Summary

Joffre Field is located in south-central Alberta, Canada, between Calgary and Edmonton, and produces oil from Devonian carbonates in the Western Canada Sedimentary Basin. A 3-D, three-component (3-C) seismic survey was originally acquired over the Joffre Field area as a part of a study characterizing reservoir properties of Devonian Nisku and Leduc reefs. For this study, however, the seismic volumes were utilized in an attempt to identify and characterize the top of the regional Paleozoic unconformity that has long limited exploration efforts in this stratigraphic interval. The unconformity at the top of the Paleozoic was found to be well imaged in the compressional (P)-wave data. Additionally, amplitude anomalies and velocity ratios (V_p/V_s) support the presence of the unconformity as defined on the P-wave volume.

The detection of the unconformity on seismic has great implications for defining elusive oil and gas targets that potentially exist in association with the unconformity. Seismic interpretation allows for detailed understanding of geologic systems and their distributions above and below the unconformity surface. Considerable evidence for stratigraphic and structural settings suitable for potential hydrocarbon entrapment were also interpreted form the seismic in close association with the unconformity. These potential reservoirs include Manville valley fill sequences above the unconformity surface, and Mississipian carbonate erosional remnants and shoaling environments below the unconformity.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah