Estimating Productivity-Controlling Parameters in Gas/Condensate Wells From Transient Pressure Data
- Manijeh Bozorgzadeh (Imperial College) | Alain C. Gringarten (Imperial College)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- April 2007
- Document Type
- Journal Paper
- 100 - 111
- 2007. Society of Petroleum Engineers
- 5.1 Reservoir Characterisation, 5.2.1 Phase Behavior and PVT Measurements, 5.6.4 Drillstem/Well Testing, 2.2.2 Perforating, 3.3 Well & Reservoir Surveillance and Monitoring, 7.5.3 Professional Registration/Cetification, 5.3.2 Multiphase Flow, 4.6 Natural Gas, 5.8.8 Gas-condensate reservoirs, 5.5 Reservoir Simulation
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The ability to predict well deliverability is a key issue for the development of gas/condensate reservoirs. We show in this paper that well deliverability depends mainly on the gas relative permeabilities at both the endpoint and the near-wellbore saturations, as well as on the reservoir permeability. We then demonstrate how these parameters and the base capillary number can be obtained from pressure-buildup data by using single-phase and two-phase pseudopressures simultaneously. These parameters can in turn be used to estimate gas relative permeability curves. Finally, we illustrate this approach with both simulated pressure-buildup data and an actual field case.
Introduction and Background
In gas/condensate reservoirs, a condensate bank forms around the wellbore when the bottomhole pressure (BHP) falls below the dewpoint pressure. This creates three different saturation zones around the well. Close to the wellbore, high condensate saturation reduces the effective permeability to gas, resulting in severe well productivity decline (Kniazeff and Nvaille 1965; Afidick et al. 1994; Lee and Chaverra 1998; Jutila et al. 2001; Briones et al. 2002). This decline is reduced at high gas rates and/or low capillary forces, which lower condensate saturation in the immediate vicinity of the wellbore, resulting in a corresponding increase in the gas relative permeability. This is called the capillary-number effect, positive coupling, viscous stripping, or velocity stripping (Boom et al. 1995; Henderson et al. 1998, 2000a; Ali et al. 1997a; Blom et al. 1997). High gas rates, on the other hand, induce inertia (also referred to as turbulent or non-Darcy flow effects), which reduces productivity. Well productivity is thus a balance between capillary number and inertia effects (Boom et al. 1995; Henderson et al. 1998, 2000a; Ali et al. 1997a, 1997b; Blom et al. 1997; Mott et al. 2000.).
Well-deliverability forecasts for gas/condensate wells are usually performed with the help of numerical compositional simulators. Compositional simulation requires fine gridding to model the formation of the condensate bank with the required accuracy (Ali et al. 1997a). Non-Darcy flow and capillary-number effects (Mott 2003)are accounted for through empirical correlations, which require inputs such as the base capillary number (i.e., the minimum value required to see capillary-number effects), the reservoir absolute permeability, and the relative permeability curves. These are usually determined experimentally, but laboratory measurements at near-wellbore conditions are very difficult and expensive to obtain. An alternative, as shown in this paper, is to obtain them from well-test data.
Well-test analysis is recognized as a valuable tool for reservoir surveillance and monitoring and provides estimates of a number of parameters required for reservoir characterization, reservoir simulation, and well-productivity forecasting. In gas/condensate reservoirs, when the BHP is below the dewpoint pressure, the effective permeability to gas in the near-wellbore region and at initial liquid saturation can be estimated with single-phase pseudopressures (Al-Hussainy et al. 1966) and a two- or three-region radial composite well-test-interpretation model (Chu and Shank 1993; Gringarten et al. 2000; Daungkaew et al. 2002), whereas the reservoir absolute permeability may be determined with two-phase steady-state pseudopressures (Raghavan et al. 1999; Xu and Lee 1999). In this paper, we show that well-test analysis can provide additional parameters, such as the gas relative permeabilities at both the endpoint and the near-wellbore saturations and the base capillary number. These in turn can be used to generate estimated relative permeability curves for gas.
