In Chapter 2, the committee identified four major needs that the U.S. Geological Survey’s (USGS’s) Energy Resources Program (ERP) might address. Specifically, there are needs for:
- a robust understanding of the national resource endowment and its associated uncertainties;
- environmentally and socially responsible exploration and development of geologic energy resources;
- overcoming technical and economic barriers to new resource development processes; and
- adapting to variable power-generation sources and related energy storage (e.g., wind and solar).
This chapter describes the major activities in which the ERP engages to understand the energy resource endowment and how those activities now contribute to meeting the challenges listed above. The current ERP portfolio reflects many of the energy priorities of ERP product consumers. The brief outlines of selected projects described herein are examples of both long-standing ERP obligations (e.g., oil, gas, coal, and uranium assessments) and newer efforts in the rapidly changing energy landscape (e.g., methane hydrates, geothermal energy, and produced waters). Described are the types of ERP products and their alignment with the needs of federal and non-federal consumers, factors that have led to the success of ERP efforts, and challenges that may have led to suboptimal alignment with consumer needs or in missed opportunities. The examples also are used to illustrate general aspects of the ERP, including the balance between basic research versus service products (e.g., databases, resource assessments, maps); the uniqueness of the products (e.g., field data collection, lab analyses); and the use of those products by the targeted communities. Publication formats in the last 20 years generally have shifted from paper publications and compact disks to a range of digital products, precipitated by the wide availability of broadband Internet and emerging methods of digital data dissemination and publication of reports, basic data, and geographic information systems (GIS). Virtually all publications now are delivered online through the USGS’s website and through third-party publication outlets such as journals and society publications (e.g., Warwick et al., 2011).
Examples provided in this chapter reflect the present mix of projects in the ERP portfolio, including mandated service products and opportunistic research that has evolved in response to rapid changes in the energy landscape over the past 10 to 20 years. The committee provides its conclusions based on members’ personal experiences with ERP products, interaction with ERP staff, and interactions with federal and nonfederal consumers of ERP products. The experience and interactions suggest a continued demand for ERP products and ongoing recognition by decision makers of the importance of geologic information for energy policy decisions. Chapter 4 provides more detail about aligning the ERP with ERP product consumer needs, and Chapter 5 describes directions in which the ERP might move its portfolio to meet future needs.
Using a geology-based approach, the ERP assesses technically recoverable oil and gas resources in priority basins within the United States and globally. The program does not assess economically recoverable resources. A single methodology has been adapted for - assessing both conventional oil and gas resources and oil and gas resources requiring high water-volume hydraulic fracturing (see Box 3.1). Multiple ERP publications describe the assessment methodologies.1 Inputs to assessment models include subsurface geology based on literature studies and data compilation and, when available, well completions and production data. The primary source for well data is a widely used commercial database of
1 A list of references describing methodologies is found at https://energy.usgs.gov/OilGas/AssessmentsData/NationalOilGasAssessment/Methodology.aspx.
well records from regulatory agencies and operators.2 Outputs consist of probability distributions of estimated ultimate recoveries (EURs) for each assessment unit, with areas of highest density of technically recoverable resources delineated.
The methodologies have been peer-reviewed by the Committee on Resource Evaluation (CORE) of the American Association of Petroleum Geologists (AAPG).3 In 1998, CORE published a review and endorsement of the ERP’s conventional assessment methods4 and in 2000, an endorsement of assessment methods for resources requiring high-water-volume hydraulic fracturing.5
Oil and Gas Assessment Products and Timelines
Individual assessments, once complete and reviewed within the USGS and state geological surveys, are released by the ERP. Figures 3.1 and 3.2 show the status of U.S. and global basin assessments as of October 2017. The ERP plans to release a compilation of results from the current cycle of assessments for high-priority U.S. and global areas of resource interest (“plays”) in FY2019. The assessments are published online, with information released in a series of products, including press releases, USGS fact sheets, data releases, GIS products, and, ultimately, geologic reports. To illustrate the variety of ERP products, Table 3.1 lists oil and gas assessment products released in the last quarter of 2017. The table includes information about the region assessed, the type and description of product released, and the year the assessment was initially completed.
