Methane hydrate is a naturally occurring solid that forms in sediments when methane, in high concentrations, and water combine at low temperatures and high pressures. The incentive for research on methane hydrate1 is the less than 30-year-old realization that methane hydrate occurs in abundance on the world’s continental margins and in permafrost regions, and that it could ultimately provide an additional, potentially significant, unconventional source of methane to augment conventional natural gas supplies. Because methane, the main component of natural gas, releases less carbon dioxide per unit of energy produced during combustion than other fossil fuels, strong interest exists to use natural gas as a key source of energy in the nation’s transition to a less carbon-intensive energy portfolio.
In the United States, significant accumulations of methane hydrate occur in the Gulf of Mexico, off the Pacific and Eastern seaboards, and on the Alaska North Slope. The production of methane from methane hydrate accumulations could help to provide greater energy security for the United States and help to address future energy needs globally. However, the environmentally and economically sustainable production of methane from methane hydrate in these locations has not yet been achieved. Complex scientific challenges, which may require the development of new technologies, remain before methane from methane hydrate can be realized as an energy resource. Major research efforts to achieve this production goal are now being pursued seriously in several countries, including the United States.
In addition to its use as an energy resource, methane is an important component of the Earth’s carbon cycle on geologic timescales. Methane itself is a potent greenhouse gas and is always present in the Earth’s atmo-
sphere, but at varying concentrations. However, whether methane once stored as methane hydrate has contributed to past climate change or will play a role in the future global climate remains unclear. The potential local environmental impacts associated with either natural or human-caused seepage of methane from methane hydrate are also poorly understood and need to be differentiated from other seepage processes before methane is commercially produced from methane hydrate. Potential impacts include gas leakage to the ocean, land surface, or atmosphere, settling of the seafloor or ground around a well, and effects on biological communities at the sea-floor or on the land surface. Although methane hydrate is also commonly perceived as posing geohazard risks to industry, little documentation exists to constrain the extent and magnitude of these potential risks. Present industry practice is to try to avoid methane hydrate–bearing areas during drilling and production for conventional oil and gas resources. The current industry approach of avoidance will be untenable if methane hydrate itself becomes the production target.
Although several U.S. federal agencies conduct significant research on methane hydrate, the Department of Energy’s (DOE’s) Methane Hydrate Research and Development Program (hereafter “the Program”), established through the Methane Hydrate Research and Development Act of 2000 (P.L. 106-193), and reauthorized in the Energy Policy Act of 2005 (P.L. 109-58), has been tasked specifically to implement and coordinate a national methane hydrate research effort. The Program is directed specifically to understand the
Physical nature of methane hydrate occurrences;
Methods to quantify and explore for methane hydrate deposits;
Stability and behavior of methane hydrate when disturbed by drilling and production;
Technological requirements to produce methane from methane hydrate; and
Potential impacts of methane from methane hydrate deposits venting into the environment during methane production or in response to natural changes in the environment.
In response to DOE’s request for the National Research Council (NRC) to conduct a review of the Program, as mandated in P.L. 109-58, the NRC established the Committee on Assessment of the Department of Energy’s Methane Hydrate Research and Development Program to address several issues including
Brief review of the research conducted by the Program from 2000 to 2005;
Detailed review of the research supported by the Program since 2005;
Evaluation of the Program’s review mechanisms and of the processes used by the Program to facilitate collaborations with other agencies, academia, research laboratories, industry, the international community, and the Program’s advisory board;
Evaluation of future methane hydrate research and development needs and programmatic changes necessary to meet these needs; and
Recommendations regarding (a) the suitability of methane hydrate as a significant contributor to the U.S. natural gas supply by 2025, (b) the effective coordination of the Program’s domestic and international collaborations, and (c) graduate education and training in this field of research.
This report constitutes the committee’s response to the DOE request and is intended for nonspecialists interested in future, environmentally and economically viable energy options which include national efforts to understand and develop methane gas contained in methane hydrate.
The overarching Program goal is to stimulate the development of knowledge and technology necessary for commercial production of methane from methane hydrate in a safe and environmentally responsible way. The majority of the Program’s modest resources are directed toward research
through field projects and other cooperative agreements. The remainder of the Program’s annual funding allocation is directed toward support for activities at national laboratories, with smaller proportions allocated to program management, selected activities at other federal agencies, graduate research fellowships, and technology transfer.
