Modeling Low-Salinity Waterflooding
- Authors
- Gary R. Jerauld (BP) | Kevin J. Webb (BP Exploration) | Cheng-Yuan Lin (BP plc) | James C. Seccombe (BP)
- DOI
- https://doi.org/10.2118/102239-PA
- Document ID
- SPE-102239-PA
- Publisher
- Society of Petroleum Engineers
- Source
- SPE Reservoir Evaluation & Engineering
- Volume
- 11
- Issue
- 06
- Publication Date
- December 2008
- Document Type
- Journal Paper
- Pages
- 1,000 - 1,012
- Language
- English
- ISSN
- 1094-6470
- Copyright
- 2008. Society of Petroleum Engineers
- Disciplines
- 5.3.1 Flow in Porous Media, 5.6.4 Drillstem/Well Testing, 2.2.2 Perforating, 5.1 Reservoir Characterisation, 1.8 Formation Damage, 5.2.1 Phase Behavior and PVT Measurements, 5.2 Reservoir Fluid Dynamics, 4.1.2 Separation and Treating, 5.5 Reservoir Simulation, 5.5.8 History Matching, 5.3.2 Multiphase Flow, 5.4.2 Gas Injection Methods, 5.4.7 Chemical Flooding Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex), 2.5.2 Fracturing Materials (Fluids, Proppant), 4.1.5 Processing Equipment, 5.6.5 Tracers, 4.3.4 Scale, 5.4.1 Waterflooding, 6.5.2 Water use, produced water discharge and disposal, 1.6.9 Coring, Fishing, 5.8.7 Carbonate Reservoir, 5.3.4 Reduction of Residual Oil Saturation
- Downloads
- 12 in the last 30 days
- 4,053 since 2007
- Show more detail
- View rights & permissions
| SPE Member Price: | USD 12.00 |
| SPE Non-Member Price: | USD 35.00 |
Summary
Low-salinity waterflooding is an emerging enhanced-oil-recovery (EOR) technique in which the salinity of the injected water is controlled to improve oil recovery vs. conventional, higher-salinity waterflooding. Corefloods and single-well chemical-tracer tests have shown that low-salinity waterflooding can improve basic waterflood performance by 5 to 38%. This paper describes a model of low-salinity flooding that can be used to evaluate projects; shows the implications of that model and demonstrates its use to represent corefloods, single-well tests, and field-scale simulations; and gives insight into the reservoir engineering of low-salinity floods.
The model represents low-salinity flooding using salinity-dependent oil/water relative permeability functions resulting from wettability change. This is similar to other EOR modeling, and conventional fractional-flow theory can be adapted to describe the process in 1D for secondary and tertiary low-salinity waterflooding. This simple analysis shows that while some degree of connate-water banking occurs, it need not hinder the process.
Mixing of injected water with in-situ water delays the attainment of low salinity, potentially preventing attainment of low salinity all together if very small slugs of low-salinity water are used. This paper demonstrates the importance of mixing to modeling of low-salinity flooding and suggests addressing it in engineering calculations. Care must be taken in representing mixing appropriately in interpreting data and in constructing models. The use of numerical dispersion to represent physical dispersion in 1D, radial, and pattern simulations of this process is demonstrated (i.e., coarse-grid simulations are shown to give the same result as fine-grid simulations with an appropriately large physical dispersion). In many applications, the fine-grid simulation necessary to represent appropriate levels of dispersion is not practical, and pseudoization is necessary. We demonstrate that this can be achieved by changing the salinity dependence and shapes of relative permeability curves.
