--> Rock Physics Analysis and 3-D Seismic Interpretation: Examples From the Mannville Deep-Basin Alberta

2019 AAPG Annual Convention and Exhibition:

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Rock Physics Analysis and 3-D Seismic Interpretation: Examples From the Mannville Deep-Basin Alberta

Abstract

Rock Physics workflows have generally shown to be successful in conventional high-porosity clastic sands where fluid discrimination and reservoir characterization are the main goals. Adoption of these techniques in a Deep-Basin setting has been challenging from a budgeting and technical perspective; the reservoirs are known to be gas charged, relative changes in reservoir quality are minor, and we are in a low commodity price environment. This presentation shows how Rock Physics can be applied successfully in this setting. The Mannville Group in the study area is comprised mainly of a fluvial depositional sequence with interbedded coal seams. 3D stratigraphic slicing techniques have been used, historically, to identify channel features throughout the Mannville section. These techniques have been limited to interpreting geologic features like channel geometries, and channel edges. Assessing the potential reservoir quality of the fill in these channels depended on having a vertical well that penetrated the channel. This approach has limited our ability to step-out from existing production and assess the risk of our prospect inventory. Rock Physics analysis of the well log data in the area suggests that a robust facies classification can be used to separate tight and porous sandstone units from non-reservoir silts, shales and coals. Once the data have been separated into individual facies units, there is a strong correlation between acoustic impedance and porosity. This correlation has then been used to derive porosity volumes from our initial pre-stack simultaneous inversion data set. This classification and prediction workflow has been used to successfully extend and high grade our prospect inventory.