Geology, Geostatistical Modeling, and Production Performance from Suncor’s Oil Sands In-Situ Project in northeastern Alberta, Canada
Eugene A. Dembicki, Marina Skoblikova, and Randolph J. Rice
Suncor Energy Inc., Calgary, Alberta
Suncor has produced bitumen from the Lower Cretaceous McMurray Formation since 1967 by mining the shallow oilsands deposit adjacent to the Athabasca River and upgrading the bitumen into refinery feedstock and diesel fuel in northeastern Alberta, Canada. In January 2006, Suncor produced 1 billion barrels of oil sands crude and Suncor’s reserve base consists of 5 billion barrels of mineable synthetic crude oil and 9 billion barrels of in-situ synthetic crude oil. Today, Suncor’s production capacity stands at 260,000 barrels per day, with plans in place to expand to 500,000 barrels per day by 2010 to 2012.
In 2003, Suncor began to exploit its in-situ reserves at a lease called Firebag using the Steam Assisted Gravity Drainage (SAGD) process. SAGD utilizes a pair of stacked horizontal wells that are positioned near the base of the reservoir. Steam is injected into the upper horizontal well and hot bitumen and water flow into the lower horizontal well. A typical well pair is spaced vertically 5-6 m apart with a horizontal length of 1000 m. The true vertical depth (TVD) of the lower producer well ranges between 315 and 330 m.
At Firebag, the McMurray Formation is subdivided into four informal units: continental, estuarine channel complex (which is the bitumen reservoir unit), estuarine tidal flat, and shoreface. The continental unit occurs at the base of the McMurray Formation and it is usually present in paleotopographic lows on the eroded Devonian surface. It is a hetereogeneous unit and consists of narrow sandy fluvial channels, shaly overbank deposits, and thin argillaceous coal seams. Above the continental unit is the estuarine channel complex and in places it can be up to 70 m thick. This is the primary reservoir target and it is comprised of bitumen saturated stacked channel bar sands, abandoned channel-fill shales, and interbedded sand and shale sequences. Capping the estuarine channel complex is the shale dominated estuarine tidal flat complex and it forms an internal seal within the McMurray Formation for the recovery of bitumen from the underlying estuarine channel complex. The uppermost unit within the McMurray Formation is the shoreface and it consists of lower to upper shoreface sands.
To provide input into a reservoir simulation, a large study area (~83 km2) containing approximately 300 coreholes was built. Geostatistical models of facies, volume of shale, porosity, bitumen saturation, horizontal permeability, and vertical permeability were constructed to predict the range of geological heterogeneity between wells as well as to provide input data for reservoir simulation.
Steam was first injected in October 2003 and the first barrel of bitumen was processed in January 2004. Field production is continuing to ramp-up and some wells have produced more than 2,500 barrels/day. Cumulative bitumen production to the end of December 2006 is 23,000,000 barrels.
AAPG Search and Discovery Article #90075©2008 AAPG Hedberg Conference, Banff, Alberta, Canada