Oil Recovery From Fractured Carbonates by Surfactant-Aided Gravity Drainage: Laboratory Experiments and Mechanistic Simulations
- Bhargaw Adibhatla (ExxonMobil Corp.) | Kishore K. Mohanty (U. of Houston)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- February 2008
- Document Type
- Journal Paper
- 119 - 130
- 2008. Society of Petroleum Engineers
- 5.4.1 Waterflooding, 5.8.7 Carbonate Reservoir, 5.1.1 Exploration, Development, Structural Geology, 5.4.7 Chemical Flooding Methods (e.g., Polymer, Solvent, Nitrogen, Immiscible CO2, Surfactant, Vapex), 5.8.6 Naturally Fractured Reservoir, 2.5.2 Fracturing Materials (Fluids, Proppant), 5.7.2 Recovery Factors, 4.1.2 Separation and Treating, 1.6.9 Coring, Fishing, 5.2.1 Phase Behavior and PVT Measurements, 4.1.5 Processing Equipment, 4.3.4 Scale, 1.8.5 Phase Trapping
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Waterflooding recovers little oil from naturally fractured carbonate reservoirs if the matrix is oil-wet and fracture intensity is high. Laboratory experiments and mechanistic simulations have been conducted to understand the injection of dilute anionic surfactant solutions into oil-wet, fractured reservoirs. In this process, surfactant diffuses into the matrix, lowering the interfacial tension (IFT) and contact angle, which decreases the capillary pressure and increases oil relative permeability, enabling gravity to drain up the oil. The rate of oil recovery increases with an increase in matrix permeability, a decrease in initial gas saturation, a decrease of fracture height or spacing, and an increase in the wettability-altering capabilities of the surfactant. Increasing the surfactant concentration does not necessarily enhance the oil recovery rate, because IFT and wettability alterations are not linearly related to surfactant concentration. Adsorption of anionic surfactants on calcite can be suppressed with an increase in pH and a decrease in salinity.
Approximately 60% of the world's oil is found in carbonate reservoirs (Akbar et al. 2000). Recovery from reservoirs depends on reservoir heterogeneity, oil quality, drive mechanisms, and reservoir management. Many carbonate reservoirs are naturally fractured and oil-wet/mixed-wet (Roehl and Choquette 1985, Chillenger and Yen 1983). Such reservoirs are difficult to produce after the primary production if the fractures form a connected network (Allan and Sun 2003). Waterflooding is effective only if the formation is water-wet. Flooding processes do not work in general, because large, viscous gradients cannot be imposed. Gravity drainage (surfactant, gas, and thermal) techniques can be applied, but the recovery is slow. Surfactant-enhanced gravity drainage and imbibition processes are being developed (Yang and Wadleigh 2000; Austad and Milter 1997; Standnes and Austad 2000a, 2000b, 2003a, 2003b, 2003c; Xie et al. 2005; Seethepalli et al. 2004; Hirasaki and Zhang 2004) to improve oil recovery from oil-wet/mixed-wet, fractured carbonate formations and are the subject of this study.
Cationic surfactants of the type alkyl trimethyl ammonium bromide, CnTAB, are effective [recovery approximately 70% original oil in place (OOIP)] in imbibing water into originally oil-wet chalks at concentrations greater than their critical micellar concentration (approximately 1 wt%) (Austad and Milter 1997; Standnes and Austad 2000a, 2000b, 2003b). Cationic surfactants form ion pairs with adsorbed organic carboxylates of the crude oil, and solubilize them into the oil thereby changing the rock surface to be water-wet. This wettability alteration can lead to countercurrent imbibition of brine and, thus, to oil recovery. The IFT between the surfactant solution and oil are not low (> 0.1 dynes/cm). Several cheaper cationic surfactants of the form C10NH2 and bioderivatives from the coconut palm, termed Arquad and Dodigen (priced at 3 USD/kg), have been identified (Standnes and Austad 2003c, 2003a; Strand et al. 2003). The two key problems with this method are still the high concentration and the high surfactant cost.
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Adibhatla, B., Sun, X., and Mohanty, K.K. 2005. Numerical Studies of Oil ProductionFrom Initially Oil-Wet Fracture Blocks by Surfactant Brine Imbibition.Paper SPE 97687 presented at the SPE International Improved Oil RecoveryConference in Asia Pacific, Kuala Lumpur, 5-6 December. DOI:10.2118/97687-MS.
