Quantitative Seismic Geomorphology Applied to Heterogeneous Sediment Distribution in a Point-Bar Setting, Example from the Fluvio-Estuarine McMurray Formation, Northeast Alberta, Canada
Richard Labourdette, 2010. "Quantitative Seismic Geomorphology Applied to Heterogeneous Sediment Distribution in a Point-Bar Setting, Example from the Fluvio-Estuarine McMurray Formation, Northeast Alberta, Canada", Seismic Imaging of Depositional and Geomorphic Systems, Lesli J. Wood, Toni T. Simo, Norman C. Rosen
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Quantitative seismic geomorphology adds new insight to our knowledge of subsurface reservoirs. By using empirical equations, seismically derived measurements of geobody shapes and morphological evolutions, it is possible to quantify hydraulic parameters at the time of deposition. This methodology can lead to a three-dimensional characterization of heterogeneous architectures and facies distributions, which also suggest depositional environments.
In the McMurray Formation, fine-scale heterogeneity in facies distribution in point-bar depositional settings has proved to be of paramount significance, particularly for hydrocarbon extraction using Steam Assisted Gravity Drainage. Our study area is a pointbar in the Surmont lease in the Athabasca heavy oil province (Alberta, Canada) and presents the typical architecture of a point-bar interpreted as having developed in a fluvio-estuarine setting. The evolution of the point-bar through time leads to a complex arrangement of facies and associated shaly heterogeneities.
Our quantitative seismic geomorphology analysis is based on a 3D survey over about 52 km2, with data from more than 32 wells drilled at regular intervals within the studied point-bar. The parameters extracted for each point-bar accretion bed include channel width, depth, width:depth, and paleocurrent directions. Compared with other published datasets, the measured channel morphological characteristics do not appear to be a discriminating factor of the depositional setting; however, changes in these parameters over time and space allow the dynamic evolution of the point-bar to be quantified, and thus, the heterogeneous sediment distribution within the point-bar to be modeled. Morphological measurements are used to quantify hydraulic parameters using empirical equations. The results indicate that hydraulic parameters coupled with facies analysis imply that both tidal and fluvial processes lead to complex point-bar morphology. The comparison between hydraulic parameters and facies proportions extracted from wells allows for production of linear regressions, which help model spatial heterogeneity as a function of measured point-bar morphology. These results can then be integrated into reservoir models in order to optimize heterogeneity distributions and proportions in point bar deposits.