Integrated geological and geophysical interpretation case study, and Lamé rock parameter extractions using AVO analysis on the Blackfoot 3C‐3D seismic data, southern Alberta, Canada

Abstract

Blackfoot field, southeast of Calgary, Alberta, Canada, has produced oil and gas from a Glauconitic compound incised‐valley system. The Glauconitic compound incised valley has three cycles of incision and valley fill: lower, lithic, and upper incised valleys. The upper and lower incised valleys are the main reservoirs. The geophysical interpretation of compressional PP‐seismic data resulted in the definition of the compound‐valley extent, and in the mapping of the upper and lower incised valleys. A stratigraphic well‐log template was built using the most significant lithological information and well logs. To integrate both geological and geophysical interpretations, the well log cross‐sections and corresponding depth‐converted seismic were superimposed. Furthermore, a detailed geological facies interpretation of the upper and lower incised valleys was undertaken and incorporated. A good correlation was found between the interpreted geological facies and the seismic data response. Information about the nature of the fill within the compound valley was gained from the integration of the PP‐ and PS‐wave interpretations. However, this is limited to Vp/Vs analyses on given intervals. Amplitude‐variation‐with‐offset analysis of the PP‐data was run to discriminate lithology and pore‐fluid saturates. The products of the Lamé rock parameters, incompressibility (λ) and rigidity (μ), with density (ρ) were extracted from seismic inversions for P‐ and S‐impedances. The extraction of λ ρ and μρ showed the presence of gas‐bearing porous sandstone within the Glauconitic incised‐valley system.