Typically, the ERP issues a press release announcing the completion of an oil or a gas assessment. A brief technical summary of that assessment is released soon after. These are typically in the form of USGS fact sheets. Such fact sheets include maps of assessment unit boundaries, a short geologic summary, assessment input data (e.g., number of fields, field size, potential production area, average drainage area), and assessment results (see Appendix C for an example). Input data forms (see Appendix C) are released with the fact sheets and may include general characteristics of the assessment unit, potential for additional reserves, estimated ultimate recovery per well, and select ancillary data. GIS data are provided for most assessment units but are limited to shape files that define the boundaries of assessment units and some geologic data (e.g., isopach maps).
At some point after the release of the fact sheet technical summary, the ERP releases a geologic report with a more complete description of the critical oil or gas system elements that informed the assessment (e.g., the source rock, migration, reservoir characteristics, and oil and gas maturation processes). It can be several years after a fact sheet is released, however, that the detailed geologic report is made available (e.g., 10 years in the case of the assessment of the Gulf of Mexico Paleogene stratigraphic interval; see Table 3.1). The
TABLE 3.1 Oil and Gas Assessment Products released between Sept-Dec 2017
|Unit/Region||Product (release date)||Product Description||Assessment Completed|
|Federal, State and Tribal Lands and Waters in Alaska||Press Release (Dec. 2017)||Updated assessment; increases oil and gas resource estimates relative to 2010, 2005 studies||2017|
|Ventura Basin, California||Fact Sheet 2017-3050 (Oct. 2017)||Assessment unit boundaries, brief geologic summary, key assessment data, assessment results, references (conventional and continuous/unconventional)||2016|
|Permian Basin, TX - Spraberry||Assessment Input – Open File Report 2017-1117 (Sept 2017)||Supplemental documentation of input parameters used in the USGS 2017 Spraberry Formation assessment||2017|
|North-Central MT; Williston Basin||GIS compilation and Data Release (Sept 2017)||GIS shape files with geographic limits and geologic boundaries of assessment units within the defined total petroleum systems||2017|
|Lower Paleogene Midway and Wilcox Groups, and Carrizo Sand of the Claiborne Group - Northern Gulf Coast||Geologic Report -Open-File Report 2017-111 (Sept 2017)||Full geologic framework for Tertiary strata, including source rocks, maturation, migration, trap and reservoir characteristics. Original assessment results were published in USGS Fact Sheets by Dubiel and others (2007) and Warwick and others (2007a).||2007|
|Mississippian Barnett Shale, Bend Arch–Fort Worth Basin Province||Scientific Investigations Report 2017-5102 (Nov. 2017)||Updated assessment; increases oil and gas resource estimates relative to 2010, 2005 studies||2015|
geologic reports are published in a variety of formats, among them USGS Digital Data Series, open file reports, and professional papers. The level of detail in the reports varies depending on the exploration stage of the assessed region. Examples include:
- Full basin-scale petroleum systems analyses (Magoon and Dow, 1994), including 3-dimensional numerical models of source rock distribution, thermal maturation, petroleum migration, and accumulation (e.g., Anadarko Basin; Higley, 2014).
- Compilations of regional geology, structural setting, and petroleum systems for specific reservoir units (e.g., Lower Paleogene of the Northern Gulf Coast; Warwick, 2017).
Based on interactions with ERP product consumers, the geologic information in these reports is useful. Some of those consumers, however, raised concerns about the lag time between the release of the fact sheets and of the full geologic reports.
Much of the data used to develop the oil and gas assessments are not included with the products described above. The lack of data limits the ability of consumers to evaluate the reliability of ERP assessments. For example, it is not possible to determine how much stratigraphic mapping of reservoir units was conducted as part of the assessment or where the producing wells are located relative to assessment units. In addition, detailed petrophysical data, such as those that support physical models to estimate net reservoir thickness and porosity, can be difficult to locate or are unpublished for many of the assessments. ERP reliance on literature data for model input parameters in lieu of detailed petrophysical analyses is a limitation of some of the assessments. Chapter 4 includes an extended discussion of the publicly available (i.e., not proprietary), unbiased, and trusted data that would be helpful to ERP product consumers.
