Quantitative Seismic Fracture Characterization Using Azimuthal Anisotropy from WAZ 3D: Case Studies from USA Onshore Ba

Onshore wide-azimuth 3D seismic data show great potential for characterizing natural fractures, faults and stress fields. In this paper we illustrate the application of an innovative seismic anisotropy workflow in two study areas: i) the Williston Basin of North Dakota (Bakken and Three Forks formations), and ii) South Texas (Eagle Ford Formation). The results show the location and orientation of natural fracture networks at the reservoir level, and that information can be used to optimize drilling, completion and development strategies in the reservoirs.

The new azimuthal anisotropy workflow for fracture characterization includes three key steps:

(a) Gather conditioning for anisotropy diagnostics and optimizing offset cut off values and sector scheme; (b) Seismic interpretations followed by attributes of azimuthal anisotropy; (c) Workflow validation by data integrations. The Bakken and Eagle Ford case studies we present illustrate the workflow and results. Strike-slip faults interpreted for the Middle Bakken interval are strongly correlated with regional lineament maps and DEM data. In South Texas, anisotropy features show a strong alignment with faults and flexures. Finally, the workflow was adapted for use in a second South Texas 3D where we note good correspondence between anisotropy-defined features, mapped faults and production from newly drilled wells.