Browsing by Author "Wilson, Malcolm"

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Open Access
Estimation of Relative Permeability and Capillary Pressure for Hydrocarbon Reservoirs Using Ensemble-Based History Matching Techniques
(Faculty of Graduate Studies and Research, University of Regina, 2014-07) Zhang, Yin; Yang, Daoyong; Torabi, Farshid; Wilson, Malcolm; Bend, Stephen; Yang, Chaodong
Reservoir simulation is generally used in modern reservoir management to make sound reservoir development strategies, requiring a reliable and up-to-dated reservoir model to predict future reservoir performance in an accurate and efficient way. It is the history matching that is able to provide a reliable reservoir model by using the observed data to calibrate the reservoir model parameters. In this study, assisted history matching techniques have been developed to inversely and accurately evaluate relative permeability and capillary pressure for the hydrocarbon reservoirs. An assisted history matching technique based on the confirming Ensemble Kaman Filter (EnKF) algorithm has been developed, validated, and applied to simultaneously estimate relative permeability and capillary pressure curves by assimilating displacement experiment data in conventional reservoirs and tight formations, respectively. Subsequently, the confirming EnKF algorithm has been extended its application to a synthetic 2D reservoir model where two-phase and three-phase relative permeability and capillary pressure curves are respectively evaluated by assimilating field production data. The power-law model and/or B-spline model can be used to represent relative permeability and capillary pressure curves, whose parameters are to be tuned automatically and finally determined once the measurement data has been assimilated completely and history matched. The estimated relative permeability and capillary pressure curves, in general, have been found to improve progressively, while their associated uncertainties are mitigated gradually as more measurement data is assimilated. Finally, there exists a generally good agreement between both the updated relative permeability and capillary pressure curves and their corresponding reference curves, leading to excellent history matching results. As such, the uncertainties associated with both the updated relative permeability and capillary pressure curves and the updated production profiles are reduced significantly. In addition, a novel damped iterative EnKF (EnKF) algorithm has been proposed and applied to evaluate relative permeability and capillary pressure for the laboratory coreflooding experiment. It has been found that relative permeability and capillary pressure can be simultaneously determined by using the damped IEnKF algorithm to only assimilate the cumulative oil production and pressure drop, while there exist better history matching results than those of the confirming EnKF. Compared with the initial cases, the uncertainties associated with both updated relative permeability and capillary pressure curves and the updated production history profiles have been decreased greatly. Finally, the standard test case based on a real field, i.e., PUNQ-S3 reservoir model, is used to further evaluate performance of the damped IEnKF algorithm. After assimilating all of the measurement data, the three-phase relative permeability and capillary pressure curves can be estimated accurately. The damped IEnKF algorithm is found to reduce the uncertainties associated with both the updated relative permeability and capillary pressure curves and the updated production profiles significantly compared with their corresponding initial cases. In addition to its better performance than the confirming EnKF algorithm, the damped IEnKF algorithm is found to be special suitable for the strongly nonlinear data assimilation system, though there still exist certain variations in the updated relative permeability and capillary pressure curves as well as the predicted production profiles.
Open Access
Weathering the Political and Environmental Climate of the Kyoto Protocol
(Saskatchewan Institute of Public Policy, 2004-01) Blake, Raymond; Diaz, Polo; Piwowar, Joe; Polanyi, Michael; Robinson, Reid; Whyte, John D.; Wilson, Malcolm
When Canada’s Minister of the Environment, David Anderson, notified the United Nations (UN) on 17 December 2002 that Canada would ratify the UN Framework Agreement on Climate Change, known best as the Kyoto Protocol, Canada joined nearly 100 countries to do so. Together, these countries represented about 40 per cent of the 1990 emissions, still some distance from the 55 per cent threshold necessary for the UN Agreement to come into effect. A day earlier, then Prime Minister Jean Chretien had signed the 1997 treaty limiting greenhouse gas emissions at a ceremony in Ottawa after the House of Commons had approved the treaty. Because the United States, which is responsible for more than 36 per cent of all emissions, had rejected the treaty, there was great hope that Russia would soon ratify the protocol. Once Russia became a signatory to the agreement, it and all other signatories would have committed themselves to reducing greenhouse gas emissions to six per cent below 1990 rates by 2012. In Canada, that necessitated a reduction of 20 to 30 per cent from current levels. However, Russia, like the United States and Australia, has not yet ratified the Kyoto Protocol and, without Russia, which accounts for 17.4 per cent of emissions, the Protocol may be in serious trouble.