Basic Research Related to Oil and Gas
The ERP conducts basic research in support of oil and gas resource assessments: for example, ERP publications on “basin-centered” gas from the late 1980s through late 1990’s (e.g., Spencer, 1989; Law, 2002) led the field in the recognition of large, continuous gas resources that subsequently became the shale-gas revolution. The ERP commitment to basic oil and gas research continues through large research projects on the regional structure, stratigraphy, and geochemistry in the Gulf Coast region and Alaska. The research provides insights on the geology of those regions and on the potential impacts of oil and gas development. Recent ERP publications describe research related to the fate of injected
carbon dioxide (CO2) in the Wilcox group of Louisiana in the Gulf of Mexico (Shelton et al., 2014); land loss in southern Louisiana associated with the exploitation of subsurface geologic resources (Olea and Coleman, 2014); the composition and content of asphaltenes in spilled and original wellhead oils from the Deepwater Horizon incident (Lewan et al., 2014); and U-Pb ages of detrital zircons in the Mississippi delta as an indicator of sediment provenance (Craddock and Krylander-Clark, 2013). These research products provide valuable information to help address the energy challenges described in Chapter 2 and listed at the head of this chapter (e.g., related to carbon capture, and environmental impacts of energy production). They also result in raw data that might be used as input for assessments (e.g., geochemical analyses of formation waters and gases). The research, however, may not always directly be used in resource assessments. For instance, basic research in the Gulf Coast (Olea and Coleman, 2014) has not been used in assessments of the Haynesville formation (Paxton et al., 2017). The ERP may already be integrating this research into their assessments, but the extent to which that occurs was difficult to ascertain from the existing publications.
The ERP operates chemical analytical laboratories that support ERP analysis needs as well as the analytical needs of other federal agencies, state and local agencies, and universities in its Central Energy Science Center in Denver, Colorado. They offer a unique and broad complement of experimental and analytical capabilities that enable fully integrated characterization of a broad suite of geological based energy resources. As an example, the ERP organic geochemistry lab analyzes the composition and maturity of oil and gas samples to support research on geochemical petroleum systems, research on the geochemistry of solid fuels, coal research assessment methodologies, fossil fuel environmental issues (such as natural sources of greenhouse gases), and prediction and monitoring of fossil-fuel quality and baseline studies of fossil fuel in the environment.6 The laboratories also emphasize analytical data preservation and management. One unique and new contribution is that of being a repository for a new suite of national gas standards, replacing standards formerly maintained by the U.S. National Institute of Standards and Technology and used in research and technology development by industry, academia, and governmental agencies.7
The audience for ERP oil and gas assessments and supporting data and research includes federal, state, and local government offices, industry, the financial community,
academe, and the general public. The ERP informs these consumers of upcoming products through presentations to state-level entities; USGS alerts regarding new fact sheets; presentations at national conferences (e.g., AAPG and Unconventional Resources Technology Conferences]); local-level conferences; and its website. According to ERP staff members, ERP assessments are used by a variety of organizations to inform decision making: other Department of the Interior (DOI) units use the assessments of federal lands for leasing and other management decisions; local governments use the assessments for land-use planning; and banks and other investors use the assessments to construct baseline data for potential transactions. The current trend, according to ERP staff, is for consumers to access information online and download the products they need, including through smart phone technology. Statistics regarding who accesses ERP products, how they are used, and of the impacts of that use are not tracked.
Although ERP research and assessment products appear to be widely used, the ERP does not have a formal process to capture information about product use or alignment with consumer needs. Based on the anecdotal information received through committee interactions with representatives from the Department of Energy (DOE), the Energy Information Administration (EIA), state geological surveys, federal environmental agencies, and industry (see the meeting agendas in Appendix C for a sampling of those with whom the committee interacted), there is wide use and appreciation of ERP products, but also opportunities to increase product utility. For example, consumers expressed the desire for greater ease of access to products and information on the ERP website. Consumers also expressed concern about the limited availability of raw and derived data both online and in reports. Some consumers suggested that the absence of available data and the time taken by the ERP to release full geologic reports may lead consumers to produce their own assessments. They expressed concern that the long lag times may render information in the full reports obsolete by the time they are published. No specific examples were provided.
