Imaging the Earth using Incoherently Scattered Seismic Waves in Exploration Geophysics
D. M. Leslie
Curtin University of Technology, Dept. of
Exploration Geophysics, Perth, Western Australia
Seismic methods are commonly used by the petroleum industry to obtain reflections from geological boundaries that are prospective for oil and gas production. In the presence of strongly scattering rugose or high-velocity layers at or near the Earth’s surface, no coherent signal is received from the subsurface. This research will use and extend the technique of Time Reversed Acoustics (TRA) in an effort to solve this imaging problem.
Numerical and physical modeling will be conducted using the developed imaging techniques. Preliminary physical modeling using simple models in a homogeneous background was conducted at the Laboratory of Waves and Acoustics (Paris) in 2000. The complexity of this study will be extended to simple geophysical models deliberately obscured by multi-scattering layers placed between the model and the signal source. Mathematical methods for achieving suitable imaging of the model will be developed and tested.
The first outcome of this research is a better understanding of the diffuse and multiple scattering processes in seismic exploration, which obscure the coherent signals used currently in seismic processing and imaging of the Earth’s interior. The ability to construct images below multiply scattering layers would open up areas for oil and gas exploration which are currently precluded due to the lack of coherent signal reflected from the subsurface.
The improved understanding of multiple scattering of seismic signals has the potential for the development of new data processing techniques to image the subsurface in areas where no seismic signals can otherwise be obtained. Examples particular to Australia include the North West Shelf, Timor Sea, and offshore Perth Basin.
AAPG Search and Discovery Article #90902©2001 AAPG Foundation Grants-in-Aid