47th Annual AAPG-SPE Eastern Section Joint Meeting

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Integrating Petrophysical And Geophysical Data To Delineate The Internal Facies Of A Pinnacle Reef Complex, Michigan Basin, Usa


The Silurian Niagaran pinnacle reefs of the Michigan Basin have been extensively studied due to their significance as hydrocarbon producers. These carbonate buildups retain their relevance after primary recovery of hydrocarbons and are excellent candidates for carbon dioxide sequestration, natural gas storage, and enhanced oil recovery. Due to the nature of carbonate rocks, these reef complexes are heterogeneous and lateral interpolation between observations in wells, is ambiguous. Despite being extensively studied since the 1960’s, the ambiguity has led to large uncertainty and disagreement regarding reef architectures and their internal facies distributions. Previous models of these reef complexes have relied almost entirely on well logs and conventional core. This study focuses on integrating well logs with a 3D seismic reflection survey to reduce uncertainty when interpreting the internal and off-reef architectures. The focal point of this study is the Charlton 30-31 reef complex in the northern trend of the Michigan Basin. Specifically, I intend to determine whether this reef is symmetrical with unpredictable internal facies patterns or if it was influenced by paleowind during growth, resulting in a highly asymmetric architecture with predictable internal facies distributions. In addition to a 3D seismic reflection survey, I have petrophysical data from 12 wells that penetrate the Charlton 30-31 reef complex. The facies log signatures of core, from the nearby Charlton 1-4 reef complex, were utilized to refine facies interpretations of the log signatures in the Charlton 30- 31 reef. These interpretations will be used to generate at least 2 models of the reef with either random or leeward and windward based morphology. Synthetic seismograms will be generated for the Charlton 1-4 well using high- to low-frequency wavelets, to determine the frequency at which the synthetic seismic reflection can no longer distinguish the reef facies identified in the core. Synthetic seismograms of the Charlton 30-31 reef models will be generated at the lowest frequency that allows resolution of facies and at the frequency observed in the seismic survey. I anticipate that comparison of these synthetic profiles with the 3D seismic survey data will allow me to determine if there is an asymmetric, wind-influenced pattern to the reef facies.