Introduction
Waterflooding is widely used to improve recovery from oil reservoirs but, except to avoid formation damage, is largely designed without regard to the composition of the brine injected. Yildiz and Morrow (1996) showed that changes in injection-brine composition can improve recovery, thereby introducing the idea that the composition of the brine could be varied to optimize waterflood recovery. Tang and Morrow (1997) (Tang and Morrow 1999; Morrow et al. 1998; McGuire et al. 2005) built on this idea by demonstrating the benefit lowering brine salinity has on oil recovery. There has been a substantial amount of research on low-salinity injection, which has included more than 20 reservoir-conditions corefloods on a range of sandstone reservoirs both in secondary and tertiary mode, more than 10 single-well chemical-tracer tests (SWCTTs), and a log/inject/log test (McGuire et al. 2005;Webb et al. 2004; Webb et al. 2005; Lager et al. 2006). These tests have shown improvements of waterflood-process efficiency by 5 to 38% by using low-salinity water or by corresponding reductions in residual-oil saturation of 3 to 17% pore volumes (PV). The purpose of this work is to present a simple extension to waterflood simulators that can be used to translate corefloods or SWCTTs into field-scale estimates of low-salinity waterflood (LSWF) oil recovery and demonstate this with examples from a sandstone reservoir.
| File Size | 4 MB | Number of Pages | 13 |
References
Appelo, C.A. 1994. Cation andproton exchange, pH variations, and carbonate reactions in a fresheningaquifer. Water Resources Research 30 (10): 2793-2805.DOI:10.1029/94WR01048.
Arya, A., Hewett, T.A., Larson, R.G., and Lake, L.W. 1988. Dispersion and ReservoirHeterogeneity. SPERE 3 (1): 139-148. SPE-14364-PA. DOI:10.2118/14364-PA.
Brown, W.O. 1957. The Mobility ofConnate Water During a Water Flood. Trans., AIME, 210:190-195.
Coats, K.H. and Smith, B.D. 1964. Dead-End Pore Volume and Dispersion inPorous Media. SPEJ 4 (1): 73-84; Trans., AIME,231. SPE-647-PA. DOI: 10.2118/647-PA.
Element, D.J., Goodyear, S.G., Sargent, N.C., and Jayasekera, A.J. 2001.Comparison of polymer and waterflood residual oil saturations. Presented at the11th European Symposium on Improved Oil Recovery, Amsterdam, 11-12 June.
Fassi-Fihri, O., Robin, M., and Rosenberg, E. 1995. Wettability Studies at thePore-Level: A New Approach by Use of Cryo-SEM. SPEFE 10 (1):11-19. SPE-22596-PA. DOI: 10.2118/22596-PA.
Graue, A., Moe, R.W., and Bognø, T. 2000. Oil Recovery in FracturedReservoirs, http://www.ift.uib.no/SAFT/reservoarfysikk/Filer/PDFfiler/Nordisk2001 graue moebogno.pdf.
Jerauld, G.R. and Rathmell, J.J. 1997. Wettability and Relative Permeabilityof Prudhoe Bay: A Case Study In Mixed-Wet Reservoirs. SPERE12 (1): 58-65. SPE-28576-PA. DOI: 10.2118/28576-PA.
Jones, S.C. 1985. SomeSurprises in the Transport of Miscible Fluids in the Presence of a SecondImmiscible Phase. SPEJ 25 (1): 101-112. SPE-12125-PA. DOI:10.2118/12125-PA.
Kelly, D.L. and Caudle, B.H. 1966. The Effect of Connate Water on theEfficiency of High-Viscosity Waterfloods. JPT 18 (11):1481-1486; Trans., AIME, 99. SPE-1615-PA. DOI:10.2118/1615-PA.
Kralik, J.G., Manak, L.J., Jerauld, G.R., and Spence, A.P. 2000. Effect of Trapped Gas on RelativePermeability and Residual Oil Saturation in an Oil-Wet Sandstone. Paper SPE62997 presented at the SPE Annual Technical Conference and Exhibition, Dallas,1-4 October. DOI: 10.2118/62997-MS.
Lager, A., Webb, K.J., Black, C.J.J., Singleton, M., and Sorbie, K.S. 2006.Low salinity oil recovery--An experimental investigation. Presented at theInternational Symposium of Core Analysts, Trondheim, Norway.
Lake, L.W. 1989. Enhanced Oil Recovery, 175-181. London:Prentice-Hall.
Lake, L.W. and Helfferich, F.G. 1978. Cation Exchange in Chemical Flooding:Part 2--The Effect of Dispersion, Cation Exchange, and Polymer/SurfactantAdsorption on Chemical Flood Environment. SPEJ 18 (6):435-444. SPE-6769-PA. DOI: 10.2118/6769-PA.