The project portfolio from 2000 to 2005 was reviewed in part by an earlier NRC report from 2004, Charting the Future of Methane Hydrate Research in the United States. In addition to serving a coordinating role for interagency methane hydrate research in these initial years, the Program solicited proposals and provided partial support for three large field projects coordinated as cooperative agreements with industry (one in the Gulf of Mexico and two on the Alaska North Slope). Twenty other projects in the laboratory and the field were also supported by the Program, and were performed by researchers at universities, institutes, and national laboratories. Three projects undertaken as part of a federal collaborative effort were managed by and received primary support from the U.S. Geological Survey (USGS). The Program also participated in an international drilling consortium at Mallik in the Canadian Arctic, managed by the Geological Survey of Canada.
The research portfolio of the Program from fiscal year 2006 to present includes two key production-related goals: (1) to provide by 2015 an initial assessment of the scale of the potential commercial development of methane from methane hydrate resources on the Alaska North Slope, and (2) to demonstrate the technical recoverability and assess the economic recoverability of marine methane hydrate–bearing sand reservoirs by 2025. During the past 5 years, the Program has increased the number and scope of its smaller-scale research projects, established two new industry-managed projects on the Alaska North Slope, and supported the continuation of the Gulf of Mexico and one of the Alaska North Slope projects into more intricate phases in their planned research. In total, 38 projects supported since late 2005 include field production and drilling, resource characterization
and remote sensing, environmental research, experimental laboratory and theoretical modeling, and geomechanics and geohazard research.
Projects in the Gulf of Mexico and Alaska have been cornerstones of the Program’s portfolio since 2001. These projects have been oriented toward improving exploration methods and quantifying methane hydrate resources, as well as evaluating the challenges of methane hydrate production. Important to the research in both regions has been their coordination as cooperative agreements with industry, with significant input from multiple federal agencies, national laboratories, and the academic community. These field projects have received a significant proportion of Program resources (~$52 million has been allocated since 2001), although cost sharing with industry partners is noteworthy. The scientific merits and successes of the research conducted through these field projects have generated new knowledge toward achieving sustained production of methane from methane hydrate. Project priorities include verifying methane hydrate accumulation models and the design, drilling, logging, coring, and continuous monitoring of production wells to test the commercial potential of producing gas. Field trials of a new production methodology that exchanges carbon dioxide molecules for methane molecules within a hydrate structure are also of interest. In the Gulf of Mexico, geohazards associated with the natural occurrence of methane hydrate in areas with conventional petroleum production have not yet been systematically appraised.
The Program has supported several experimental projects since 2005, focused on physical property measurements, computer modeling projects that include reservoir and production modeling, and the development of the U.S. methane hydrate database. The major limitation of the laboratory-based experimental projects has been the nature of the formations being characterized and measured. The samples need to be close analogs to natural methane hydrate samples if the measurement results are to be scaled and extended to the reservoir system, but developing these synthetic analogs in the laboratory has proven difficult.
Six resource characterization and remote-sensing projects to detect and quantify methane hydrate in nature have been conducted in the past 5 years. Focus has been on two areas: (1) seismic and/or acoustic techniques
and (2) controlled-source electromagnetic imaging. Useful advances have been provided by some of these research projects to detect and estimate the extent of subsurface methane hydrate accumulations. However, accurate assessment of the temperature and pressure conditions for potential methane hydrate–bearing sediments is still needed to make better predictions of the quantity of the methane hydrate resource, as are seismic surveys dedicated to detecting shallow methane hydrate targets.
Of the 14 projects addressing environmental issues that are supported by the Program, 10 have focused on some aspect of environmental impacts resulting from the natural degassing of methane hydrate. Most projects specifically propose to generate new information regarding the role of methane hydrate and its natural degassing in the global carbon cycle and/or in global climate change. As yet, no major breakthroughs have appeared from this research. To date none of the Program’s projects has substantially addressed the environmental impacts expected from the commercial exploitation of methane hydrate, nor has any project considered the mitigation of the environmental impacts of natural methane hydrate degassing and degassing associated with commercial oil and gas development.