In consideration of ERP oil and gas assessments moving forward, product consumers identified how expanding assessments to consider economically recoverable resources within a range of oil prices, given fluctuations of prices in recent years, would expand the utility of ERP assessments (see Box 3.2 regarding supply curves). They also offered suggestions regarding new research the ERP might conduct using new or available data as part of the assessments, such as that related to enhanced oil recovery8 and subsurface energy disposal and storage (discussed further in Chapter 5). Finally, consumers suggested that the rapid evolution of energy technologies and the increasing volumes of available geologic and production data warrant more dynamic assessment methodologies that better accommodate new information and may be more readily updated. This suggests that consumers need the independent assessments provided by the ERP, but at a pace consistent with their own work. These issues are discussed in Chapter 4. The committee’s conclusions regarding how the ERP might establish its priorities in response to consumer needs are described in Chapters 5 and 6.
8 For example, increasing recovery by injecting gas or chemicals.
The ERP quantifies technically recoverable coal resources on and under federal lands9 as well as the coal resources and reserves at the basin and national scale (e.g., East, 2013). Recognizing the changing role of coal resources in our society and the continuous evolution of coal reserve estimation methodologies, the ERP solicits periodic external review of its assessment methodology, the most recent of which was in 2005, by a panel of six experts
in coal geology, mining, management, economics, and resource evaluation (Rohrbacher et al., 2005). That review was timely, given advances in GIS and digital data dissemination and major technological advances such as automation in coal mining and processing technologies. However, continued technology advances in information technology and data analyses, as well as changes in coal utility and the coal market may indicate the need for a new external review.
Recent products available through the USGS website include a major assessment of the Powder River Basin in Wyoming and Montana, which is the most productive coal basin in the United States (Luppens et al., 2015). Assessments of the coal resources of China and Mongolia (Trippi et al., 2015; Trippi and Belkin, 2015) have also been released. Publication of major compendia of data and research has been deemphasized by the ERP
in recent years, and an example of such a compendium is a professional paper on the coal and oil and gas rescue of the Appalachian Region (Ruppert and Ryder, 2014).
Digital data management has been central to coal resources assessments at the USGS since establishment of the National Coal Resources Data System (NCRDS) in 1975.10 The NCRDS includes a cooperative program in which state geological surveys from all coal states compile basic stratigraphic and coal quality data. This information populates the primary database used to quantify coal resources and reserves. Funding of this cooperative program originated within the USGS and has decreased significantly over the years, even though large amounts of new data have been provided as a result of the expansion of the deep longwall mining and coalbed methane industries.
The NCRDS database is used by a range of governmental, industrial, and academic stakeholders, as well as by landowners wishing to evaluate coal lands prior to mining or other activities that require compensation for loss of access to resource. The core NCRDS database, which includes basic data on coal occurrence (e.g., depth, thickness, associated rock types) can be expanded greatly in areas of coalbed methane development, where wells penetrate parts of coal basins that were previously unexplored; but overall, the bulk of the nation’s endowment of coal has been explored and assessed in most basins. Ancillary to the NCRDS database is the USGS COALQUAL11 (coal quality) database (Bragg et al., 1998), which provides an unprecedented inventory of proximate (ash, moisture, volatile matter, and fixed carbon), ultimate (carbon, hydrogen, oxygen, nitrogen, and sulfur), and trace element analyses of coal seams throughout the United States. This database has been updated periodically, most recently in 2015 (Palmer et al., 2015).
Research is an important part of the ERP’s coal-related activities, supporting assessments and spanning basic and applied topics ranging from paleoclimate to coal utilization. Paleoclimate research (Cecil and Edgar, 2003) contributed to the understanding of the fundamental controls on coal genesis and resource distribution. A more recent workshop on mercury in coal underscored the need for the ERP to continue research on trace elements in coal to support policy and regulation on air quality (Kolker, 2016). This research has significance for environmental protection as well as for identifying sources of commercial products, such as rare-earth elements. ERP research on the geology of coalbed methane reservoirs began as that industry approached maturity. This is an example of untimely entry into a strategic research field. Even so, that work resulted in major advances in the organic geochemistry of formation water, which can affect human health, and the genesis of microbial gas in coal, which accounts for the majority of the known coalbed methane resource base (Flores, 2008; Orem et al., 2014). The burgeoning discipline of medical geology has its foundation in USGS research, much of which focused on the effects of combusting unprocessed coal in rural areas of emerging nations (Selinus et al., 2010).