Akbar, M. , Vissapragada, B., Alghamdi, A.H., et al. 2000. A Snapshot ofCarbonate Reservoir Evaluation. Oilfield Review 12 (4):20-21.
Allan, J. and Sun, S.Q. 2003. Controls on Recovery Factor inFractured Reservoirs: Lessons Learned From 100 Fractured Fields. Paper SPE84590 presented at the SPE Annual Technical Conference and Exhibition, Denver,5-8 October. DOI: 10.2118/84590-MS.
Austad, T. and Milter, J. 1997. Spontaneous Imbibition of Water IntoLow Permeable Chalk at Different Wettabilities Using Surfactants. Paper SPE37236 presented at the SPE International Symposium on Oilfield Chemistry,Houston, 18-21 February. DOI: 10.2118/37236-MS.
Bragg, J.R. et al. 1982. LoudonSurfactant Flood Pilot Test. Paper SPE 10862 presented at the SPE EnhancedOil Recovery Symposium, Tulsa, 4-7 April. DOI: 10.2118/10862-MS.
Chillenger, G.V. and Yen, T.F. 1983. Some Notes on Wettability and RelativePermeability of Carbonate Rocks. II. Energy and Sources 7 (1):67-75.
Cuiec, L.E., Bourbiaux, B., and Kalaydjian, F. 1994. Oil Recovery by Imbibition inLow-Permeability Chalk. SPEFE 9 (3): 200-208. SPE-20259-PA.DOI: 10.2118/20259-PA.
Du Prey, L. and Lefebvre, E. 1978. Gravity and Capillary Effects onImbibition in Porous Media. SPEJ 18 (3): 195-206.SPE-6192-PA. DOI: 10.2118/6192-PA.
Falls, A.H. et al. 1994. FieldTest of Cosurfactant-Enhanced Alkaline Flooding. SPERE 9 (3):217-223. SPE-24117-PA. DOI: 10.2118/24117-PA.
Hagoort, J. 1980. Oil Recoveryby Gravity Drainage. SPEJ 20 (3): 139-150. SPE-7424-PA. DOI:10.2118/7424-PA.
Hirasaki, G. and Zhang, D.L. 2004. Surface Chemistry of Oil RecoveryFrom Fractured, Oil-Wet, Carbonate Formation. SPEJ 9 (2):151-162. SPE-88365-PA. DOI: 10.2118/88365-PA.
John, A., Han, C., Delshad, M., Pope, G.A., and Sepehrnoori, K. 2005. A New Generation Chemical-FloodingSimulator. SPEJ 10 (2): 206-216. SPE-89436-PA. DOI:10.2118/89436-PA.
Kalpakci, B. et al. 1990. TheLow-Tension Polymer Flood Approach to Cost-Effective Chemical EOR. PaperSPE 20220 presented at the SPE/DOE Enhanced Oil Recovery Symposium, Tulsa,22-25 April. DOI: 10.2118/20220-MS.
Krumrine, P.H., Falcone, J.S. Jr., and Campbell, T.C. 1982a. Surfactant Flooding 1: The Effect ofAlkaline Additives on IFT, Surfactant Adsorption, and Recovery Efficiency.SPEJ 22 (4): 503-513. SPE-8998-PA. DOI: 10.2118/8998-PA.
Krumrine, P.H, Falcone, J.S. Jr., and Campbell, T.C. 1982b. Surfactant Flooding 2: The Effect ofAlkaline Additives on Permeability and Sweep Efficiency. SPEJ22 (6): 983-992. SPE-9811-PA. DOI: 10.2118/9811-PA.
Li, K. and Horne, R.N. 2006. Generalized Scaling Approach forSpontaneous Imbibition: An Analytical Model. SPEREE 9 (3):251-258. SPE-77544-PA. DOI: 10.2118/77544-PA.
Ma, S., Zhang, X., and Morrow, N.R. 1999. Influence of Fluid Viscosity onMass Transfer Between Rock Matrix and Fractures. J. Can. Pet. Tech.38 (7): 25-30.
Mattax, C.C. and Kyte, J.R. 1962. Imbibition Oil Recovery From Fractured,Water-Driven Reservoir. SPEJ 2 (2): 177-184; Trans.,SPE 225. SPE-187-PA. DOI: 10.2118/187-PA.
Morrow, N.R. and Mason, G. 2001. Recovery of Oil bySpontaneous Imbibition. Current Opinion in Colloid & InterfaceScience 6 (4): 321-337. DOI: 10.1016/S1359-0294(01)00100-5.
