SPE Journal
Volume 15, Number 1, March 2010, pp. 171-183

SPE-116735-PA

Modeling Foam Displacement With the Local-Equilibrium Approximation: Theory and Experimental Verification

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DOI  More information 10.2118/116735-PA http://dx.doi.org/10.2118/116735-PA

Citation

  • Chen, Q., Gerritsen, M.G., and Kovscek, A.R. 2010. Modeling Foam Displacement With the Local-Equilibrium Approximation: Theory and Experimental Verification. SPE J.  15 (1): 171-183. SPE-116735-PA. doi: 10.2118/116735-PA.

Discipline Categories

  • 6.4 Primary and Enhanced Recovery Processes
  • 6.3 Fluid Dynamics

Keywords

  • foam displacement

Summary

The gas-mobility-control aspects of foamed gas make it highly applicable for improved oil recovery. Gas-bubble size, often referred to as foam texture, determines gas-flow behavior in porous media. A population-balance model has been developed previously for modeling foam texture and flow in porous media. The model incorporates pore-level mechanisms of foam-bubble generation, coalescence, and transport. Here, we propose a simplified foam model to reduce computational costs. The formulation is based on the assumption of local equilibrium of foam generation and coalescence and is applicable to high- and low-quality foams. The proposed foam model is compatible with a standard reservoir simulator. It provides a potentially useful, efficient tool to predict foam flows accurately at the field scale for designing and managing foamed-gas applications.

There are three main contributions of this paper. First, foam-displacement experiments in a linear sandstone core are conducted. A visualization cell is employed to measure the effluent foam-bubble sizes for a transient flow as well as to estimate the in-situ foam-bubble sizes along the length of the core during steady-state flow. These appear to be the first measurements of foam-bubble texture in the entrance region of a core. Additionally, the evolution of aqueous-phase saturation is monitored using X-ray computed tomography (CT), and the pressure profile is measured by a series of pressure taps. Second, the population-balance representation of foam generation by gas-bubble snap-off is modified to extend the capability of the population-balance approach to predict foam-flow behaviors in both the so-called high-quality and low-quality regimes. Third, a simplified population-balance model is developed and implemented with the local-equilibrium approximation. Good agreement is found between the experimental results and the predictions of the simplified model, with a minor mismatch in the entrance region.

© 2010. Society of Petroleum Engineers

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History

  • Original manuscript received: 7 July 2008
  • Meeting paper published: 21 September 2008
  • Revised manuscript received: 11 March 2009
  • Manuscript approved: 31 August 2009
  • Published online: 2 March 2010
  • Version of record: 12 March 2010