Geologic Controls of Gas Production from Tight-Gas Sandstones of the Late Jurassic Monteith Formation, Deep Basin, Alberta, Canada

Abstract

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. SPE-167177-MSKeeping this in mind, results of two research projects focused on the Monteith strata are joined and are expected to provide important feedback for future hydrocarbon exploration and development of these low-permeability gas intervals using the available dataset. In addition, an enhanced methodology provides an excellent opportunity to improve our understanding of other similarly underexploited, undercored tight gas reservoirs with the incorporation of different data sources and analytical techniques presented in the here described workflow.The purpose of this investigation is the identification of key geologic and engineering aspects of the Monteith A and Monteith C intervals including: (1) nature of porosity and permeability, and their relation to petrophysical properties as qualitative indicators of storage and flow capacities; (2) mineralogical composition and dominant pore geometries; (3) identification of characteristic flow-units, (4) investigation of possible relationships between sedimentary facies, mineralogy and diagenetic processes, and petrophysical rock properties, and (5) relationship of the previous properties and gas production from individual wells.The previous knowledge combined with multi-fractured stimulated horizontal wells is critical to economic success of the Monteith tight gas reservoir, which is becoming an increasingly important producer. In order to provide support for the results of this work and to guide future drilling and development activities; acquisition of se...

Use of a Variable Shape Distribution (VSD) Model to Populate Reservoir Properties in Tight Fractured Reservoirs for Numerical 3D Modeling

“…Previous research on understanding the rocks in 'unconventional reservoirs has been performed by GFREE members (for example, Solano (2010), Ortega (2012, Olusola (2013), Olusola et al (2013), Zambrano et al (2013) and Zambrano (2014) …”