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Afidick, D., Kaczorowski, N.J., andBette, S. 1994. ProductionPerformance of a Retrograde Gas Reservoir: A Case Study of the Arun Field.Paper SPE 28749 presented at the SPE Asia Pacific Oil and Gas Conference,Melbourne, Australia, 7-10 November. DOI: 10.2118/28749-MS.
Al-Hussainy, R., Ramey, H.J. Jr., andCrawford, P.B. 1966. The Flow ofReal Gases Through Porous Media. JPT 18 (5): 624-636;Trans., AIME, 237. SPE-1243-A. DOI: 10.2118/1243-A.
Ali, J.K., McGauley, P.J., and Wilson,C.J. 1997a. The Effects ofHigh-Velocity Flow and PVT Changes Near the Wellbore on Condensate WellPerformance. Paper SPE 38923 presented at the SPE Annual TechnicalConference and Exhibition, San Antonio, Texas, 5-8 October. DOI:10.2118/38923-MS.
Ali, J.K., McGauley, P.J., and WilsonC.J. 1997b. Experimental Studiesand Modeling of Gas Condensate Flow Near the Wellbore. Paper SPE 39053presented at the Latin American and Caribbean Petroleum Engineering Conference,Rio de Janeiro, 30 August-3 September. DOI: 10.2118/39053-MS.
Al-Khalifah, A.-J. A., Horne, R.N., andAziz, K. 1987. In-PlaceDetermination of Reservoir Permeability Using Well Test Analysis. Paper SPE16774 presented at the SPE Annual Technical Conference and Exhibition, Dallas,27-30 September. DOI: 10.2118/16774-MS.
Asar, H. and Handy, L.L. 1988. Influence of Interfacial Tension onGas/Oil Relative Permeability in a Gas Condensate System. SPERE3 (1): 257-264. SPE-11740-PA. DOI: 10.2118/11740-PA.
Bardon, C. and Longeron, D.G. 1980. Influence of Very Low InterfacialTensions on Relative Permeability. SPEJ 20 (5): 391-401.SPE-7609-PA. DOI: 10.2118/7609-PA.
Blom, S.M.P., Hagoort, J., and Soetekouw,D.P.N. 1997. Relative permeabilityat Near-Critical Conditions. Paper SPE 38935 presented at the SPE AnnualTechnical Conference and Exhibition, San Antonio, Texas, 5-8 October. DOI:10.2118/38935-MS.
Bøe, A., Skjaeveland, S.M., and Whitson,C.H. 1989. Two-Phase Pressure TestAnalysis. SPEFE 4(4): 604-610; Trans., AIME,287. SPE-10224-PA. DOI: 10.2118/10224-PA.
Boom, W., Wit, K., Schulte, A.M., Oedai,S., Zeelenberg, J.P.W., and Maas, J.G. 1995. Experimental Evidence for ImprovedCondensate Mobility at Near-Wellbore Flow Condition. Paper SPE 30766presented at the SPE Annual Technical Conference and Exhibition, Dallas, 22-25October. DOI: 10.2118/30766-MS.
Bozorgzadeh, M. and Gringarten, A.C.2006. Condensate-BankCharacterization From Well-Test Data and Fluid PVT Properties.SPEREE 9 (5): 596-611. SPE-89904-PA. DOI:10.2118/89904-PA.
Briones, M., Zambrano, J.A., and Zerpa,C. 2002. Study of Gas-CondensateWell Productivity in Santa Barbara Field, Venezuela, by Well Test Analysis.Paper SPE 77538 presented at the SPE Annual Technical Conference andExhibition, San Antonio, Texas, 29 September-2 October. DOI:10.2118/77538-MS.
Chen, H.L., Wilson, S.D., andMonger-McClure, T.G. 1999. Determination of RelativePermeability and Recovery for North Sea Gas-Condensate Reservoirs.SPEREE 2 (4): 393-402. SPE-57596-PA. DOI:10.2118/57596-PA.
