Seismic data recorded by subsurface seismic sensors placed in a borehole, such as an oil or gas well, are transformed via a process of upward wavefield propagation to pseudo-receivers at the surface of the earth. The seismic data thus transformed can be processed as though the data had been recorded by the pseudo-receivers at the surface rather than in the borehole where the data were actually recorded. This method accurately accounts for seismic source statics, anisotropy, and all velocity effects between the real receivers in the borehole and the pseudo-receivers at the surface of the earth.

A technique facilitates improved data acquisition and analysis with downhole tools and systems. The downhole tools and systems utilize arrays of sensing devices which are deployed in arrangements for improved sensing of data related to environmental features and/or tool parameters of tools located downhole in a borehole. For example, the tools and sensing systems may be operated to effectively sense and store characteristics related to components of downhole tools as well as formation parameters at, for example, elevated temperatures and pressures. Similarly, chemicals and chemical properties of interest in oilfield exploration and development also may be detected, measured and stored for analysis.

A fault control beam tomography regularization method and apparatus, a computer, and a storage medium are provided. The method includes: acquiring a seismic imaging data volume; extracting a coherence attribute from the seismic imaging data volume; resampling data of the coherence attribute to obtain a resampling coherence attribute corresponding to a tomography grid; obtaining an input ray density by ray tracing; calculating a fault control beam tomography operator according to the resampling coherence attribute and the input ray density; and introducing the fault control beam tomography operator to a tomography inversion target function for regularization constraint, to obtain a tomography inversion target function into which the regularization constraint has been added.

Method for building a subsurface model of velocity or other elastic property from seismic reflection data using tomography. The method uses velocity scans to pick a focusing velocity model at each image point (40). The focusing velocities are used to pick depth errors from tables (60) generated using a tomographic inversion matrix (30) and a suite of different velocity models (10). The depth errors are then reconstructed at each image point from the velocity scans based on the difference between the base velocity model and the most coherent velocity from the scan (70). The reconstructed depth errors are used to compute the velocity model update (80).

Disclosed herein is a system and method for building a velocity model for a geographical area of interest (GAI). The system and method comprise determining a ray based tomography velocity image of said GAI using acquired data, determining a high resolution velocity guide (HRVG) image of said GAI, scaling said determined HRVG of said GAI, adding the scaled HRVG to the ray based tomography velocity image to determine an updated ray based tomography velocity image, and determining whether said updated ray based tomography velocity image has experienced convergence by determining whether a cost function of said ray based tomography velocity image does not improve compared to a previously determined cost function value of said ray based tomography velocity image.

According to one embodiment, subsurface ray directions in beam migration or subsurface wave propagation directions in reverse time migrations are used to obtain additional Specular Filter (SF) and Dip Oriented Partial Imaging (DOPI) images. SF migration applies a specular imaging condition during migration with a pre-specified subsurface dip field. It boosts the S/N ratio in both images and gathers, by effectively removing migration noise. DOPI images are produced by decomposing a standard migration image according to subsurface dip inclination or/and dip azimuth groups, providing various views of the subsurface image. Both SF and DOPI migration images can supply valuable additional information compared to a standard migration image, and they can be efficiently generated during migration.

Systems and methods for generating a three-dimensional image of a proppant-filled hydraulically-induced fracture in a geologic formation are provided. The image may be generated by capturing electromagnetic fields generated or scattered by the proppant-filled fracture, removing dispersion and/or an attenuation effects from the captured electromagnetic fields, and generating the image based on the dispersion and/or attenuation corrected fields. Removing the dispersion and/or attenuation effects may include back propagating the captured electromagnetic fields in the time domain to a source location. The image may be generated based on locations at which the back propagated fields constructively interfere or may be generated based on a model of the fracture defined using the back propagated fields.

Systems and methods for estimating orthorhombic anisotropy parameters of subsurface rock layers are provided. An initial three-dimensional (3D) model of layers in a subsurface formation is generated. Particular combinations of seismic source and receiver locations associated with a vertical seismic profile (VSP) survey of the formation are selected based on a simulation of seismic wave propagation through each layer of the initial 3D model. A global inversion is performed using data points selected from travel time data associated with the VSP survey in order to estimate different sets of anisotropy parameters for the layers of the initial 3D model, where the selected data points correspond to the selected source-receiver combinations. The initial 3D model is refined with an optimal set of anisotropy parameters selected from the estimated parameter sets. The refined 3D model is provided for seismic analysis and well planning operations to be performed for the subsurface formation.

A method for maximizing a repeatability between a base seismic survey and a monitor seismic survey of a same surveyed subsurface during a 4-dimensional (4D) project. The method includes receiving first seismic data associated with the base seismic survey; receiving second seismic data associated with the monitor seismic survey, wherein the monitor seismic survey is performed later in time than the base seismic survey; estimating subsurface reflection-points and incidence angles; determining 4D-binning based on the estimated subsurface reflection-points and incidence angles; and maximizing the repeatability between the first seismic data and the second seismic data by using the 4D-binning.

According to one embodiment, subsurface ray directions in beam migration or subsurface wave propagation directions in reverse time migrations are used to obtain additional Specular Filter (SF) and Dip Oriented Partial Imaging (DOPI) images. SF migration applies a specular imaging condition during migration with a pre-specified subsurface dip field. It boosts the S/N ratio in both images and gathers, by effectively removing migration noise. DOPI images are produced by decomposing a standard migration image according to subsurface dip inclination or/and dip azimuth groups, providing various views of the subsurface image. Both SF and DOPI migration images can supply valuable additional information compared to a standard migration image, and they can be efficiently generated during migration.