HR: 09:15h
AN: S41B-06    [Abstracts]
TI: Efficient calculation of the Green function in time-lapse seismic studies using boundary- integral representations
AU: * Douma, H
EM: hdouma@princeton.edu
AF: princeton university, Department of Geosciences, Princeton, NJ 08544, United States
AU: Dahlen, F
EM: fad@princeton.edu
AF: princeton university, Department of Geosciences, Princeton, NJ 08544, United States
AB: There are many applications where one is interested in calculating the response of a wavefield to a local perturbation in a medium. For example, in time-lapse seismic monitoring extensive modelling of the seismic response to local perturbations in the medium is often needed to determine the feasibility of detecting changes due to CO₂ sequestration or production of hydrocarbons. We show the connection between a convolution-type acoustic reciprocity theorem of wavefields in two media with different medium parameters and the Lippmann-Schwinger integral equation. This connection leads to a boundary-integral representation of the full Green function in a perturbed medium between any two points outside of the perturbation and two points, one of which is inside and one of which is outside the perturbed area. This integral contains the impulse reponses due to both monopole and dipole sources located on the bounding surface of the perturbation only. If the bounding surface can be covered with sufficiently fewer sources than the number of sources in the acquisition geometry, the boundary-integral representations we present allow efficient calculation of the full Green function due to the local perturbation. There is no constraint on the magnitude of the perturbation. We verify numerically the accuracy of these representations for the simple case of wave propagation in one dimension, and discuss its potential use in time- lapse seismic studies such as monitoring of CO₂ sequestration, hydrocarbon reservoirs, or nuclear- waste storage sites.
DE: 0902 Computational methods: seismic
DE: 0935 Seismic methods (3025, 7294)
SC: Seismology [S]
MN: 2007 Joint Assembly