The sedimentology and stratigraphy of the Lower Triassic Montney Formation in the subsurface of the Peace River area, northwestern Alberta.

摘要

The Montney Formation within the study area of the Peace River Embayment consists of dominantly fine-grained siliciclastic strata that thicken in a westward direction and have been progressively truncated in an eastward direction. Parasequence sets deposited during the four stages of the Early Triassic can be divided into three main sequence stratigraphic events. These include a transgressive to highstand systems tract of Griesbachian to Dienerian age, a lowstand systems tract of late Dienerian to early Smithian age, and a transgressive to highstand systems tract of Smithian to Spathian age.; There are a total of fourteen lithofacies found in three lithofacies associations. These range from bivalve/lingulid coquinas, very fine- to fine-grained sandstone, and varying degrees of interlaminated sandstone/siltstone with shale. Coquina and sandstone are two known producing reservoir units. A potential reservoir unit encountered and described, is an Early Griesbachian sharp-based shoreface sandstone.; The Montney is a primary hydrocarbon target with an estimated undiscovered 15 oil pools (22–54 × 106m3) and 427 gas pools (23,258 × 106m3) in three major play areas. The three Montney plays include Subcrop South-Fir, Distal Shelf-Glacier, and Subcrop North-Ring. The estimated volumes for the Montney are approximately 50% of the estimated undiscovered oil and gas in the Western Canada Sedimentary Basin for the Triassic.