Method for obtaining resistivity from controlled source electromagnetic data

摘要

Method for generating a three-dimensional resistivity data volume for a subsurface region from an initial resistivity model and measured electromagnetic field data from an electromagnetic survey of the region, where the initial resistivity model is preferably obtained by performing multiple ID inversions of the measured data [100]. The resulting resistivity depth profiles are then registered at proper 3D positions [102]. The 3D electromagnetic response is simulated [106] assuming the resistivity structure is given by the initial resistivity model. The measured electromagnetic field data volume is scaled by the simulated results [108] and the ratios are registered at proper 3D positions [110] producing a ratio data volume [112]. A 3D resistivity volume is then generated by multiplying the initial resistivity volume by the ratio data volume (or some function of it), location-by location [114]. A related method emphasizes deeper resistive anomalies over masking effects of shallow anomalies.