Comparison of rock properties and production performance between the uppermost lithostratigraphic unit ("Monteith A") and the lowermost portion ("Monteith C") of the Monteith Formation in the Western Canada Sedimentary Basin (WCSB) in Alberta is carried out with the use of existing gas wells. The analyses are targeted to understand the major geologic controls that differentiate the two strata.
The approach involves multi-scale description and evaluation techniques of cores and drill cuttings, including multiple laboratory measurements of key reservoir parameters. The ultimate goal is to understand the distribution of reservoir quality in each stratigraphy unit within the Monteith in the study area.
This study comprises basic analytical tools available for geological characterization of tight gas Formations based on the identification and comparison of different rock types for each lithostratigraphic unit: depositional, petrographic, and hydraulic. As these low-permeability sandstone reservoirs have been subjected to post-depositional diagenesis, a comparison of the various rock types allows to generate a more accurate reservoir description, and to better understand the key geologic characteristics that control gas production potential.
It is concluded that "Monteith A" Unit has better rock quality than the Monteith C", due to less heterogeneous reservoir geometry, less complex mineralogical composition, and larger pore throat apertures. These results are linked successfully with Monteith production capabilities.