The coal program is aligned with the needs of a broad range of consumers and stakeholders, including federal energy agencies, state geological surveys, the coal research community, the coal and coalbed methane industries, and environmental stakeholders. For example, the Environmental Protection Agency (EPA) uses NCRDS data to fulfill their
mandates under the Clean Air Act Amendments of 1990 and the Acid Precipitation Act of 1980 (P.L. 101-549). ERP assessments also support the Bureau of Land Management (BLM) mandates regarding quantification of coal reserves on federal lands under the Federal Land Policy and Management Act of 1976 (43 U.S.C. 1701 et seq.) and the Federal Coal Leasing Amendments Act of 1976 (30 U.S.C. 201).
Decreasing coal demand in favor of natural gas, however, indicates that realignment needs to be considered so that the the relevance of the program is maintained. Increased engagement with international institutions is a positive development that increases the relevance and reach of ERP assessments, but the magnitude of the ERP coal resource program is likely to continue to decrease as coal becomes a less significant component of the domestic energy mix. In addition, limited funding of the NCRDS program has adversely affected cooperative activities with the states, which are vital sources of information for continued expansion of domestic coal resource databases and assessment products. Although low natural gas prices and a move toward lower carbon fuel sources have resulted in decreased domestic coal production—likely to lead to decreased production globally in future years (see Chapter 2)—coal remains a major fuel for a variety of purposes, including metallurgy. The ERP has a wealth of knowledge that can facilitate efficient and responsible development of coal resources in countries such as India and Indonesia, where production is expected to increase (EIA, 2017a; IEA, 2017). To address this issue, assessment activities increasingly include international resources, and the ERP can provide expertise to foreign agencies that promote and regulate the coal industry. There is the potential to address differentiation of specific coal products in addition to the mineable resources that currently form the backbone of the ERP coal resource program. For example, opportunity exists to assess coal resources in terms of utility and to develop a metallurgical coal assessment that would fill a major gap in understanding the nation’s steelmaking capacity. Opportunities also exist to include geologic and spatial information in coal resource assessments related to the larger portfolio of coal products and by-products such as liquid fuels, lubricants, rare-earth elements, and for use for decisions regarding the human health and safety aspects associated with coal mining and utilization.
The ERP has supported development of two sources of renewable energy: geothermal sources and wind energy, described below. Of these, only geothermal sources are truly geologically based. The role of the ERP in wind energy development has appropriately ended. Other sources of renewable energy are not geologically based and not part of the ERP portfolio.
Geothermal energy resources in the United States are used for baseload electric power generation and for direct-use applications (e.g., greenhouse heating, swimming pool heating, drying agricultural products, and building heating systems). Electrical-grade
(>120° C) geothermal resources are predominantly found in the western United States (California, Nevada, Utah, Idaho, Oregon, and New Mexico), Alaska, and Hawaii. Total installed nameplate capacity (i.e., the intended full-load sustained output of a facility) is approximately 3,700 megawatt electrical (MWe; ~2,700 MWe net) (GEA, 2016)—approximately 3% of total power generation capacity in the United States. In terms of actual generation, geothermal contributes approximately 0.4% to the annual electricity production in the United States (EIA, 2018). The resource potential is significant, however, with estimates of undiscovered hydrothermal (conventional) systems of approximately 30,000 MWe, and more than 500,000 MWe of potential resources if EGS can be commercially developed (Williams et al., 2008b). Figure 3.3 is an example of a spatial model map showing the relative favorability of the occurrence for geothermal resources (Williams et al., 2000b).
The USGS has engaged periodically in geothermal research since the early 1900s. The current ERP geothermal program area began in 2005 and collaborates with other USGS focus areas (e.g., Water Resources, Mineral Resources, Geologic Mapping, Earthquake Hazards, and Volcano Hazards) as well as externally with the DOE, Bureau of Land Management, Bureau of Indian Affairs, National Aeronautics and Space Administration, the National Labs, state agencies, academia, and industry (e.g., Ormat Nevada Inc., and
Calpine). The initial emphasis in 2005 was updating the National Geothermal Resource Assessment, completed and described in 2008 (Williams et al., 2008a,b). Although this product focused only on the western United States, where the highest-temperature geothermal resources are located and used for power generation, it is the only regional/national-scale geothermal resource assessment that has been conducted since the 1978 USGS assessment (USGS, 1978). The resource estimates documented by Williams and others (2008a), with quantified uncertainties, have been widely used to promote opportunities for geothermal in the United States to broad audiences, and as such, their study was influential. Ongoing collaborative work with the DOE’s Geothermal Technologies Office (GTO) is intended to expand the geothermal assessment methodology applied throughout the United States and includes assessments of low temperature, EGS, and sedimentary basin geothermal resources. The ERP contributes through characterization of the nation’s geothermal resource endowment, complementing GTO technology development programs that address exploration and operational issues and reduction of the costs and risks of geothermal development.
