Insights on the Thermal Efficiency of SAGD from Data Analytics
Date
2020-02-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The research in this thesis explores three aspects of Steam-Assisted Gravity Drainage (SAGD) oil recovery using public information, with the aim of uncovering new insights about field performance that cannot be deduced from reservoir physics alone. Topics are chosen by the amount and type of public data available, and each analysis spans multiple SAGD fields. A literature review is presented to understand how machine-learning algorithms have been used in SAGD research. Machine learning does not guarantee physically consistent results, therefore particular attention is paid to how analysis results are validated. A description of an ideal SAGD machine learning study is compiled and used to rate all the studies reviewed. The first thesis study uses temperature profiles from observation wells near 13 SAGD well pairs to estimate the volume of gas accumulated at the top of a steam chamber. Together with known or estimated volumes of gas co-injected, produced, and mobilized within the reservoir, a gas material balance is calculated to estimate the unknown volume of gas generated in situ. Heat transfer is also examined in relation to the presence of gas. The second thesis study develops a new Bayesian biclustering method to find and differentiate groups within 328 SAGD well pairs based on their oil production response to steam injection over time. Clusters are described with probability distributions that capture the likelihood of transitioning between discrete steam-to-oil ratio states. Behaviour differences are then described and explained. The third thesis study specifies performance of 1,520 well pairs as a ratio of energy produced to energy injected (EPEI), noting that EPEI ratios become almost constant within the first year of operation. This distinctive behaviour is discussed within the context of five manually defined groups, five case study well pads, and 26 independent parameters. One-by-one parameters are eliminated until only a few remain. Interactions of the remaining parameters are examined with sensitivity analysis. Lastly, corroborating or contradicting findings are reconciled across all three studies – this is the best approach found to verify insights. The results of this research demonstrate that data analytics and machine learning can play a complementary role to physical modelling.
Description
Keywords
Citation
Pinto, H. (2020). Insights on the Thermal Efficiency of SAGD from Data Analytics (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.