--> --> Seismic Azimuthal Anisotropy Analysis Applied to Natural Fracture Intensity and Azimuth Prediction: Barnett Shale Example
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Previous HitSeismicNext Hit Azimuthal Previous HitAnisotropyNext Hit Analysis Applied to Natural Fracture Intensity and Azimuth Prediction: Barnett Shale Example


Studying Previous HitseismicNext Hit responses of velocity and amplitude on wide/full azimuth Previous HitseismicNext Hit data is now common for unconventional reservoir characterization. In general, azimuth variation with velocity (VVAz) and azimuth variation with amplitude (AVAz) are two major tools for azimuthal Previous HitanisotropyNext Hit analysis. To accelerate azimuthal Previous HitanisotropyNext Hit analysis, a new attribute-based AVAz workflow was employed and validated using a Barnett Shale wide azimuth data. The Previous HitseismicNext Hit data is migrated into eight azimuths. Prestack structure-oriented filtering is applied to the Previous HitseismicNext Hit amplitude data for noise reduction. Spectral peak magnitude, envelope, and P-wave impedance inversion were computed on each azimuthally-limited Previous HitseismicNext Hit volume. Then, 2D-flattened computed attributes and Previous HitseismicNext Hit amplitude along picked horizons were extracted and input into the AVAz workflow. The results indicate intensity, orientation, and confidence of azimuthal Previous HitanisotropyNext Hit effects on Previous HitseismicNext Hit velocity and amplitude which can be referred to smaller scale vertical natural fractures.

All the analysis results consistently reveal four zones of high Previous HitanisotropyNext Hit intensity with the corresponding azimuth throughout the entire Barnett formation that can be tied to either the regional structures or older local stress field. To further correlate the outcome with regional structural features and natural fractures, a regional production map was projected on the Previous HitanisotropyNext Hit map and confirms the Previous HitanisotropyNext Hit interpretation result that regional Previous HitanisotropyNext Hit is mainly caused by the vertical sealed fractures and the sealed fracture network is inhibiting production in the study area according to the literature and field observations. The result indicates that horizon-based azimuthal Previous HitanisotropyNext Hit analysis effectively avoids the Previous HitseismicTop migration error and can be utilized on the fracture and regional stress field prediction.