imaging can be performed using existing well casings as long electrodes, the need for additional drilling of observation wells is minimized. Using a model patterned after an oil field undergoing CO{sub 2} flood, forward and inverse simulations of ERT surveys have been run to test the sensitivity of the method to changes resulting from CO{sub 2} migration. Factors considered include resistivity contrast, anomaly proximity to electrodes, anomaly size and shape, measurement noise, and the electrode configuration used to perform the measurements. Field data suggest that CO{sub 2} migration changes the resistivity of a layer, producing an anomalous region. In our numerical study, the anomalous region s resistivity ranges from 0.2 to 10 times that of the initial value. Its geometry ranges from a thin, horizontal finger to a planar, horizontal mass having vertical protrusions simulating leakage of CO{sub 2} through caprock. Results of simulations run assuming that well casings are used as long electrodes or with arrays of point electrodes (simulating high resolution surveys) show useful information for even the narrowest simulated CO{sub 2} fingers.
Date: February 28, 2001
Creator: Newmark, R L; Ramierz, A L & Daily, W D
Partner: UNT Libraries Government Documents Department

California Levee Risk, Now and in the Future:Identifying Research and Tool Development Needs

Description: The Center for Catastrophic Risk Management (CCRM) and the California Center for Environmental Law and Policy (CCELP) at UC Berkeley and the Lawrence Livermore National Laboratory (LLNL) joined together to cosponsor a workshop to define research requirements to mitigate the hazards facing the Sacramento-San Joaquin Delta Levee system. The Workshop was intended to provide a forum to (1) Report assessments of current vulnerabilities facing the levees, such as structural failure, seismic loading, flooding, terrorism; (2) Consider longer term challenges such as climate change, sea level rise; and (3) Define research requirements to fill gaps in knowledge and reduce uncertainties in hazard assessments.
Date: November 28, 2006
Creator: Newmark, R L; Hanemann, M & Farber, D
Partner: UNT Libraries Government Documents Department

Shallow Drilling In The Salton Sea Region, The Thermal Anomaly

Description: During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09 C/m) to extreme (0.83 C/m) in only 2.4 km. The heat flow in the central part of the anomaly is >600 mW/m{sup 2} and in some areas exceeds 1200 mW/m{sup 2}. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes. These observations of the thermal anomaly provide important constraints for models of the circulation of the hydrothermal system. Thermal budgets based on a simple model for this hydrothermal system indicate that the heat influx rate for local ''hot spots'' in the region may be large enough to account for the rate of heat flux from the entire Salton Trough.
Date: January 1, 1987
Creator: Newmark, R. L.; Kasameyer, P. W. & Younker, L. W.
Partner: UNT Libraries Government Documents Department

High-performance computational and geostatistical experiments for testing the capabilities of 3-d electrical tomography

Description: This project explores the feasibility of combining geologic insight, geostatistics, and high-performance computing to analyze the capabilities of 3-D electrical resistance tomography (ERT). Geostatistical methods are used to characterize the spatial variability of geologic facies that control sub-surface variability of permeability and electrical resistivity Synthetic ERT data sets are generated from geostatistical realizations of alluvial facies architecture. The synthetic data sets enable comparison of the �truth� to inversion results, quantification of the ability to detect particular facies at particular locations, and sensitivity studies on inversion parameters
Date: January 19, 1999
Creator: Carle, S F; Daily, W D; Newmark, R L; Ramirez, A & Tompson, A
Partner: UNT Libraries Government Documents Department

Thermal cleanups using dynamic underground stripping and hydrous pyrolysis oxidation

Description: In the early 1990s, in collaboration with the School of Engineering at the University of California, Berkeley, Lawrence Livermore National Laboratory developed dynamic underground stripping (DUS), a method for treating subsurface contaminants with heat that is much faster and more effective than traditional treatment methods. more recently, Livermore scientists developed hydrous pyrolysis/oxidation (HPO), which introduces both heat and oxygen to the subsurface to convert contaminants in the ground to such benign products as carbon dioxide, chloride ion, and water. This process has effectively destroyed all contaminants it encountered in laboratory tests. With dynamic underground stripping, the contaminants are vaporized and vacuumed out of the ground, leaving them still to be destroyed elsewhere. Hydrous pyrolysis/oxidation technology takes the cleanup process one step further by eliminating the treatment, handling, and disposal requirements and destroying the contamination in the ground. When used in combination, HPO is especially useful in the final polishing of a site containing significant free-product contaminant, once the majority of the contaminant has been removed.
Date: May 1, 1999
Creator: Aines, R D; Knauss, K; Leif, R & Newmark, R L
Partner: UNT Libraries Government Documents Department

Dynamic Underground Stripping: In situ steam sweeping and electrical heating to remediate a deep hydrocarbon spill

