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At least 523 records · Page 29Linked to original sources
USGS2000

Oil and gas reserve growth-a model for the Volga-Ural Province, Russia

An understanding of reserve growth in known oil and gas fields has become a critical component of energy resource analysis. Significant statistical studies of reserve growth have been published in the U.S., whereas little information is available on other regions of the world. It may be expected that in many countries the magnitude of reserve growth is different from that in the U.S. because of differences in reporting systems and in exploration and production practices. This paper describes the results of a reserve growth study in a group of largest oil and gas fields of the Volga-Ural petroleum province, Russia. The dynamics of reserve growth in these fields shows rapid reserve additions during the first 5 years of field exploration and development, which results from intensive step-out and delineation drilling. Later reserve growth is slow and is related to improvements in recovery technologies and discoveries of new pools and extensions. These two stages of reserve growth are described by two different groups of empirical models. A comparison of these models with the models developed for the lower 48 states and Gulf Coast offshore of the U.S. demonstrates that the reserve growth in the Volga-Ural province is significantly lower than in the U.S. The proposed models may be used for assessment of future reserve additions in known fields of countries that presently have or recently had a centrally-planned economic system.

Conference Paper↗
USGS2017

Case study - Dynamic pressure-limited capacity and costs of CO2 storage in the Mount Simon sandstone

Widespread deployment of carbon capture and storage (CCS) is likely necessary to be able to satisfy baseload electricity demand, to maintain diversity in the energy mix, and to achieve climate and other objectives at the lowest cost. If all of the carbon dioxide (CO 2 ) emissions from stationary sources (such as fossil-fuel burning power plants, and other industrial plants) in the United States needed to be captured and stored, it could be possible to store only a small fraction of this CO 2 in oil and natural gas reservoirs, including as a result of CO 2 utilization for enhanced oil recovery. The vast majority would have to be stored in saline-filled reservoirs (Dahowski et al., 2005). Given a lack of long-term commercial-scale CCS projects, there is considerable uncertainty in the risks, dynamic capacity, and their cost implications for geologic storage of CO 2 . Pressure buildup in the storage reservoir is expected to be a primary source of risk associated with CO 2 storage, and could severely limit CO 2 injection rates (dynamic storage capacities). Most cost estimates for commercial-scale deployment of CCS estimate CO 2 storage costs under assumed availability of a theoretical capacity to store tens, hundreds, or even thousands of gigatons of CO 2 , without considering geologic heterogeneities, pressure limitations, or the time dimension. This could lead to underestimation of the costs of CO 2 storage (Anderson, 2017). This paper considers the impacts of pressure limitations and geologic heterogeneity on the dynamic CO 2 storage capacity and storage (injection) costs. In the U.S. Geological Survey (USGS)’s National Assessment of Geologic CO 2 Storage Resources (USGS, 2013), the mean estimate of the theoretical storage capacity in the Mount Simon Sandstone was about 94 billion metric tons of CO 2 . However, our results suggest that the pressure-limited capacity after 50 years of injection could be only about 4% of the theoretical geologic storage capacity in this formation. Because this is far less than emissions of CO 2 from stationary sources in the region around the Mount Simon Sandstone, the costs to accommodate the potential annual demand for CO 2 storage in this formation could be significantly greater than current estimates. Our results could have implications for how long and to what extent decision makers can expect to be able to deploy CCS before transitioning to other low- or zero-carbon energy technologies.

