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Sequera B.,University of Calgary | Sequera B.,Norwest Corporation | Moore R.G.,University of Calgary | Mehta S.A.,University of Calgary | Ursenbach M.G.,University of Calgary
Journal of Canadian Petroleum Technology | Year: 2010

During in-situ combustion (ISC) processes, different chemical reactions occur depending on the temperature level. In heavy oils and bitumens, low temperature oxidation (LTO) reactions dominate below 300°C, increasing the density and viscosity and producing coke which could prevent the success of ISC. Above 350°C, combustion reactions dominate, known as high temperature oxidation (HTO), producing carbon oxides and water. Numerical models tend to include only thermal cracking and HTO reactions, as LTO reactions are not well understood. In the present work, ISC experiments operated under LTO were simulated, using Saturates, Aromatics, Resins and Asphaltenes (SARA) fractions to characterize the Athabasca bitumen. Concentration profiles and coke deposition for individual temperatures were matched for isothermal experiments from 60°C to 150°C. Based on these results, ramped temperature oxidation (RTO) experiments were then modelled, incorporating the heat of reaction at LTO. Different reaction models were studied to match temperature profiles along the reactor, oxygen consumption, coke formation and fluids production. This research will greatly increase the understanding of LTO reactions occurring in Athabasca bitumen during ISC and contribute to the creation of a reliable numerical model that predicts ISC performance under ideal (HTO) and, importantly, non-ideal (LTO) temperature conditions. Source


Huang M.,University of Saskatchewan | Huang M.,Northwest Agriculture and Forestry University | Rodger H.,Norwest Corporation | Barbour S.L.,University of Saskatchewan
Canadian Journal of Soil Science | Year: 2015

The saturated hydraulic conductivity (Ks) of soil covers used in land reclamation is known to change over time as the result of weathering processes. Guelph permeameter (GP) measurements have been used to track the evolution of Ksfor soil covers at an oil sands mine near Ft. McMurray , Alberta. Although successful, the method was time consuming and consequently a rapid method of estimating Ksbased on in situ air permeability measurements was developed. The objectives of this study were: (1) to use air permeability measurements to characterize the spatial variations of Ksfor typical reclamation soils and (2) to compare air permeability measurements to direct measurements obtained through laboratory and GP measurements. The results highlight that the values of Ksestimated from measured air permeability values were higher than the values of Ksmeasured directly using the GP. This is likely due to swelling of clay soils or air-entrapment during GP measurements. Although the magnitude was over-estimated, the variability of Kswas captured by the air permeability measurements. Consequently, a limited program of comparative GP and air permeameter measurements could be used to more rapidly characterize the Ksof reclamation covers over time. ©, 2015 Agricultural Institute of Canada, All rights reserved. Source


Eglington B.M.,University of Saskatchewan | Pehrsson S.J.,Geological Survey of Canada | Ansdell K.M.,University of Saskatchewan | Lescuyer J.-L.,AREVA | And 3 more authors.
Precambrian Research | Year: 2013

Studies of the evolution of the Earth require a better understanding of regional geological geology, particularly for earth scientists who do not have broad, domain-specific knowledge. The Palaeoproterozoic geology of North America and Greenland has been summarized at domain level using the database system developed for the IGCP 509 project "Palaeoproterozoic Supercontinents and Global Evolution", with additional geochronological information from the DateView database. A series of diagrams illustrate and contrast the geochronology and isotopic evolution of the Trans-Hudson Orogen and its bounding older crustal domains. These are accompanied by several time-space correlation charts and time-slice tectonic reconstructions showing the lithostratigraphy of the region. The origin and setting of uranium mineralization in Canada is discussed in order to illustrate the knowledge potential captured within these databases. © 2013 Elsevier B.V. Source


Ronayne M.J.,Colorado State University | Houghton T.B.,Colorado State University | Houghton T.B.,Norwest Corporation | Stednick J.D.,Colorado State University
Journal of Hydrology | Year: 2012

Three different measurement techniques (a mini-disk infiltrometer, a double-ring infiltrometer, and a Guelph permeameter) were used to characterize the saturated hydraulic conductivity of an alpine glacial till in the Rocky Mountains of southern Wyoming, USA. Measurements from 32 locations reveal significant spatial heterogeneity. The hydraulic conductivity varies over two orders of magnitude from approximately 0.05-5. m/d. Along with natural variability throughout the study area, the results also indicate that the estimated hydraulic conductivity is dependent on measurement technique. Compared to the mini-disk infiltrometer, hydraulic conductivities are consistently higher for the double-ring infiltrometer and Guelph permeameter. By considering surface-subsurface hydrologic response during snowmelt, we demonstrate the importance of accurately characterizing the hydraulic conductivity. A model parameterized with a low hydraulic conductivity underestimates the rate of shallow groundwater flow, suggesting that the subsurface saturated zone may not be able to accommodate all of the snowmelt-derived recharge. Saturation-excess overland flow is predicted as a result. These findings have important implications for integrated hydrologic assessments focused on understanding water flows in glaciated alpine watersheds. © 2012 Elsevier B.V. Source


Bhattacharyya S.,Norwest Corporation | Nelson M.G.,University of Utah
2015 SME Annual Conference and Expo and CMA 117th National Western Mining Conference - Mining: Navigating the Global Waters | Year: 2015

Coal bearing rocks are low in strength and have geological discontinuities and moisture sensitivity. Roof and rib falls have been a major cause of fatalities in underground coal mines. Mine engineers design ground control plans for regulatory approvals. A number of tools are available from the National Institute for Occupational Safety and Health to design and assess these plans. Quite often there is not enough geotechnical input information available and databases are used. The Appalachian coalfields have extensive scientific studies to provide reliable regional inputs. Coal mines in the western United States and Canada have different geological and geotechnical conditions, and less available data. Use of inappropriate inputs in the tools like Analysis of Retreat Mining Pillar Stability, Analysis of Longwall Pillar Stability, and Analysis of Roof Bolt Systems may result in unsafe designs or over conservative designs. The tools are convenient but thorough understanding of the inputs, calibration with local test results, and operating experience are important for effective designs. The current paper contains examples of difficulties faced during mine planning using the above tools. Copyright © 2015 by SME. Source

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