Geological characterization of the Lower Cretaceous McMurray Formation, Alberta, Canada

Please join us for a special seminar this Friday February 15 at 3:30 pm in rm 155 Geology presented by Greg Baniak, BP Canada Energy Group:

Geological characterization of the Lower Cretaceous McMurray Formation, Alberta, Canada

The Lower Cretaceous McMurray Formation in northeastern Alberta, Canada, is host to one of the largest bitumen resources in the world with over 1 trillion barrels of bitumen in place. The bitumen itself has a low API gravity (6 to 12) and viscosities at reservoir conditions exceeding 1 million cp. As a result, traditional primary (pump jacks) and secondary (water flood) recovery techniques cannot be used. Instead, economic extraction of the bitumen occurs either via surface mining or subsurface steam-assisted gravity drainage (SAGD). Within this talk, it will be shown that successful SAGD operations requires a thorough understanding of the depositional fabric and stratigraphic architecture of the reservoir.

In most scenarios, the primary reservoir intervals within the McMurray Formation appear in core as cross-bedded sandstones and sandy inclined heterolithic strata (IHS). These reservoir facies, in combination with non-reservoir facies such as bioturbated mudstones and muddy inclined heterolithic strata (IHS), collectively reflect a complex association of fluvial-estuarine to open marine depositional elements. Additionally, preservation of these reservoir facies most often occurs in two stratigraphically distinct successions known as the ‘middle’ and ‘upper’ McMurray. The end result of these geological complexities is that steamable reservoir unit commonly has relatively rapid thickness variations over short distances (i.e., less than 100m). For SAGD to be economic, the intervals targeted are those that contain greater than 15 m of continuous sandstone pay and are void of any major barriers to steam distribution (e.g., muddy point bars, clast-dominated breccia, abandoned channel deposits). Given these subsurface challenges, utilization of a rich dataset (e.g., core, dip meter, seismic) is essential to properly characterizing the reservoir facies present within the middle and upper McMurray.