Geophysics Meets Geology: Chrono-Stratigraphic Interpretation of the McMurray Formation

Abstract

The McMurray Formation in the Athabasca Oil Sands consists of a complex succession of unconsolidated sand and mud deposited in fluvial to marginal marine environments during the lower Cretaceous. When the formation is too deep for mining extraction methods, Steam Assisted Gravity Drainage is commonly used to bring bitumen to the surface. One of the main development challenge of SAGD is the heterogeneity of the reservoir. Well data alone cannot predict the small scale features that will affect the propagation of steam. 3D seismic must be used to estimate the correlation between wells. Traditionally 3D seismic has been used to interpret the top and base of the reservoir and to estimate reservoir rock properties using inversion methods, giving a fair estimate of the amount of bitumen in place, but very little insight of the connectivity within the reservoir. A new methodology to better use seismic to predict the reservoir connectivity is to interpret the stratigraphic trends within the reservoir from seismic reflectors and well stratigraphic correlations and to interpolate those following geological rules into a full 3D volume of chrono-stratigraphic time. The resulting volume can be used to convert the 3D seismic and well data in the chrono-stratigraphic domain. Moving the interpretation in the chrono-stratigraphic domain allows to better characterize geological features such as geomorphologic trends, but also enable the interpreter to further refine seismic attributes. For example filtering can be applied without merging stratigraphic sequences. Examples from multiple projects in the Athabasca Oil Sands will be used to illustrate the methodology.

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