Description: Dynamic Underground Stripping is a combination of in situ steam injection, electrical resistance heating, and fluid extraction for rapid removal and recovery of subsurface contaminants such as solvents or fuels. Underground imaging and other measurement techniques monitor the system in situ for process control. Field tests at a deep gasoline spill at Lawrence Livermore National Laboratory recovered over 7000 gallons of gasoline during several months of field operations. Preliminary analysis of system cost and performance indicate that Dynamic Underground Stripping compares favorably with conventional pump-and-treat and vacuum extraction schemes for removing non-aqueous phase liquids such as gasoline from deep subsurface plumes.
Date: July 1, 1994
Creator: Yow, J. L. Jr.; Aines, R. D.; Newmark, R. L.; Udell, K. S. & Ziagos, J. P.
Partner: UNT Libraries Government Documents Department

Accelerated cleanup risk reduction

Description: There is no proven technology for remediating contaminant plume source regions in a heterogeneous subsurface. This project is an interdisciplinary effort to develop the requisite new technologies so that will be rapidly accepted by the remediation community. Our technology focus is hydrous pyrolysis/oxidation (HPO) which is a novel in situ thermal technique. We have expanded this core technology to leverage the action of steam injection and place an in situ microbial filter downstream to intercept and destroy the accelerated movement of contaminated groundwater. Most contaminant plume source regions, including the chlorinated solvent plume at LLNL, are in subsurface media characterized by a wide range in hydraulic conductivity. At LLNL, the main conduits for contaminant transport are buried stream channels composed of gravels and sands; these have a hydraulic conductivity in the range of 10{sup -1} to 10{sup -2} cm/s. Clay and silt units with a hydraulic conductivity of 10{sup -1} to 10{sup -6} cm/s bound these buried channels; these are barriers to groundwater movement and contain the highest contaminant concentrations in the source region. New remediation technologies are required because the current ones preferentially access the high conductivity units. HPO is an innovative process for the in situ destruction of contaminants in the entire subsurface. It operates by the injection of steam. We have demonstrated in laboratory experiments that many contaminants rapidly oxidize to harmless compounds at temperatures easily achieved by injecting steam, provided sufficient dissolved oxygen is present. One important challenge in a heterogeneous source region is getting heat, contaminants, and an oxidizing agent in the same place at the same time. We have used the NUFT computer program to simulate the cyclic injection of steam into a contaminated aquifer for design of a field demonstration. We used an 8 hour, steam/oxygen injection cycle followed by a 56 hour ...
Date: February 1, 1998
Creator: Knapp, R.B.; Aines, R.M.; Blake, R.G.; Copeland, A.B.; Newmark, R.L. & Tompson, A.F.B.
Partner: UNT Libraries Government Documents Department

Summary of the LLNL gasoline spill demonstration - dynamic underground stripping project

Description: Underground spills of volatile hydrocarbons (solvents or fuels) can be difficult to clean up when the hydrocarbons are present both above and below the water table and are found in relatively impermeable clays. Years of groundwater pumping may not completely remove the contamination. Researchers at Lawrence Livermore National Laboratory (LLNL) and the College of Engineering at the University of California at Berkeley (UCB) have collaborated to develop a technique called Dynamic Underground Stripping to remove localized underground spills in a relatively short time. The U.S. Department of Energy`s Office of Environmental Restoration and Waste Management has sponsored a full-scale demonstration of this technique at the LLNL gasoline spill site. When highly concentrated contamination is found above the standing water table, vacuum extraction has been very effective at both removing the contaminant and enhancing biological remediation through the addition of oxygen. Below the water table, however, these advantages cannot be obtained. For such sites where the contamination is too deep for excavation, there are currently no widely applicable cleanup methods. Dynamic Underground Stripping removes separate-phase organic contaminants below the water table by heating the subsurface above the boiling point of water, and then removing both contaminant and water by vacuum extraction. The high temperatures both convert the organic to vapor and enhance other removal paths by increasing diffusion and eliminating sorption. Because this method uses rapid, high-energy techniques in cleaning the soil, it requires an integrated system of underground monitoring and imaging methods to control and evaluate the process in real time.
Date: April 3, 1995
Creator: Newmark, R.L. & Aines, R.D.
Partner: UNT Libraries Government Documents Department

An integrated approach to monitoring a field test of in situ contaminant destruction