Lantz, R.B. 1971. QuantitativeEvaluation of Numerical Diffusion (Truncation Error). SPEJ 11(3): 315-320; Trans., AIME, 251. SPE-2811-PA. DOI:10.2118/2811-PA.
Mahadevan, J., Lake, L.W., and Johns, R.T. 2003. Estimation of True Dispersivity inField-Scale Permeable Media. SPEJ 8 (3): 272-279.SPE-86303-PA. DOI: 10.2118/86303-PA.
McGuire, P.L., Chatam, J.R., Paskvan, F.K., Sommer, D.M., and Carini, F.H.2005. Low Salinity Oil Recovery:An Exciting New EOR Opportunity for Alaska's North Slope. Paper SPE 93903presented at the SPE Western Regional Meeting, Irvine, California, USA, 30March-1 April. DOI: 10.2118/93903-MS.
McGuire, P.L., Spence, A.P., and Redman, R.S. 2000. Performance Evaluation of a MatureMiscible Gas Flood at Prudhoe Bay. Paper SPE 59326 presented at the SPE/DOEImproved Oil Recovery Symposium, Tulsa, 3-5 April. DOI: 10.2118/59326-MS.
McGuire, P.L., Spence, A.P., Stalkup, F.I., and Cooley, M.W. 1995. Core Acquisition and Analysis forOptimization of the Prudhoe Bay Miscible-Gas Project. SPERE10 (2): 94-100. SPE-27759-PA. DOI: 10.2118/27759-PA.
Morrow, N.R., Tang, G-Q., Valat, M., and Xie, X. 1998. Prospects of improvedoil recovery related to wettability and brine composition. J. Pet. Sci.Eng. 20 (3-4): 267-276. DOI: 10.1016/S0920-4105(98)00030-8.
Moulds, T.P., McGuire, P.L., Jerauld, G.R., Lee, S.-T., and Solano, R. 2005.Pt. McIntyre: A Case Study of GasEnrichment Above MME. SPEREE 8 (3): 182-188. SPE 84185presented at the SPE Annual Technical Meeting and Exhibition, Denver, 5-8October. DOI: 10.2118/84185-PA.
Nicholls, C.I. and Heaviside, J. 1988. Gamma-Ray-Absorption TechniquesImprove Analysis of Core Displacement Tests. SPEFE 3 (1):69-75; Trans., AIME, 285. SPE-14421-PA. DOI:10.2118/14421-PA.
Nielsen, C.M., Olsen, D., and Bech, N. 2000. Imbibition Processes in FracturedChalk Core Plugs With Connate Water Mobilization. Paper SPE 63226 presentedat the SPE Annual Technical Conference and Exhibition, Dallas, 1-4 October.DOI: 10.2118/63226-MS.
Osterloh, W.T. and. Law, E.J. 1998. Polymer Transport and RheologicalProperties for Polymer Flooding in the North Sea Captain Field. Paper SPE39694 presented at the SPE\DOE Improved Oil Recovery Symposium, Tulsa, 19-22April. DOI: 10.2118/39694-MS.
Ovens, J.E.V., Larsen, F.P., and Cowie, D.R. 1998. Making Sense of Water InjectionFractures in the Dan Field. SPEREE 1 (6): 556-566.SPE-52669-PA. DOI: 10.2118/52669-PA.
Pickens, J.F. and Grisak, G.E. 1981. Scale-dependent dispersion in astratified granular aquifer. Water Resources Research 28:10310-10317.
Pope, G.A. 1980. The Applicationof Fractional Flow Theory to Enhanced Oil Recovery. SPEJ 20(3): 191-205. SPE-7660-PA. DOI: 10.2118/7660-PA.
Pope, G.A., Lake, L.W., and Helfferich, F.G. 1978. Cation Exchange in Chemical Flooding:Part 1--Basic Theory Without Dispersion. SPEJ 18 (6):418-434. SPE-6771-PA. DOI: 10.2118/6771-PA.
Rueslåtten, H., Øren, P-E., Robin, M., and Rosenberg, E. 1994. A Combined Use of CRYO-SEM andNMR-Spectroscopy for Studying the Distribution of Oil and Brine inSandstones. Paper SPE 27804 presented at the SPE/DOE Improved Oil RecoverySymposium, Tulsa, 17-20 April. DOI: 10.2118/27804-MS.