Conference Paper↗
USGS2018

Preliminary 2018 national seismic hazard model for the conterminous United States

The 2014 U.S. Geological Survey national seismic hazard model for the conterminous U.S. will be updated in 2018 and 2020 to coincide with the Building Seismic Safety Council’s Project 17 timeline for development of new building code design criteria. The two closely timed updates are planned to allow more time for the Provisions Update Committee to analyze the consequences of the hazard model changes in the design criteria. To prepare the 2018 update we held a workshop (March 7-8, 2018) with scientists and engineers to solicit feedback on the model. The 2018 model will be available for public comment during the summer of 2018. The purpose of this paper is to solicit feedback on the modeling choices and results. The 2018 NSHM considers an updated seismicity catalog and certain key changes in the way ground motions are calculated. First, we implemented new Next Generation Attenuation Relationships for the Central and Eastern North America Region and other published models that allow for the calculation of ground motions at additional periods and site classes in the central and eastern U.S. (CEUS). Second, basin depth terms were implemented in the ground motion models in select regions of the western U.S. (WUS) to account for enhanced long-period ground motions at softer soil sites overlying sedimentary basins. Preliminary results indicate higher ground motions for all periods in parts of the CEUS and for long-periods and soft soils in urban areas overlying sedimentary basins in the WUS.

Conference Paper↗
USGS2007

Regional dynamics of grassland change in the western Great Plains

This paper examines the contemporary land-cover changes in two western Great Plains ecoregions between 1973 and 2000. Agriculture and other land uses can have a substantial effect on grassland cover that varies regionally depending on the primary driving forces of change. In order to better understand change, the rates, types, and causes of land conversion were examined for 1973, 1980, 1986, 1992, and 2000 using Landsat satellite data and a statistical sampling strategy. The overall estimated rate of land-cover change between 1973 and 2000 was 7.4% in the Northwestern Great Plains and 11.5% in the Western High Plains. Trends in both ecoregions have similarities, although the dynamics of change differ temporally depending on driving forces. Between 1973 and 1986, grassland cover declined when economic opportunity drove an expansion of agriculture. Between 1986 and 2000, grassland expanded as public policy and a combination of socioeconomic factors drove a conversion from agriculture to grassland. ?? 2007 Copyright by the Center for Great Plains Studies, University of Nebraska-Lincoln.

Conference Paper↗
USGS1997

Amplitude versus offset modeling of the bottom simulating reflection associated with submarine gas hydrates

A bottom simulating seismic reflection (BSR) that parallels the sea floor occurs worldwide on seismic profiles from outer continental margins. The BSR coincides with the base of the gas hydrate stability field and is commonly used as indicator of natural submarine gas hydrates. Despite the widespread assumption that the BSR marks the base of gas hydrate-bearing sediments, the occurrence and importance of low-velocity free gas in the sediments beneath the BSR has long been a subject of debate. This paper investigates the relative abundance of hydrate and free gas associated with the BSR by modeling the reflection coefficient or amplitude variation with offset (AVO) of the BSR at two separate sites, offshore Oregon and the Beaufort Sea. The models are based on multichannel seismic profiles, seismic velocity data from both sites and downhole log data from Oregon ODP Site 892. AVO studies of the BSR can determine whether free gas exists beneath the BSR if the saturation of gas hydrate above the BSR is less than approximately 30% of the pore volume. Gas hydrate saturation above the BSR can be roughly estimated from AVO studies, but the saturation of free gas beneath the BSR cannot be constrained from the seismic data alone. The AVO analyses at the two study locations indicate that the high amplitude BSR results primarily from free gas beneath the BSR. Hydrate concentrations above the BSR are calculated to be less than 10% of the pore volume for both locations studied.

Conference Paper↗
USGS2006

A semi-empirical model for the estimation of maximum horizontal displacement due to liquefaction-induced lateral spreading

During the 1906 San Francisco Earthquake, liquefaction-induced lateral spreading and resultant ground displacements damaged bridges, buried utilities, and lifelines, conventional structures, and other developed works. This paper presents an improved engineering tool for the prediction of maximum displacement due to liquefaction-induced lateral spreading. A semi-empirical approach is employed, combining mechanistic understanding and data from laboratory testing with data and lessons from full-scale earthquake field case histories. The principle of strain potential index, based primary on correlation of cyclic simple shear laboratory testing results with in-situ Standard Penetration Test (SPT) results, is used as an index to characterized the deformation potential of soils after they liquefy. A Bayesian probabilistic approach is adopted for development of the final predictive model, in order to take fullest advantage of the data available and to deal with the inherent uncertainties intrinstiic to the back-analyses of field case histories. A case history from the 1906 San Francisco Earthquake is utilized to demonstrate the ability of the resultant semi-empirical model to estimate maximum horizontal displacement due to liquefaction-induced lateral spreading.