Description: The development of in situ thermal remediation techniques requires parallel development of techniques capable of monitoring the physical and chemical changes for purposes of process control. Recent research indicates that many common contaminants can be destroyed in situ by hydrous pyrolysis/oxidation (HPO), eliminating the need for costly surface treatment and disposal. Steam injection, combined with supplemental air, can create the conditions in which HP0 occurs. Field testing of this process, conducted in the summer of 1997, indicates rapid destruction of polycyclic aromatic hydrocarbons (PAHs). Previous work established a suite of underground geophysical imaging techniques capable of providing sufficient knowledge of the physical changes in the subsurface during thermal treatment at sufficient frequencies to be used to monitor and guide the heating and extraction processes. In this field test, electrical resistance tomography (ERT) and temperature measurements provided the primary information regarding the temporal and spatial distribution of the heated zones. Verifying the in situ chemical destruction posed new challenges. We developed field methods for sampling and analyzing hot water for contaminants, oxygen, intermediates and products of reaction. Since the addition of air or oxygen to the contaminated region is a critical aspect of HPO, noble gas tracers were used to identify fluids from different sources. The combination of physical monitoring with noble gas identification of the native and injected fluids and accurate fluid sampling resulted in an excellent temporal and spatial evaluation of the subsurface processes, from which the amount of in situ destruction occurring in the treated region could be quantified. The experimental field results constrain the destruction rates throughout the site, and enable site management to make accurate estimates of total in situ destruction based on the recovered carbon. As of October, 1998, over 400,000 kg (900,000 lb) of contaminant have been removed from the site; about 18% of ...
Date: December 1, 1998
Creator: Aines, R D; Carrigan, C; Chiarappa, M; Eaker, C; Elsholtz, A; Hudson, G B et al.
Partner: UNT Libraries Government Documents Department

Semivolatile organic (GC-MS) and inorganic analyses of groundwater samples during the hydrous pyrolysis/oxidation (HPO) field test in Visalia, CA, 1997

Description: Hydrous pyrolysis/oxidation (HPO) is a novel, in situ, thermal-remediation technology that uses hot, oxygenated groundwater to completely oxidize a wide range of organic pollutants. A field demonstration of HPO was performed during the summer of 1997 at the Southern California Edison Pole Yard in Visalia, California, a site contaminated with creosote. The goal of the field experiment was to confirm the success of HPO under field remediation conditions. The groundwater was heated by steam injections, and oxygen was added by co-injection of compressed air. The progress of the HPO remediation process was evaluated by monitoring groundwater from multiple wells for dissolved oxygen, dissolved inorganic carbon, and dissolved organic contaminant levels. Analyses of groundwater chemistry allowed us to measure the concentrations of creosote components and to identify oxygenated intermediates produced by the HPO treatment. Dissolved organic carbon levels increased in response to steam injections because of the enhanced dissolution and mobilization of the creosote into the heated groundwater. Elevated concentrations of phenols and benzoic acid were measured in wells affected by the steam injections. Concentrations of other oxygenated compounds (i.e., fluorenone, anthrone, and 9,10-anthracenedione) increased in response to the steam injections. The production of these partially oxidized compounds is consistent with the aqueous-phase HPO reactions of creosote. Additional changes in the groundwater in response to steam injection were also consistent with the groundwater HPO chemistry. A drop in dissolved oxygen was observed in the aquifer targeted for the steam injections, and isotope shifts in the dissolved inorganic pool reflected the input of oxidized carbon derived from the creosote carbon.
Date: February 5, 1998
Creator: Chiarappa, M; Knauss, K G; Kumamoto, G; Leif, R N & Newmark, R L
Partner: UNT Libraries Government Documents Department

Stochastic Engine: Direct Incorporation of Measurements Into Predictive Simulations

Description: We are creating a new method of combining disparate types of geologic observations and process simulations. Using Bayesian inferencing and an efficient search algorithm, we obtain a consolidated body of knowledge in the form of multiple configurations and parameter values of the system that are consistent with our existing data and process models. In so doing, we effectively estimate the distributions of both individual parameters and system-wide states, and their likelihood of occurrence. This is in contrast with conventional inversion methods, which produce a single deterministic understanding lacking quantitative information about the distribution of uncertainty. We call this combination of probabilistic evaluation and deterministic process simulators the stochastic engine. Our approach allows the investigators to rapidly improve their understanding of system progress, making it particularly valuable for active processes like injection. The Bayesian inferencing is driven by forward process models that predict data values, such as temperature or electrical voltage, for direct comparison to measured field values. We stage the stochastic searches of possible configurations and run the simplest models, such as lithology estimators, at the lower stages. The majority of possible configurations are eliminated from further consideration by the higher stages' more complex models, such as electrical resistance models for geophysical imaging, or flow and transport models for fluid movement. The approach allows for the continuous augmentation of existing data with newly available information to enhance our understanding and reduce the number of high likelihood configurations. This effectively creates a tool capable of dynamically finding models of underground geological systems that are consistent with all available data. The stochastic engine approach will dramatically increase our understanding of large-scale complex systems and the accuracy of predicting their future behavior under natural or man-made conditions.
Date: August 2, 2001
Creator: Newmark, R L; Aines, R D; Nitao, J J; Hanley, W G; Carle, S; Ramirez, A L et al.
Partner: UNT Libraries Government Documents Department

