Patent classifications
G01V2210/52
AUTOMATIC IMAGE REGISTRATION OF MULTICOMPONENT SEISMIC DATA
A method is described that includes obtaining a multicomponent seismic data set for a subterranean region of interest and determining, using a computer processor, a PP stacked time-domain seismic image and a PS stacked time-domain seismic image from the multicomponent seismic data set. The method further includes transforming a recording-time axis of at least one of the PP stacked time-domain seismic image and the PS stacked time-domain seismic image to produce a pair of coarsely-registered PP and PS seismic images and filtering at least one of the pair to produce a pair of spectrally-matched PP and PS seismic images. Further, the method includes dynamically warping at least one of the pair of spectrally-matched PP and PS seismic images to produce a pair of fully-registered PP and PS seismic images.
Method to Estimate and Remove Direct Arrivals From Arrayed Marine Sources
A method for obtaining zero-offset and near zero offset seismic data from a marine survey, with separation of direct arrival information and reflectivity information, the method including: modeling a direct arrival estimate at a passive near-field hydrophone array by using a notional source separation on active near-field hydrophone data; generating reflection data for the passive near-field hydrophone array by subtraction of the modeled direct wave from data recorded by the passive near-field hydrophone array; generating near zero-offset reflectivity traces by stacking the reflection data for the passive near-field hydrophone array on a string-by-string basis or on a combination of strings basis; generating reflectivity information at the active near-field hydrophone array by subtracting the direct arrival estimate modeled using the notional source separation from the active near-field hydrophone data; and generating an estimate of zero-offset reflectivity traces by calculating a cross-correlation between the between the reflectivity information at the active near-field hydrophone array and the near zero-offset traces and performing an optimized stacking with summation weights based on coefficients of the cross-correlation.
Full waveform inversion in the midpoint-offset domain
Methods for full waveform inversion (FWI) in the midpoint-offset domain include using a computer system to sort seismic traces into common midpoint-offset bins (XYO bins). For each XYO bin, a linear moveout correction is applied to a collection of seismic traces within the XYO bin. The collection of seismic traces is stacked to form a pilot trace. The computer system determines a surface-consistent residual static correction for each seismic trace. The computer system determines that the surface-consistent residual static correction for each seismic trace is less than a threshold. Responsive to the determining that the surface-consistent residual static correction is less than the threshold, the computer system stacks the collection of seismic traces to provide the pilot trace. The computer system groups the pilot traces for the XYO bins into a set of virtual shot gathers. The computer system performs one-dimensional FWI based on each virtual shot gather.
PROVIDING SEISMIC IMAGES OF THE SUBSURFACE USING ENHANCEMENT OF PRE-STACK SEISMIC DATA
A system provides seismic images of the subsurface by enhancing pre-stack seismic data. The system obtains seismic data comprising a plurality of seismic traces that are generated by measuring reflections of seismic waves emitted into a geological formation. The system sorts seismic data into at least one multidimensional gather comprising a data domain. The system determines local kinematical attributes of a seismic trace. The system forms an ensemble of seismic traces, each representing a reference point. The system applies local moveout corrections to each seismic trace of the ensemble. The system applies residual statics and phase corrections for each seismic trace that is corrected by the local moveout corrections. The system sums the seismic traces of the ensemble to obtain an output seismic trace having an increased signal-to-noise ratio (SNR) relative to the seismic trace that represents the reference point for the ensemble of seismic traces.
Identifying geologic features in a subterranean formation using angle domain gathers sampled in a spiral coordinate space
Systems and methods for seismic imaging of a subterranean geological formation include receiving parameter data representing one or more parameters of a seismic survey, the seismic data specifying an incident angle and an azimuth angle for each trace of the seismic survey; determining a relationship between the incident angle and the azimuth angle for each trace and a location in a spiral coordinate system, and generating a weighting function for applying a weight value to each trace seismic data based on the incident angle and the azimuth angle associated with each trace; and determining a residual moveout value of the seismic data for each location in the spiral coordinate system by applying the weighting function to each; and generating a seismic image representing the residual moveout value of the seismic data for each location in the spiral coordinate system.
ENHANCEMENT OF SINGLE SENSOR SEISMIC DATA
Disclosed are methods, systems, and computer-readable medium to perform operations including: receiving prestack single sensor seismic data; representing traveltime moveout of the prestack single sensor seismic data locally as a second-order curve; calculating, using the prestack single sensor seismic data, local kinematic parameters that define the second-order curve; and performing, based in part on the local kinematic parameters, wavefield transformation on the single sensor seismic data to generate enhanced prestack single sensor seismic data.
Method and system that uses an anisotropy parameter to generate high-resolution time-migrated image gathers for reservoir characterization, and interpretation
A method and a system for implementing the method are disclosed wherein the pre-stack seismic input data, an initial anellipticity anisotropy parameter, and a baseline normal moveout velocity from a non-flat surface, are sometimes mild or foothill topography as well as the shot and receiver lines might not necessarily be straight, and often curve to avoid obstacles on the land surface. In particular, the method and system disclosed, allows for updating the anisotropy parameters iteratively and when the stopping criteria is satisfied, the final estimated parameter can be directly used for time migration. This method and system are mainly used for time migration with the purpose of obtaining the high fidelity (accurate amplitude, i.e. not only travel-time correct but also amplitude correct) image gathers which are used for reservoir characterization and interpretation.
Automatic data enhancement for full waveform inversion in the midpoint-offset domain
This specification describes workflows for, but is not limited to, performing full waveform inversion (FWI) to build high resolution velocity models to improve the accuracy of seismic imaging of a subterranean formation. This specification describes processes to automatically edit and enhance S/N quality of seismic data (such as land seismic data) to prepare the datasets for FWI. The methods for automatic corrections and pre-processing include: automatic iterative surface-consistent residual statics calculation, automatic rejection of anomalous traces (such as dead traces), and the automatic correction of surface-consistent amplitude anomalies (such as by scalar or deconvolution approaches). The operations include automatic “muting” of noise before first arrivals.
METHOD FOR COMBINED UP-DOWN WAVEFIELD SEPARATION AND REDUCING NOISE IN VERTICAL PARTICLE MOTION MEASUREMENTS USING JOINT SPARSITY RECOVERY
A method for estimating noise in particle motion seismic recordings and upgoing (deghosted) and downgoing components of ecorded wavefields includes inputting pressure related and particle motion related seismic signals. A sparsity promoting transformation is applied to the input seismic signals. A matrix à and column vector {tilde over (b)} are constructed according to the expression:
wherein d represents a down-going seismic wavefield, u represents an up-going seismic wavefield, n represents the noise and λ represents a user-chosen scalar to adjust emphasis of the noise. A constrained minimization is solved according to the expression
for {tilde over (x)}; wherein μ represents a us
Wave velocity determination for seismic imaging
Techniques are described for generating seismic images based on pressure-shear (PS) wave information. Sensor data is generated by through seismic probing of an underground environment. The sensor data can include pressure (P) wave data. The sensor data is analyzed to determine PS wave data present in the sensor data. A CFP gathers spectrum is generated using the P wave velocity. An optimal curve through the CFP gathers spectrum is determined, and PS image(s) of the underground environment are generated by scanning along the optimal curve. The PS image(s) can be provided for presentation through interface(s). The generated PS wave images are correlated with P wave images, and can be plotted on the same coordinate system as P wave images.