Other ERP efforts focus on continued geochemical and geophysical data collection and analyses from hydrothermal systems in the western United States; improved understanding of the geologic, mechanical, and hydrologic aspects of EGS exploration and development, supporting the improvement of the National Geothermal Data System;12 and collaborative research supported by the DOE and BLM. An example of the latter is the Fallon Frontier Observatory for Research in Geothermal Energy (FORGE) project that is evaluating a potential field-research laboratory to test and develop EGS technologies (Blankenship et al., 2016), the Washington Play Fairway Project (Forson et al., 2017), and the Nevada Play Fairway project (Faulds et al., 2017). Results from these efforts have been incorporated into open-access data repositories (e.g., Sciencebase.gov,13 the National Geothermal Data System,14 and the Geothermal Data Repository15) and released as USGS Data Series and Scientific Investigations (e.g., Farrar et al., 2010; Bergfeld et al., 2013) or conference papers (e.g., e.g., Ayling et al., 2018, Forson et al., 2017; Siler et al., 2018).
The ERP geothermal research program also contributes to other USGS program area research including that related to geothermal and hydrogeologic controls on groundwater temperature distribution (e.g., Burns et al., 2016); to the geologic factors controlling the viability of enhanced geothermal systems (e.g., Taron et al., 2017); and to temperature distribution in seismically active areas (e.g., Han et al., 2016).
The ERP has contributed to assessing the impacts—especially on federal lands—associated with widespread development of wind energy. The ERP was to develop and apply a quantitative methodology used in oil and gas to wind development. The ERP
created an interactive map and database of onshore industrial wind turbines installed by 2013 in the continental United States.16 The database synthesizes publicly available data from multiple sources and is helpful for prioritizing and focusing research into the most relevant impacts on wildlife ecology in different regions. An actual assessment would combine this methodology with species-specific understanding, utilizing expertise in wildlife ecology and wind-wildlife research. The ERP released a preliminary methodology to assess wind energy development impacts on birds and bats on a national scale (Diffendorfer et al., 2015).
In 2011, the USGS began work on a project to update U.S. uranium assessments of undiscovered resources (Integrated Uranium Resource and Environmental Assessment Project; IUREAP), as recommended by the National Research Council (NRC, 1999). They developed a method to assess the environmental impacts of extracting these resources. Earlier estimates date back to the DOE’s National Uranium Resource Evaluation program in the late 1970s (Smith, 2006). A number of projects have been completed, including an assessment of groundwater recovery after uranium mining (Hall, 2018), updated estimates of sandstone-hosted uranium resources in south Texas (Mihalasky, et al., 2015), and calcrete-hosted deposits on the southern high plains (Hall et al., 2017), which included the identification of a new species of uranium mineralization (Klein, 2017). The ERP also is developing a model of Coles Hill, Virginia, the largest undeveloped uranium deposit in the United States, and plans to update uranium resource estimates for sandstone in the Colorado Plateau or the Wyoming Basins, subject to available funding (Hall, S.M., USGS, personal communication, December 7, 2017).17
In addition to updating resource estimates, the ERP is conducting collaborative studies with other USGS researchers the impacts of uranium extraction by solution mining—the primary method of uranium mining in the United States today—on groundwater (Naftz and Walton-Day, 2016; Beisner et el., 2017). In 2017, an evaluation of the remediation of legacy uranium mines in the Navajo Nation was undertaken by the ERP at the request of the EPA. And in response to a USGS management request, IUREAP members evaluated how the ERP could contribute to decision making in the ongoing siting process for a long-term nuclear waste storage facility in the United States.18
The ERP conducts valuable and unbiased work related to the nation’s uranium endowment that no other government agency or private company does. In collaboration with the International Atomic Energy Agency, the ERP developed new methods to estimate undiscovered uranium resources, and results of ERP efforts support international assessments of uranium resources.19
