Abstract: Methods and systems for modeling a reservoir system are described. The method includes constructing a reservoir model of a reservoir system. The reservoir model includes a reservoir and a plurality of wells. Also, one or more material balance groups are constructed with each material balance group having a portion of at least one of the plurality of wells, a portion of the reservoir, and at least one well management algorithm to track material balance within the respective material balance group. Then, fluid flow through the reservoir model is simulated based on the material balance groups by a simulator and the results are reported.

Abstract: A method for identifying and suppressing water column reverberations (“multiple reflections”) in two-component ocean bottom seismic data is disclosed. The method involves processing the hydrophone (P) data and the geophone (Z) data separately to produce two stacked images of the subsurface (21). Analyzing the stacked P-image and the stacked Z-image together can be used to identify multiple reflections (22). Analyzing the stacked /?-image and the stacked Z-image together with an image of the subsurface created from hydrophone and geophone data combined in the usual way (PZ-image) (20) can be used to identify residual multiples in the PZ image (23). The stacked P and Z images can be combined using an existing PZ combination technique to suppress multiples (24). The efficiency of the PZ combination technique at suppressing multiples is increased because of the higher signal-to-noise ratio of stacked data.

Abstract: A probabilistic method for classifying observed CSEM response for a resistive anomaly to classify the response into multiple geologic categories indicative of hydrocarbon production potential. Each category is assigned a prior probability (301). For each category, conditional joint probability distributions for observed CSEM data in the anomaly region are constructed (303) from rock property probability distributions (302) and a quantitative relationship between rock/fluid properties and the CSEM data (304). Then, the joint probability distributions and prior probabilities for each category (305) are combined with observed data (307) and used in Bayes' Rule (306) to update the prior category probabilities (308). Seismic data may be used to supplement CSEM data in the method.

Abstract: Method for modeling anisotropic elastic properties of a subsurface region comprising mixed fractured rocks and other geological bodies. P-wave and fast and slow S-wave logs are obtained, and an anisotropic rock physics model of the subsurface region is developed (21). P- and fast and slow S-wave logs at the well direction are calculated using a rock physics model capable of handling fractures and other geological factors (22). Calculated values are compared to measured values in an iterative model updating process (23). An upscaled ID model is developed by averaging elastic properties in each layer using an upscaling theory capable of handling at least orthorhombic anisotropy (24). The ID model may be used to generate synthetic seismic response for well ties or AVO modeling (25). Further, a method is disclosed for estimating anisotropy parameters from P- and fast/slow S-wave logs from one or more deviated wells.

Abstract: A method for designing a controlled-source electromagnetic survey that will discriminate between a defined deep marginal-interest reservoir (2) and specified false positive resistivity structures of concern (3, 4, 5). A reservoir model and a false positive model are constructed for each false positive scenario. The resistivity of the false positive model may be tuned to give electromagnetic data similar enough to the reservoir model when forward modeled that any differences fall in the model null space. A null-space discriminating ratio (“NSDR”) is defined, for example as the peak normalized difference of the two related modeled electromagnetic field data sets. An area coverage display of NSDR values (6) allows determination of such additional data as may be needed to distinguish the false positive body, and a survey design is developed accordingly (7). Reduction of the number of variables affecting the area coverage displays is a key feature of the method.

Abstract: Method for reducing air wave and/or magnetotelluric noise in controlled source electromagnetic surveying by either shielding the source (61) from the air interface, shielding the receivers from downward traveling electromagnetic energy, or by employing a second source (62) to preferentially cancel the air wave (and MT) part of the signal, or a combination of the preceding.

Abstract: Method for obtaining rock parameters such as porosity and vshale directly from inversion of seismic data corresponding to a single trace location. This method is distinguished from existing methods that obtain elastic properties from inversion of seismic data, then relate the elastic parameters to rock lithology parameters such as porosity or vshale because it is accomplished in one step, can incorporate anisotropy and does not require multiple trace locations for stability. The data are separated into partial stacks, and a wavelet is specified for each stack. A set of linearized equations are constructed relating seismic reflectivity to changes in elastic parameters, and another set of linearized equations is constructed relating the changes in elastic parameters to the lithologic parameters. The linearized reflectivity equations are combined with the linearized rock physics equations, convolved with the specified wavelets, and equated to the seismic data.

Abstract: Method for efficient inversion of controlled-source electromagnetic survey data to obtain a resistivity model of the subsurface of the survey area. The method extracts the dimensions and location of sub-surface structures as they may be revealed by existing seismic or other available high resolution survey data from the subsurface area (33). This structure geometry information is used to construct a discretization (grid, or mesh) for the inversion computation (34) that is different from the mesh used for the forward modeling calculations (32) in that (a) it has fewer and hence larger cells; and (b) the cells honor the assumed structural information. The inversion need only extract resistivity information (35), the geometry of the resistive structures being specified by the inversion mesh.

Abstract: Method for determining best and worst cases for values of model parameters such as porosity and shale volume fraction generated by non-unique matrix inversion of physical data such as seismic reflection amplitudes. The matrix is diagonalized, and then orthonormal basis vectors associated with insignificant diagonal elements are used to generate upper and lower bounds on the solution. Best and worst case solutions are determined as linear combinations of the null basis vectors, where the expansion coefficients are determined by making a best fit to the upper and lower bounds.

