Saudi Arabian Oil Company

Young Seo Kim

Constantinos Tsingas

Woodon Jeong

Tong Wang Fei

Jewoo Yoo

Yi He

Roald Van Borselen

Ali Ameen Almomin

Adam J Fox

Krzysztof K Sliz

Wooden Jeong

A method for picking first breaks on a synthetic seismic dataset for a full wavefield travel-time inversion is provided. This method includes obtaining a synthetic seismic dataset and for each synthetic trace, determining a plurality of synthetic trace amplitude maxima and minima, determining a modified energy ratio trace, and forming a trace mask based at least in part, on an amplitude of the synthetic trace and on an amplitude of the modified energy ratio trace. The method further includes determining for each synthetic trace, a positive estimated first break based on the plurality of synthetic trace amplitude maxima and the trace mask and a negative estimated first bread based on the plurality of synthetic trace amplitude minima and the trace mask. The method concludes with determining a predicted first break for each synthetic trace from the positive estimate first break and the negative estimate first break.

First break picking for full wavefield travel-time inversion

Methods and systems, including computer programs encoded on a computer storage medium can be used for identifying primary-wave (P-wave) and secondary-wave (S-wave) characteristics of an underground formation by separating P-wave and S-wave modes of seismic data generated by applying a seismic source to a subterranean region of a geological area. Particle motion vectors of a P-wave are parallel to a propagation vector of the P-wave, whereas particle motion vectors of an S-wave are perpendicular to a propagation vector of the S-wave. The parallel and perpendicular relationship between the motion and propagation vectors of the respective P- and S-waves provide a basis for separating P- and S-wave components from a wavefield. The separation methodology extracts P-wave components and S-wave components from the wavefield based on an estimated angle between propagation vectors and wave motion vectors for the wavefield.

Identifying characteristics of a subterranean region using vector-based wavefield separation of seismic data from the subterranean region

A method of determining an arrival-time of a first seismic event in a seismic data set including, obtaining the seismic data set and an initial seismic velocity model, and determining an updated seismic velocity model based on the seismic data set. Furthermore, the method includes determining a simulated arrival-time of the first seismic event based on the updated seismic velocity model and defining a predicted time-window based on the simulated arrival-time of the first seismic event, and picking the arrival-time of the first seismic event in the seismic data set based on the predicted time-window.

Full waveform inversion velocity guided first arrival picking

A method for building a three dimensional (3D) model of a subsurface formation includes selecting, from a set of seismic shots, a plurality of first arrival signals representing the seismic shots. The method includes applying a quality control function to the plurality of first arrival signals to obtain a set of remaining first arrival signals. For each remaining first arrival signals, the method includes applying a velocity inversion function to obtain a depth velocity value at a common-midpoint (CMP) location in a shot gather including the seismic shot associated with that remaining first arrival signal, the CMP location representing a lateral variation of the shot gather including that seismic shot. The method includes, based on the depth velocity value for the seismic shot associated with each remaining first arrival signal, generating a velocity model representing the 3D model of the subsurface formation.

Generating a model for seismic velocities in a subsurface region using inversion with lateral variations

The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for generating geophysical images. One computer-implemented method includes receiving a set of seismic data associated with a subsurface region; generating source analytic wavefields and receiver analytic wavefields based on the set of seismic data; decomposing the source analytic wavefields and receiver analytic wavefields; computing directions of propagations for the source analytic wavefields and receiver analytic wavefields; computing, for a plurality of subsurface points, an azimuth angle and a reflection angle for a respective subsurface point based on the directions of propagations; generating for each of the plurality of subsurface points, a weighting function for a respective subsurface point based on the azimuth angle and the reflection angle of the respective subsurface point; and generating a subsurface image using the weighting functions of the plurality of subsurface points.

Generating geophysical images using directional oriented wavefield imaging

The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for generating a reflectivity model for a subsurface area. One method includes: receiving a set of seismic data associated with the subsurface area; generating analytic source wavefields; generating analytic residual wavefields based on the set of seismic data and an initial reflectivity model; decomposing the analytic source wavefields and the analytic residual wavefields to obtain down-going and up-going components of the analytic source wavefields and the analytic residual wavefields; calculating a gradient vector using the down-going components of the analytic source wavefields and the up-going components of the analytic residual wavefields; calculating a source illumination factor using the down-going components of the analytic source wavefields; calculating a preconditioned gradient vector, based on the gradient vector and the source illumination factor; and generating an updated reflectivity model based on the preconditioned gradient vector.

Generating a reflectivity model of subsurface structures

The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for generating a velocity model for a subsurface area. One computer-implemented method includes obtaining, at a data processing apparatus, source wavefields and residual wavefields, wherein the source wavefields and the residual wavefields are calculated based on seismic data associated with the subsurface area; decomposing, by the data processing apparatus, the source wavefields and the residual wavefields into a subsurface azimuth and reflection angle domain; calculating, by the data processing apparatus, a plurality of gradient direction components based on the decomposed source wavefields and the residual wavefields; scaling, by the data processing apparatus, the plurality of gradient direction components based on azimuths and angles associated with each of the plurality of gradient direction components; calculating a gradient direction based on the scaled gradient direction components; and generating the velocity model using the gradient direction.

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Abqaiq, Saudi Arabia

Young Seo Kim