Geology topics

Tanya J. Gallegos

Publications and source records attributed to Tanya J. Gallegos.

26 records · Page 2Linked to original sources

USGS2015

Trends in hydraulic fracturing distributions and treatment fluids, additives, proppants, and water volumes applied to wells drilled in the United States from 1947 through 2010: data analysis and comparison to the literature

Hydraulic fracturing is presently the primary stimulation technique for oil and gas production in low-permeability, unconventional reservoirs. Comprehensive, published, and publicly available information regarding the extent, location, and character of hydraulic fracturing in the United States is scarce. This national spatial and temporal analysis of data on nearly 1 million hydraulically fractured wells and 1.8 million fracturing treatment records from 1947 through 2010 (aggregated in Data Series 868) is used to identify hydraulic fracturing trends in drilling methods and use of proppants, treatment fluids, additives, and water in the United States. These trends are compared to the literature in an effort to establish a common understanding of the differences in drilling methods, treatment fluids, and chemical additives and of how the newer technology has affected the water use volumes and areal distribution of hydraulic fracturing. Historically, Texas has had the highest number of records of hydraulic fracturing treatments and associated wells in the United States documented in the datasets described herein. Water-intensive horizontal/directional drilling has also increased from 6 percent of new hydraulically fractured wells drilled in the United States in 2000 to 42 percent of new wells drilled in 2010. Increases in horizontal drilling also coincided with the emergence of water-based “slick water” fracturing fluids. As such, the most current hydraulic fracturing materials and methods are notably different from those used in previous decades and have contributed to the development of previously inaccessible unconventional oil and gas production target areas, namely in shale and tight-sand reservoirs. Publicly available derivative datasets and locations developed from these analyses are described.

Scientific Investigations Report↗

USGS2013

Uranium(VI) interactions with mackinawite in the presence and absence of bicarbonate and oxygen

Mackinawite, Fe(II)S, samples loaded with uranium (10 -5 , 10 -4 , and 10 -3 mol U/g FeS) at pH 5, 7, and 9, were characterized using X-ray absorption spectroscopy and X-ray diffraction to determine the effects of pH, bicarbonate, and oxidation on uptake. Under anoxic conditions, a 5 g/L suspension of mackinawite lowered 5 × 10 -5 M uranium(VI) to below 30 ppb (1.26 × 10 -7 M) U. Between 82 and 88% of the uranium removed from solution by mackinawite was U(IV) and was nearly completely reduced to U(IV) when 0.012 M bicarbonate was added. Near-neighbor coordination consisting of uranium–oxygen and uranium-uranium distances indicates the formation of uraninite in the presence and absence of bicarbonate, suggesting reductive precipitation as the dominant removal mechanism. Following equilibration in air, mackinawite was oxidized to mainly goethite and sulfur and about 76% of U(IV) was reoxidized to U(VI) with coordination of uranium to axial and equatorial oxygen, similar to uranyl. Additionally, uranium-iron distances, typical of coprecipitation of uranium with iron oxides, and uranium-sulfur distances indicating bidentate coordination of U(VI) to sulfate were evident. The affinity of mackinawite and its oxidation products for U(VI) provides impetus for further study of mackinawite as a potential reactive medium for remediation of uranium-contaminated water.

Environmental Science & Technology↗

USGS2013

A framework for quantitative assessment of impacts related to energy and mineral resource development

Natural resource planning at all scales demands methods for assessing the impacts of resource development and use, and in particular it requires standardized methods that yield robust and unbiased results. Building from existing probabilistic methods for assessing the volumes of energy and mineral resources, we provide an algorithm for consistent, reproducible, quantitative assessment of resource development impacts. The approach combines probabilistic input data with Monte Carlo statistical methods to determine probabilistic outputs that convey the uncertainties inherent in the data. For example, one can utilize our algorithm to combine data from a natural gas resource assessment with maps of sage grouse leks and piñon-juniper woodlands in the same area to estimate possible future habitat impacts due to possible future gas development. As another example: one could combine geochemical data and maps of lynx habitat with data from a mineral deposit assessment in the same area to determine possible future mining impacts on water resources and lynx habitat. The approach can be applied to a broad range of positive and negative resource development impacts, such as water quantity or quality, economic benefits, or air quality, limited only by the availability of necessary input data and quantified relationships among geologic resources, development alternatives, and impacts. The framework enables quantitative evaluation of the trade-offs inherent in resource management decision-making, including cumulative impacts, to address societal concerns and policy aspects of resource development.

