Wettability Alteration in Gas-Condensate Reservoirs to Mitigate Well Deliverability Loss by Water Blocking
- Myeong H. Noh (Chevron Corp.) | Abbas Firoozabadi (Reservoir Engr. Research Inst.)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- August 2008
- Document Type
- Journal Paper
- 676 - 685
- 2008. Society of Petroleum Engineers
- 1.8 Formation Damage, 1.8.5 Phase Trapping, 5.4.2 Gas Injection Methods, 3.2.4 Acidising, 6.5.2 Water use, produced water discharge and disposal, 4.1.2 Separation and Treating, 5.8.8 Gas-condensate reservoirs, 5.8.1 Tight Gas, 1.6 Drilling Operations, 4.6 Natural Gas, 5.2.1 Phase Behavior and PVT Measurements, 5.3.2 Multiphase Flow, 3.2.3 Hydraulic Fracturing Design, Implementation and Optimisation, 2.5.2 Fracturing Materials (Fluids, Proppant), 1.6.9 Coring, Fishing, 5.3.1 Flow in Porous Media, 3 Production and Well Operations
- 2 in the last 30 days
- 1,425 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 5.00|
|SPE Non-Member Price:||USD 35.00|
Liquid blocking in some gas-condensate reservoirs is a serious problem when the permeability is low (for example, of the order of 10 md or less). The current practice centers mainly on hydraulic fracturing to improve gas flow. In most cases, the frequency of application results in high costs. An alternative is the permanent alteration of wettability from liquid-wetting to preferentially gas-wetting. In this work, we present an experimental study of wettability alteration to preferential gas-wetting using a multifunctional surfactant and polymer synthesized for this particular application. The treatments are performed with an alcohol-based-surfactant/polymer solution. We treat Berea cores and reservoir-rock samples from two gas-condensate reservoirs. In one of the reservoirs, water blocking has resulted in a significant reduction of well deliverability. The treatment provides significant improvement on the phase mobility. In this study, our focus is the investigation of water/gas two-phase flow at high temperatures (80 and 140°C).
Basic measurements such as contact angle, spontaneous imbibition, and the effect on the absolute permeability are discussed. The initial liquid saturation at the time of treatment may have an influence on the wettability alteration. The results of the treatment on oil-saturated and water-saturated cores are presented. The treatment by alcohol without using the polymer is compared and discussed. Two-phase-flow tests in single-phase and two-phase injections are performed before and after the treatment using brine and gas. Relative permeabilities of gas and water are measured, and the improvement after the treatment is presented. Various measurements in our work show that water and gas relative permeability increase significantly in a wide range, especially at high liquid saturation.
The exploitation of low-permeability gas-condensate reservoirs has received increased emphasis in recent years. Liquid trapping (water or condensate blocking) around a wellbore is one of the major causes of reduced productivity in low-permeability gas-condensate reservoirs. Formation damage by the loss of aqueous fluids by operations such as drilling, fracturing, or acidizing is a potential source of reduced productivity of gas reservoirs because it causes water accumulation (water blocking) near the wellbore.
Water blocking is caused by capillary pressure, which tends to imbibe and hold the liquid phase, resulting in a reduction of gas mobility. The decrease in water saturation from hydraulic fracturing around the wellbore is a slow process when the permeability is low and the capillary forces are high. The investigation of the gas/water relative permeabilities can determine the gas-mobility loss associated with the change of water saturation.
|File Size||2 MB||Number of Pages||10|
Abrams, A. and Vinegar, H.J. 1985. Impairment Mechanisms in VicksburgTight Gas Sands. Paper SPE 13883 presented at the SPE/DOE Low PermeabilityGas Reservoirs Symposium, Denver, 19-22 March. DOI: 10.2118/13883-MS.
Ali, J., McGauley, P.J., and Wilson, C.J. 1997. The Effects of High-Velocity Flow andPVT Changes Near the Wellbore on Condensate Well Performance. Paper SPE38923 presented at the SPE Annual Technical Conference and Exhibition, SanAntonio, Texas, 5-8 October. DOI: 10.2118/38923-MS.
Bennion, D.B., Cimolai, M.P., Bietz, R.F., and Thomas, F.B. 1993. Reductionsin the Productivity of Oil and Gas Reservoirs due to Aqueous Phase Trapping.Paper CIM 93-24 presented at the Annual General Meeting of the PetroleumSociety of CIM, Calgary, 9-12 May.
Cable, A., Mott, R., and Spearing, M. 1999. Experimental Techniques for theMeasurement of Relative Permeability and In-Situ Saturation in Gas-CondensateNear-Wellbore and Drainage Studies. Paper 9928 presented at the InternationalSymposium of the Society of Core Analysts, Golden, Colorado, 2-4 August.
