Reservoir Modeling by Constraining Stochastic Simulation to Deterministically Interpreted Three-dimensional Geobodies: Case Study from Lower Cretaceous McMurray Formation, Long Lake Steamassisted Gravity Drainage Project, Northeast Alberta, Canada
Milovan Fustic, Adal Al-Dliwe, David Thurston, Dale A. Leckie, Dany Cadiou, 2013. "Reservoir Modeling by Constraining Stochastic Simulation to Deterministically Interpreted Three-dimensional Geobodies: Case Study from Lower Cretaceous McMurray Formation, Long Lake Steamassisted Gravity Drainage Project, Northeast Alberta, Canada", Heavy-oil and Oil-sand Petroleum Systems in Alberta and Beyond, Frances J. Hein, Dale Leckie, Steve Larter, John R. Suter
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Tidally influenced meandering river deposits of the Cretaceous middle McMurray Formation are characterized by rapid vertical and lateral lithological and associated reservoir property changes. Within the reservoir, water may occur below, above, and in the middle of the bitumen column, and there may be multiple gas intervals. Although conceptual understanding about the depositional environment and its control on distribution of different fluids (bitumen, water, and gas) is documented in literature, integration of these concepts into reservoir models and history matching through flow simulation is lacking. Thus, even in areas with closely spaced wells (as much as several hundred meters apart), geostatistical modeling approaches show high degrees of randomness. This chapter closes the gap between the conceptual mapping and numerical modeling approaches. Specifically, the workflow for creating a deterministic three-dimensional (3-D), object-based (geobody) model, which integrates data from closely spaced wells, high-quality 3-D seismic data, and sound geologic concepts is shown. The geobodies are typically large-scale depositional elements comprising meandering river deposits. Geobodies include channel lag breccia (tens to hundreds of meters wide and as much as several meters thick), lower and upper point-bar deposits (from several hundreds of meters to as much as 5 km [3 mi] wide and as much as 40m [131 ft] thick), and mud plug deposits (as much as 500m [1640 ft] wide and as much as 40m [131 ft] thick). Because of the potential impact on reservoir development economics, top water, top gas, and low-bitumen, high-water saturated zones are mapped as distinct geobodies. Based on their reservoir development potential, geobodies can then be classified as reservoir flow unit types 1 and 2, reservoir flow barriers, and reservoir flow impairments.