| 摘要 |
A method of processing electromagnetic signals which are injected into the earth from a capacitor and subsequently detected after reflection from subsurface layers, in order to determine the physical and electrical properties of those layers. The method is based on an iterative process which models the earth as a series of vertically stacked horizontal layers, each characterized by its physical properties of depth beneath the surface and thickness, and its electrical properties of resistivity (or conductivity) and relative dielectric constant. An initial propagation model which specifies the electrical properties of a particular layer or set of layers is constructed and applied to a model input pulse to produce a predicted return pulse which results from the reflection and/or transmission of the input pulse at the boundaries of the layer(s). The predicted return pulse is then compared to actual return pulse data which is selected so as to roughly correspond to a return pulse produced at the location of the modeled layer(s). The result of the comparison forms the basis for adaptively varying the parameters of the propagation model in a manner which is intended to increase the correlation between the predicted return pulse and the actual data. Repetition of the method for different layers or additional locations permits the electrical characteristics of the earth beneath a specified region to be determined. Knowledge of these characteristics can be used to infer the type of geologic formation responsible for transforming the input pulse into the received pulse.
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