|Natural Gas Hydrates in Permafrost and Marine Settings: Resources, Properties, and Environmental Issues
||Last Reviewed 6/3/2015
The objective of this DOE-USGS Interagency Agreement is to provide world-class expertise and research in support of the goals of the 2005 Energy Act for National Methane Hydrates R&D, the DOE-led U.S. interagency roadmap for gas hydrates research, and elements of the USGS mission related to energy resources, global climate, and geohazards. This project extends USGS support to the DOE Methane Hydrate R&D Program previously conducted under DE-AI26-05NT42496.
U.S. Geological Survey at Woods Hole, MA, Denver, CO, and Menlo Park, CA
The USGS Interagency Agreement (IA) involves laboratory research and international field studies in which DOE/NETL has a significant interest. Geological and geophysical support for these efforts is critical to their success, and the USGS is uniquely qualified to provide this support. This IA is currently divided into five separate tasks.
The primary objective of several tasks is to evaluate the production potential of the known gas hydrate accumulations on the North Slope of Alaska and in the Gulf of Mexico (GoM), respectively. These tasks are designed as a cooperative research effort among the USGS, DOE, other fedewral agancies, and various industry representatives. The USGS provides technical and scientific leadership and advice for formulation, planning, and implementation of field-based research projects.
In order to develop a better understanding of gas hydrates, the USGS conducts laboratory research to measure the properties of sediments containing synthetic hydrates using a range of experimental methods. These experiments investigate the interactions among gas hydrate, water, and free- or dissolved-phase gas during hydrate nucleation and dissociation, and serve to establish geotechnical indices for studying the properties of natural hydrate-bearing sediments retrieved from pressure core.
The USGS also supports cooperative projects between the U.S. and international partners. USGS scientists provide a range of capabilities from assessing resource potential to providing scientific and operational advice about the formulation of field programs, as well as participating in a scientific leadership capacity during joint field projects.
The USGS is also studying the links between Late Pleistocene to contemporary climate change and the state of the gas hydrate reservoir in high-latitude regions, specifically the U.S. Arctic. As part of this effort, the USGS is investigating a new noble gas fingerprinting technique for gas released from methane hydrates and will conduct field research in the shallow offshore Arctic at locations of rapidly degrading subsea permafrost, which presumably are coincident with hydrate degassing. The offshore work is intended to complement onshore research at lake-based gas seeps on the Alaskan North Slope (see University of Alaska project DE-NT0005665).
The technical depth of USGS scientists and engineers brings an additional important dimension to the research activities of the DOE Methane Hydrate R&D Program. In the Arctic, decades of geological and geophysical investigation are being brought to bear to help understand the full extent of the hydrate resource and the role of hydrates in high-latitude climate change. USGS research on marine hydrates is making important advances in our understanding of the occurrence and potential hazard of drilling of subsurface gas hydrates in the northern GoM. This information will provide industry with better tools and data as oil and gas development moves into areas where gas hydrates could present potential hazards. USGS scientists are developing new tools and techniques in the laboratory to better understand the hydrate-bearing sediments. USGS and DOE scientists and engineers, along with industry, will work together to gain a better understanding of the nature and distribution of marine gas hydrates and develop this valuable resource.
Accomplishments (most recent listed first)
The USGS participated in a one-week cruise on the R/V Endeavor in July 2014. The cruise, funded by NSF, was undertaken to gather data to quantify fluxes from mid-shelf seeps in New England, some New England canyon seeps, and some seeps in Hudson Canyon. This research expands on recent discoveries of methane seeps on the upper slope of the U.S. Atlantic margin acquired by the Okeanos Explorer between September 2011 and August 2013 (see Skarke et al).
The USGS participated in a successful June 2014 cruise aboard the University of Tromso vessel R/V Helmer Hanssen on the western Svalbard margin where they deployed the USGS cavity ring-down spectrometers (CRDS) for ocean-atmosphere and atmospheric marine boundary layer methane flux.
The USGS has completed retooling of the Instrumented Pressure Testing Chamber (IPTC). This included replacement of shear-wave probes that had showed indications of internal leakage and installation of an oscilloscope designed for acquiring low signal-to-noise ratio P- and S-wave seismic signals. The USGS Gas Hydrates Project laboratory facility at the Woods Hole Oceanographic Institute (WHOI) has been modified to accommodate the IPTC when the instrument is not being deployed. The IPTC has been pressure tested in this new configuration. The IPTC temperature control system has also been installed and verified. Recently, the Woods Hole researchers have successfully made hydrate in the IPTC for the first time.
