Summary
The Avalon shale is an example of a basin central unconventional carbonate play. Little has been published on parameters that control the quality of this reservoir. This study can improve understanding of deepwater carbonate deposition, and resultant reservoir character. Sediment gravity flow deposits dominate the Avalon shale. In the study area, grainy, carbonate-rich deposits form poor reservoir, whereas muddy deposits form good reservoir. Depositional trends change repeatedly during Avalon deposition as source direction and sediment dispersal shift through time. The strata can be mapped as four types of geobodies: aprons, sheets, fans, and linear. Overall, there are two phases of fan development, which occurred during regressions and lowstands. They are separated by a phase of apron development, which occurred during transgression and highstand. The thickest mudstones, deposited during transgressions and highstands, occur on the margins of fan lobes; these mudstones should be the focus of drilling to encounter the best unconventional reservoir quality.
