SPE Journal
Volume 15, Number 2, June 2010, pp. 260-273

SPE-121579-PA

Fractional-Flow Theory of Foam Displacements With Oil

View full textPDF ( 680 KB )

DOI  More information 10.2118/121579-PA http://dx.doi.org/10.2118/121579-PA

Citation

  • Ashoori, E., van der Heijden, T.L.M., and Rossen, W.R. 2010. Fractional-Flow Theory of Foam Displacements With Oil. SPE J. 15 (2): 260-273. SPE-121579-PA. doi: 10.2118/121579-PA.

Discipline Categories

  • 6.4.7 Miscible Methods
  • 6.4.2 Gas-Injection Methods
  • 6.4.6 Chemical Flooding Methods Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex)
  • 6.5 Reservoir Simulation

Keywords

  • Primary and Enhanced Recovery Processed

Summary

Fractional-flow theory provides key insights into complex foam enhanced-oil-recovery (EOR) displacements and acts as a benchmark for foam simulators. In some cases with mobile oil present, the process can be represented as a two-phase displacement. We examine three such cases.

A first-contact-miscible (FCM) gasflood with foam injection includes a chemical shock defining the surfactant front and a miscible shock defining the gas front. The optimal water fraction for the foam, that which gives the fastest oil recovery in 1D, maintains the gas front slightly ahead of the foam (surfactant) front.

The success of a foam process with FCM CO2 and surfactant dissolved in the (supercritical) CO2 depends on the strength of foam at very low water fractional flow, such as for a surfactant-alternating-gas (SAG) process with surfactant dissolved in water. The speed of propagation of the foam front depends on surfactant adsorption on rock and on the partitioning of surfactant between water and CO2 but is always less than the velocity of the foam front in a SAG flood with surfactant ahead of the gas. A foam with surfactant that partitions preferentially into water rather than into CO2 would propagate slowly, regardless of the surfactant’s absolute solubility or the level of adsorption on rock. An aqueous surfactant preflush can speed the advance of foam, however.

An idealized model of a surfactant flood pushed by foam suggests that it is best to inject a relatively high water content into the foam to ensure that the gas front remains behind the surfactant front as the flood proceeds. Any gas that passes ahead of the surfactant front would finger through the oil and be wasted.

We present simulations to verify the solutions obtained with fractional-flow methods and illustrate the challenges of accurate simulation of these processes.

© 2010. Society of Petroleum Engineers

View full textPDF ( 680 KB )

History

  • Original manuscript received: 2 March 2009
  • Meeting paper published: 20 April 2009
  • Revised manuscript received: 11 November 2009
  • Manuscript approved: 11 September 2009
  • Published online: 3 March 2010
  • Version of record: 17 June 2010