ALBERT

Description: The bitumen of the Lower Cretaceous McMurray Formation in Alberta arguably represents one of the most important hydrocarbon accumulations in the world. In-situ development relies on heat transfer through the reservoir via horizontal steam injection wells placed 4 to 6 m (13-20 ft) above horizontal producers near the base of the sandstone reservoirs. Given this technology, understanding the distribution of the resource is paramount for a successful development program. Sedimentary facies provide a direct control on bitumen distribution and recovery. Most facies models developed to describe and predict sedimentary units of the McMurray Formation consider fluvial, estuarine, and/or deltaic depositional settings. In-situ development, however, requires a particularly high-resolution sedimentologic interpretation. High-quality three-dimensional seismic reflection data and extensive drill cores from acreage located approximately 50 km (31 mi) south of Fort McMurray provide important insights into the sedimentologic organization of reservoir and nonreservoir deposits in the upper one third (40 m [131 ft]) of the reservoir interval. Geomorphologic characteristics of the strata observed in seismic time slices reveal that a fluvial depositional setting was prevalent. Ichnologic and palynologic data, as well as sedimentary structures suggestive of tidal processes, indicate a marine influence in the upper reaches of a fluvial system characterized by channels that were 390 to 640 m (1280-2100 ft) wide and 28 to 36 m (92-118 ft) deep. The complex stratigraphic architecture consists of a mosaic of large-scale depositional elements, including abandoned channels or oxbow lake fills, point bars associated with lateral accretion, point bars associated with downstream accretion, counter point bars, and sandstone-filled channels. Reservoir deposits are primarily associated with point bars and sandstone-filled channels.

Description: Nonmarine strata of the Lower Cretaceous Mannville Group and marine strata of the Upper Jurassic Ellis Group in southern Alberta were deposited in the low-accommodation, eastern, and distal margin of the Western Canada sedimentary basin. The Manyberries oil field produces hydrocarbons from preserved interfluves as well as the deposits of compound valley fills. These Mannville Group sediments provide an end-member component for nonmarine sedimentation in a low-accommodation setting. The succession is characterized by thin sediment accumulations deposited over a long period of time; multiple unconformities, some profound; incised valleys, typically compound in nature; paleosols of varying degrees and maturity; and a general absence of coal. Dale Leckie is chief geologist at Nexen Inc. He is a specialist in sedimentology, sequence stratigraphy, and basin analysis. He has worked on Australia, Colombia, Yemen, and New Zealand basins. Leckie has received numerous awards from the AAPG, SEPM, and Canadian Society of Petroleum Geologists. He coedited AAPG Memoir 55 entitled Foreland Basins and Fold Belts and Canadian Society of Petroleum Geologists Memoir 15 entitled Sequence StratigWraphy: Surface, Subsurface and Sedimentology. Karen Wallace-Dudley is a scientist at the Geological Survey of Canada, Calgary. She specializes in the sedimentology, stratigraphy, and petroleum geology of Jurassic and Cretaceous hydrocarbon-bearing strata in western Canada. Nancy Vanbeselaere is the principal of Rocky Mountain Consultants. She is a specialist on Mannville stratigraphy of southern Alberta and Saskatchewan. Nancy worked for several years at Imperial Oil Limit and as a consultant at the Geological Survey of Canada. David James is manager of geology at Anadarko Canada; his main interests are exploration, sedimentology, and sequence stratigraphy. He has worked extensively throughout the Western Canada basin, Canada's frontiers, and internationally. He has received awards from the Canadian Society of Petroleum Geologists, AAPG, and SEPM and was coeditor of Canadian Society of Petroleum Geologists Memoirs 15 and 18 on sequence stratigraphy and the Mannville Group.

Description: The Lower Cretaceous Qishn Clastics Member in Masila Block 14, Hadhramaut region, Republic of Yemen, has estimated reserves of 1.1 billion bbl recoverable oil and has produced 600 million bbl of oil. Sedimentation took place in an elongate paleogulf of the Say'un-al Masila basin, with open-marine carbonates to the east. The Qishn Clastics Member unconformably overlies mixed carbonates and clastics of the Sa'af Member. Lower Qishn onlap resulted in deposition of brackish and tidal (likely macrotidal) estuarine to open-bay or gulf deposits. The middle portion of the lower Qishn Clastics Member shows evidence of arid nonmarine sedimentation, including debris-flow deposits, red beds, and shale-clast conglomerates, in turn, overlain by interfingering coastal and nonmarine deposits. The lower Qishn Clastics Member is truncated by a sequence boundary overlain by an extensive sandstone deposited in a low-accommodation braid plain close to the shoreline. A flooding surface is present at the top of the sandstone, over which progradational, tide-influenced deltaic strata were deposited. Delta progradation culminated in shallow-water clastic dolomitic deposits on the coastal plain. With subsequent transgression, a rising water table caused a nonmarine flooding surface with lakes and lacustrine deltas, overlain by tidal-flat deposits. Ongoing transgression resulted in wave ravinement overlain by shallow-shelf clastics and then deposition of slightly deeper shelf carbonates. The uppermost unit comprises bioturbated, clastic-shelf deposits related to a drop in relative sea level. Throughout much of the Qishn Clastics interval, accommodation was moderate, except for low accommodation associated with regional sheet sandstone at the base of the upper Qishn Clastics Member. Virtually all marine and brackish deposits show evidence of tidal sedimentation. Climate was arid and seasonally wet. Dale Leckie is chief geologist at Nexen. He is a specialist in sedimentology, sequence stratigraphy, and basin analysis. He has worked on Australia, Colombia, Yemen, and New Zealand basins. He has received numerous awards from AAPG, SEPM, and the Canadian Society of Petroleum Geologists. Dale coedited (AAPG Memoir 55), Foreland Basins and Fold Belts and (Canadian Society of Petroleum Geologists Memoir 15), Sequence Stratigraphy: Surface, Subsurface and Sedimentology .Thomas (Tom) Rumpel is staff geological consultant with Nexen, working in the Yemen Operations Team. In a 27-year career as a professional petroleum geoscientist, Tom has worked in a variety of capacities for several intermediate and junior exploration and production companies, including field geologist, exploration/exploitation geologist, consulting geologist, vice president of Exploration, and chief of Computer Geoscience.