The USGS has completed integration of a total organic carbon analyzer with an isotope ratio mass spectrometer (IRMS). The TOC-IRMS at WHOI is state of the art and one of only a few such instruments in North America. In February 2014, USGS participated in an international laboratory comparison conducted by Concordia University in Montreal, the results of which will be presented at the Advances in Stable Isotope Techniques and Applications (ASITA) conference in June 2014.
In support of future climate change-related expeditions, the USGS continues to develop and integrate advanced peripheral devices into their Picarro G-2301f and the Picarro G-2201i CRDS systems for improved measurement of methane concentrations (and fluxes) in air and water. One of the new peripherals processes and purifies gas extracted from near-surface ocean water and includes a flood prevention system to protect the laser cavity. The other peripheral draws air from intakes mounted at 3 or 4 elevations on the ship and subsequently purifies the gas and analyzes the gas composition at each level. The third peripheral delivers gas from as many as six standard cylinders to each CRDS at programmed intervals to ensure frequent calibration. The USGS has also upgraded data handling for the sonic anemometers that are deployed to measure environmental parameters at each location where air sampling occurs. The new system is weatherproof power-over-Ethernet that will allow for more robust transmittal of the sonic anemometer data to our data handling system. Although the system has yet to be fully tested, all components are in place to run the system as partially autonomous. Finally, the USGS has acquired a dedicated sonde (conductivity-temperature-depth or CTD) instrument needed to continuously monitor environmental parameters in near-surface water as its methane content is measured.
In September 2013, the USGS deployed their CRDS on the R/V Pelagia in the Dogger Bank seep area of the Dutch sector of the North Sea. The goal of this research was to distinguish between diffusive and ebullitive flux of methane to the atmosphere from this shallow-water seep. Results were presented at the final meeting of the EU PERGAMON program in Kiel in November 2013. In October 2013, USGS scientists embarked upon the USCG Healy from Dutch Harbor, Alaska. For nearly three weeks, the USGS deployed two CRDS systems as part of this National Science Foundation (NSF) expedition. One CRDS was used for multilevel air sampling to capture greenhouse gas gradients in the atmospheric marine boundary layer and the other collected water column samples for conventional determinations of methane concentrations. The USGS obtained over 6,000 km of continuous, real-time flux measurements in the western Arctic from the Chukchi Sea to the Amundsen Gulf. This research supports the DOE/NETL mission to assess gas hydrate stability and the role dissociating hydrates may play in global climate change.
Between April 18 and May 3, 2013, USGS scientists used low-energy seismic sources to collect new information on gas hydrate reservoirs at two Joint Industry Partnership (JIP) Gulf of Mexico sites: Green Canyon 955 and Walker Ridge 313. This expedition, jointly planned by USGS, DOE, and Bureau of Ocean Energy Management (BOEM) also provided insight into the source of gas, migration pathways for the gas, the distribution of hydrate-bearing sediments, and the traps that hold the hydrate and free gas in place. These high-resolution data help to inform the BOEM effort to assess the resource potential of gas hydrates on the U.S. Outer Continental Shelf (see related Fire in the Ice article). A Department of Energy Office of Fossil Energy news release and Fire in the Ice news article provide more information on this expedition.
In January 2013, U.S. and Japanese researchers analyzed pressure cores using specialized Pressure Core Characterization Tools (PCCT) designed to keep cores at their natural, stable conditions (see related Fire in the Ice articles; October 2012 and October 2013). PCCT devices include a manipulator for moving pressure cores from storage chambers into various testing chambers, special pressure vessels that measure the strength of the sediments and how quickly fluids can flow through them, and a biological chamber that can be used to study the microbes that live in the deep-sea sediments. A key tool in the suite of PCCT instruments is the IPTC, which was the first device capable of measuring certain properties of pressure cores without first depressurizing them. The IPTC was built by Georgia Tech in 2005 and is now operated and maintained by USGS researchers Bill Winters and Bill Waite (see related Fire in the Ice article).
The USGS has submitted several abstracts and presented oral and poster presentations at the fall American Geophysical Union Meeting in San Francisco in December 2012. These presentations cover recent research conducted in marine and permafrost gas hydrate systems. USGS and DOE supported research investigating the possible link between methane hydrates and climate change has also been highlighted in several articles in periodicals including Petroleum News (July 15, 2012), USGS Science Features (January 2012) and Nature Education Knowledge (2012).
