摘要:
Method and apparatus for producing a bubble curtain with a diversity of bubble diameters for purposes such as suppressing surface-related multiple reflections in marine seismic surveys. Bubble generating elements are used that combine porous wall material with discrete holes.
摘要:
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.
摘要:
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.
摘要:
Method for determining an expected value for a proposed reconnaissance electromagnetic (or any other type of geophysical) survey using a user-controlled source. The method requires only available geologic and economic information about the survey region. A series of calibration surveys are simulated with an assortment of resistive targets consistent with the known information. The calibration surveys are used to train pattern recognition software to assess the economic potential from anomalous resistivity maps. The calibrated classifier is then used on further simulated surveys of the area to generate probabilities that can be used in Value of Information theory to predict an expected value of a survey of the same design as the simulated surveys. The calibrated classifier technique can also be used to interpret actual CSEM survey results for economic potential.
摘要:
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.
摘要:
The present invention is a method of processing seismic data in which one or more seismic vibrators are activated with one or more pilot signals and vibrator motions are recorded along with seismic data. Vibrator signatures are computed from measured vibrator motions, such as the ground force signal. A desired impulse response is specified from either a measured vibrator motion or from test data or field data from a location near the location from which the seismic data was acquired. A deconvolution filter is computed from the impulse response and the vibrator signature. Alternatively, a single separation and deconvolution filter is derived from the impulse response and from vibrator signatures from multiple vibrators and sweeps. The deconvolution or deconvolution and separation filter is used to process the seismic data. The vibrators are then moved to a new location, and the activation is repeated.
摘要:
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. The resulting matrix equations are then inverted and a solution is obtained for all offsets simultaneously.
摘要:
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.
摘要:
Method for identifying, determining and correcting source-related phase errors in data from a controlled source electromagnetic survey by using data from ordinary survey receivers, i.e. without benefit of source monitoring data. Abrupt anomalies indicating source malfunctions are identified (71) in the time domain by plotting time intervals between neighboring zero crossings or by zero-lag cross correlation between consecutive bins of receiver data, and the amount of the time error (73) can be determined by performing cross correlation between two bins on either side of an anomaly. In the frequency domain, transmitter anomalies can be identified by looking for discontinuities in plots of phase vs. offset, and the corrective phase shift can be determined by matching the phase on one side of the anomaly to that on the other side. A global time/phase shift (76) can be determined by using phase frequency-scaling behavior at near offsets.
摘要:
The method for suppressing noise in the controlled seismic source electromagnetic survey data based on the frequency content of the noise (51) contained in the data. The invention recognizes that some data variations across bins cannot be attributed to resistivity variations within the earth. This variation across the bins constitutes a model of noise in such surveys, and the invention mitigates noise that obeys this model.