AVAZ/FAVAZ Analysis to Predict Permeable Fractured Terrigenous Reservoirs Using Full-Azimuth Seismic Data in Local Angle Domain

This work presents the technology and results of applying full-azimuth seismic data processing in the Local Angle Domain (LAD) in order to study the frequency absorption of reflected signals versus azimuthal direction of incident and reflected rays, to assess fracture permeability zones in an oil field in Western Siberia. Terrigenous (sandstones) of the Jurassic reservoirs are located at great depths and have low porosity and permeability values. In addition, low-amplitude faults influence their distribution and properties, which are poorly allocated when using traditional processing technologies. On the positive side, terrigenous reservoirs of Jurassic age have dual porosity (fracturing plus grain porosity), which makes it possible to use new approaches to predict oil-saturated zones based on LAD processing. This work shows that by using LAD processing together with AVAZ/FAVAZ analysis, it is possible to predict zones of permeable (and as a rule, oil-saturated) fractures in terrigenous sediments. This increases reliability when predicting oil-saturated fractures compared to AVAZ analysis. This work also shows the effectiveness of using the results of AVAZ/FAVAZ analysis with an integrated interpretation of the seismic image and diffractor forming a structural-skeleton (SI-STS) to predict Jurassic terrigenous oil reservoirs.