Description: The bitumen of the Lower Cretaceous McMurray Formation in Alberta arguably represents one of the most important hydrocarbon accumulations in the world. In-situ development relies on heat transfer through the reservoir via horizontal steam injection wells placed 4 to 6 m (13–20 ft) above horizontal producers near the base of the sandstone reservoirs. Given this technology, understanding the distribution of the resource is paramount for a successful development program. Sedimentary facies provide a direct control on bitumen distribution and recovery. Most facies models developed to describe and predict sedimentary units of the McMurray Formation consider fluvial, estuarine, and/or deltaic depositional settings. In-situ development, however, requires a particularly high-resolution sedimentologic interpretation. High-quality three-dimensional seismic reflection data and extensive drill cores from acreage located approximately 50 km (31 mi) south of Fort McMurray provide important insights into the sedimentologic organization of reservoir and nonreservoir deposits in the upper one third (40 m [131 ft]) of the reservoir interval. Geomorphologic characteristics of the strata observed in seismic time slices reveal that a fluvial depositional setting was prevalent. Ichnologic and palynologic data, as well as sedimentary structures suggestive of tidal processes, indicate a marine influence in the upper reaches of a fluvial system characterized by channels that were 390 to 640 m (1280–2100 ft) wide and 28 to 36 m (92–118 ft) deep. The complex stratigraphic architecture consists of a mosaic of large-scale depositional elements, including abandoned channels or oxbow lake fills, point bars associated with lateral accretion, point bars associated with downstream accretion, counter point bars, and sandstone-filled channels. Reservoir deposits are primarily associated with point bars and sandstone-filled channels. Steve Hubbard is an assistant professor in the Department of Geoscience at the University of Calgary. He received his B.Sc. and M.Sc. degrees in geology from the University of Alberta, and his Ph.D. in geological and environmental sciences from Stanford University. His research interests include the evolution and stratigraphic architecture of channel deposits from nonmarine to deep-marine settings. Derald Smith, now professor emeritus, retired from the University of Calgary in 2006. His academic interests are in fluvial geomorphology, sedimentology, and stratigraphy. He received his Ph.D. from Johns Hopkins University, supervised by the late “Reds” M. Gordon Wolman. His initial academic inspiration came from Chester Beaty, Don Winston, James Peterson, and David Alt from the University of Montana. His recent retirement passion is alpine ski racing at the master's level. Haley Nielsen graduated with her B.Sc. degree from the Department of Geoscience at the University of Calgary in 2008. Her undergraduate honors thesis focused on sedimentary characterization of channels in the McMurray Formation. Since graduation, she has been working as a geologist at Encana in Calgary. Dale Leckie, chief geologist at Nexen, Inc., specializes in petroleum systems, focusing on sedimentology, marine and nonmarine sequence stratigraphy, basin analysis, and unconventional hydrocarbon reservoirs. He was president of SEPM, is associate editor for the AAPG Bulletin , co-organized a 2007 AAPG Hedberg Conference on Heavy Oil and Bitumen in Foreland Basins, and has coedited books from AAPG, SEPM, and the Canadian Society of Petroleum Geologists (CSPG). Milovan Fustic is a geologist at Nexen, Inc., in Calgary. He received a B.Sc. honors degree in geology from the University of Belgrade (Serbia) and a Ph.D. in petroleum geology from the University of Calgary. Fustic has 17 yr of professional experience, including 10 yr of working on various aspects of the oil sands industry (research in sedimentology, geochemistry, and reservoir modeling). Ron Spencer is a faculty professor in the Department of Geoscience at the University of Calgary. He received his B.A. degree in geology from the University of Colorado, his M.S. degree in geochemistry from the University of Nevada, and his Ph.D. in sedimentary geochemistry from Johns Hopkins University. His research interests include the evolution of seawater chemistry through time as well as depositional and geochemical aspects of petroleum systems in unconventional reservoirs. Lorraine Bloom is a senior research technician in the Department of Geoscience at the University of Calgary. Her specialization is in palynology, and her research interests include Paleozoic spores and pollen, as well as Mesozoic spores, pollen, dinoflagellates, and acritarchs.