Chapter 13: Characterization of Heavy-oil Reservoir Using VP/VS Ratio and Neural Networks Analysis
Carmen C. Dumitrescu, Larry Lines, 2010. "Characterization of Heavy-oil Reservoir Using VP/VS Ratio and Neural Networks Analysis", Heavy Oils: Reservoir Characterization and Production Monitoring, Satinder Chopra, Laurence R. Lines, Douglas R. Schmitt, Michael L. Batzle
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The oil-sands reservoir related to the Long Lake South (LLS) project is contained within the McMurray formation, which is the basal unit of the Lower Cretaceous Mannville Group. The McMurray formation directly overlies the sub-Cretaceous unconformity, which is developed on Paleozoic carbonates of the Beaver Hill Lake Group and is overlain by the Wabiskaw, Clearwater, and Grand Rapids Formations of the Mannville Group.
The study area (Figure 1) is located along the axis of the McMurray Valley system, which was localized by the dissolution of underlying Devonian evaporates, creating the preferred depositional fairway for the Lower Cretaceous McMurray sediments. The most significant bitumen reservoirs within the McMurray formation are found within the multiple channels that represent lowstand system tracts, incised into the regional, prograding parase-quence sets that represent highstand system tracts. During sea level rise, these incised channel systems were filled with a transgressive estuarine complex, consisting of sandy to muddy estuarine point bars. In the Long Lake area, the McMurray formation is dominantly composed of these multiple, sand-rich, fluvial, and estuarine channels, which are incised into each other and stacked along a preferred path of deposition. This preferred path is aligned north-northwest to south-southeast in the Long Lake area (Dumitrescu et al., 2009).
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Heavy oil is an important global resource with reserves comparable to those of conventional oil. As conventional resources get thinner, attention is being focused on heavy oil and bitumen, which hold the promise of becoming useful fuels. Already more than 1 million barrels of oil are being produced from the oil sands in Canada; heavy oil represents half of California’s crude oil production in the United States and is a major production in Mexico. With demand for global energy soaring, heavy oil will undoubtedly be an important resource to be exploited in a big way in the near future.
The SEG Development and Production Committee held its Heavy Oil Forum in Edmonton, Alberta, in July 2007. This was a joint research forum cosponsored by the Canadian Society of Exploration Geophysicists (CSEG) and SEG and hosted by the University of Alberta. Preceding the forum, a field trip took the participants to the vast Athabasca Oil Sands region where they observed the outcrops, open pit mining, and steam injection operations, followed by a tour of the steam-assisted gravity drainage projects. Topics of the well-attended forum included the definition of heavy oil; where is heavy oil found; how it is produced; heavy-oil reservoir characterization; fluid and rock properties; electrical, tilt, and gravity techniques; borehole, surface seismic measurements; and microseismicity.