18 S.M. Hall, USGS, personal communication, December 7, 2017.
Improved produced water management requires a fundamental understanding of the volumes and chemical characteristics of produced water. The ERP is beginning to characterize produced water volumes as part of their oil and gas assessments and to develop projections for future volumes, as exemplified by a recent study of produced water volumes associated with development of the Bakken Formation in Montana, North Dakota, and into Canada (Haines et al., 2017b). The chemical constituents of produced water are analyzed by the ERP and other groups and collated in an online database (Blondes et al., 2016). The database includes information on salinity, major and trace element chemistry, and organic chemistry of produced water from conventional and continuous (tight oil, shale gas, coalbed methane) reservoirs (Blondes et al., 2016). During open session meetings of the committee, some ERP product consumers indicated concern that the analytical methods applied by the ERP are currently quite limited; that samples were analyzed for relatively few constituents; that few samples are in the public domain; and that the general understanding of the toxicity of these waters is poor. Approximately 95% of the data in these sets are for produced waters derived from conventional reservoirs, even though there is a growing volume of production from continuous (unconventional) reservoirs. Given the possibility of the reuse or recycling of some of this water, development of a more thorough understanding of the chemical nature of produced water is warranted.
Produced water is thought to have a central role in recent induced seismicity (earthquakes from anthropogenic sources), particularly in the midcontinent states of Arkansas, Oklahoma, Kansas, Texas, and Colorado. Much of the recent increase in induced seismic activity is related to the dramatic increase in the disposal of produced water into deep geologic formations. A small percentage of midcontinent events, and those elsewhere, have been attributed to hydraulic fracturing [Rubenstein and Mahani, 2015]). The USGS Hazards Program, along with a variety of state agencies and academic institutions, have intensively monitored, analyzed, and reported on induced seismicity. Providing data on the volume and chemistry of produced water, in support of the work of others on induced seismicity, is an appropriate role for the ERP. Produced water is discussed in greater detail in Chapter 5.
Methane hydrates form when water and methane are compressed at high pressure and moderate temperature. Water freezes to form a lattice (i.e., an “ice cage”) that traps the methane gas (see Box 3.3). The USGS completed the first systematic assessment of in-place methane hydrate resources in the United States in 1995 (Collett, 2004). The results of this assessment suggest that gas in the nation’s hydrate accumulations exceeds the volume of known conventional gas resources. If economically feasible and safe technologies to develop methane hydrates are developed, then methane hydrates may substantially change the global and domestic energy mix. That finding became the basis for a sustained, multiagency effort to solve the scientific and technical challenges of
converting methane hydrates into a usable energy resource, beginning with the Methane Hydrate Research and Development Act of 2000 (HR1753-106th Congress, 1999-2000). Among other provisions, the Act required the Secretary of Energy to: (1) facilitate partnerships among government, industry, and academia, (2) undertake basic research programs, (3) ensure wide dissemination of results, (4) promote cooperation among agencies, and (5) report annually to Congress. These mandates provided a compelling external driver for the collaboration and communication efforts that have become a hallmark of this program. The Interagency Roadmap for Methane Hydrate Research and Development (DOE, 2006) outlines the roles and nature of the collaboration across the
federal agencies such as the DOI, DOE, and the National Science Foundation, including the periodic resources assessments led by the DOI.
The ERP and the DOI Minerals Management Service (MMS), in collaboration with the DOE, identified onshore Alaska and the offshore Gulf of Mexico were as focus study areas with large hydrate accumulations and the infrastructure that would allow for drilling and production of accumulations. Other countries, including Japan, Canada, and India, have also established research programs to investigate the energy resource potential of gas hydrates, although the government of Canada stopped funding gas hydrate research in 2012 (Arango, 2013). As a key partner in methane hydrate research programs, the USGS participates in consortia of government agencies—both domestically, through the Interagency Roadmap, and internationally, with India, China, and Japan—and with industry and academic institutions in all of these regions.
The collaborative programs have significantly advanced methane hydrate science. As a result of those programs, laboratory studies have become more realistic; the complexity of naturally occurring hydrate systems has been recognized and is now a research focus. Emphasis has been placed on porous and permeable strata: remote sensing tools for methane hydrate detection have been developed, recoverability estimates have improved, and the first validated reservoir simulators have been developed (Boswell, 2007). Recent major ERP accomplishments in methane hydrate research are highlighted in Table 3.2. The scientific results of these studies are published in an American Association of Petroleum Geologists Memoir (Collett et al., 2009), several special issues of the Journal of Marine and Petroleum Geology (e.g., Boswell et al., 2011; Collett and Boswell, 2012), and Geoscience Canada (Dallimore and Collett, 2005). Field experiments in Alaska and the Gulf of Mexico continue.