Chu, W.C. and Shank, G.D. 1993. A New Model for a Fractured Well in aRadial Composite Reservoir. SPEFE 8 (3): 225-232.SPE-20579-PA. DOI: 10.2118/20579-PA.
Daungkaew, S. 2002. New Development inWell Test Analysis. PhD thesis, Centre for Petroleum Studies, Imperial College,London (October).
Daungkaew, S., Ross, F., and Gringarten,A.C. 2002. Well Test Investigation of Condensate Drop-Out Behaviour in a NorthSea Lean Gas Condensate Reservoir. paper SPE 77548 presented at the SPE AnnualTechnical Conference and Exhibition, San Antonio, Texas, 29 September-2October.
ECLIPSE 300. 2003. Schlumberger Geoquest,Version 2003a.
Fevang, Ø. and Whitson, C.H. 1996. Modeling Gas Condensate WellDeliverability. SPERE 11 (4): 221-230. SPE-30714-PA. DOI:10.2118/30714-PA.
Fussell, D.D. 1973. Single-Well Performance Predictionsfor Gas Condensate Reservoirs. JPT 25 (7): 860-870.SPE-4072-PA. DOI: 10.2118/4072-PA.
Geertsma, J. 1974. Estimating the Coefficient of InertialResistance in Fluid Flow Through Porous Media. SPEJ 14 (5):445-450. SPE-4706-PA. DOI: 10.2118/4706-PA.
Gringarten, A.C., Al-Lamki, A.,Daungkaew, S., Mott, R., and Whittle, T.M. 2000. Well Test Analysis in Gas-CondensateReservoirs. Paper SPE 62920 presented at the SPE Annual TechnicalConference and Exhibition, Dallas, 1-4 October. DOI:10.2118/62920-MS.
Haniff, M.S. and Ali, J.K. 1990. Relative Permeability and Low TensionFluid Flow in Gas Condensate Systems. Paper SPE 20917 presented at the SPEEuropean Petroleum Conference, The Hague, 21-24 October. DOI:10.2118/20917-MS.
Hatzignatiou, D.G. and Reynolds, A.C.1996. Determination of Effectiveor Relative Permeability Curves From Well Tests. SPEJ 1 (1):69-82. SPE-20537-PA. DOI: 10.2118/20537-PA.
Henderson, G.D., Danesh, A., Tehrani,D.H., Al-Shaidi, S., and Peden, J.M. 1998. Measurement and Correlation of GasCondensate Relative Permeability by the Steady-State Method. SPEREE1 (2): 134-140. SPE-30770-PA. DOI: 10.2118/30770-PA.
Henderson, G.D., Danesh, A., Tehrani,D.H., and Al-Kharusi, B. 2000a. The Relative Significance of PositiveCoupling and Inertial Effects on Gas Condensate Relative Permeabilities at HighVelocity. Paper SPE 62933 presented at the SPE Annual Technical Conferenceand Exhibition, Dallas, 1-4 October. DOI: 10.2118/62933-MS.
Henderson, G.D., Danesh, A., Tehrani,D.H., and Al-Kharusi, B. 2000b. Generating Reliable Gas Condensate RelativePermeability Data Used to Develop a Correlation with Capillary Number. J.Pet. Sci. & Eng. 25: 79-91. DOI: http://dx.doi.org/10.1016/S0920-4105(00)00004-8.
Jones, J.R. and Raghavan, R. 1988. Interpretation of Flowing WellResponse in Gas-Condensate Wells. SPEFE 3 (3): 578-594.SPE-14204-PA. DOI: 10.2118/14204-PA.
Jutila, H.A, Logmo-Ngog, A.B., Sarkar,R., Killough, J.E., and Ross, F.C. 2001. Use of Parallel CompositionalSimulation To Investigate Productivity Improvement Options for aRetrograde-Gas-Condensate Field: A Case Study. Paper SPE 66397 presented atthe SPE Reservoir Simulation Symposium, Houston, 11-14 February. DOI:10.2118/66397-MS.
Kniazeff, V.J., and Nvaille, S.A. 1965.Two-Phase Flow of VolatileHydrocarbons. SPEJ 5 (1): 37-44; Trans., AIME,234. SPE-962-PA. DOI: 10.2118/962-PA.
Lee, S.-T. and Chaverra, M. 1998. Modeling and Interpretation ofCondensate Banking for the Near Critical Cupiagua Field. Paper SPE 49265prepared for presentation at the SPE Annual Technical Conference andExhibition, New Orleans, 27-30 September. DOI: 10.2118/49265-MS.
Liu, J.S., Wilkins, J.R., Al-Qahtani,M.Y., and Al-Awami, A.A. 2001. Modeling a Rich Gas CondensateReservoir With Composition Grading and Faults. Paper SPE 68178 presented atthe SPE Middle East Oil Show, Bahrain, 17-20 March. DOI:10.2118/68178-MS.
Meunier, D.F., Kabir, C.S., and Wittmann,M.J. 1987. Gas Well Test Analysis:Use of Normalized Pressure and Time Functions. SPEFE 1 (4):629-636. SPE-13082-PA. DOI: 10.2118/13082-PA.
Mott, R. 2003. Engineering Calculations ofGas-Condensate-Well Productivity. SPEREE 6 (5): 298-306.SPE-86298-PA. DOI: 10.2118/86298-PA.
Mott, R., Cable, A., and Spearing, M.2000. Measurements and Simulationof Inertial and High Capillary Number Flow Phenomena in Gas-Condensate RelativePermeability. Paper SPE 62932 presented at the SPE Annual TechnicalConference and Exhibition, Dallas, 1-4 October. DOI:10.2118/62932-MS.
Munkerud, P.K. 1989. Measurement of Relative Permeabilityand Flow Properties of a Gas Condensate System During Pressure Depletion andPressure Maintenance. Paper SPE 19071 presented at the SPE Gas TechnologySymposium, Dallas, 7-9 June. DOI: 10.2118/19071-MS.
O'Dell, H.G. and Miller, R.N. 1967. Successfully Cycling aLow-Permeability, High-Yield Gas Condensate Reservoir. JPT 19(1): 41-47. SPE-1495-PA. DOI: 10.2118/1495-PA.
Raghavan, R. 1976. Well Test Analysis: Wells Producing bySolution Gas Drive. SPEJ 16 (4): 196-208; Trans.,AIME, 261. SPE-5588-PA. DOI: 10.2118/5588-PA.
Raghavan, R. 1989. Well Test Analysis for MultiphaseFlow. SPEFE 4 (4): 585-594. SPE-14098-PA. DOI:10.2118/14098-PA.
Raghavan, R., Chu, W.-C., and Jones, J.R.1999. Practical Considerations inthe Analysis of Gas-Condensate Well Tests. SPEREE 2 (3):288-295. SPE-56837-PA. DOI: 10.2118/56837-PA.
Serra, K.V., Peres, A.M.M., and Reynolds,A.C. 1990. Well-Test Analysis forSolution-Gas-Drive Reservoirs: Part 1—Determination of Relative and AbsolutePermeabilities. SPEFE 5 (2): 124-132. SPE-17020-PA. DOI:10.2118/17020-PA.
von Schroeter, T., Hollaender, F., andGringarten, A.C. 2004. Deconvolution of Well-Test Data as aNonlinear Total Least-Squares Problem. SPEJ 9(4): 375-390.SPE-77688-PA. DOI: 10.2118/77688-PA.
Whitson, C.H. and Torp, S.B. 1983. Evaluating Constant-Volume DepletionData. JPT 35 (3): 610-620. SPE-10067-PA. DOI:10.2118/10067-PA.
Xu, S. and Lee, W.J. 1999. Two-Phase Well Test Analysis of GasCondensate Reservoirs. Paper SPE 56483 presented at the SPE AnnualTechnical Conference and Exhibition, Houston, 3-6 October. DOI:10.2118/56483-MS.