Compositional Modeling of Retrograde Gas-Condensate Reservoirs in Multimechanistic Flow Domains
- Luis F. Ayala (Pennsylvania State U.) | Turgay Ertekin (Pennsylvania State U.) | Michael A. Adewumi (Pennsylvania State U.)
- Document ID
- Society of Petroleum Engineers
- SPE Journal
- Publication Date
- December 2006
- Document Type
- Journal Paper
- 480 - 487
- 2006. Society of Petroleum Engineers
- 5.5 Reservoir Simulation, 5.3.2 Multiphase Flow, 5.4.3 Gas Cycling, 5.2 Reservoir Fluid Dynamics, 5.1 Reservoir Characterisation, 5.2.2 Fluid Modeling, Equations of State, 5.8.8 Gas-condensate reservoirs, 2.2.2 Perforating, 4.2 Pipelines, Flowlines and Risers, 5.2.1 Phase Behavior and PVT Measurements, 4.6 Natural Gas, 5.8.6 Naturally Fractured Reservoir
- 0 in the last 30 days
- 940 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 35.00|
A multimechanistic flow environment is the result of the combined action of a Darcian flow component (the macroscopic flow of the phase caused by pressure gradients) and a Fickian-like or diffusive flow component (diffusive flow caused by molecular concentration gradients) taking place in a hydrocarbon reservoir. The present work presents the framework needed for the assessment of the impact of multimechanistic flow on systems where complex fluid behavior—such as that of retrograde gas-condensate fluids—requires the implementation of compositional reservoir simulators. Because of the complex fluid behavior nature of gas-condensate fluids, a fully-implicit (IMPISC-type) compositional model is implemented and the model is used for the study of the isothermal depletion of naturally fractured retrograde gas reservoirs. In these systems, especially those tight systems with very low permeability (k < 0.1 md), bulk fluid flow as predicted by Darcy's law might not take place despite the presence of large pressure gradients. The use of an effective diffusion coefficient in the gas phase—which accounts for the combined effect of the different diffusion mechanisms that could take place in a porous medium—and its relative contribution to fluid recovery is discussed. The compositional tracking capabilities of the model are tested, and the conditions where Fickian flow can be the major player in recovery predictions and considerably overcome the flow impairment to gas flow posed by the eventual appearance of a condensate barrier—typical of gas-condensate systems—are investigated. Finally, a mapping that defines different domains where multimechanistic flow can be expected in compositional simulators of retrograde gas-condensate reservoirs is presented.
In typical natural-gas reservoirs, all hydrocarbons exist as a single free gas phase at conditions of discovery. Depending on the composition of the initial hydrocarbon mixture in place and their depletion behavior, we recognize up to three kinds of natural gas reservoirs: dry gas reservoirs, wet gas reservoirs, and retrograde gas or gas-condensate reservoirs. The latter is the richest in terms of heavy hydrocarbons, and thus it is very likely to develop a second heavier hydrocarbon phase (liquid condensate) upon isothermal depletion. This situation is illustrated by Fig. 1. In contrast, dry gases and wet gases do not undergo phase changes upon reservoir depletion, as their phase envelope's cricondentherms are found to the left of the reservoir temperature isotherm.
|File Size||1 MB||Number of Pages||8|
Ayala, L.F. 2004. Compositional Modeling of Naturally-FracturedGas-Condensate Reservoirs in Multi-Mechanistic Flow Domains. PhD dissertation.Penn State U., University Park, Pennsylvania.
Ayala, L.F., Ertekin, T., and Adewumi, M.A. 2004. Analysis of Recovery Mechanisms forNaturally Fractured Gas-Condensate Reservoirs. SPE paper 90010 presented atthe SPE Annual Technical Conference and Exhibition, Houston, 26-29 September.DOI: http://dx.doi.org/10.2118/90010-MS.
Coats, K.H. 1999. A Note onIMPES and Some IMPES-Based Simulation Models. SPE paper 49774 prepared forpresentation at the SPE Reservoir Simulation Symposium, Houston, 14-17February. DOI: http://dx.doi.org/10.2118/49774-MS.
Craft, B.C., Hawkins, M., and Terry, R.E. 1990. Applied PetroleumReservoir Engineering. Second edition. Englewood Cliffs, New Jersey:Prentice Hall PTR.
Cussler, E.L. 1976. Multicomponent Diffusion. Chemical EngineeringMonograph 3. Amsterdam: Elsevier Scientific Publishing Co.
Cussler, E.L. 2001. Diffusion: Mass Transfer in Fluid Systems. Secondedition. Third reprint. New York: Cambridge U. Press.
da Silva, F.V. and Belery, P. 1989. Molecular Diffusion in NaturallyFractured Reservoirs: A Decisive Recovery Mechanism. SPE paper 19672presented at the SPE Annual Technical Conference and Exhibition, San Antonio,Texas. DOI: http://dx.doi.org/10.2118/19672-MS.
Ertekin, T., King, G., and Schwerer, F. 1986. Dynamic Gas Slippage: A UniqueDual-Mechanism Approach to the Flow of Gas in Tight Formations.SPEFE 1 (1): 43-52; Trans., AIME, 281.SPE-12045-PA. DOI: http://dx.doi.org/10.2118/12045-PA.
Ghorayeb, K. and Firoozabadi, A. 2000. Modeling Multicomponent Diffusion andConvection in Porous Media. SPEJ 5 (2): 158-171.SPE-62168-PA. DOI: http://dx.doi.org/10.2118/62168-PA.
Katz, D., Cornell, D., Kobayaski, R., Poettman, F.H., Vary, J.A., Elenbaas,J.R., and Weinaug, C.F. 1959. Handbook of Natural Gas Engineering. York,Pennsylvania: McGraw-Hill.
Kenyon, D. and Behie, G.A. 1987 Third SPE Comparative Project: GasCycling of Retrograde Condensate Reservoirs. JPT 39 (8):981-997. SPE-12278-PA. DOI: http://dx.doi.org/10.2118/12278-PA.
Landmark Graphics Corporation. 2002. Introduction to DESKTOP-VIP,User's Manual.
Peaceman, D.W. 1976. Convectionin Fractured Reservoirs—The Effect of Matrix-Fissure Transfer on theInstability of a Density Inversion in a Vertical Fracture. SPEJ16 (5): 269-280; Trans., AIME, 261. SPE-5523-PA. DOI:http://dx.doi.org/10.2118/5523-PA.
Peng, D.Y. and Robinson, D.B. 1976. A New Two-Constant Equation of State.Ind. Eng. Chem. Fund. 15 (1): 59-64. DOI: http://dx.doi.org/10.1021/i160057a011.
Perkins, T.K. and Johnston, O.C. 1963. A Review of Diffusion and Dispersion inPorous Media. SPEJ 3 (1): 70-84; Trans., AIME,228. SPE-480-PA. DOI: http://dx.doi.org/10.2118/480-PA.
Saidi, Ali M. 1987. Reservoir Engineering of Fractured Reservoirs:Fundamental and Practical Aspects. Singapore: TOTAL Edition Press, GeneralPrinting and Publishing Services.
Sigmund, P. M. 1976. Prediction of Molecular Diffusion at ReservoirConditions. Part I—Measurement and Prediction of Binary Dense Gas DiffusionCoefficients. Journal of Canadian Petroleum Technology (2): 48-57.
Smith, D.M. and Williams, F.L. 1984. Diffusional Effects in the Recoveryof Methane From Coalbeds. SPEJ 24 (5): 529-535. SPE-10821-PA.DOI: http://dx.doi.org/10.2118/10821-PA.
Van-Golf-Racht, T.D. 1982. Fundamentals of Fractured ReservoirEngineering. Developments in Petroleum Science. Vol. 12. New York:Elsevier.
Warren, J.E. and Root, P.J. 1963. The Behavior of Naturally FracturedReservoirs. SPEJ 3 (1): 245-255; Trans., AIME,228. SPE-426-PA. DOI: http://dx.doi.org/10.2118/426-PA.
Watts, J.W. 1986. ACompositional Formulation of the Pressure and Saturation Equations.SPERE 1 (3): 243-252; Trans., AIME, 281. May 1986.SPE-12244-PA. DOI: http://dx.doi.org/10.2118/12244-PA.
Webb, S. and Pruess, K. 2003. The Use of Fick's Law for Modeling Trace GasDiffusion in Porous Media. Transport in Porous Media 51 (3):327-341. DOI: http://dx.doi.org/10.1023/A:1022379016613.
Yamamoto, R.H., Padgett, J.B., Ford, W.T., and Boubeguira, A. 1971. Compositional Reservoir Simulator forFissured Systems—The Single-Block Model. SPEJ 11 (2):113-128. SPE-2666-PA. DOI: http://dx.doi.org/10.2118/2666-PA.
Young, L.C. and Stephenson, R.E. 1983. A Generalized Compositional Approachfor Reservoir Simulation. SPEJ 23 (5): 727-742. SPE-10516-PA.DOI: http://dx.doi.org/10.2118/10516-PA.