Despite improved understanding of methane hydrate occurrence and distribution, development of hydrates as an energy resource remains infeasible. An understanding of the types of natural hydrate occurrences is necessary, and more long-range research is required before the viability of hydrates as a resource can be determined. The best hydrate reservoirs are likely to occur in high-cost deep-water and arctic environments, and the long-term production testing has yet to achieve sustained, economically viable economic gas flow-rates from these reservoirs (e.g., Spalding and Fox, 2014; Chong et al., 2016). There also is broad concern about potential environmental impacts of the release of methane to the atmosphere during production and associated warming of Arctic and oceanic sediment and the atmosphere.20 Nonetheless, if long-term field tests demonstrate commercial flow rates, or large-volume, high-density resources are found in deep-water areas with substantial existing production and development infrastructure, the economic equation might change. Hydrates are likely more economic for nations such as Japan and India, which lack access to conventional, non-coal resources, and for which imports of oil and liquefied natural gas are expensive (e.g., Vedechalam et al., 2015).
Involvement of the ERP in methane hydrate research has been instrumental for advancing the science and technology. Continued ERP collaboration with hydrate programs in these countries has the potential to bring substantial technical capability to the United States.
TABLE 3.2 Recent Accomplishments of the USGS Methane Hydrates Program in ERP
|Project||Roles and Responsibilities||Accomplishments|
|MacKenzie delta hydrate geologic and production studies (2002 and 2007)||Coordinated by Geological Survey of Canada, contributions from DOE and USGS||Drilled two test wells, acquired a full suite of wireline log, core, and formation pressure test data, and performed the first long-term production test of natural gas hydrates|
|Gulf of Mexico Gas Hydrate Joint Industry projects I and II (2005 and 2009)||Led by the DOE, USGS, MMS, and energy companies coordinated by Chevron||Confirmed gas hydrate occurs at high saturations in reservoir quality sands, and defined locations for future research into the energy potential of the hydrates|
|Assessment of Gas Hydrate Resources on the North Slope of Alaska (2008)||USGS lead role||Used well-established geologic assessment methodology to estimate ~85 trillion cubic feet of undiscovered, technically recoverable gas within hydrates in northern Alaska|
|India National Gas Hydrate Program Expeditions I and II (2008 and 2015)||Led by the government of India, with the support of the USGS||Characterized the hydrate resource off the east coast of India—confirmed pre-drill predictions of large, highly saturated hydrate accumulations in coarse-grained sand-rich depositional systems|
|Marine Methane Hydrate Field Research Plan (2013)||Coordinated by DOE and Consortium for Ocean Leadership, and led by the USGS||Describes key scientific and technical challenges facing hydrate researchers today, lays out scientific drilling programs that address outstanding challenges, and outlines educational opportunities for supporting the growing public interest in methane hydrates|
Geologically based carbon dioxide (CO2) sequestration is the pumping of carbon dioxide into the subsurface for permanent storage. The USGS released an assessment of technically accessible resources for CO2 sequestration (USGS, 2013) in the United States, including state waters. The work was undertaken in response to a mandate in the Energy Independence and Security Act of 2007.21 Products of that work are a resource for the DOE and its Regional Carbon Sequestration Partnership Program (Litynski et al., 2009), as well as a resource for the Environmental Protection Agency. Those estimates are based on current geologic knowledge, hydrologic knowledge, and engineering practices, but they do
21 Public Law 110-140 enacted December 19, 2007. See https://www.gpo.gov/fdsys/pkg/PLAW-110publ140/pdf/PLAW-110publ140.pdf.
not include an economic cutoff. The ERP has since assumed responsibility of carbon sequestration research within the USGS and now focuses those efforts on supporting technology development for use of CO2 for enhanced oil recovery (CO2-EOR). In CO2-EOR, carbon dioxide is injected into oil reservoirs to increase volumes of recovered oil, and a fraction of the injected CO2 is permanently trapped in those reservoirs. For example, the ERP has produced publications on factors that influence CO2-EOR (e.g., Olea, 2017).
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