Seismic Gas Hydrate Quantification by Cumulative Attributes (CATTs)
Last Reviewed 05/31/2011
The overall objective of this project is to develop a new method to assess methane hydrate distribution using 3-D seismic data calibrated to wellbore data. The method will be capable of detecting hydrates in multiple thin beds as well as in thick, massive beds.
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Reliable gas hydrate characterization from seismic data is a key step in understanding and ultimately developing the nation’s hydrate resource. The hydrate-rich areas will be the first targets for commercial development. If even 1% of this gas could be produced, it would be more than double current U.S. proven natural gas reserves, thus benefiting gas customers, creating jobs in the United States, and reducing our dependence on imported energy. Accurate characterization of worldwide hydrate accumulations also will benefit environmental researchers by providing data for climate models and helping to guide public policy with regard to climate change.
This project will provide a new, seismic-based technology for detecting and appraising hydrate distribution and the nature of the associated geologic sediments and structures. By integrating geology, 3-D seismic, well logs, and rock physics, we can accurately assess the volume of gas hydrate over broad regions. The major advantage of this method is that it uses conventional 3-D seismic and well log data as inputs. No special tools or acquisition methods are needed; hence, the method will be economical and practical to apply.
The method the researchers propose is based on the computation of cumulative seismic attributes (CATTs) and its calibration to in situ data from well logs and/or core measurements. CATTs is fundamentally different from other seismic reservoir characterization methods such as amplitude-versus-offset and acoustic impedance inversion. It is designed to respond to multiple stacked layers of hydrocarbon-filled zones, and, unlike most seismic attributes, well-suited to calibration with well log data. The unique advantage of CATTs is its ability to be used in areas where the thickness of the hydrocarbon-bearing intervals is below standard seismic resolution.
Impact of this research
Accurate characterization of subsurface hydrate accumulations using 3-D seismic would result in (1) better estimates of the nation’s gas hydrate resources, (2) improved characterization of hydrate-rich target areas for development, and (3) improved mapping of worldwide hydrate accumulations to aid in modeling the climatic impact of gas hydrates.
The success of this project will contribute to an overall NETL objective of assessing the extent and potential commercial viability of the domestic methane hydrate resource base by 2010.
While this technology will be developed and tested with methane hydrates in mind, it also will have potential applications to a broader spectrum of oil and gas exploration targets, particularly those in areas of scarce well control, such as the U.S. Gulf of Mexico Deep Shelf.
The project plan was modified to allow testing of the CATTs methodology on two, rather than one, seismic datasets as was originally planned. The first dataset is from the Milne Point area of northern Alaska and was obtained from Tim Collett, Ph.D., of the U.S. Geological Survey. A second dataset from a marine setting was also selected for testing. This second data set is from ODP Leg 204 on Hydrate Ridge, offshore Oregon.
The project team has completed the tasks for the first phase of the project. The project team has selected and obtained seismic and well log datasets from the U.S. Geological Survey, and has focused its efforts on seismic and well log data from a known hydrate occurrence beneath the permafrost in the Milne Point area of northern Alaska. The project team has developed hydrate type logs and synthetic seismograms using the Milne Point data set. They have also developed CATTs transforms for hydrates based on the seismic attributes modeled from the hydrate type logs. Phase 2 has also been completed. It involved up-scaling of well bore data and the calibration of CATTs for hydrate quantification. The result of Phase 2 was a geologic model for the occurrence of hydrates in Milne Point and a quantification of the amount of hydrates present.
Current Status (May 2011)
The project has been completed. The final technical report is available below under "Additional Information".
Project Start: October 1, 2006
Project End: October 30, 2009
Project Cost Information:
Phase 1: DOE Contribution: $349,088, Performer Contribution: $87,272
Phase 2: DOE Contribution: $182,748, Performer Contribution: $78,320
Phase 3: DOE Contribution: $116,286, Performer Contribution: $49,837
Planned Total Funding (if project continues through all project phases):
DOE Contribution: $648,122, Performer Contribution: $215,430
NETL – William Fincham (email@example.com or 304-285-4268)
RSI – Scott Singleton (firstname.lastname@example.org or 713-783-5593)
In addition to the information provided here, a full listing of project related publications and presentations as well as a listing of funded students can be found in the Methane Hydrate Program Bibliography [PDF].
Final Technical Report [PDF-7.91MB] - June, 2011
Quarterly Report [PDF-878KB] April - June, 2007
Technology Status Assessment [PDF-246KB]
Kick-off meeting presentation [PDF-1.09MB] - January 9, 2007