Quantitative Evaluation and Population Statistics of Point Bar Dimensions, McMurray Formation, Northeastern Alberta

Abstract

Point bars of the middle McMurray Formation are the main reservoir for heavy oil (bitumen) in the Athabasca oil sands region, where heavy oil is extracted through the Steam Assisted Gravity Drainage (SAGD) process. Intra-reservoir architectural complexity of the point bar deposits including inclined heterolithic stratification (IHS), mud clast breccias, and abandoned channel fills are challenges to optimal bitumen extraction. Understanding the geometry and spatial distribution of the point bar deposits is essential for constructing the character of the reservoir. This study has established population statistics of point bar dimensions from a collection of multiple point bars that occur on multiple 3D seismic surveys. Point bar scrolls and abandoned channel fills were interpreted and can be manipulated as shape files. After scroll bar outlines were interpreted, dipmeter data was integrated to confirm point bar geometries. Dimensional data (e.g., length, width, area) was collected directly from point bars displayed on seismic time slices from five different study areas. Across all five study areas, measurements were collected for 43 point bars and point bar fragments and 23 abandoned channel fill deposits. Study area A contained 15 seismically-interpreted point bar deposits and 10 associated abandoned channel fills. The average area of point bars was 1.6 km² while the average area of abandoned channel fills was 1.0 km². The average width of abandoned channel width was 303 m. At study area B, 8 point bars and 4 abandoned channel fills were interpreted. Point bars were slightly larger in this area, with an average area of 3.1 km². Abandoned channel fills at study area B represented an average area of 1.1 km² and an average width of 303 m. Over all five study areas, the average area of point bars was 3.8 km² and average width of abandoned channels of 313 m. This data set can provide an analogue for exploration areas with low well density, so that general trends in point bar and abandoned channel size can be estimated. In a development setting, these data speak to the level of inter-point bar heterogeneity that will be encountered at the SAGD pad scale.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016