HARRIS, C. R., and M. K. GINGRAS, Ichnology Research Group, University of Alberta, Edmonton; M. J. RANGER, M. J. Ranger Consulting Company, Calgary; and S. G. PEMBERTON, Ichnology Research Group, University of Alberta, Edmonton
Abstract: The Detailed Mapping And Analysis Of A Frozen Paleo Oilwater Contact
The McMurray Formation is an upper Aptian to lower Albian deposit located in northeast Alberta. It contains almost one trillion barrels of original bitumen in place and is the worlds largest hydrocarbon resource known. The sediments are indicative of fluvial and estuarine deposition. At present, the McMurray formation sits near the surface and is exposed by many river cuts. Bitumenization has frozen the oil in place. This allows three dimensional inspection of the paleo oil-water contact.
The oil-water contact in the McMurray Formation is a mappable and complex feature of the deposit. Although it has been studied regionally, no explanation or model has been put forward to explain the contact?s patchy, undulating, and generally variable nature (at the outcrop scale). Development of such an explanation through detailed mapping of this contact helps elucidate these variations and provides insight to other deposits, notably subsurface reservoirs. It also serves to provide data pertaining to the migration history of the oil.
Various outcrops along the Steepbank River were measured, correlated, and sampled to generate maps and cross-sections. Hand samples and thin sections were also examined for grain size and bitumen content. A new method of measuring a contact at outcrop scale, by using a fluid level and hydrostatic pressure, obtained reliable vertical centimeter accuracy data on the contact?s behaviour.
AAPG Search and Discovery Article #90919©1999 AAPG Rocky Mountain Section Meeting, Bozeman, Montana