Research on methane hydrate to date has not revealed technical challenges that the committee believes are insurmountable in the goal to achieve commercial production of methane from methane hydrate in an economically and environmentally feasible manner. However, many scientific and engineering questions in methane hydrate research remain to be answered before it will be possible to achieve commercial production. When this knowledge is available, informed decisions can be made as to whether or not to proceed with the commercial exploitation of methane hydrate.
The committee has determined that the overall management of the Program has been consistent and effective. The Program has worked to develop, promote, and improve its scientific directions and management processes since 2005 by (1) increasing the success of the research funded by the Program,
(2) supporting education and training of young researchers, (3) enhancing collaborative engagements with other research entities domestically and internationally, and (4) strengthening management efficiency and the transparency of its activities.
The Program includes project selection and performance evaluation for two primary types of projects: (1) cooperative agreements selected competitively through public announcements and (2) interagency agreements and National Laboratory Field Work Proposals. Once projects have begun, external reviewers are selected to periodically evaluate project quality, relevance, progress, and results. The peer review process established by the Program is reasonably thorough, with considerable effort being made to appraise the progress of funded projects with regularity and in an open forum. Nonetheless, the large, multipartner field projects could benefit from more nuanced and frequent evaluations including open and comprehensive reviews of site survey data; the design of well completion, production, and monitoring approaches; risk assessments; and mitigation strategies.
Peer-reviewed publications based on results of the Program’s research projects are increasing, in part because of encouragement from Program management. Continued and enhanced emphasis on peer-reviewed publication is necessary to demonstrate the quality of the results and to establish lasting benchmark contributions. Information about the Program’s projects is also being disseminated through the Program Web site, online newsletter, and international conference reports.
Training and educating new researchers in methane hydrate are essential for continued growth of the field. The Program provides the only national funding specifically including education and training of the next generation of methane hydrate scientists. Between 2000 and 2008, the Program provided research opportunities and financial support to over 150 students (mostly master’s and doctoral degree students) and 16 post-doctoral researchers from 42 U.S. universities. In 2006, the Program also initiated a Methane Hydrate R&D Fellowship program to provide 2 years of support for particularly deserving graduate or postdoctoral fellows. The Program’s large field projects and international collaborations represent valuable additional educational experiences for young researchers, and the
Program should seek to maximize these opportunities for the students and young graduates it supports.
Most of the six federal agencies involved in the interagency collaboration on methane hydrate research and development have their own internally funded methane hydrate research programs. Contributions to the interagency methane hydrate research effort are thus conducted under collaborative agreements with DOE. These agencies include the Bureau of Land Management, Minerals Management Service (MMS), National Oceanographic and Atmospheric Administration, National Science Foundation, Naval Research Laboratory, and the USGS, and each agency has contributed specific, useful research results to the national methane hydrate research and development effort. In the past 2 years, research products from the USGS and MMS, in particular, have notably and significantly advanced the state of understanding of methane hydrate as a potential energy resource. All agencies have indicated satisfaction with the Program’s coordination of these interagency efforts.
Although the Program has participated in some international collaborations, active engagement with international partners has been challenging to develop. The Program management has developed formal collaborative ties with international programs investigating methane hydrate (e.g., India, Korea, and Japan), and representatives from the Program are participating in several international field projects. However, the full potential of these endeavors to advance science of value to the U.S. national effort is still to be developed, and the Program has been somewhat reliant on the international research engagement of other agencies, such as the USGS, to provide research results to the Program through the interagency coordination. Enhanced international collaboration under the Program’s auspices could serve to expose a broader range of U.S. scientists to these international efforts, to advance education and training, and to encourage lasting working collaborations that are in keeping with the specific goals of the U.S. national effort. Adequate, sustained, and specifically dedicated resources for international collaborations as well as administrative support from high levels within DOE for the Program’s efforts in this area are important to strengthening the Program’s international research relationships.
