Abstract: A method for measuring the resistivity of geologic formations is described. An electromagnetic field may be generated using at least one stationary long-range transmitter. The frequency of the electromagnetic field may be between and/or including the ULF/ELF range. At least one component of the electromagnetic field may be measured by land, marine, submarine, and/or airborne receiver. A conductivity distribution may be determined based on the at least one measured component. The determined conductivity distribution may be correlated with geological formations and/or hydrocarbon deposits.

Abstract: A method for 3D modeling and inversion of potential field geophysical survey data measured above a geological formation having density and/or magnetization and/or susceptibility is described, using potential field data including but not limited to gravity and/or magnetic scalar and/or vector and/or tensor data. The 3D earth model is parameterized in terms of spatially variable contrast surfaces between different geological formations which are characterized by physical properties such as density and/or magnetization and/or susceptibility values and/or functions. The properties of the 3D earth model may be constrained from a priori information. The potential field responses and/or Frechet derivatives (sensitivities) of the spatially variable contrast surfaces between different geological formations and/or physical properties are analytically evaluated using Cauchy-type integral representations of the potential fields for each of the contrast surfaces.

Abstract: A method for rapid real time imaging of geological formations and/or man-made objects having density and/or magnetization is described, using gravity and/or magnetic scalar and/or vector and/or tensor data measured by a moving platform. The gravity and/or magnetic field sensors may measure gravity and/or magnetic data at the at least one receiver along the survey lines by the moving platform. The recorded data may be applied as an artificial source of the potential field to generate an evolving migration (backpropagating) field, and may be applied iteratively. An integrated sensitivity of the potential field to density and/or magnetization perturbation may be calculated. A spatial weighting of at least one of the evolving migration fields may form an evolving real time holographic image. At least one desired property of the medium may be derived providing real time reconstruction of the volume physical properties of the geological formations and/or man-made objects.

Abstract: A method for measuring the resistivity of sea-bed formations is described. An electromagnetic field is generated using at least one stationary long-range transmitter. The frequency of the electromagnetic field is between and/or including the ULF/ELF range. At least one component of the electromagnetic field is measured. A conductivity distribution is determined based on the at least one measured component. The determined conductivity distribution is correlated with geological formations and/or hydrocarbon deposits.