SPE Journal
Volume 15,
Number 3,
September 2010,
pp. 634-645
Summary
Many studies involving the application of geophysical methods in the field
of gas hydrates have focused on determining rock-physics relationships for
hydrate-bearing sediments, with the goal being to delineate the boundaries of
gas-hydrate accumulations and to estimate the quantities of gas hydrate that
such accumulations contain using remote-sensing techniques. However, the
potential for using time-lapse geophysical methods to monitor the evolution of
hydrate accumulations during production and, thus, to manage production has not
been investigated. In this work, we begin to examine the feasibility of using
time-lapse seismic methods--specifically, the vertical-seismic-profiling (VSP)
method--for monitoring changes in hydrate accumulations that are predicted to
occur during production of natural gas. A feasibility study of this nature is
made possible through the coupled simulation of large-scale production in
hydrate accumulations and time-lapse geophysical (seismic) surveys. We consider
a hydrate accumulation in the Gulf of Mexico that may represent a promising
target for production. Although the current study focuses on one seismic method
(VSP), this approach can be extended easily to other geophysical methods,
including other seismic methods (e.g., surface seismic or crosshole
measurements) and electromagnetic surveys. In addition to examining the
sensitivity of seismic attributes and parameters to the changing conditions in
hydrate accumulations, our long-term goals in this work are to determine
optimal sampling strategies (e.g., source frequency, time interval for data
acquisition) and measurement configurations (e.g., source and receiver spacing
for VSP), while taking into account uncertainties in rock-physics
relationships. The numerical-modeling strategy demonstrated in this study may
be used in the future to help design cost-effective geophysical surveys to
track the evolution of hydrate properties. Here, we describe the modeling
procedure and present some preliminary results.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
21 February 2008
- Meeting paper published:
6 May 2008
- Revised manuscript received:
5 September 2009
- Manuscript approved:
29 September 2009
- Published online:
22 March 2010
- Version of record:
22 September 2010