Resource Assessment of Oil and Gas Plays in Paleozoic Basins of Eastern Canada
There are three major Paleozoic basins in eastern Canada: 1) the Cambrian-Ordovician St. Lawrence shallow marine platform and coeval deep water facies 2) the Silurian-Devonian shallow to deep marine Gaspé Belt and 3) the Devonian-Permian terrestrial to shallow marine Maritimes Basin. The sedimentary successions are bounded by tectonically-generated unconformities - the Taconian unconformity separating Cambrian-Ordovician from Silurian-Devonian strata and the Acadian unconformity at the base of the late Devonian-Permian strata. Each basin contains unique source rock and reservoir units and specific trap types. All of the basins contain producing or discovered hydrocarbon fields but there has been no independent evaluation of their oil and gas resource potential.
Over the past five years the Geological Survey of Canada and its partners have acquired new hydrocarbon systems data, in preparation for a first regional hydrocarbon play assessment of Paleozoic strata in eastern Canada. A total of 16 conventional and 2 unconventional plays have been identified. Seven conventional plays are recognized in Cambrian-Ordovician strata: 1) Cambrian rift sandstones, 2) Lower Ordovician hydrothermal dolomite (HTD), 3) carbonate thrust slices at the Appalachian structural front, 4) Middle-Upper Ordovician HTD, 5) passive margin slope clastics, 6) foreland sandstones and carbonates and 7) Quaternary sands. There are six conventional plays in the Silurian-Devonian strata: 1) Lower Silurian sandstones, 2) Lower Silurian HTD, 3), Upper Silurian HTD reefs, 4) lowermost Devonian HTD reefs, 5) Lower Devonian fractured carbonates, and 6) Lower Devonian nearshore sandstones There are three conventional plays in Carboniferous strata: 1) Lower Carboniferous sandstones 2) Lower Carboniferous (Visean) carbonate reefs, and 3) Upper Carboniferous sandstones and an unconventional coal bed methane play. Unconventional shale gas plays may occur in Cambro-Ordovician and/or Carboniferous strata.
Of the 16 conventional plays, 6 plays have enough production or exploration data to prepare quantitative estimates of resource potential: the Lower Ordovician and Middle-Upper Ordovician HTD, the carbonate thrust slice, the Lower Devonian sandstone, and the Lower and Upper Carboniferous sandstone. For each of the quantitative play assessments, we present play maps, parametric pool-size data, exploration risk factors, prospect numbers and estimates of in-place oil and gas resource potential.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009