Journal of Canadian Petroleum Technology
Volume 49, Number 10, October 2010, pp. 75-82

SPE-141650-PA

Optimal Parametric Design for Water-Alternating-Gas (WAG) Process in a CO2-Miscible Flooding Reservoir

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DOI  More information 10.2118/141650-PA http://dx.doi.org/10.2118/141650-PA

Citation

  • Chen, S., Li, D., Yang, D., and Tontiwachwuthikul, P. 2010. Optimal Parametric Design for Water-Alternating-Gas (WAG) Process in a CO2-Miscible Flooding Reservoir. J Can Pet Technol  49 (10): 75-82. SPE-141650-PA. doi: http://dx.doi.org/10.2118/141650-PA.

Discipline Categories

  • 6.4.2 Gas-Injection Methods
  • 6.4.7 Miscible Methods

Keywords

  • WAG process, production optimization, CO2 injection, genetic algorithm, hybrid technique

Summary

A pragmatic method has been developed to efficiently design the production-injection parameters to optimize the water-alternating-gas (WAG) performance in a field-scale CO2-miscible flooding project. The net present value (NPV) is selected as the objective function, while the controlling variables are chosen to be the injection rates, ratios of gas slug size to water slug size (WAG ratio) and cycle time (i.e., the injection time for each gas or water slug) for the injectors and bottomhole pressures (BHPs) for the producers. A hybrid technique, which integrates the orthogonal array (OA) and Tabu technique into the genetic algorithm (GA), is then developed and employed to determine the optimum WAG production-injection parameters. Sensitivity analysis of the WAG parameters on oil recovery is conducted and a field case is finally presented to demonstrate the successful application of the newly developed technique.

© 2010. Society of Petroleum Engineers

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History

  • Original manuscript received: 23 June 2009
  • Meeting paper published: 17 June 2009
  • Revised manuscript received: 8 June 2010
  • Manuscript approved: 13 August 2010
  • Published online: 1 October 2010
  • Version of record: 1 October 2010