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Critical and trace element data for drill cuttings from Beowawe, Dixie Valley, and Roosevelt Hot Springs-Blundell geothermal production fields, for drill cuttings from Uinta basin producing oil-gas wells, and from outcrops in the Sevier Thermal Anomaly-Utah.
Geothermal energy resources are present in the Hot Springs Bay Valley geothermal area, and the City has invested considerable money and time in the exploration of the resource for future use. Exploration activities funded primarily through a grant the City was awarded from Alaska Energy Authority and later supplemented by the U. S. Department of Energy (DOE), with cost share from the City. The exploration led to the development of a geothermal resource conceptual model that was built and refined between 2008 and 2018. During this period, geological and geophysical studies, exploration drilling and other activities were completed, including a preliminary feasibility study for a power project, investigations of the terrain for suitability for access and development, environmental and archeological review, plus TG well abandonment and a review of economic considerations. The model of the resource predicts that there is a viable geothermal resource in two general areas: on the northwest edge of Hot Springs Bay Valley going northwest of the valley (hot springs area) and southwest of the Valley (fumarole area). The resource temperature for the valley area is expected to be about 170°C (340°F) and given the size and permeability estimates (with a factor for the level of confidence in the estimates), the mean power capacity of the outflow resource is 3 MWe and the P50 (most likely) power capacity is 1 MWe. The fumarole area has an expected resource temperature of 240°C (464°F) and given the size and permeability estimates mean capacity is 20 MWe and the P50 (most likely) capacity is 9 MWe. Permeability is the most difficult factor to predict and has a significant impact on the available geothermal fluids and therefore the amount of power that can be generated. The uncertainty in this value is the main reason for lower confidence in the likelihood of exploration success and the wide range in predicted MW values. The permeability has been difficult to locate as indicated by the results of the flow test at AK-3 in 2017. The test resulted in the production of some fluid, but due to low permeability, the recharge to the wellbore was too slow to sustain flow. The greatest probability of overall MWe production is in the fumarole region, but development is hampered by poor accessibility. The extremely high cost of road building for exploratory drilling, put an end to planning at an intermediate stage of the project and refocused attention on the viability of development in the hot spring outflow part of the resource. The City will be determining what the next steps are with AK-3, which is still that is still open and maintained in a suspended status in HSBV. While AK-3 remains accessible (not plugged with cement) it will need to be maintained. The City has a bond with AOGCC that will remain in place until the well is abandoned. GRG recommends that the well be maintained open as an asset for the foreseeable future.
As a result of a spectroscopic survey of stars classified as nonemission OB+, Drilling (1983) has detected 12 new subluminous O stars. It was found that these stars are the hottest known O type subdwarfs. The effective temperatures of the stars are 60,000 K or higher. It has been possible to observe two of these stars with Voyager 1, taking into account LSE 21 and LS IV +10.9 deg. LSE 21 is one of the hottest of the new subdwarfs, with an effective temperature of at least 100,000 K. The optical spectrum indicates a hydrogen-rich atmosphere of high surface gravity. LX IV +10.9 deg is one of the cooler objects with an effective temperature of 65,000 K. The optical spectrum indicates an extremely helium-rich atmosphere and a somewhat lower surface gravity than LSE 21. The Voyager 1 observations confirm the temperature scale set up by Schoenberger and Drilling (1984) for the hottest O type subdwarfs.
Future NASA missions to Mars require sampling techniques for in-situ analysis and/or sample return to Earth. One of the major limitations of sample collection on Mars and other low gravity environments using conventional drilling is the need for high axial force during drilling.
A novel ultrasonic drilling and coring device (USDC) was demonstrated to drill a wide variety of rocks: from ice and chalk to granite and basalt.
The Hanford site in Washington State is possibly the most radioactive-contaminated site in the USA presenting a major environmental problem requiring urgent clean-up. Sealed capsules containing halides of strontium (Sr) and cesium (Cs) account for over a third of the total radioactivity. Interim storage for a period of 10-half-lives is an unappealing option since many of the capsules contain Cs-135, which has a half-life of 2.3 million years, and the dose received from the shorter-lived isotopes would remain dangerously high for several generations. Deep geological disposal of the capsules would be a safer solution. We discuss a new and revised conceptual model for disposal of the entire Hanford capsule inventory in a single deep geological borehole with a diameter that could be as little as 31 cm. The concept involves placing thirty capsules inside a steel-disposal container. Holes up to this size are regularly drilled to depths much greater than 5 km by the hydrocarbon industry and are well within current drilling capabilities. Numerical modeling work demonstrates the feasibility of the conceptual model. In particular we examine the thermal envelope generated as a function of time enabling decisions to be made on possible fillings for the borehole annulus. Variations on the disposal concept include disposing different combinations of capsules to control the heat output and thus the temperature rise. The results lend support to a comment attributed to Secretary Moniz that the Hanford capsules could be the world's first HLW to be disposed of in a deep borehole. (authors)
An engineering study has developed alternative concepts for waste packaging and for emplacing/retrieving packages in deep boreholes. The study compared costs and risks associated with emplacement using wire-line vs. drill-string technologies. Selection of a method is needed to proceed with demonstration as part of the Deep Borehole Field Test being conducted by the U.S. Department of Energy, Office of Used Nuclear Fuel Disposition. Each emplacement method was described as a series of steps, and each step was analyzed for potential to cause any of four off-normal events including drops and getting stuck. Each such event was supported by a fault tree. The hazard analysis identified a number of improvements including: 1) impact limiters; 2) safety systems; 3) instrumentation; and 4) methods to mitigate casing collapse or borehole debris during operations. Off-normal events were related in a top-level event tree with normal and off-normal outcomes. Costs were estimated for each outcome (including recovery and decontamination). A panel of subject matter experts was convened to review the study and provide key inputs. The wire-line method is less costly for normal operations, while the drill-string method has advantages if waste packages become stuck. The wire-line method has a lower aggregate probability of accidents resulting in waste package breach. The integrated probability of off-normal events is on the order of a few percent per borehole, and engineered measures are quite important to prevent and mitigate accidents, limiting radiological consequences. Development of these measures during design will help to further improve system reliability. (authors)
Los Alamos National Laboratory (LANL) is the primary plutonium science and manufacturing facility in the United States supporting multiple national security programs. It is responsible for completing a high variety of small-batch manufacturing tasks requiring the handling and precision machining of Special Nuclear Materials (SNM). Given the myriad of tasks that must be completed in a limited workspace, LANL intends to utilize flexible, multi-use robotic work-cells capable of completing a variety of mission critical tasks in a single glovebox with no re-tooling needed between batch jobs. This approach would allow LANL more flexibility in its production schedule and to meet its future production and research objectives. In this paper, we present a system that integrates multiple sensors and other manufacturing peripherals into existing glovebox infrastructure. Currently, a technician can place an object in the work area where vision sensors and supervisory software identify the object and its pose and automatically determine which manufacturing task to complete. Pose uncertainty is addressed in real-time by the task planner, eliminating the need for fixtures. Grasps are validated using pressure sensors, payload sensors, and grasp quality metrics to ensure that objects are not dropped or damaged during manipulation. The robot, sensors, and peripherals are controlled using open-source software built utilizing ROS (Robot Operating System), which minimizes redevelopment and allows for re-use and extensibility. Established capabilities support vision, collision-free path planning, and more, minimizing development time. For this effort, particular attention was given to the integration of general peripheral devices (drill, chuck, etc.), which is critical to efficiently utilizing ROS in manufacturing environments. This integration is achieved with an in-development framework that allows for quick integration of peripherals, including I/O devices and motors. Contact tasks utilize the Generalized Contact Control Framework (GCCF) previously developed at UT Austin. GCCF allows application developers to easily define multiple contact control tasks for a single robot. This paper summarizes the key software components necessary to develop the multi-use work-cell including existing ROS components. UT-developed software for grasp validation, peripheral integration, and contact control is presented in more depth. Finally the glovebox system is demonstrated completing a set of tasks with no fixturing necessary. Primary tasks include surface preparation/ablation, drilling, press-fitting, and sorting, as well as supporting material transfer and inspection tasks. The glovebox work-cell reduces cost, operator dose, ergonomic issues, and time loss due to material transfer between gloveboxes that only support one task. If multiple glovebox work-cells are in use, they have the potential to eliminate bottlenecks and scale production capabilities beyond current limits. (authors)
Characterization of natural attenuation of hexavalent (Cr(VI)) on aquifer sediments within the Cr plume at Los Alamos National Laboratory has been conducted to (1) refine conceptual and numerical models of chromium fate and transport, (2) evaluate the long-term stability of Cr(III)/Cr(VI) in the complex groundwater system along flow paths from the source to the regional aquifer, and (3) evaluate and develop options for successful remediation. The naturally high chromium abundance in aquifer sediments at Los Alamos pose an unique challenge for characterization of chromium reduction, making conventional approaches such as uptake tests and advanced spectroscopic measurements ineffective in identifying relatively small amounts of anthropogenic Cr(VI) in the sediments. To address this challenge and as complimentary to these conventional methods, sequential leaching tests were conducted on core hole sediments obtained from sonic drilled cores taken from both contaminated and non-contaminated horizons among two mineralogically distinct formations (Puye formation and Miocene Pumiceous Unit) within the Cr plume. A series of three and coherent sequential leaching steps were conducted: 1) an alkaline leach to determine the amount of Cr(VI) sorbed on the sediments. 2) a weak acid leach (using 0.01 M and 0.1 M HNO{sub 3}) to determine the amount of anthropogenic chromium (Cr(III) and Cr(VI)) on aquifer sediment surfaces, and 3) a strong acid leach (using 2 M HNO{sub 3}) to characterize the amount of releasable Cr(III) from aquifer minerals. Additionally we tested the efficiency and detection limit of sequential leaching on bentonite, which consists mainly of smectite, used in drill muds and laboratory-grade biotite spiked with known concentrations of Cr(VI). Smectite and biotite are two phases considered to be potentially important host minerals in aquifer sediments within the plume. Thus, by comparing contaminated and uncontaminated sediment leachate results of chromium and other major and trace elements, the signature and quantity of anthropogenic Cr(VI) can be derived. Our results from the weak acid leaching test indicate that the method detection limit for Cr 'uptake' was about 1 μg/g for biotite and about 0.5 μg/g for bentonite. Our results also indicate that all samples taken from known contaminated horizons in comparison to non-contaminated ones within the Puye formation showed no statistical difference in the amount of Cr leached indicative of its insignificant Cr(VI) attenuation capacity. The amount of excess Cr leached from the magnetic fraction of the contaminated Miocene Pumiceous samples was about 2 μg/g of sediment. Considering that the magnetic fraction was about 11% by mass of the bulk sample, the excess amount of Cr leached from the bulk material would be about 0.2 μg/g of sediment, suggesting the potential for some Cr(VI) attenuation capacity in the Miocene pumice unit. (authors)
Earthquakes trigger the eruption of mud and magmatic volcanoes and affect ongoing eruptive activity. One mechanism that could trigger an eruption is clay liquefaction. In this work we model the propagation of seismic waves beneath the Lusi mud eruption (East Java, Indonesia) using available seismic velocity and density models to assess the effect of subsurface structure on the amplification of incident seismic waves. We find that using an updated subsurface density and velocity structure, there is no significant amplification of incident seismic energy in the Upper Kalibeng Formation, the source of the erupting solids. Thus, the hypothesis that the Lusi eruption was triggered by clay liquefaction appears unlikely to be correct. Independent constraints from gas chemistry as well as analyses of drilling activities at the nearby Banjar-Panji 1 gas exploration well and an analysis of the effects of other earthquakes all favor a drilling trigger.
Bottom-simulating reflectors (BSRs) on marine seismic data are commonly used to identify the presence of natural gas hydrate in marine sediments, although the exact relationship between gas hydrate and BSRs is undefined. In this paper, to clarify this relationship we compile a data set of probable gas hydrate occurrence as appraised from well logs of 788 industry wells in the northern Gulf of Mexico. We combine the well log data set with a data set of BSR distribution in the same area identified from 3-D seismic data. We find that a BSR increases the chances of finding gas hydrate by 2.6 times as opposed to drilling outside a BSR and that the wells within a BSR also contain thicker and higher resistivity hydrate accumulations. Finally, even so, over half of the wells drilled through BSRs have no detectable gas hydrate accumulations and gas hydrate occurrences and BSRs do not coincide in most cases.
An evolutionary inversion approach is suggested for the interpretation of nuclear and resistivity logs measured by direct-push tools in shallow unsaturated sediments. The efficiency of formation evaluation is improved by estimating simultaneously (1) the petrophysical properties that vary rapidly along a drill hole with depth and (2) the zone parameters that can be treated as constant, in one inversion procedure. In the workflow, the fractional volumes of water, air, matrix and clay are estimated in adjacent depths by linearized inversion, whereas the clay and matrix properties are updated using a float-encoded genetic meta-algorithm. The proposed inversion method provides an objective estimate of the zone parameters that appear in the tool response equations applied to solve the forward problem, which can significantly increase the reliability of the petrophysical model as opposed to setting these parameters arbitrarily. The global optimization meta-algorithm not only assures the best fit between the measured and calculated data but also gives a reliable solution, practically independent of the initial model, as laboratory data are unnecessary in the inversion procedure. The feasibility test uses engineering geophysical sounding logs observed in an unsaturated loessy-sandy formation in Hungary. The multi-borehole extension of the inversion technique is developed to determine the petrophysical properties and their estimation errors along a profile of drill holes. The genetic meta-algorithmic inversion method is recommended for hydrogeophysical logging applications of various kinds to automatically extract the volumetric ratios of rock and fluid constituents as well as the most important zone parameters in a reliable inversion procedure.
We report resistivity and acoustic logs are widely used to estimate gas hydrate saturation in various sedimentary systems using one of the two popular methods ((1) acoustic velocity and (2) electrical resistivity), but the limitations of these two methods are often overlooked, which include (i) well-specific calibration of empirical exponents in the electrical resistivity method, (ii) assumption of known pore morphology for gas hydrates in the acoustic velocity method, and (iii) presence of unknown mineralogy and bulk modulus terms in the acoustic velocity method. NMR-density porosity-derived gas hydrate saturation based on the analysis of the transverse magnetization relaxation time (T2) is considered the most precise method, but acquisition of NMR-based logs is limited at relatively recent drilled sites; additionally, its use in conventional oil and gas reservoirs is not that common due to higher cost and operational deployment limitations associated with acquiring NMR well-logs. This study proposes a new method that predicts gas hydrate saturation (S h ) for any well using porosity, bulk density, and compressional wave (P wave) velocity well-logs with neural network (or stochastic gradient descent regression) without any well-specific calibration and/or other aforementioned shortcomings of the existing methods. The method is developed by examining the underlying dependency between S h and different combinations of well-logs, chosen from 6 routine logs, with 12 different machine learning (ML) algorithms. The accuracy of the proposed method in predicting S h is ~ 84%, which is better than the accuracy of seismic and electrical resistivity methods (≤ 75%) per the results reported by three different studies. The robustness of the method in the specific case of permafrost-associated gas hydrates is demonstrated with well-log data from two wells drilled on the Alaska North Slope.
Micro-slotting, a microscale relaxation residual stress measurement technique, has been shown in recent years to be a reliable method for measuring local residual stresses in metallic materials. This study demonstrates the unique application of the micro-slotting residual stress measurement technique for measuring near-edge tangential residual stresses around cold-expanded holes in Ti-6Al-4V plates. Knowledge of the near-edge elastic strains induced by the hole processing, in combination with plastic strain information obtained using electron backscatter diffraction, allowed for interpretation of fatigue life differences and crack growth behavior between the as-drilled and cold-expanded conditions. The similar crack initiation lives of the as-drilled and cold-expanded open-hole coupons were attributed to the similar elastic and plastic strains present at the hole edges. The subsequent crack growth resistance observed for the cold-expanded holes was a result of the large compressive residual stress region induced by cold expansion.