Natural Resources Research↗

USGS2013

U.S. Geological Survey Energy and Minerals science strategy: A resource lifecycle approach

Executive Summary The economy, national security, and standard of living of the United States depend heavily on adequate and reliable supplies of energy and mineral resources. Based on population and consumption trends, the Nation’s use of energy and minerals can be expected to grow, driving the demand for ever broader scientific understanding of resource formation, location, and availability. In addition, the increasing importance of environmental stewardship, human health, and sustainable growth places further emphasis on energy and mineral resources research and understanding. Collectively, these trends in resource demand and the interconnectedness among resources will lead to new challenges and, in turn, require cutting-edge science for the next generation of societal decisions. The long and continuing history of U.S. Geological Survey contributions to energy and mineral resources science provide a solid foundation of core capabilities upon which new research directions can grow. This science strategy provides a framework for the coming decade that capitalizes on the growth of core capabilities and leverages their application toward new or emerging challenges in energy and mineral resources research, as reflected in five interrelated goals. Goal 1.—Understand fundamental Earth processes that form energy and mineral resources Goal 2.—Understand the environmental behavior of energy and mineral resources and their waste products Goal 3.—Provide inventories and assessments of energy and mineral resources Goal 4.—Understand the effects of energy and mineral development on natural resources and society Goal 5.—Understand the reliability and availability of energy and mineral supplies Within each goal, multiple actions are identified. The level of specificity and complexity of these actions varies, consistent with the reality that even a modest refocus can yield large payoffs in the near term whereas more ambitious plans may take years to reach fruition. As such, implementation of these actions is largely dependent on available resources and the sequencing of prerequisite steps. This science strategy places an emphasis on interdisciplinary collaboration and leveraging of expertise across the U.S. Geological Survey and with external partners.

Circular↗

USGS2013

Energy and minerals science at the U.S. Geological Survey

The economy, national security, and standard of living of the United States depend on adequate and reliable supplies of energy and mineral resources. Based on population and consumption trends, the Nation’s and World’s use of energy and minerals is expected to grow, driving the demand for scientific understanding of resource formation, location, and availability. The importance of environmental stewardship and human health in sustainable growth emphasizes the need for a broader understanding of energy and mineral resources. The U.S. Geological Survey (USGS) is a world leader in conducting research needed to address these challenges and to provide a scientific foundation for policy and decisionmaking with respect to resource use, sustainability, environmental protection, and an adaptive resource management approach.

Fact Sheet↗

USGS2012

Water quality studied in areas of unconventional oil and gas development, including areas where hydraulic fracturing techniques are used, in the United States

Domestic oil and gas production and clean water are critical for economic growth, public health, and national security of the United States. As domestic oil and gas production increases in new areas and old fields are enhanced, there is increasing public concern about the effects of energy production on surface-water and groundwater quality. To a great extent, this concern arises from the improved hydraulic fracturing techniques being used today, including horizontal drilling, for producing unconventional oil and gas in low-permeability formations. The U.S. Geological Survey (USGS) John Wesley Powell Center for Analysis and Synthesis is hosting an interdisciplinary working group of USGS scientists to conduct a temporal and spatial analysis of surface-water and groundwater quality in areas of unconventional oil and gas development. The analysis uses existing national and regional datasets to describe water quality, evaluate water-quality changes over time where there are sufficient data, and evaluate spatial and temporal data gaps.

Fact Sheet↗

USGS2012

U.S. Geological Survey energy and minerals science strategy

The economy, national security, and standard of living of the United States depend heavily on adequate and reliable supplies of energy and mineral resources. Based on current population and consumption trends, the Nation's use of energy and minerals can be expected to grow, driving the demand for ever broader scientific understanding of resource formation, location, and availability. In addition, the increasing importance of environmental stewardship, human health, and sustainable growth place further emphasis on energy and mineral resources research and understanding. Collectively, these trends in resource demand and the interconnectedness among resources will lead to new challenges and, in turn, require cutting-edge science for the next generation of societal decisions. The contributions of the U.S. Geological Survey to energy and minerals research are well established. Based on five interrelated goals, this plan establishes a comprehensive science strategy. It provides a structure that identifies the most critical aspects of energy and mineral resources for the coming decade. * Goal 1. - Understand fundamental Earth processes that form energy and mineral resources. * Goal 2. - Understand the environmental behavior of energy and mineral resources and their waste products. * Goal 3. - Provide inventories and assessments of energy and mineral resources. * Goal 4. - Understand the effects of energy and mineral development on natural resources. * Goal 5. - Understand the availability and reliability of energy and mineral resource supplies. Within each goal, multiple, scalable actions are identified. The level of specificity and complexity of these actions varies, consistent with the reality that even a modest refocus can yield large payoffs in the near term whereas more ambitious plans may take years to reach fruition. As such, prioritization of actions is largely dependent on policy direction, available resources, and the sequencing of prerequisite steps that will lead up to the most visionary directions. The science strategy stresses early planning and places an emphasis on interdisciplinary collaboration and leveraging of expertise across the U.S. Geological Survey.

Open-File Report↗

USGS2008

Geochemical data from analyses of rock, sediment, water, and solid-phase leaching at the Tuba City Open Dump, Tuba City, Arizona

This report releases data collected by the U.S. Geological Survey from the Tuba City Open Dump area from January 2008 to September 2008 with cooperation from the U.S. Bureau of Indian Affairs and the Navajo and Hopi Tribes. These data were collected in support of investigations into the possible sources and resulting transport of radionuclides and other dissolved constituents in the surrounding ground water from the Tuba City Open Dump. This report provides a discussion of data collection and analytical methods with the data in a tabular format.

Arizona↗