Abstract: A geophysical model of a subsurface region is generated based on seismic data, e.g., seismic reflection data. Migration and seismic inversion are applied to the seismic data to generate estimates of one or more physical or seismic properties of the subsurface region. Seismic inversion, such as spectral shaping inversion, is applied before or after migrating the seismic data through a variety of techniques that each avoid the amplification of dipping energy while optimizing computational efficiency and/or accuracy.

Abstract: This invention relates generally to a method of simulating the signal of an electromagnetic source using one or more dipole sources. In the method a dipole source is located at an excitation location corresponding to a segment of the electromagnetic source to be simulated. The dipole source is activated, and an electromagnetic signal recorded at one or more receiver locations. This process is repeated for additional excitation locations corresponding to additional segments of the electromagnetic source. The data from the sequence of dipole source excitation locations is processed to determine the simulated signal of the electromagnetic source.

Abstract: A method, apparatus and computer program for improving the signal-to-noise ratio of a signal S(t), S(t) containing Signal and noise, are disclosed. A measurement of S(t) at a frequency-of-interest is obtained. Noise measurements of S(t) at one or more noise frequencies where the Signal portion of S(t) is expected to be small are obtained. The noise at the frequency-of-interest is estimated using the noise measurements at the one or more noise frequencies. The estimated noise is subtracted from the measurement of S(t) at the frequency-of-interest.

Abstract: A method is disclosed for using a three-dimensional seismic image of a subsurface earth volume to construct a geologic model specifying the spatially-varying grain size distribution, porosity, and permeability throughout the volume. The method applies to earth volumes composed of water-lain clastic sedimentary deposits and involves, in one embodiment, (a) identifying the outline forms of geologic bodies in geologic data; (b) using the outline forms of the geologic bodies to determine the spatially-varying grain size distribution within the bodies, guided by assumptions about the nature and behavior of the paleoflow that deposited the bodies; (c) determining rock properties such as, porosity and permeability within the geologic bodies based on grain-size distribution, mineralogy and burial history information.

Abstract: Method for designing a converted mode (PS or SP) seismic survey to accomplish specified vertical and lateral resolution objectives at target depth. An equation (181) is provided for determining the minimum bandwidth required for a desired vertical resolution at a selected scattering angle, as a function of incident and reflected wave velocities, one of which is the P-wave velocity and the other is the S-wave velocity. A second equation (182) is provided for determining migration acceptance angle from the desired vertical and lateral resolutions. Source and receiver apertures may then be determined by ray tracing. Finally, a third equation (183) is provided for the maximum bin size to avoid aliasing, given the migration acceptance angle and a maximum frequency needed to achieve the bandwidth requirement. Source and receiver spacing may then be based on the maximum bin size.

Abstract: Method for organizing computer operations on a system of parallel processors to invert electromagnetic field data (11) from a controlled-source electromagnetic survey of a subsurface region to estimate resistivity structure (12) within the subsurface region. Each data processor in a bank of processors simultaneously solves Maxwell's equations (13) for its assigned geometrical subset of the data volume (14). Other computer banks are simultaneously doing the same thing for data associated with a different source frequency, position or orientation, providing a “fourth dimension” parallelism, where the fourth dimension requires minimal data passing (15). In preferred embodiments, a time limit is set after which all processor calculations are terminated, whether or not convergence has been reached.

Abstract: Method for separating responses of multiple transmitters m a controlled source electromagnetic survey by using mutually orthogonal transmitter waveforms and transforming the combined response to the frequency domain (144) The mutual orthogonality can be based disjoint frequency spectra or on phase encoding of a common waveform element (FIG. 14).

Abstract: The method for correcting the phase of measured electric signals or magnetic signals of field data from a controlled source electromagnetic survey (CSES) by comparing the measured field data corresponding to a selected frequency to the simulated data for various signal source receiver offsets (71) and correcting the phases of the actual data based on the phase difference for a selected range of small signal offsets (76) based on a go-electric model.

Abstract: Described herein are methods of evaluating reservoirs. At least one of the methods includes providing a three dimensional reservoir framework having a plurality of cells; assigning one or more constant reservoir property values to some or all of the cells to provide a first three dimensional reservoir model; updating the first three dimensional reservoir model by populating some or all of the cells with one or more variable reservoir property values to provide a second three dimensional reservoir model; and updating the second three dimensional reservoir model by populating some or all of the cells with one or more reservoir property values derived from seismic data to provide a third three dimensional reservoir model. Other methods are also described.

Abstract: This patent delineates methods for quantifying and mitigating dip-induced azimuthal AVO effects in seismic fracture detection using Azimuthal AVO analysis by accurately accounting for the divergence correction and azimuthal dependence of the reflection angle. Solutions are provided for three cases: (1) dipping isotropic reservoirs; (2) anisotropic reservoirs with fractures aligned in arbitrary direction; and (3) anisotropic reservoirs where vertical fractures are aligned perpendicular to the dip direction.

Abstract: The invention relates to a computer system and method for simulating transport phenomena in a complex system. The computer system comprises a logic interface that enables a user of the computer system to dynamically construct logic to customize simulation of the physical system, a means for converting the constructed logic into corresponding object-oriented code, a means for integrating the object-oriented code with the main simulation system which comprises a simulation data model and simulation algorithms, resulting in an integrated simulation system, and a means for executing the integrated simulation system.