Object Characterisation and Simulation of Thermal Recovery from Karstified, Brecciated and Fractured Bitumen Carbonate Reservoirs

A continued increase in energy demand has amplified the significance of commercial heavy oil and bitumen recovery from complex carbonates formations such as the Grosmont Formation (OOIP ~ 406.5 billion barrels) in Alberta, Canada. To facilitate commercial development of bitumen carbonates, we have designed reservoir simulation models of complex carbonate reservoirs based on the concept of multiple interacting objects. Spatial distribution of different objects including fractures, vugs, breccia, and matrix are constructed by using stochastic methods with intensity functions derived from cores, logs, drilling and geologic data. Thermal reservoir simulations are conducted directly on realizations of these 'objects network' reservoir models. Although data from the highly fractured, karstified and vuggy bitumen-rich Grosmont Formation is used in this paper, this methodology is generic and applicable to other complex carbonate reservoirs. Results suggest that continuous type steam-based enhanced oil recovery (EOR) such as steam-assisted gravity drainage (SAGD) may not be best suited for bitumen recovery from complex carbonates.