Machine-Learning Approach for Forecasting Steam-Assisted Gravity-Drainage Performance in the Presence of Noncondensable Gases

Abstract

Steam-assisted gravity drainage (SAGD) is an effective enhanced oil recovery method for heavy oil reservoirs. The addition of certain amounts of noncondensable gases (NCG) may reduce the steam consumption, yet this requires new design-related decisions to be made. In this study, we aimed to develop a machine-learning-based forecasting model that can help in the design of SAGD applications with NCG. Experiments with or without carbon dioxide (CO 2 ) or n -butane ( n -C 4 H 10 ) mixed with steam were performed in a scaled physical model to explore SAGD mechanisms. The model was filled with crushed limestone that was premixed with heavy oil of 12.4° API gravity. Throughout the experiments, temperature, pressure, and production were continuously monitored. The experimental results were used to train neural-network models that can predict oil recovery (%) and cumulative steam–oil ratio (CSOR). The input parameters included injected gas composition, prior saturation with CO 2 or n -C 4 H 10 , separation between wells, and pore volume injected. Among different neural-network architectures tested, a 3-hidden-layer structure with 40, 30, and 20 neurons was chosen as the forecasting model. The model was able to predict oil recovery and CSOR with R 2 values of 0.98 and 0.95, respectively. Variable importance analysis indicated that pore volume injected, distance between wells, and prior CO 2 saturation are the most critical parameters that would affect the performance, in agreement with the experiments.

A new pressure control scheme on steam‐assisted gravity drainage for heavy oil production

“…Previous studies noticed the impact of the content of gas on the chamber growth and oil production rate, but few paid close attention to the variation of inclination angle and its effects on the gravity drainage. More recent studies, either through numerical simulators [42][43][44] or data analysis technologies (such as machine learning approaches and connectionist modelling) [45,46] have been attempted to improve the optimization efficiency and forecasting accuracy. However, none of them investigated the role of slip angle in SAGD performance, along which the heated oil drains to the producer.…”