Morrow, N.R. and Songkran, B. 1982. Effect Of Viscous and Buoyancy Forces onNonwetting Phase Trapping in Porous Media. In Surface Phenomena in EOR,ed. D. Shah, 387-411. New York City: Plenum Press.
Roehl, P.O. and Choquette, P.W. 1985. Carbonate Petroleum Reservoirs.New York: Springer-Verlag.
Schechter, D.S., Zhou, D., and Orr, F.M. Jr. 1994. Low IFT Drainage andImbibition. JPSE 11 (4): 283-300. DOI:10.1016/0920-4105(94)90047-7.
Seethepalli, A., Adibhatla, B., and Mohanty, K.K. 2004. Physicochemical Interactions DuringSurfactant Flooding of Fractured Carbonate Reservoirs. SPEJ 9(4): 411-418. SPE-89423-PA. DOI: 10.2118/89423-PA.
Shutang, G. et al. 1996. Alkaline/Surfactant/Polymer PilotPerformance of the West Central Saertu, Daqing Oil Field. SPERE11 (3): 181-188. SPE-35383-PA. DOI: 10.2118/35383-PA.
Somasundaran, P. and Agar, G.E. 1967. The Zero Point of Chargeof Calcite. J. Colloid and Interface Science 24 (4): 433-440.DOI: 10.1016/0021-9797(67)90241-X.
Standnes, D.C. and Austad, T. 2003a. Nontoxic Low-Cost Aminesas Wettability Alteration Chemicals in Carbonates. JPSE 39(3-4): 431-446. DOI: 10.1016/S0920-4105(03)00081-0.
Standnes, D.C. and Austad, T. 2000a. Wettability Alterationin Chalk 1. Preparation of Core Material and Oil Properties. JPSE28 (3): 111-121. DOI: 10.1016/S0920-4105(00)00083-8.
Standnes, D.C. and Austad, T. 2000b. Wettability Alterationin Chalk 2. Mechanism for Wettability Alteration from Oil-Wet to Water-WetUsing Surfactants. JPSE 28 (3): 123-143. DOI:10.1016/S0920-4105(00)00084-X.
Standnes, D.C. and Austad, T. 2003b. Wettability Alterationin Carbonates: Interaction Between Cationic Surfactant and Carboxylates as aKey Factor in Wettability Alteration from Oil-Wet to Water-Wet Conditions.Colloids and Surfaces A 216 (1-3): 243-259. DOI:10.1016/S0927-7757(02)00580-0.
Standnes, D.C. and Austad, T. 2003c. Wettability Alterationin Carbonates: Low-Cost Ammonium Surfactants Based on Bio-Derivatives From theCoconut Palm as Active Chemicals to Change the Wettability From Oil-Wet toWater-Wet Conditions. Colloids and Surfaces A 218 (1-3):161-173. DOI: 10.1016/S0927-7757(02)00581-2.
Strand, S., Standnes, D.C., and Austad, T. 2003. Spontaneous Imbibition of AqueousSurfactant Solutions Into Neutral to Oil-Wet Carbonate Cores: Effects of BrineSalinity and Composition. Energy & Fuels 17 (5):1133-1144. DOI: 10.1021/ef030051s.
Tabatabal, A., Gonzalez, M.V., Harwell, J.H., and Scamehorn, J.F. 1993. Reducing Surfactant Adsorption inCarbonate Reservoirs. SPERE 8 (2): 117-122. SPE-24105-PA.DOI: 10.2118/24105-PA.
Xie, X., Weiss, W.W., Tong, Z., and Morrow, N.R. 2005. Improved Oil Recovery From CarbonateReservoirs by Chemical Stimulation. SPEJ 10 (3): 276-285.SPE-89424-PA. DOI: 10.2118/89424-PA.
Yang, H.D. and Wadleigh, E.E. 2000. Dilute Surfactant IOR—DesignImprovement for Massive, Fractured Carbonate Applications. Paper SPE 59009presented at the SPE International Petroleum Conference and Exhibition inMexico, Villahermosa, Mexico, 1-3 February. DOI: 10.2118/59009-MS.
Zhou, X., Morrow, N.R., and Ma, S. 1996. Interrelationship of Wettability,Initial Water Saturation, Aging Time, and Oil Recovery by SpontaneousImbibition and Waterflooding. Paper SPE 35436 presented at the SPE/DOEImproved Oil Recovery Symposium, Tulsa, 21-24 April. DOI: 10.2118/35436-MS.