Halliburton Energy Services, Inc.

Baker Hughes Corporation

Ran Zhou

Holger Mathiszik

Donghong Pei

Bruce Edward Cornish

Daniel Joseph Quinn

Robert Jason Gibbs

At least some of the disclosed systems and methods employ one or more seismic receivers that gather seismic data from a plurality of positions in a borehole that penetrates a formation. Further, at least some of the disclosed systems and methods employ a memory to store the gathered seismic data. Further, at least some of the disclosed systems and methods employ logic that inverts the seismic data for simultaneous determination of asymmetric axis velocity (V) and Thomsen parameters, epsilon (&#x3b5;) and delta (&#x3b4;), in a tilted transversely isotropic (TTI) model.

Methods and systems for seismic data analysis using a tilted transversely isotropic (TTI) model

A seismic data analysis system includes seismic receivers to collect seismic survey data, wherein the seismic survey data includes direct and reflected arrival data in response to at least one seismic source fired at different shot offsets. The system also includes memory that stores the collected seismic survey data. The system also includes a processing unit that extracts traveltimes for direct and reflected arrivals from the seismic survey data and performs an inversion using the direct and reflected arrival traveltimes simultaneously to determine anisotropy parameters, including Thomsen parameters, epsilon (&#x3b5;) and delta (&#x3b4;), for at least one layer of a vertical transversely isotropic (VTI) model.

Anisotropy analysis using direct and reflected arrivals in seismic survey data

A method comprises obtaining vertical seismic profile (VSP) data using seismic sources positioned at corresponding shot locations at desired offsets from seismic receivers positioned in a borehole drilled through a formation. The method further comprises receiving seismic waves emanating from the seismic sources, processing the VSP data to determine vertical slowness of the formation, and analyzing an azimuthal anisotropy of the formation. This is performed by calculating modified total slowness of the formation using the vertical slowness and vertical polarization angle, calculating and applying a polar anisotropy correction to the modified total slowness to obtain a corrected value of the modified total slowness, and normalizing the corrected modified total slowness to a desired polarization angle. The method further comprises estimating azimuthal anisotropy based on the corrected value of the modified total slowness, outputting an anisotropy depth profile of the formation, and performing borehole operations based on the anisotropy depth profile.

Determining P-wave azimuthal anisotropy from walkaround VSP with offset dependent slowness corrections

A controllable seismic source is used in a seismic-while-drilling system for obtaining VSP data. Coded information is sent downhole about the signal generated by said controllable source. The information about the seismic source is used for reconstructing the source waveform and processing the VSP data. Optionally, a reference signal measured at one depth of the BHA is used for processing of signals at subsequent depths.

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Houston, TX, United States of America

Ran Zhou