RECOMMENDATIONS FOR FUTURE RESEARCH AND DEVELOPMENT
Although methane is a cleaner-burning energy source than other fossil fuels, it is itself a significant greenhouse gas, and understanding the role of methane in the global carbon cycle remains a topic of considerable scientific interest. With respect to considering eventual commercial production of methane from methane hydrate, understanding the potential environmental impacts of methane hydrate degassing2 and the seafloor hazards (“geohazards”) resulting from methane hydrate dissociation as a result of oil and gas drilling and production are of specific importance. Thus, the mandated goals and levels of support that have been available for this Program may require that the Program’s future environmental and geohazard research directions be focused on applied and theoretical efforts related to the production of methane from methane hydrate and related oil and gas drilling through methane hydrate occurrences.
In particular, designing production tests, appraising and mitigating environmental and geohazard issues related to production, and quantification of the methane hydrate resource are identified as critical to achieving the Program goals on the Alaska North Slope by 2015 and in marine methane hydrate–bearing sand reservoirs by 2025.
Production tests should be designed to include
Development and demonstration of well completions with appropriate production technologies.
Long-term production tests on methane hydrate in a variety of geologic settings, beginning in the Arctic where technical issues may initially be less challenging than in marine settings. Demonstrating potential commercial rates for production is essential for future evaluation of production economics. Study of the factors that affect the production of gas and water should also be
considered. These factors include, for example, the distribution of methane hydrate, its concentration, the physical properties of the host rock, sediment heterogeneity, and the influence of overlying and underlying sedimentary units.
Establishing initial conditions, monitoring changes during production, and determining formation response after testing by using repeated geophysical surveys; in situ formation temperature, pressure, and geomechanical measurements; and other techniques. The field production tests should also be closely integrated with reservoir modeling studies.
A staged approach with open and comprehensive reviews of site survey data; completion, production, and monitoring design; risk assessments; and mitigation strategies.
Appraisal and mitigation of environmental and geohazard issues related to production should include:
Compilation of industry experience associated with conventional oil and gas production in areas where methane hydrate occurs.
Organized workshops to solicit input and identify research goals needed to evaluate and mitigate geohazards and environmental issues specific to the production of methane from methane hydrate and to perturbations of methane hydrate associated with other oil and gas development activities.
Studies specifically addressing potential geohazards associated with methane production from methane hydrate (e.g., laboratory measurements, modeling, and natural perturbation experiments) to provide more confidence in risk assessments and effective mitigation strategies.
Quantification of the resource should include
Pilot seismic surveys using existing geophysical methods optimized to map and quantify in-place methane hydrate accumulations.
Improved understanding of in situ properties of sediments containing methane hydrate through comprehensive testing (geophysical, geochemical, microbiological, geomechanical) of undisturbed natural drill cores and synthetic samples.
Consideration of the development of new geophysical imaging, processing, and quantification techniques, particularly with respect to quantifying the in-place resource.
In the future, efforts to collect data that maximize resolution within the zones where methane hydrate occurs and allow the potential resource to be better quantified should be encouraged. New seismic and electromagnetic survey techniques should be developed and preferably used in conjunction with conventional seismic surveys.
Although understanding the role of methane hydrate as a source of global greenhouse gas is of general interest, this research is not uniquely related to realizing methane hydrate as an energy resource. However, quantifying ongoing, natural methane fluxes from methane hydrate on a local scale is needed to provide a baseline to evaluate the effects of any future production and development of the methane hydrate resource. Thus,
Studies are required to address the processes involved (a) in the transmission of methane from the subsurface through the methane hydrate stability zone to the surface and (b) in the subsequent fate of the released methane. These studies should focus on degassing processes and potentially enhanced environmental impacts from commercial production of methane from methane hydrate and from methane hydrate associated with other oil and gas developments.
Investigation of the role of methane hydrate in the global carbon cycle is best pursued in collaboration with other agencies. Resolution of these questions is not central to the Program’s goal of resource development.
The committee was impressed with the overall quality of much of the research that is under way through the support and coordination of the Program. The research progress, the positive impact the Program is having on raising the profile of and interest in methane hydrate as a potential energy resource, and the rate at which the Program is moving toward the goal of achieving production of methane from methane hydrate accumulations are all commendable. Achieving the Program goals will require sustained national commitment, because the cost of the necessary pre- and post-drilling assessments, field tests, and the associated laboratory and modeling studies will be substantial.