A method for displaying slowness data after defects of anisotropy and heterogeneity have been removed includes visually depicting a slowness image on a computer monitor in which the slowness image includes a log of slowness values at a plurality of depths of a wellbore and a plurality of azimuth angles about a periphery of the wellbore. The image is processed via filtering such as with a bandpass filter. The filter may be obtained via fitting a periodic function to the slowness values at each depth or via a selected periodicity value and center angle. A resultant image is displayed.

A fracture mapping system for use in hydraulic fracturing operations utilizing non-directionally sensitive fiber optic cable, based on distributed acoustic sensing, deployed in an observation well to detect microseismic events and to determine microseismic event locations in 3D space during the hydraulic fracturing operation. The system may include a weighted probability density function to improve the resolution of the microseismic event on the fiber optic cable.

Systems and methods for determining mechanical properties of anisotropic media are disclosed. A method for determining mechanical properties of an anisotropic media includes obtaining log data of the anisotropic media, the log data corresponding to measurements of the anisotropic media collected with a logging tool; determining values for a plurality of first stiffness components of a stiffness matrix based on horizontal and vertical velocities derived from the log data; determining an upper bound for a second stiffness component of the stiffness matrix based on the values for the plurality of first stiffness components; estimating a value for the second stiffness component based on the determined upper bound; determining a mechanical property of the anisotropic media based on the estimated value of the second stiffness component; and providing the determined mechanical property.

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.

Embodiments of determining a vertically transverse isotropy (VTI) anisotropy along a horizontal section of a wellbore drilled into a formation are provided. One embodiment comprises determining elastic constants C11, C44, and C66 of the horizontal section and determining a vertical compressional slowness of the horizontal section corresponding to an elastic constant C33 of the horizontal section using a model with a condition. The model is built using second sonic log data and second density log data of the vertical wellbore. The condition is that the shear slowness (DTS) of the vertical wellbore is equal to the vertically polarized shear slowness (DTSV) of the horizontal section. The embodiment further comprises determining a VTI anisotropy along the horizontal section using the elastic constants C11, C44, C66, and C33 of the horizontal section.

A method may comprise: disposing an acoustic logging tool in a wellbore, wherein the acoustic logging tool comprises a transmitter and a receiver; emitting a flexural wave from the transmitter; recording a four component dipole waveform with the receiver, wherein the four component dipole waveform comprises XX, XY, YX, and YY components; rotating the four component dipole waveform using Alford rotation to produce rotated waveform components, wherein the rotated waveform components comprise XX.sub.Θ, XY.sub.Θ, YX.sub.Θ, and YY.sub.Θ components; comparing a travel time of XX.sub.Θ and YY.sub.Θ components to identify a fast wave and a slow wave from the rotated waveform components; processing the fast wave and the slow wave using high-resolution data-driven processing to obtain a fast wave flexural dispersion curve and a slow wave flexural dispersion curve; determining a frequency dependent anisotropy curve using the fast wave flexural dispersion curve and the slow wave flexural dispersion curve; and determining a low-resolution shear anisotropy.

A method is described for stochastic modeling of seismic velocity and anisotropic parameters, including receiving 3D bounds of normal moveout velocity (V.sub.nmo) and anisotropic parameter η; modeling 3D bounds for vertical velocity V and anisotropic parameter δ based on the 3D bounds of V.sub.nmo and η; generating 3D model realizations of V, η, and δ within the 3D bounds; and testing detectability of each of the 3D model realizations to create a detectable subset of model realizations wherein the detectability identifies which 3D model realizations will produce images with flat migrated gathers. The method may be executed by a computer system.

A fracture mapping system for use in hydraulic fracturing operations utilizing non-directionally sensitive fiber optic cable, based on distributed acoustic sensing, deployed in an observation well to detect microseismic events and to determine microseismic event locations in 3D space during the hydraulic fracturing operation. The system may include a weighted probability density function to improve the resolution of the microseismic event on the fiber optic cable.

Methods to estimate formation shear wave slowness from multi-firings of different types of acoustic sources and multi-mode dispersion estimation systems are presented. The method includes obtaining waveform data of waves traversing through a downhole formation, where the waves are generated from multi-firings of different types of acoustic sources. The method also includes performing a multimode dispersion analysis of the waveform data for each firing of the multi-firings, and removing one or more tool waves generated from the multi-firings. The method further includes determining a formation type of the formation the waves traverse based properties of the waves and determining an initial shear wave slowness estimate of the waves. The method further includes generating a modeling of the waves, and reducing a mismatch between the modeling of the waves and a slowness dispersion of the waves to improve the modeling of the waves.

Systems and methods for determining mechanical properties of anisotropic media are disclosed. A method for determining mechanical properties of an anisotropic media includes obtaining log data of the anisotropic media, the log data corresponding to measurements of the anisotropic media collected with a logging tool; determining values for a plurality of first stiffness components of a stiffness matrix based on horizontal and vertical velocities derived from the log data; determining an upper bound for a second stiffness component of the stiffness matrix based on the values for the plurality of first stiffness components; estimating a value for the second stiffness component based on the determined upper bound; determining a mechanical property of the anisotropic media based on the estimated value of the second stiffness component; and providing the determined mechanical property.