PS and PP AVO Analysis; A Multi-component Seismic Case Study for the Long Lake Oil Sands Project

Summary In this paper, three-component 3D data from the Long Lake Project (Nexen/OPTI synthetic oil joint venture) in North-East Alberta are analyzed. The Long Lake Project uses the commercially proven Steam Assisted Gravity Drainage (SAGD) process for extraction of raw bitumen. The goal of integrating multi-component data analysis is the identification of lithologies and barriers to steam. This is one of the first such converted-wave (PS) AVO projects presented in Canada. The analysis included: comparison between the PP and PS migrated stack registered in PP time; comparison between PP AVO rigidity reflectivity and PS AVO rigidity and density reflectivity; and comparison betweeen inverted PP and PS AVO attributes registered in PP time. The PS radial component section is of good quality, with many coherent reflections correlating well to those of the PP vertical component. The converted-wave section, however, has a much lower bandwidth than the vertical component section. Careful analysis of the vertical component seismic gathers at the zone of interest shows measurable variation in amplitude with offset. PP AVO, based on the Gray et al (1999) equation was done and allowed estimation of the incompressibility and rigidity components based upon variations in reflection amplitude of the PP component. In addition, converted-wave AVO, based on Aki and Richards (1980) equation, was done and allowed estimation of the rigidity and density components based upon variations in reflection amplitude of the PS component. Special attention was paid to registration of the PS seismic section from PS time to PP time. PP seismic sections were compared with corresponding PS seismic section registered in PP time.