Conference Paper↗
USGS2005

Steam injection pilot study in a contaminated fractured limestone (Maine, USA): Modeling and analysis of borehole radar reflection data

Steam-enhanced remediation (SER) has been successfully used to remove DNAPL and LNAPL contaminants in porous media. Between August and November 2002, SER was tested in fractured limestone at the former Loring Air Force Base, in Maine, USA. During the SER investigation, the U.S. Geological Survey conducted a series of borehole radar surveys to evaluate the effectiveness of radar methods for monitoring the movement of steam and heat through the fractured limestone. The data were collected before steam injection, 10 days after the beginning of injection, and at the end of injection. In this paper, reflection-mode borehole radar data from wells JBW-7816 and JBW-7817A are presented and discussed. Theoretical modeling was performed to predict the variation of fracture reflectivity owed to heating, to show displacement of water and to assess the effect of SER at the site. Analysis of the radar profile data indicates some variations resulting from heating (increase of continuity of reflectors, attenuation of deeper reflections) but no substantial variation of traveltimes. Spectral content analysis of several individual reflections surrounding the boreholes was used to investigate the replacement of water by steam in the fractures. Observed decrease in radar reflectivity was too small to be explained by a replacement of water by steam, except for two high-amplitude reflectors, which disappeared near the end of the injection; moreover, no change of polarity, consistent with steam replacing water, was observed. The decrease of amplitude was greater for reflectors near well JBW-7817A and is explained by a greater heating around this well.

Maine↗
USGS2017

Responses of a 64-story unique San Francisco, CA. building to four earthquakes and ambient motions

We analyze the ambient and earthquake responses of a 64-story, instrumented, concrete core shear wall building in San Francisco, Calif. equipped with tuned sloshing liquid dampers (TSDs) and buckling restraining braces (BRBs). In an earlier paper [1], only ambient data were used to identify dynamic characteristics. Recently, the 72-channel instrumental array of the building recorded the 24 August 2014 Mw6.0 South Napa and three other earthquakes – allowing comparison of the dynamic characteristics using ambient and earthquake data. Peak accelerations of ambient and the larger South Napa EQ responses at the basement are 0.12 and 5.2 cm/s/s, respectively – a factor of ~ 42 and, at the 61st level, are 0.30 and 16.8 cm/s/s, respectively –a factor of ~56. Fundamental frequencies determined from spectral ratios for the NS (~0.3Hz), EW (0.27Hz) and torsional accelerations for the earthquake response vary within an insignificant frequency band of ~ 0.02-0.03 Hz as compared to those determined from ambient data. At the level of shaking, BRBs or TSDs are not effective enough to alter dynamic characteristics (frequency or damping). Under future stronger (e.g. design level) shaking of the building, the nonlinearities caused by actions of TSDs and BRBs can substantially shift the dynamic characteristics of the building.

California↗
USGS2022

Modeling reservoir release using pseudo-prospective learning and physical simulations to predict water temperature

This paper proposes a new data-driven method for predicting water temperature in stream networks with reservoirs. The water flows released from reservoirs greatly affect the water temperature of downstream river segments. However, the information of released water flow is often not available for many reservoirs, which makes it difficult for data-driven models to capture the impact to downstream river segments. In this paper, we first build a state-aware graph model to represent the interactions amongst streams and reservoirs, and then propose a parallel learning structure to extract the reservoir release information and use it to improve the prediction. In particular, for reservoirs with no available release information, we mimic the water managers' release decision process through a pseudo-prospective learning method, which infers the release information from anticipated water temperature dynamics. For reservoirs with the release information, we leverage a physics-based model to simulate the water release temperature and transfer such information to guide the learning process for other reservoirs. The evaluation for the Delaware River Basin shows that the proposed method brings over 10% accuracy improvement over existing data-driven models for stream temperature prediction when the release data is not available for any reservoirs. The performance is further improved after we incorporate the release data and physical simulations for a subset of reservoirs.

