Thoughts on Simulating the VAPEX Process
- Dave Cuthiell (Consultant to Laricina Energy Limited) | Neil Edmunds (Laricina Energy Limited)
- Document ID
- Society of Petroleum Engineers
- Journal of Canadian Petroleum Technology
- Publication Date
- May 2013
- Document Type
- Journal Paper
- 192 - 203
- 2013. Society of Petroleum Engineers
- 5.5 Reservoir Simulation, 3 Production and Well Operations, 4.1.5 Processing Equipment, 4.1.2 Separation and Treating, 5.4.7 Chemical Flooding Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex)
- 6 in the last 30 days
- 446 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
The vapour extraction (VAPEX) process and its many hybrid variants have attracted a great deal of attention as potentially lessenergy-intensive alternatives for exploiting heavy-oil and bitumen resources. However, despite significant work over the past 2 decades, uncertainty remains about the basic mechanisms, the scaling aspects, and the most appropriate methods of numerically simulating these processes. This paper offers some insights into several of these outstanding questions. The questions are examined in the context of an extensive and well-documented set of VAPEX experiments carried out by Maini and his colleagues over the past 10 years.
We have experimented with different methods of simulating these experiments using a physics-based reservoir simulator. Despite the high permeability (greater than 200 darcies in all of the experiments), we find that capillary pressure plays a significant role in the drainage. The simulations suggest that most of the drainage takes place in the capillary transition zone along the edge of the vapour chamber, rather than in the single-phase zone ahead of it which has not yet been contacted by vapour. It has been emphasized in the literature that the near-linear scaling of oil rate with height observed in the experiments is dramatically different from the square-root-of-height dependence predicted by the original analytic model of VAPEX. However, the experiments also show an increasing solvent fraction in the produced-oil phase as height increases. When this "solvent mixing" effect is separated from the rates, the remaining height dependence is less than linear, though still greater than square root of height. The relative roles of molecular diffusion and mechanical dispersion in VAPEX have been discussed widely in the literature.
Generally, mechanical dispersion is expected to play a larger role in these high-permeability experiments (compared with the field) because of larger fluid velocities. We present a method of inferring the diffusion/dispersion present in the simulations, despite a hidden component of numerical dispersion caused by the numerical method itself. We find that the experiments are well matched with values of diffusion and dispersion in line with literature correlations, and that the contribution of mechanical dispersion is perhaps not as large as might be expected relative to that of molecular diffusion.
The paper also provides some thoughts on questions we expect are still unanswered, including mechanisms behind the height dependent mixing phenomenon and the scaling of the experimental results to the significantly greater heights and lower permeability characteristic of the field.
|File Size||778 KB||Number of Pages||12|
Ahmadloo, F., Asghari, K., Henni, A. et al. 2011. Interplay ofCapillarity, Drainage Height, and Aqueous Phase Saturation on Mass TransferRate of Solvent Vapor into Heavy Oil. Presented at the Canadian UnconventionalResources Conference, Calgary, 15-17 November. SPE-148682-MS. http://dx.doi.org/10.2118/148682-MS.
Alkindi, A., Al-Wahaibi, Y., and Muggeridge, A. 2011.Experimental and Numerical Investigations Into Oil-Drainage Rates During VaporExtraction of Heavy Oils. SPE J. 16 (2): 343-357.SPE-141053-PA. http://dx.doi.org/10.2118/141053-PA.
Ayub, M. and Tuhinuzzaman, M. 2007. The Role of Capillarity inthe VAPEX Process. Presented at the Canadian International PetroleumConference, Calgary, 12--14 June. PETSOC-2007-075. http://dx.doi.org/10.2118/2007-075.
Boustani, A. and Maini, B.B. 2001. The Role of Diffusion andConvective Dispersion in Vapour Extraction Process. J Can Pet Technol 40 (4): 68-77. PETSOC-01-04-05. http://dx.doi.org/10.2118/01-04-05.
Butler, R.M. and Mokrys, I.J. 1989. The Rise of Interfering SolventChambers: Solvent Analog Model of Steam-Assisted Gravity Drainage. AOSTRAJournal of Research 5 (1): 17-32.
Butler, R.M. and Mokrys, I.J. 1991. A New Process (VAPEX) for RecoveringHeavy Oils Using Hot Water and Hydrocarbon Vapour. J Can Pet Technol 30 (1): 97-106.
Collins, R.E. 1961. Flow of Fluids Through PorousMaterials. Tulsa, Oklahoma: PennWell Books.
