History matching and prediction of a polymer flood pilot in heavy oil reservoir on Alaska North Slope

• Main Author: Wang, Xindan
• Other Authors: Zhang, Yin, Dandekar, Abhijit, Khataniar, Santanu
• Format: Thesis
• Language: English
• Published: 2021
• Subjects: Polymer flooding; Petroleum engineering; Oil field flooding; Enhanced oil recovery; Heavy oil; Master of Science in Petroleum Engineering; Fairbanks; Alaska North Slope; north slope; Alaska
• Online Access: http://hdl.handle.net/11122/12923

Thesis (M.S.) University of Alaska Fairbanks, 2021 The first-ever polymer flood pilot to enhance heavy oil recovery on Alaska North Slope is ongoing. After more than 3 years of polymer injection, significant benefit has been observed from the decrease in water cut from 65% to less than 15% in the project producers. The primary objective of this study is to develop a robust history-matched reservoir simulation model capable of predicting future polymer flood performance. In this work, the reservoir simulation model has been developed based on the geological model and available reservoir and fluid data. In particular, four high transmissibility strips were introduced to connect the injector-producer well pairs, simulating short-circuiting flow behavior that can be explained by viscous fingering and reproducing the water cut history. The strip transmissibilities were manually tuned to improve the history matching results during the waterflooding and polymer flooding periods, respectively. It has been found that higher strip transmissibilities match the sharp water cut increase very well in the waterflooding period. Then the strip transmissibilities need to be reduced with time to match the significant water cut reduction. The viscous fingering effect in the reservoir during waterflooding and the restoration of injection conformance during polymer flooding have been effectively represented. Based on the validated simulation model, numerical simulation tests have been conducted to investigate the oil recovery performance under different development strategies, with consideration for sensitivity to polymer parameter uncertainties. The oil recovery factor with polymer flooding can reach about 39% in 30 years, twice as much as forecasted with continued waterflooding. Besides, the updated reservoir model has been successfully employed to forecast polymer utilization, a valuable parameter to evaluate the pilot test's economic efficiency. All the investigated development strategies indicate polymer utilization lower than ...