Abstract: To construct a reduced order model of a subterranean structure, a model reduction algorithm is applied to produce the reduced order model that is an approximation of a true model of the subterranean structure. The model reduction algorithm uses interpolating frequencies that are purely imaginary to enhance computational efficiency of the algorithm.

Abstract: A method is disclosed for performing optimal gridding in reservoir simulation, the method comprising: establishing an optimal coarse grid proxy that can replace all or parts of a fine grid with a coarse grid while preserving an accuracy of a predefined simulation model output, the step of establishing an optimal coarse grid proxy including finding, by using an optimizer, a best fit of a coarse grid output to the output of a training set.

Abstract: A method of determining the nature of a submarine or subterranean reservoir having an electromagnetic characteristic is described. The method comprises analyzing data associated with the application of a time varying electromagnetic field from above the reservoir using a data analysis methodology that does not utilize an estimate of the reservoir's geometry in determining one or more characteristics of the reservoir.

Abstract: To construct a reduced order model of a subterranean structure, a model reduction algorithm is applied to produce the reduced order model that is an approximation of a true model of the subterranean structure. The model reduction algorithm uses interpolating frequencies that are purely imaginary to enhance computational efficiency of the algorithm.

Abstract: A method of determining the nature of a submarine or subterranean reservoir having an electromagnetic characteristic is described. The method comprises analyzing data associated with the application of a time varying electromagnetic field from above the reservoir using a data analysis methodology that does not utilize an estimate of the reservoir's geometry in determining one or more characteristics of the reservoir.

Abstract: A method is disclosed for performing optimal gridding in reservoir simulation, the method comprising: establishing an optimal coarse grid proxy that can replace all or parts of a fine grid with a coarse grid while preserving an accuracy of a predefined simulation model output, the step of establishing an optimal coarse grid proxy including finding, by using an optimizer, a best fit of a coarse grid output to the output of a training set.

Abstract: Inception of hydrocarbon extraction from a reservoir causes the oil-water interface to warp and cusp toward the extraction gates along a well. This invention proposes time-lapse DC/AC measurements with an array of permanently deployed sensors in order to detect and estimate the change in geometry and proximity of the oil-water interface as a result of production, and therefore as a function of time. The estimation is carried out with a parametric inversion technique whereby the shape of the oil-water interface is assumed to take the form of a three-dimensional surface describable with only a few unknown parameters. A nonlinear optimization technique is used to search for the unknown parameters such that the differences between the measured data and the numerically simulated data are minimized in a least-squares fashion with concomitant hard bound physical constraints on the unknowns.