Chapter 14 - Characterizing alluvial architecture of point bars within the McMurray Formation, Alberta, Canada, for improved bitumen resource prediction and recovery

Abstract

Abstract Point bars comprise the dominant reservoir type within the McMurray Formation, Athabasca, Canada. A combination of high-resolution 3D seismic, outcrop, well, and core data are used to characterize reservoirs within these point bars. Due to the immobility of bitumen at reservoir temperature, two preferred nonconventional hydrocarbon recovery methods are used, steam-assisted gravity drainage (SAGD) and surface mining. Resource density and recovery efficiency (resource quality) are strongly dependent on the alluvial architecture. A single point bar within the McMurray may contain 100s millions of barrels of oil and is capable of producing in excess of 100 thousand barrels per day. The highest quality resource is found within the lower parts of the bar head to bar apex region and should be targets for initial development areas. Resource continuity may be enhanced or disrupted by channel migration history, stacking, and channel avulsion impacting preservation potential and reservoir connectivity. Recovery processes are sensitive to the vertical and lateral distribution of net pay, and the accurate characterization of point bar reservoirs at different scales is necessary at various stages of the project life cycle to ensure project success. In early evaluation phases, identification of a suitable resource for development through the high grading of resources with minimal data is the key objective. In the early stages of development planning, production facility design and size, along with pad location, well pair length, spacing and orientation for SAGD and opening cut location, bench design, and sequencing for mining, are considered to optimize resource capture. In late life, more marginal reservoirs are targeted for production plateau maintenance. This phased approach to data acquisition allows capital investments and operational constraints to be managed. However, improved alluvial architecture models are also required to offset the costs of increasing data acquisition. Examples presented in this chapter focus on key criteria for characterizing oil sand resources within point bar deposits necessary at different investment stages to establish resource quality.