Two papers pertaining to the physical properties of hydrates were completed: The first, “Anomalous waveforms observed in laboratory-formed gas hydrate-bearing and ice-bearing sediments,” was published in the Journal of the Acoustical Society of America in April 2011. The second, “Inter-laboratory comparison of wave velocity measurements in a sand under hydrate-bearing and other set conditions,” was presented in July 2011 at the 7th International Conference on Gas Hydrates (ICGH). (see also Fire in the Ice article)
Researchers completed initial studies on the partitioning of noble gas in methane clathrates: Unlike traditional stable isotope measurements, which can only distinguish between microbial and thermogenic methane, USGS researchers have confirmed the unique noble gas fractionation pattern in which the solid hydrate lattice retains, and is enriched in, heavy noble gases (e.g., xenon and krypton) while preferentially excluding lighter noble gases such as argon. This preliminary research utilizing synthetic hydrate samples was presented in a paper at the ICGH in July 2011. A key finding from this initial research was that storage of samples in liquid nitrogen alters the noble gas signature of gas hydrates. The USGS recognized this and was able to collect natural samples from the UBGH2 (Ulleung Basin Gas Hydrate) expedition for further noble gas fingerprinting. This technique, if successful, will provide a method of evaluating modern natural gas seeps for a signature associated with gas hydrate dissociation (see Fire in the Ice article).
USGS contributed to and co-edited the North Slope of Alaska Mount Elbert Gas Hydrate Stratigraphic Test Well scientific results volume published as a special edition of Marine and Petroleum Geology in February 2011. USGS scientists also coordinated and contributed to a special thematic volume on Gulf of Mexico gas hydrates published in late 2011 in Marine and Petroleum Geology. This special volume highlights results from the 2009 Gulf of Mexico Gas Hydrate Joint Industry Project Leg II drilling program.
On March 15 and 16, 2011, the USGS coordinated the assembly of about 20 scientists to review ongoing research and discuss future research priorities focused on the interaction of gas hydrates with the global climate system (see Fire in the Ice article).
In early August 2010, the USGS conducted a reconnaissance high-resolution geophysical survey focused on the shallow (up to ~100 meters) subsea floor of Harrison Bay in the Beaufort Sea. The primary goal of the survey was to image the distribution of subsea permafrost and methane as part of an effort to understand the impact of Late Pleistocene to contemporary climate warming on formerly terrestrial permafrost and, possibly, associated methane hydrates. Approximately 185 km of new mini-sparker, Chirp, and sonar data were collected during the cruise, and one sonobuoy was deployed for a short-offset velocity survey. For more information, see the USGSSound Waves newsletter for October/November 2010. In early August 2011, USGS scientists returned to Harrison Bay to conduct further geophysical surveying of the shallow Beaufort shelf. The surveys included sonar imaging of the water column and seafloor, mini-sparker (penetration up to 100 m subseafloor) seismic and Chirp seismic, collection of short vibracores from gas-charged and gas-free sediments, and surface water sampling for analysis of methane concentrations. These data will be used to determine the depth of subsea permafrost, the seaward extent of thawing permafrost, the distribution of shallow methane in the sediments, and the location of seafloor methane expulsion features and water column methane plumes. The USGS returned to the North Slope in August 2012 to conduct a site survey of the Beaufort shelf in the area considered most prone to active dissociation of methane hydrate in response to rising sea levels. The project yielded the first modern high-resolution seismic data acquired by non-industry groups across the entire shelf of the U.S. Beaufort since 1977, the first-ever real-time seawater methane map for a circum-Arctic Ocean shelf, and the first suite of methane oxidation rate measurements (see Fire in the Ice article).
The USGS provided scientific expertise aboard the drillship Fugro Synergy during the UBGH2 expedition. This expedition was funded by the Korean government to examine the gas hydrate in marine sediments east of Korea. The expedition ran from July through the beginning of October 2010 (See Fire in the Ice May 2011). In addition, USGS personnel have been actively engaged in providing technical information and review of the United Nations Environmental Program (UNEP) Gas Hydrate study.
Current Status (June 2015)
The penultimate task of this DOE/USGS interagency agreement was completed in April 2015. On April 13th, the USGS mobilized operations in Rhode Island for an Atlantic Seep cruise aboard the R/V Endeavor. By the 17th of April, the science team had collected 300 km of 72-channel multichannel seismic data, with coincident methane plume imaging of the water column. Air-sea methane and CO2 flux/real-time methane carbon isotope data from the ship’s seawater feed were also analyzed. The Simrad EK60 echo sounder provided amazing imagery of gas distribution and gas migration features. With mixed weather following, the final tally was 560 km of data. Results from this research cruise will help to constrain the Atlantic margin’s upper slope gas system including the distribution of deep seep sites within the hydrate stability zone (1000 m, 1400 m). The datasets collected should prove invaluable for laying the groundwork for future climate studies as well as resource related gas hydrate studies on the Atlantic margin.
Project Start: June 1, 2010
Project End: May 31, 2015
DOE Contribution: $1,709,348
Performer Contribution: na
NETL – Robert Vagnetti (email@example.com or 304-285-1334)
USGS – Carolyn Ruppel (firstname.lastname@example.org or 508-457-2339)
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