Quantitative characterization of ichnology based on CT scan: A case study of Mackay-Ⅲ oil sands, Canada

Based on high-resolution core photos, CT scan pictures, and well logging, the classification, features and spatial distributions of trace fossils in McMurray Formation, Lower Cretaceous, Mackay-III oil sands, Canada, were characterized quantitatively.Based on lithofacies, a new parameter, bioturbation comprehensive index(BCI), was proposed by combining bioturbation index(BI), size diversity index(SDI), and the mean grain size of hostrock.A three-dimension BCI model was built by sequential Gaussian stochastic simulation.Results show that there are nine lithofacies and nine genera trace fossils in McMurray Formation.Lithofacies were dominated by oil saturated medium-grained sandstone, high bioturbation fine-grained sandstone, and high bioturbation muddy siltstone.Trace fossils were dominated by Skoliths, Palaeophycus, and Planolites. According to BCI model, the study area was subdivided into Type Ⅰ weak Bioturbation(BCI < 1.5), Type Ⅱ moderate bioturbation(1.53).This