Russel, R.G., Morgan, F., and Muskat, M. 1947. Some Experiments on the Mobility ofInterstitial Waters. Trans., AIME, 170: 51-61.
Salter, S.J. and Mohanty, K.K. 1982. Multiphase Flow in Porous Media: I.Macroscopic Observations and Modelling. Paper SPE 11017 presented at theSPE Annual Technical Conference and Exhibition, New Orleans, 26-29 September.DOI: 10.2118/11017-MS.
Sharma, M.M. and Filoco, P.R. 2000. Effect of Brine Salinity andCrude-Oil Properties on Oil Recovery and Residual Saturations. SPEJ5 (3): 293-300. SPE-65402-PA. DOI: 10.2118/65402-PA.
Sincock, K.J. and Black, C.J.J. 1988. Validation of Water/Oil DisplacementScaling Criteria Using Microvisualization Techniques. Paper SPE 18294presented at the SPE Annual Technical Conference and Exhibition, Houston, 2-5October. DOI: 10.2118/18294-MS.
Sorbie, K.S. 1991. Polymer-Improved Oil Recovery. Boca Raton,Florida: CRC Press.
Sorbie, K.S. and Walker, D.J. 1988. A Study of the Mechanism of OilDisplacement Using Water and Polymer in Stratified Laboratory Core Systems.Paper SPE 17397 presented at the SPE Enhanced Oil Recovery Symposium, Tulsa,16-21 April. DOI: 10.2118/17397-MS.
Sorbie, K.S., Wat, R.M.S., and Rowe, T.C. 1987. Oil Displacement Experiments inHeterogeneous Cores: Analysis of Recovery Mechanisms. Paper SPE 16706presented at the SPE Annual Technical Conference and Exhibition, Dallas, 27-30September. DOI: 10.2118/16706-MS.
Strange, L.K. and Cloud, W.B. 1976. Displacement of Reservoir Brine byFresh Water--Four Field Case Histories. Paper SPE 5834 presented at the SPEImproved Oil Recovery Symposium, Tulsa, 22-24 March. DOI: 10.2118/5834-MS.
Sutanto, E., Davis, H.T. and Scriven, L.E. 1990. Liquid Distributions in Porous RockExamined by Cryo Scanning Electron Microscopy. Paper SPE 20518 presented atthe SPE Annual Technical Conference and Exhibition, New Orleans, 23-26September. DOI: 10.2118/20518-MS.
Tang, G-Q. and Morrow, N.R. 1997. Salinity, Temperature, OilComposition, and Oil Recovery by Waterflooding. SPERE 12 (4):269-276. SPE-36680-PA. DOI: 10.2118/36680-PA.
Tang, G-Q. and Morrow, N.R. 1999. Influence of brinecomposition and fines migration on crude oil/brine/rock interactions and oilrecovery. J. Pet. Sci. Eng. 24 (2-4): 99-111. DOI:10.1016/S0920-4105(99)00034-0.
Wang, F.H.L. 1988. Effect ofWettability Alteration on Water/Oil Relative Permeability, Dispersion, andFlowable Saturation in Porous Media. SPERE 3 (2): 617-628.SPE-15019-PA. DOI: 10.2118/15019-PA.
Webb, K.J., Black, C.J.J., and Al-Ajeel, H. 2004. Low Salinity OilRecovery--Log-Inject-Log. Paper SPE 89379 presented at the SPE/DOESymposium on Improved Oil Recovery, Tulsa, 17-21 April. DOI:10.2118/89379-MS.
Webb, K.J., Black, C.J.J., and Edmonds, I.J. 2005. Low salinity oilrecovery: The role of reservoir condition corefloods. Paper C18 presented atthe 13th EAGE Symposium on Improved Oil Recovery, Budapest, Hungary, 25-27April.
Yildiz, H.O. and Morrow, N.R. 1996. Effect of brinecomposition on recovery of Moutray crude oil by waterflooding. J. Pet.Sci. Eng. 14 (3-4): 159-168. DOI:10.1016/0920-4105(95)00041-0.
