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Title: CO 2 water-alternating-gas injection for enhanced oil recovery: Optimal well controls and half-cycle lengths

We report that CO 2 water-alternating-gas (WAG) injection is an enhanced oil recovery method designed to improve sweep efficiency during CO 2 injection with the injected water to control the mobility of CO 2 and to stabilize the gas front. Optimization of CO 2 -WAG injection is widely regarded as a viable technique for controlling the CO 2 and oil miscible process. Poor recovery from CO 2 -WAG injection can be caused by inappropriately designed WAG parameters. In previous study (Chen and Reynolds, 2016), we proposed an algorithm to optimize the well controls which maximize the life-cycle net-present-value (NPV). However, the effect of injection half-cycle lengths for each injector on oil recovery or NPV has not been well investigated. In this paper, an optimization framework based on augmented Lagrangian method and the newly developed stochastic-simplex-approximate-gradient (StoSAG) algorithm is proposed to explore the possibility of simultaneous optimization of the WAG half-cycle lengths together with the well controls. Finally, the proposed framework is demonstrated with three reservoir examples.
ORCiD logo [1] ;  [1]
  1. The University of Tulsa, OK (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0098-1354
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Computers and Chemical Engineering
Additional Journal Information:
Journal Volume: 113; Journal Issue: C; Journal ID: ISSN 0098-1354
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE; TUPREP Research Group Sponsored by Oil companies
Country of Publication:
United States
42 ENGINEERING; 97 MATHEMATICS AND COMPUTING; 58 GEOSCIENCES; CO2-WAG; Production optimization; Optimal well controls; Half-cycle length; Enhanced oil recovery; Ensemble-based methods
OSTI Identifier: