Regional Scale Reservoir Characterization and Thermal History of Upper Devonian Organic-Rich Shales in the Horn River and Liard Basins, and Adjacent Western Alberta
Vast resources of unconventional gas and, potentially natural gas liquids occur in Devonian shales of the Horn River and Liard Basins in northeastern British Columbia (NEBC), and adjacent northwestern Alberta. The stratigraphic and lateral variation in lithology coupled with variable depth of burial and paleo-heat flow provides an opportunity to investigate the controls on hydrocarbon generation, retention, and producibility from these important shale reservoirs. Basin system analyses constrained by laboratory, well log, and production data show a complex interplay of lithology, heat flow, depth of burial and kerogen type on amount and type of retained hydrocarbons and petrophysical properties. Core samples from transects of wells across NEBC and Alberta are investigated utilising mercury intrusion porosimetry (MIP), helium pycnometry, N2 and CO2 low-pressure gas adsorption, and scanning electron microscopy (SEM, FIB-SEM) to fully characterize the porosity, pore structure, and pore-size distribution of the upper Devonian Horn River (Evie and Otter Park Members) and Muskwa Formations. Pyrolysis data from core and 300 cuttings samples coupled with a large regional public database constrains the thermal history of the area using one-dimensional basin models. Through much of the Horn River and Liard Basins, Devonian strata are currently within the dry gas window. To the east of the basins the strata thin and become less mature due to a combination of shallower burial and lower paleo heat flow. The lateral variation on the depth of burial is also an important control on the reservoir quality of the shales; moreover, at the centimeter scale the heterogeneity within these shales is considerable, necessitating the use of detailed laboratory analyses to form a robust understanding of reservoir properties.
AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017