Cuthiell, D., McCarthy, C., Kissel, G. et al. 2006. The Role ofCapillarity in VAPEX. Presented at the Canadian International PetroleumConference, Calgary, 13-15 June. CIPC 2006-073. http://dx.doi.org/10.2118/2006-073.
Das, S.K. and Butler, R.M. 1996. Diffusion Coefficients ofPropane and Butane in Peace River Bitumen. Can. J. Chem. Eng. 74 (6): 985-992. http://dx.doi.org/10.1002/cjce.5450740623.
Das, S.K. and Butler, R.M. 1998. Mechanism of the Vapour Extraction Processfor Heavy Oil and Bitumen. J. Pet. Sci. Eng. 21 (1-2):43-59.
Dunn, S.G., Nenniger, E.H., and Rajan, V.S.V. 1989. Astudy of bitumen recovery by gravity drainage using low temperature soluble gasinjection. The Canadian Journal of Chemical Engineering 67(6): 978-991. http://dx.doi.org/10.1002/cjce.5450670617.
Gelhar, L.W., Welty, C., and Rehfeldt, K.R. 1992. ACritical Review of Data on Field-Scale Dispersion in Aquifers. Water Resour.Res. 28 (7): 1955-1974. http://dx.doi.org/10.1029/92WR00607.
Karmaker, K. and Maini, B.B. 2003. Experimental Investigationof Oil Drainage Rates in the Vapex Process for Heavy Oil and BitumenReservoirs. Presented at the SPE Annual Technical Conference and Exhibition,Denver, 5-8 October. SPE-84199-MS. http://dx.doi.org/10.2118/84199-MS.
Leverett, M.C. 1941. Capillary Behavior in Porous Solids.In Transactions of the American Institute of Mining, Metallurgical, andPetroleum Engineers, Vol. 142, Paper SPE-941152-G, 152-169. Dallas, Texas:Society of Petroleum Engineers of AIME.
Lim, G.B., Kry, R.P., Harker, B.C. et al. 1996.Three-Dimensional Scaled Physical Modelling Of Solvent Vapour Extraction OfCold Lake Bitumen. J Can Pet Technol 35 (4): 32-40.PETSOC-96-04-03. http://dx.doi.org/10.2118/96-04-03.
Nenniger, J.E. and Dunn, S.G. 2008. How Fast is Solvent Based GravityDrainage? Presented at the Canadian International Petroleum Conference,Calgary, 17-19 June. CIPC 2008-139. http://dx.doi.org/10.2118/2008-139.
Nghiem, L.X., Kohse, B.F., and Sammon, P.H. 2001.Compositional Simulation of VAPEX Process. J Can Pet Technol 40 (8): 54-61. JCPT Paper No. 01-08-05. http://dx.doi.org/10.2118/01-08-05.
Perkins, T.K. and Johnston, O.C. 1963. A Review of Diffusionand Dispersion in Porous Media. SPE J. 3 (1): 70-84.SPE-480-PA. http://dx.doi.org/10.2118/480-PA.
Yazdani, A. 2007. Physical and Numerical Modeling ofPermeability and Drainage Height Effects in VAPEX. PhD thesis, Universityof Calgary, Calgary, Alberta.
Yazdani, A. and Maini, B.B. 2005. Effect of Drainage Height andGrain Size on Production Rates in the Vapex Process: Experimental Study. SPERes Eval & Eng 8 (3): 205-213. SPE-89409-PA. http://dx.doi.org/10.2118/89409-PA.
Yazdani, A. and Maini, B.B. 2006. Further Investigation ofDrainage Height Effect on Oil Production Rate in Vapex. Presented at the SPEAnnual Technical Conference and Exhibition, San Antonio, Texas, USA, 24-27September. SPE-101684-MS. http://dx.doi.org/10.2118/101684-MS.
Yazdani, A. and Maini, B.B. 2007. Modeling of the VAPEX Processin a Very Large Physical Model. Energy Fuels 22 (1):535-544. http://dx.doi.org/10.1021/ef700429h.
Yazdani, A. and Maini, B.B. 2009a. Pitfalls and Solutions inNumerical Simulation of VAPEX Experiments. Energy Fuels 23(8): 3981-3988. http://dx.doi.org/10.1021/ef900200f.
Yazdani, A. and Maini, B.B. 2009b. The EffectiveDiffusion/Dispersion Coefficient in Vapor Extraction of Heavy Oil. PetroleumScience and Technology 27 (8): 817-835. http://dx.doi.org/10.1080/10916460802112191.