Journal of Canadian Petroleum Technology
Volume 50, Number 1, January 2011, pp. 33-42

SPE-132459-PA

Mechanics and Upscaling of Heavy Oil Bitumen Recovery by Steam-Over-Solvent Injection in Fractured Reservoirs Method

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DOI  More information 10.2118/132459-PA http://dx.doi.org/10.2118/132459-PA

Citation

  • Singh, R. and Babadagli, T. 2011. Mechanics and Upscaling of Heavy Oil Bitumen Recovery by Steam-Over-Solvent Injection in Fractured Reservoirs Method. J Can Pet Technol  50 (1): 33-42. SPE-132459-PA. doi: 10.2118/132459-PA.

Discipline Categories

  • 6.4.5 Thermal Methods (e.g.,Steamflood, Cyclic Steam, THAI, Combustion)
  • 6.4.7 Miscible Methods

Keywords

  • thermal, solvent, oil-wet carbonates, bitumen recovery, heavy oil recovery

Summary

Recently, the steam-over-solvent injection in fractured reservoirs (SOS-FR) method was proposed as a potential solution for efficient heavy-oil/bitumen recovery in oil-wet naturally fractured reservoirs. The method is based on initial injection steam (Phase 1), followed by solvent (Phase 2). In the third cycle (Phase 3), steam is injected again to recover more oil and retrieve the solvent. Solvent retrieval during the third cycle was observed to be fast if the temperature is at approximately the boiling point of the solvent. This process is controlled by efficient matrix recovery and the mechanics of the process need to be clarified to further determine the efficient application conditions for the given matrix and oil characteristics.

Single-matrix behaviour during the process was numerically modelled for static conditions and the results were matched with the experimental observations. The physics of the recovery mechanism was analyzed through visual inspection of saturation and concentration profiles in each cycle. The major observation was the substantial effect of gravity in oil recovery when the matrix were exposed to solvent. Special attention was given to the solvent retrieval rate and amount in Phase 3 and the permeability reduction caused by asphaltene precipitation in Phase 2. This phenomenon was modelled using a permeability function changing with spatial coordinates and time (i.e., k =f (x ,y ,z ,t ). It was observed that permeability reduction caused by asphaltene precipitation is significant and needs to be taken into account in the modelling process.

After showing the effect of the matrix size on the oil recovery and solvent retrieval, an upscaling analysis was performed. The log-log relationship between the time value to reach ultimate recovery and the matrix size yielded a straight-line relationship with a noninteger exponent less than two for all three phases of the process. The observed straight-line relationship (and the exponent values obtained) is highly encouraging to extend the study to obtain a universal scaling relationship.

© 2010. Society of Petroleum Engineers

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History

  • Original manuscript received: 3 April 2010
  • Meeting paper published: 27 May 2010
  • Revised manuscript received: 20 August 2010
  • Manuscript approved: 20 August 2010
  • Published online: 1 January 2011
  • Version of record: 1 January 2011