Conference Paper↗
USGS1986

ANALYSIS OF THE U. S. GEOLOGICAL SURVEY STREAMGAGING NETWORK.

This paper summarizes the results from the first 3 years of a 5-year cost-effectiveness study of the U. S. Geological Survey streamgaging network. The objective of the study is to define and document the most cost-effective means of furnishing streamflow information. In the first step of this study, data uses were identified for 3,493 continuous-record stations currently being operated in 32 States. In the second step, evaluation of alternative methods of providing streamflow information, flow-routing models, and regression models were developed for estimating daily flows at 251 stations of the 3,493 stations analyzed. In the third step of the analysis, relationships were developed between the accuracy of the streamflow records and the operating budget. The existing streamgaging networks in four Districts were further analyzed to determine the impacts that satellite telemetry would have on the cost effectiveness. Satellite telemetry was not found to be cost effective on the basis of hydrologic-data collection alone, given present cost of equipment and operation.

Conference Paper↗
USGS2012

Post-earthquake building safety assessments for the Canterbury Earthquakes

This paper explores the post-earthquake building assessment program that was utilized in Christchurch, New Zealand following the Canterbury Sequence of earthquakes beginning with the Magnitude (M w .) 7.1 Darfield event in September 2010. The aftershocks or triggered events, two of which exceeded M w 6.0, continued with events in February and June 2011 causing the greatest amount of damage. More than 70,000 building safety assessments were completed following the February event. The timeline and assessment procedures will be discussed including the use of rapid response teams, selection of indicator buildings to monitor damage following aftershocks, risk assessments for demolition of red-tagged buildings, the use of task forces to address management of the heavily damaged downtown area and the process of demolition. Through the post-event safety assessment program that occurred throughout the Canterbury Sequence of earthquakes, many important lessons can be learned that will benefit future response to natural hazards that have potential to damage structures.

Conference Paper↗
USGS2016

Animated tectonic reconstruction of the Lower Colorado River region: Implications for Late Miocene to Present deformation

Although the majority of late Miocene to present Pacific-North America plate boundary strain has been accommodated by faults of the San Andreas and Gulf of California systems, growing evidence of dextral shear east of the San Andreas Fault indicates that a component of plate boundary deformation occurred in the lower Colorado River (LoCR) region. Large-scale tectonic reconstructions across the Gulf of California and Salton Trough (GCAST) region (Fig. 1), a ~500 km-wide zone of deformation that affected the western margin of North America, provide important constraints on the location, timing, style, and magnitude of crustal deformation in the LoCR region (Fig. 2). Characterizing Miocene to present deformation in the LoCR region is important to resolve the presence and kinematics of upper crustal structures that accommodated intracontinental strain and improves our understanding of the processes that promoted localized or diffuse strain during reorganization of the Pacific-North America plate boundary. Map-view translations of crustal blocks influence the relative motions of adjacent blocks, an approach adhered to in global plate-circuit models (Atwater and Stock, 1998; 2013). Thus, a synthesis of the magnitude and timing of horizontal strain across a broad zone of distributed deformation can provide insight into processes of strain partitioning and potential kinematic links between adjacent structural domains. Furthermore, it can help prioritize and guide future work by identifying gaps in our understanding of plate boundary deformation and provide a degree of predictability for palinspastic reconstructions in areas where little information exists. At present, detailed geologic studies of crustal deformation related to the Pacific-North America plate boundary in the LoCR region are limited, leading to considerable uncertainty in the late Cenozoic tectonic evolution of the region. This uncertainty limits our understanding of how plate coupling evolves during the transition from a convergent margin to a transform margin. In this paper, we utilize animated palinspastic fault-based reconstructions to evaluate the tectonic evolution of the LoCR region and to examine potential inconsistencies of the spatio-temporal evolution of the late Cenozoic Pacific-North America plate boundary. Based on revised palinspastic reconstructions and remaining inconsistencies, we hypothesize that (1) late Miocene transtensional faulting related to the Gulf of California shear zone and eastern California shear zone promoted tectonic subsidence in the LoCR region that permitted the subsequent southward lake spillover of the Colorado River and connection with the northern Gulf of California, (2) distributed Pliocene transtensional faulting likely occurred within the southern LoCR region, and is presently unaccounted for in most studies of geologic units related to the Pliocene Colorado River, and (3) the Chocolate Mountains anticlinorium can be reconstructed to a broadly linear, E-W-oriented structure at ca. 11 Ma, consistent with reconstruction of several other strain markers along the southern San Andreas Fault system.

