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Volume 65 Number 1
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

The existence of fractures not only provides space for oil and gas to reside in but also creates pathways for their migration. Accurate description of a fractured reservoir is thus an important subject of exploration for geophysicists and petroleum engineers. In reflection seismology, a reservoir of parallel vertical fractures is often considered a transversely isotropic medium with its symmetry axis horizontally oriented and its physical properties varying in azimuth on the horizontal symmetry‐axis plane. In the history of fractured reservoir exploration, azimuthal variation in the ‐wave amplitude, velocity, and fractional difference of the split ‐waves have been popular seismic attributes used to delineate characteristics and extract information from the reservoir. Instead of analysing the reflection signatures of ‐wave and ‐wave, the objective of this study is to demonstrate the azimuthal variation of the converted wave (‐wave) amplitude in a fractured reservoir. To facilitate our objective, both common offset and end‐on shooting reflection experiments were conducted in different azimuths on the horizontal symmetry‐axis plane of a horizontal transverse isotropic model. In the acquired profile, reflections of ‐wave, ‐wave (‐), and a mixture of ‐ (‐) and ‐waves were observed and identified. Thereafter, the laboratory observations were Hilbert transformed to compute the reflectivity strength of the relative events. Results show that the reflectivity strengths of both ‐ and ‐waves are consistently weakened from the direction of the layering strike to the layering normal. However, the azimuthal variation of the ‐wave amplitude is more significant than that of the ‐wave and can be considered another effective seismic attribute for orienting the fracture strike of a reservoir that consists of vertically aligned fractures.

© 2017 European Association of Geoscientists & Engineers © 2016 European Association of Geoscientists & Engineers
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2016-08-14
2024-04-26

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Azimuthal variation of converted‐wave amplitude in a reservoir with vertically aligned fractures − a physical model study
Geophysical Prospecting 65, 221 (2017); https://doi.org/10.1111/1365-2478.12357
/content/journals/10.1111/1365-2478.12357
/content/journals/10.1111/1365-2478.12357
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  • Article Type: Research Article

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