Automated Detection of Faults and Fractures in Well Seismic Data in the Campos Basin

Abstract

Vertical seismic profile (VSP) data is generally considered to be underutilized. Traditionally, VSP data is acquired to determine direct time-depth relationships and produce sections and images. Faults and fractures may be important to improve reservoirs exploitation as well as to monitor mechanical and hydraulic impact on reservoir rocks. This work presents a case study applied to an offshore seismic survey in the Campos Basin. A multioffset VSP data set is used as input in an automated fault and fracture detection workflow usually applied to conventional seismic data using coherence attributes. The automatic extraction of faults and fractures uses signal processing and interactive tools to reduce interpretation time compared to fully manual methods. Workflow's input is a volume of discontinuity or similarity extracted from VSP's amplitude, and the output is a volume of fault azimuths. In work carried out, the directions of faults and fractures detected from this workflow showed great correlation when compared to the interpretations in the wells. The attributes proved to be quite effective in improving the visualization of faults and fractures.