Energy Sector Vulnerability to Climate Change: Adaptation Options to Increase Resilience

Description: The U.S. Department of Energy is conducting an assessment of vulnerabilities of the U.S. energy sector to climate change and extreme weather. Emphasizing peer reviewed research, it seeks to quantify vulnerabilities and identify specific knowledge or technology gaps. It draws upon a July 2012 workshop, ?Climate Change and Extreme Weather Vulnerability Assessment of the US Energy Sector?, hosted by the Atlantic Council and sponsored by DOE to solicit industry input.
Date: February 1, 2013
Creator: Newmark, R. L.; Bilello, D.; Macknick, J.; Hallet, K. C.; Anderson, R.; Tidwell, V. et al.
Partner: UNT Libraries Government Documents Department

In situ destruction of contaminants via hydrous pyrolysis/ oxidation:Visalia Field Test

Description: A field test of hydrous pyrolysis/oxidation (HPO) was conducted during the summer of 1997, during a commercial application of thermal remediation (Dynamic Underground Stripping (DUS)) at the Visalia Pole Yard (a super-fund site) in southern California. At Visalia, Southern California Edison Co. is applying the DUS thermal remediation method to clean up a large (4.3 acre) site contaminated with pole-treating compounds. This is a full-scale cleanup, during which initial extraction of contaminants is augmented by combined steam/air injection in order to enhance the destruction of residual contaminants by HPO. Laboratory results indicate that the contaminants at Visaha react at similar rates to TCE, which has been the focus of extensive laboratory work (Knauss et al., 1998a-c). Field experimental results from this application yield valuable information (1) confirming the destruction of contaminants in soil and groundwater by HPO, (2) validating the predictive models used to design HP0 steam injection systems, (3) demonstrating that accurate field measurements of the critical fluid parameters can be obtained using existing monitoring wells and (4) obtaining a reasonable prediction of the cost and effectiveness of HPO, working at a commercial scale and with commercial partners. The goal of our additional study and demonstration in conjunction with Edison has been to obtain early proof of hydrous pyrolysis/oxidation in the field, and validate our predictive models and monitoring strategies. This demonstration provides valuable economic and practicability data obtained on a commercial scale, with more detailed field validation than is commonly available on a commercially-conducted cleanup. The results of LLNL� s field experiments constrain the destruction rates throughout the site, and enable site management to make accurate estimates of total in situ destruction based on the recovered carbon. As of October, 1998, over 900,000 lb of contaminant have been removed from the site; about 18% of this has been ...
Date: December 1, 1998
Creator: Aines, R D; Carrigan, C; Chiarappa, M; Eaker, C; Hudson, B; Knauss, K et al.
Partner: UNT Libraries Government Documents Department

Stochastic Engine Final Report: Applying Markov Chain Monte Carlo Methods with Importance Sampling to Large-Scale Data-Driven Simulation

Description: Accurate prediction of complex phenomena can be greatly enhanced through the use of data and observations to update simulations. The ability to create these data-driven simulations is limited by error and uncertainty in both the data and the simulation. The stochastic engine project addressed this problem through the development and application of a family of Markov Chain Monte Carlo methods utilizing importance sampling driven by forward simulators to minimize time spent search very large state spaces. The stochastic engine rapidly chooses among a very large number of hypothesized states and selects those that are consistent (within error) with all the information at hand. Predicted measurements from the simulator are used to estimate the likelihood of actual measurements, which in turn reduces the uncertainty in the original sample space via a conditional probability method called Bayesian inferencing. This highly efficient, staged Metropolis-type search algorithm allows us to address extremely complex problems and opens the door to solving many data-driven, nonlinear, multidimensional problems. A key challenge has been developing representation methods that integrate the local details of real data with the global physics of the simulations, enabling supercomputers to efficiently solve the problem. Development focused on large-scale problems, and on examining the mathematical robustness of the approach in diverse applications. Multiple data types were combined with large-scale simulations to evaluate systems with {approx}{sup 10}20,000 possible states (detecting underground leaks at the Hanford waste tanks). The probable uses of chemical process facilities were assessed using an evidence-tree representation and in-process updating. Other applications included contaminant flow paths at the Savannah River Site, locating structural flaws in buildings, improving models for seismic travel times systems used to monitor nuclear proliferation, characterizing the source of indistinct atmospheric plumes, and improving flash radiography. In the course of developing these applications, we also developed new methods to ...
Date: March 11, 2004
Creator: Glaser, R E; Johannesson, G; Sengupta, S; Kosovic, B; Carle, S; Franz, G A et al.
Partner: UNT Libraries Government Documents Department