There is renewed interest in using advanced techniques to characterize ancient Roman concrete due to its exceptional durability and low-carbon footprint. In the present work, samples were drilled from the “Hospitium” in Pompeii and were analyzed by synchrotron microtomography (μCT) and neutron radiography to study how the microstructure, including the presence of induced cracks, affects their water adsorption. The water distribution and absorptivity were quantified by neutron radiography. The 3D crack propagation, pore size distribution and orientation, tortuosity, and connectivity were analyzed from μCT results using advanced imaging methods. Porosity was also measured by mercury intrusion porosimetry (MIP) as a reference. Ductile fracture patterns were observed once cracks were introduced. Compared to Portland cement mortar/concrete, the Pompeii samples had relatively high porosity, low connectivity, and a similar coefficient of capillary penetration. In addition, permeability was predicted from models based on percolation theory and pore structure data to evaluate the fluid transport properties. Understanding the microstructure of ancient Pompeii concrete is important because it could inspire the development of modern concrete with high durability.
With U.S. geothermal power production expected to more than triple by 2040, and the majority of this growth expected to occur in arid and water-constrained areas, it is imperative that decision-makers understand the potential long-term limitations to and tradeoffs of geothermal development due to water availability. To this end, water consumption data, including documentation triggered by the National Environmental Policy Act (NEPA) of 1969, production and injection data, and water permit data, were collected from state and federal environmental policy sources in an effort to determine water consumption across the lifecycle of geothermal power plants. Values extracted from these sources were analyzed to estimate water usage during well drilling; to identify sourcing of water for well drilling, well stimulation, and plant operations; and to estimate operational water usage at the plant level. Nevada data were also compared on a facility-by-facility basis with other publicly available water consumption data, to create a complete picture of water usage and consumption at these facilities. This analysis represents a unique method of capturing project-level water data for geothermal projects; however, a lack of statutory and legal requirements for such data and data quality result in significant data gaps, which are also explored
The advent and advancement in hydraulic fracturing techniques have resulted in the rapid growth of unconventional shale oil and gas production over the last couple of decades. Unlike conventional hydrocarbon systems, these shale formations serve as both the source and reservoir and therefore are directly drilled into for hydrocarbon production. Studies in different shale basins have revealed that these reservoirs are geologically complex, heterogeneous, and every play is unique. Therefore, for efficient hydrocarbon recovery, physicochemical, and mechanical attributes of individual shale reservoir need to be taken into account. Even after significant technological advancements, we are still struggling to understand the spatiotemporal variations in type and amount of hydrocarbon produced within a single basin, rapid declines in hydrocarbon production, and the low fracturing fluid recovery rates. In this review article, we briefly summarize how biogeochemical tools can be used to 1) understand variations in the quantity of organic matter (OM) that ultimately controls production of hydrocarbon, 2) determine variations in the quality of OM that ultimately controls the quality and type of hydrocarbons generated, 3) predict the fracturing potential of rock, and 4) increase efficiency of hydrocarbon production by controlling the water-rock-microbe interactions that ensue after hydraulic fracturing fluids are injected into the shale reservoirs. A better understanding and utilization of these biogeochemical processes and tools will help identify sweet spots for shale gas drilling, increase hydrocarbon recovery and open up the possibility of engineering the hydraulic fracturing fluids to enhance recovery and life of these shale reservoirs.
We thank Dr. Giuseppe Etiope for his comment and the opportunity to further discuss why we consider the origin of the methane detected in subsurface fluids obtained from a peridotite aquifer in Oman to be enigmatic. The central focus of Miller et al. (2016) was the characterization of the fluids and dissolved gases recovered from 300 meter wells drilled into peridotite at two locations near Ibra. Microscale geochemical analyses of rock chips recovered during drilling gave further insight into the aqueous geochemistry measurements. These samples allowed us to analyze the extent of modern peridotite hydration and secondary mineralization in light of potential hydrogen-generating reactions. Additionally, biomass was recovered from the fluids, and 16S rRNA showed the presence of methanogens and methanotrophs. These methane-cycling microbes may be modulating the isotopic signature of CH 4 found in the wells; thus, we do not feel comfortable rejecting the hypothesis that microbial activity contributes to the unusual isotopic signature of CH 4 in the wells without further investigation.