Conclusions and Recommendations
Since the last review of the Program, considerable progress has been made toward the understanding and development of methane hydrate as a possible future energy resource. The U.S. position as one of the leaders in this field can be attributed to the overall high caliber of the research, the breadth of investigations undertaken, the training of new, highly qualified personnel under the Program’s auspices, and the successful collaboration between federal agencies conducting research on methane hydrate. Considerable progress has also been made in the overall management of the Program during the past 5 years, including enhanced interagency collaboration and specific efforts to include a peer review process in evaluation of supported research projects. The committee largely endorses the direction that the Program has established.
The accomplishments in the past 5 years of this Program, as well as of current programs in the national and international research community, provide increasing confidence from a technical standpoint that some commercial production of methane from methane hydrate in the United States could be achieved before 2025, contingent upon favorable regulatory conditions and market economics which the current study has not addressed in any detail. Although this production goal remains challenging, the committee believes it can be achieved through the provisions of the Program and the cooperation of the energy industry. The following recommendations aim to guide research priorities for the Program toward achieving an environmentally sound and efficient development pathway to recover methane from methane hydrate on a commercial scale. The
mandated goals and levels of support that have been available for this Program may require that programmatic direction in the future be focused specifically on applied and theoretical efforts related to the production of methane from methane hydrate.
Borehole research studies over the past several years have increased optimism that the long-term production of methane from methane hydrate can be technically achieved. In particular, methane gas flow by the simple depressurization technique has been demonstrated. However, the scale and duration of flow tests have been limited, uncertainty still exists in regard to identifying appropriate production technologies, and challenges remain in predicting the field-scale response.
Designing Future Production Tests
Well completions with appropriate production technologies should be developed and demonstrated in the field.
Long-term production tests on methane hydrate are required 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.
Production tests should establish initial conditions, monitor changes during production, and determine 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.
Because of the complex nature and expense of carrying out a large field program, sound research management practices should include a staged approach with open and comprehensive reviews of site survey data; completion, production, and monitoring design; risk assessments; and mitigation strategies.
Research that couples carbon dioxide sequestration and the production of methane from methane hydrate should be encouraged.
Increased effort should be devoted to the development of production technology. These efforts may involve adapting conventional production equipment and procedures or the development of new technologies, such as pressure testing, specific to methane hydrate.
APPRAISAL AND MITIGATION OF ENVIRONMENTAL AND GEOHAZARD ISSUES RELATED TO PRODUCTION
The published literature on environmental and geohazard issues specific to the production of methane from methane hydrate and the response of methane hydrate associated with traditional oil and gas development (exploratory drilling, production, and infrastructure) is surprisingly limited. To date, most studies have only considered these issues as an ancillary focus. Increased emphasis should be placed on better defining what the geohazard issues are, predicting the environmental impacts, and constraining the conditions to be avoided during production.
Industry experience associated with conventional oil and gas production in areas of methane hydrate occurrences should be compiled and made available.
Workshops should be organized 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) should be stimulated. A goal is to provide more confidence in risk assessments and to engineer mitigation strategies.
QUANTIFICATION OF THE RESOURCE
The establishment of petroleum system models for methane hydrate occurrences has been significantly advanced in the past 5 years. However, substantial challenges remain to quantify the in-place hydrate characteristics and the associated sediment conditions that would be necessary for economic development of methane hydrate accumulations. Further research is required to improve the accuracy, resolution, and reliability of methane hydrate assessments, particularly for those assessments related to economic methane production.
Pilot seismic surveys using existing geophysical methods (acoustic, electromagnetic, geothermal, etc.) that are optimized to map and quantify in-place methane hydrate accumulations should be undertaken. The goal is to provide a basis for appraisal of the use and limitations of data acquired by industry and for improvement on the design of future geophysical surveys (resolution) and associated data processing methods.
Understanding of in situ properties of sediments containing methane hydrate (pore physics models) needs to be improved through comprehensive testing (geophysical, geochemical, microbiological, geomechanical) of undisturbed natural core (controlled pressure and temperature conditions) and synthetic samples. These
data, when integrated with well-log data, will establish a basis for calibration of the geophysical surveys.
Consideration should be given to the development of new geophysical imaging, processing, and quantification techniques, particularly with respect to quantifying the in-place resource.
METHANE HYDRATE IN NATURE
Although understanding the role of methane hydrate as a source of a 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.
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 resource development goal.
Participation in International Programs
Methane hydrate is a global field of research, and direct participation in field projects is vital to any program. Although the Program has had some
level of activity in several international programs, the specific accomplishments, benefits to the Program, and the basis for participation are not always clear.
A strategic plan for international research partnerships, including estimates of the necessary levels of scientific and financial engagement, should be developed in close collaboration with other U.S. agencies.
To the degree required to establish international agreements, the Department of Energy should provide high-level administrative support to the Program.
Scientific and Expert Review Process of Major Field-Research Activities
The newly introduced peer review process is seen as a positive development of the Program. However, the procedures are not uniformly applied, especially to the major field activities where expert knowledge and close attention to the scientific goals will be required as the projects proceed and evolve. A more comprehensive and frequent peer and expert review process of major field programs is recommended.