Wavefield transform of electromagnetic fields
- Lawrence Berkeley Lab., CA (United States)
- Schlumberger-Doll Research, Ridgefield, CT (United States)
One of the recent developments in electromagnetic (EM) methods for crosshole conductivity imaging involves transformation of diffuse EM fields to wavefields (Lee and Xie, 1993). In this approach the EM fields are first transformed to wavefields. The velocity of the wavefield and the electrical conductivity are related by a simple formula. Using traveltime obtained from the transformed wavefield a ray tomography would be carried out for the wavefield velocity and then the electrical conductivity. From the transformed wavefield only the traveltime is used for the tomographic imaging. This paper examines numerical methods for obtaining travel times by transforming either the time- or the frequency-domain data to wavefields. The number of sample data used for the transform can be as little as ten for the frequency-domain approach and twenty five for the time-domain approach. The accuracy in the traveltime obtained this way seems within one percent provided that the data are sufficiently accurate. The transform originally involves the solution of a Fredholm integral equation of the first kind. Predictably, with lesser amount of data the numerical process becomes more ill-posed.
- OSTI ID:
- 80267
- Report Number(s):
- CONF-941015-; TRN: IM9532%%395
- Resource Relation:
- Conference: 64. annual meeting of the Society of Exploration Geophysicists and international exposition, Los Angeles, CA (United States), 23-27 Oct 1994; Other Information: PBD: 1994; Related Information: Is Part Of SEG international exposition and sixty-fourth annual meeting -- 1994 Technical program: Expanded abstracts with authors` biographies; PB: 1736 p.
- Country of Publication:
- United States
- Language:
- English
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