Cimolai, M.P., Gies, R.M., Bennion, D.B., and Myers, D.L. 1993. Mitigating Horizontal Well FormationDamage in a Low-Permeability Conglomerate Gas Reservoir. Paper SPE 26166presented at the SPE Gas Technology Symposium, Calgary, 28-30 June. DOI:10.2118/26166-MS.
Fevang, Ø. and Whitson, C.H. 1996. Modeling Gas-Condensate WellDeliverability. SPERE 11 (4): 221-230. SPE-30714-PA. DOI:10.2118/30714-PA.
Firoozabadi, A. and Katz, D.L. 1979. An Analysis of High-Velocity Gas FlowThrough Porous Media. JPT 31 (2): 211-216. SPE-6827-PA. DOI:10.2118/6827-PA.
Frederick, D.C. and Graves, R.M. 1994. New Correlations to Predict Non-DarcyFlow Coefficients at Immobile and Mobile Water Saturation. Paper SPE 28451presented at the SPE Annual Technical Conference and Exhibition, New Orleans,25-28 September. DOI: 10.2118/28451-MS.
Kamath, J. and Laroche, C. 2003. Laboratory-Based Evaluation of GasWell Deliverability Loss Caused by Water Blocking. SPEJ 8(1): 71-80. SPE-83659-PA. DOI: 10.2118/83659-PA.
Katz, D.L. 1959. Handbook of Natural Gas Engineering. New York City:McGraw-Hill Higher Education.
Li, K. and Firoozabadi, A. 2000. Experimental Study of WettabilityAlteration to Preferentially Gas-Wetting in Porous Media and Its Effects.SPEREE 3 (2): 139-149. SPE 62515-PA. DOI: 10.2118/62515-PA.
Liao, Y. and Lee, W.J. 1993. Production Performance ofHydraulically Fractured Gas Wells. Paper SPE 25465 presented at the SPEProduction Operations Symposium, Oklahoma City, Oklahoma, USA, 21-23 March.DOI: 10.2118/25465-MS.
Liu, X., Civan, F., and Evans, R.D. 1995. Correlation of the Non-Darcy FlowCoefficient. J. Cdn. Pet. Tech. 34 (10): 50-53.
Mahadevan, J. and Sharma, M. 2003. Clean-Up of Water Blocks in LowPermeability Formations. Paper SPE 84216 presented at the SPE AnnualTechnical Conference and Exhibition, Denver, 5-8 October. DOI:10.2118/84216-MS.
McLeod, H.O. and Coulter, A.W. 1966. The Use of Alcohol in Gas WellStimulation. Paper SPE 1663 presented at the SPE Eastern Regional Meeting,Columbus, Ohio, USA, 10-11 November. DOI: 10.2118/1663-MS.
McLeod, H.O., McGinty, J.E. and Smith, C.F. 1966. Deep Well Stimulation with AlcoholicAcid. Paper SPE 1558 presented at the Annual Meeting of the Society ofPetroleum Engineers of AIME, Dallas, 2-5 October. DOI: 10.2118/1558-MS.
Mott. R.E., Cable, A.S., and Spearing M.C. 2000. Measurements of RelativePermeabilities for Calculating Gas-Condensate Well Deliverability.SPEREE 3 (6): 473-479. SPE-68050-PA. DOI: 10.2118/68050-PA.
Tang, G. and Firoozabadi, A. 2003. Wettability Alteration to IntermediateGas-Wetting in Porous Media at Elevated Temperatures. J. of Transport inPorous Media 52 (2): 185-211.
Tang, G.-Q. and Firoozabadi, A. 2001. Effect of Pressure Gradient andInitial Water Saturation on Water Injection in Water-Wet and Mixed-WetFractured Porous Media. SPEREE 4 (6): 516-524. SPE-74711-PA.DOI: 10.2118/74711-PA.
Tang, G.-Q. and Firoozabadi, A. 2002. Relative Permeability Modification inGas/Liquid Systems Through Wettability to Intermediate Gas Wetting.SPEREE 5 (6): 427-436. SPE-81195-PA. DOI: 10.2118/81195-PA.
Tannich, J.D. 1975. LiquidRemoval from Hydraulically Fractured Gas Wells. JPT 27 (11):1309-1317. SPE-5113-PA. DOI: 10.2118/5113-PA.
Whitson, C.H., Fevang, Ø., and Sævareid, A. 1999. Gas Condensate Relative Permeabilityfor Well Calculations. Paper SPE 56476 presented at the SPE AnnualTechnical Conference and Exhibition, Houston, 3-6 October. DOI:10.2118/56476-MS.