Lower Colorado River↗
USGS1997

Cross‐hole radar attenuation tomography using a frequency centroid down‐shift method: Consideration of non‐linear frequency dependence of EM wave attenuation

This paper presents a cross-hole radar attenuation tomography method based on analysis of the down-shift in the spectrum centroid frequency, and spectral broadening of the received radar signals. The method uses a parameter that combines centroid frequency down shift and variance increase for the projection function to construct the tomography algorithm. In comparison with other methods for estimating attenuation, the frequency down shift method is relatively insensitive to the effects of geometric spreading, antenna coupling, antenna radiation pattern,and instrument response, but the method requires the data to be broad-band so the frequency shift is easily measured. This method is well suited for difference tomography when electrically conductive tracers are used. The method was tested using cross-hole radar data acquired before and during a saline tracer injection experiment at the U.S.Geological Survey’s Fractured Rock Research Site at Mirror Lake, in Grafton County, New Hampshire. The attenuation-difference tomogram clearly outlines the location of the saline tracer within the tomography plane.

New Hampshire↗
USGS2020

Automated extraction of areal extents for GNIS Summit features using the eminence core method

An important objective of the U.S. Geological Survey (USGS) is to enhance the Geographic Names Information System (GNIS) by automatically associating boundaries with terrain features that are currently spatially represented as two-dimensional points. In this paper, the discussion focuses on experiments for mapping GNIS Summit features using the eminence core region-growing method, which maps the area between a peak and its key col (saddle). A secondary goal of this project is to improve the positional accuracy of GNIS Summit features, since those locations were derived long ago and need to be snapped to local morphometric peaks detected from analysis of the highest-resolution digital elevation models (DEMs). The eminence cores delineated for a subset of GNIS Summit features were compared visually against basemaps and manually digitized polygons created by USGS staff. The comparisons revealed substantial differences between the computationally derived eminence cores and the manually generated polygons. Results clearly suggest that the default core delineation method tested must be modified to “roll back” or truncate growth of unreasonably large cores to smaller extents that would match people’s intuitive expectations. However, these results are far more encouraging than any method tested previously, since this method guarantees a 1-1 correspondence between polygons and GNIS Summit features.

Conference Paper↗
USGS2004

Updated United Nations Framework Classification for reserves and resources of extractive industries

The United Nations have studied how the oil and gas resource classification developed jointly by the SPE, the World Petroleum Congress (WPC) and the American Association of Petroleum Geologists (AAPG) could be harmonized with the United Nations Framework Classification (UNFC) for Solid Fuel and Mineral Resources (1). The United Nations has continued to build on this and other works, with support from many relevant international organizations, with the objective of updating the UNFC to apply to the extractive industries. The result is the United Nations Framework Classification for Energy and Mineral Resources (2) that this paper will present. Reserves and resources are categorized with respect to three sets of criteria: ??? Economic and commercial viability ??? Field project status and feasibility ??? The level of geologic knowledge The field project status criteria are readily recognized as the ones highlighted in the SPE/WPC/AAPG classification system of 2000. The geologic criteria absorb the rich traditions that form the primary basis for the Russian classification system, and the ones used to delimit, in part, proved reserves. Economic and commercial criteria facilitate the use of the classification in general, and reflect the commercial considerations used to delimit proved reserves in particular. The classification system will help to develop a common understanding of reserves and resources for all the extractive industries and will assist: ??? International and national resources management to secure supplies; ??? Industries' management of business processes to achieve efficiency in exploration and production; and ??? An appropriate basis for documenting the value of reserves and resources in financial statements.

Conference Paper↗
USGS2016

Wetting and drying of soil in response to precipitation: Data analysis, modeling, and forecasting

This paper investigates methods to analyze and forecast soil moisture time series. We extend an existing Antecedent Water Index (AWI) model, which expresses soil moisture as a function of time and rainfall. Unfortunately, the existing AWI model does not forecast effectively for time periods beyond a few hours. To overcome this limitation, we develop a novel AWI-based model. Our model accumulates rainfall over a time interval and can fit a diverse range of wetting and drying curves. In addition, parameters in our model reflect hydrologic redistribution processes of gravity and suction.We validate our models using experimental soil moisture and rainfall time series data collected from steep gradient post-wildfire sites in Southern California, where rapid landscape change was observed in response to small to moderate rain storms. We found that our novel model fits the data for three distinct soil textures, occurring at different depths below the ground surface (5, 15, and 30 cm). Our model also successfully forecasts soil moisture trends, such as drying and wetting rate.

Conference Paper↗
USGS1999

Strategies for ensuring global consistency/comparability of water-quality data

In the past 20 years the water quality of the United States has improved remarkably-the waters are safer for drinking, swimming, and fishing. However, despite many accomplishments, it is still difficult to answer such basic questions as: 'How clean is the water?' and 'How is it changing over time?' These same questions exist on a global scale as well. In order to focus water-data issues in the United States, a national Intergovernmental Task Force on Monitoring Water Quality (ITFM) was initiated for public and private organizations, whereby key elements involved in data collection, analysis, storage, and management could be made consistent and comparable. The ITFM recommended and its members are implementing a nationwide strategy to improve water-quality monitoring, assessment, and reporting activities. The intent of this paper is to suggest that a voluntary effort be initiated to ensure the comparability and utility of hydrological data on a global basis. Consistent, long-term data sets that are comparable are necessary in order to formulate ideas regarding regional and global trends in water quantity and quality. The author recommends that a voluntary effort similar to the ITFM effort be utilized. The strategy proposed would involve voluntary representation from countries and international organizations (e.g. World Health Organization) involved in drinking-water assessments and/or ambient water-quality monitoring. Voluntary partnerships such as this will improve curability to reduce health risks and achieve a better return on public and private investments in monitoring, environmental protection, and natural resource management, and result in a collaborative process that will save millions of dollars.In this work it is suggested that a voluntary effort be initiated to ensure the comparability and utility of hydrological data on a global basis. The strategy proposed would involve voluntary representation from countries and international organizations involved in drinking-water assessments and/or ambient water-quality monitoring.

Conference Paper↗
USGS2004

Extracting transient Rayleigh wave and its application in detecting quality of highway roadbed

This paper first explains the tau-p mapping method of extracting Rayleigh waves (LR waves) from field shot gathers. It also explains a mathematical model of physical character parameters of quality of high-grade roads. This paper then discusses an algorithm of computing dispersion curves using adjacent channels. Shear velocity and physical character parameters are obtained by inversion of dispersion curves. The algorithm using adjacent channels to calculating dispersion curves eliminates average effects that exist by using multi-channels to obtain dispersion curves so that it improves longitudinal and transverse resolution of LR waves and precision of non-invasive detection, and also broadens its application fields. By analysis of modeling results of detached computation of the ground roll and real examples of detecting density and pressure strength of a high-grade roadbed, and by comparison of shallow seismic image method with borehole cores, we concluded that: 1 the abnormal scale and configuration obtained by LR waves are mostly the same as the result of shallow seismic image method; 2 an average relative error of density obtained from LR waves inversion is 1.6% comparing with borehole coring; 3 transient LR waves in detecting density and pressure strength of a high-grade roadbed is feasible and effective.

Conference Paper↗