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Interval Azimuthal Anisotropy from Walkaround VSP with Application in Marcellus Shale
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 3rd EAGE Workshop on Borehole Geophysics, Apr 2015, cp-447-00009
- ISBN: 978-94-6282-144-6
Abstract
A walkaround VSP can provide local measurements of azimuthal anisotropy to characterize fractured rocks or stress fields around a well. When the acquisition is constrained to have irregular shot offsets, offset-dependent corrections are required. For an unconventional resource like the Marcellus Shale, a correction for background polar anisotropy is also necessary to effectively extract the azimuthal anisotropy around the well. This study introduces a procedure to remove the background VTI and overburden effects. Field data tests in the Marcellus Shale demonstrate that this new method can provide quantitative measure for the orientation and magnitude of fracture- or stress-induced local azimuthal anisotropy.