oa Fault Detection Using Azimuthal Coherence Attribute: Case Study, Central Saudi Arabia

Delineating faults is a challenging task, particularly if the faults run parallel to the strike azimuth.<br>Normally, dip azimuth faults can be identified easily by traditional time slice methods. The coherence<br>attribute is widely used for fault interpretation and determining orientation in addition to analysis of<br>stratigraphic features. Chopra introduced a new method (Chopra 2002) taking advantage of the<br>azimuthal variation of seismic signature and coherence. Chopra's (2002) approach calculates the<br>coherence between azimuthal data subset stack volumes. This study will produce four sub-volumes,<br>sorted according to different azimuths plus the original volume. After that, we will apply the coherence<br>attribute to all volumes and then compare coherency volumes having different azimuths with the<br>original volume. The result of azimuthal coherence technique shows better fault mapping, especially<br>those faults whose trends are perpendicular to the sorting azimuth. This study reports the occurrence<br>of a system of discontinuity, trending northwest to southeast, which appears in the coherence time<br>slice through the NE-SW azimuth-limited volume. In addition, the coherence time slice of the E-W<br>azimuth-limited volume reveals more discontinuities where we expect faults and fractures to exist.