Effect of Elemental-Sulfur Deposition on the Rock Petrophysical Properties in Sour-Gas Reservoirs
- Mohamed Mahmoud (KFUPM)
- Document ID
- Society of Petroleum Engineers
- SPE Journal
- Publication Date
- August 2014
- Document Type
- Journal Paper
- 703 - 715
- 2013.Society of Petroleum Engineers
- 5.2.1 Phase Behavior and PVT Measurements, 1.8 Formation Damage, 5.8.8 Gas-condensate reservoirs, 1.6.9 Coring, Fishing
- Deposition, Wettability, Sour Gas, Sulfur , Damage
- 3 in the last 30 days
- 383 since 2007
- Show more detail
- View rights & permissions
|SPE Member Price:||USD 10.00|
|SPE Non-Member Price:||USD 30.00|
The deposition of elemental sulfur as a solid phase results in plugging the pore space available for gas flow and reduces the reservoir productivity. Elemental sulfur also can be deposited as a liquid phase if the reservoir temperature is greater than 115°C. The liquid sulfur restricts the inflow of gas because of the big density difference between liquid sulfur and gas, which could be 20 times or more. For isothermal conditions in the reservoir, the reduction in reservoir pressure to lower than a critical value causes the elemental sulfur to deposit in the formation, and in turn the gas-well productivity is affected. Accurate prediction of sulfur deposition will help better manage sour-gas reservoirs with potential sulfur-deposition problems. In this paper, a new analytical model was developed to predict the effect of sulfur deposition on the damage of the near-wellbore region. The damage was quantified through the investigation of the effect of sulfur deposition on rock porosity, relative permeability of the gas phase, and the change in rock wettability. The main objective of this model is to investigate the effect of radial distance on formation damage. Different rock- and fluid-property correlations were used in the model. Previous studies did not consider the change in gas properties with pressure, and numerically modeled the sulfur deposition as a condensate in a gas/condensate reservoir. This paper will consider sulfur adsorption, and the actual physical properties of the sulfur will be used in the developed model. The optimum gas-flow velocity that will maximize the sulfur solubility in the gas will be determined. A coreflood experiment was performed to determine the effect of sulfur deposition on the carbonate-rock permeability, porosity, and wettability. The experiment was used to determine the effect of sulfur adsorption on the rock petrophysical properties. The contact angle was measured for a carbonate core saturated with sulfur by use of a pendant-drop tensiometer. Analytical and numerical solutions showed that the deposition of sulfur was affected by the radial distance from the wellbore and sulfur-solubility changes as a function of the pressure drop. Sulfur deposition was found to have a great effect on the rock wettability, and in turn the gas production will be affected. The model can be used to predict the critical flow velocity that the gas can flow without precipitating sulfur. The optimum gas-flow velocity was estimated to be a range that maximizes the sulfur solubility in the gas. It was confirmed experimentally that the sulfur deposition reduced the carbonate-core porosity and permeability, and changed the contact angle (rock wettability). The contact angle increased, which means sulfur adsorption on the rock surfaces changed the rock toward more-gas-wet rock.
|File Size||2 MB||Number of Pages||13|
Ahmed, T. 2001. Reservoir Engineering Handbook, second edition.Burlington, Massachusetts: Gulf Publishing Company.
Al-Awadhy, F., Kocabas, I., Abou-Kassem, J.H., et al. 1998. Experimental andNumerical Modeling of Sulfur Plugging in Carbonate Oil Reservoirs. Paper SPE49498 presented at the Abu Dhabi International Petroleum Exhibition andConference, Abu Dhabi, United Arab Emirates, 11-14 November. http://dx.doi.org/10.2118/49498-MS.
Bacon, R.F. and Fanelli, R., J. 1945. Laboratory Measurements of PhysicalSulfur Properties Am. Chem. Soc. 67 (5): 1832-1834.
Beskov, V.S., Kandybin, A.I. and Furmer, Y.V. 1989. Modeling of the Processof the Removal of Sulfur on Zinc Oxide Absorbents in Ammonia Production.Russ. Chem. Ind. 21 (3): 87-90.
Bojes, J., Lerbscher, J., Wamburi, W., et al. 2010. Elemental Sulfur in3-Phase Sour Gas System - Is Condensate Really Your Ally? Oral presentationgiven at the Northern Area Western Conference, Calgary, Alberta, Canada, 15-18February.
Boulinguiez, B. and Le Cloirec, P. 2010. Chemical Transformation of SulfurCompounds Adsorbed onto Actuated Carbon Materials during Thermal Desorption.Carbon 48 (5): 1558-1569. http://dx.doi.org/10.1016/j.carbon.2009.12.053.
Brunner, E., Place, M. C. Jr. and Woll, W. H. 1988. Sulfur Solubility inSour Gas. J. Pet. Tech. 40 (12): 1587-1592. http://dx.doi.org/10.2118/14264-PA.
Cézac, P., Serin, J. P., Mercadier, J., et al. 2007. Modeling Solubility ofSolid Sulfur in Natural Gas. Chem. Eng. J. 133 (1-3):283-291. http://dx.doi.org/10.1016/j.cej.2007.02.014.
Chen, C. and Kojima, T., 1997. Modeling of Sulfur Retention by Limestone inCoal Briquette. Fuel Process. Technol. 53 (1-2): 49-67. http://dx.doi.org/10.1016/S0378-3820(97)00036-2.
Chrastll, J. 1982. Solubility of Solids and Liquids in Supercritical Gases.J. Phys. Chem. 86 (15): 3016-3021. http://dx.doi.org/10.1021/j100212a041.
Dranchuk, P.M. and Abou-Kassem, J.H. 1975. Calculation of Z Factor forNatural Gases Using Equation of State. J. Cdn. Pet. Tech. 14 (3): 34-36. http://dx.doi.org/10.2118/75-03-03.
Duan, L., Gao, X., Meng, X., et al. 2012. Adsorption, Co-adsorption, andReactions of Sulfur Compounds, Aromatics, Olefins over Ce-Exchanged Y Zeolite.J. Phys. Chem. C. 116 (49): 25784-25756. http://dx.doi.org/10.1021/JP303040M.
Fanelli, R. 1950. The Surface Tension of Sulfur. J. Am. Chem. Soc. 72 (9): 4016-4018. http://dx.doi.org/10.1021/ja01165a050.
Hands, N., Oz, B., Roberts, B., et al. 2002. Advances in the Prediction andManagement of Elemental Sulfur Deposition Associated with Sour Gas Productionfrom Fractured Carbonate Reservoirs. Paper SPE 77332 presented at the SPEAnnual Technical Conference and Exhibition, San Antonio, Texas, 29 September-2October. http://dx.doi.org/10.2118/77332-MS.
Hyne, J. B. 1968. Study Aids Prediction of Sulfur Deposition in Sour-GasWells. Oil Gas J. 25 (11): 107-113.
Kennedy, H. T. and Wieland, D. R. 1960. Equilibrium in the Methane-CarbonDioxide-Hydrogen Sulfide-Sulfur System. Proc., Petroleum Trans., AIME,Vol. 219, 166-169.
Kuo, C. H. and Closmann, P. J. 1966. Theoretical Study of Fluid FlowAccompanied by Solid Precipitation in Porous Media. AIChE J. 12 (5): 995-998. http://dx.doi.org/10.1002/aic.690120527.
Lee, A., Gonzalez, M.H. and Eakin, B.E. 1966. The Viscosity of NaturalGases. J. Pet. Tech. 18 (8): 997-1000. http://dx.doi.org/10.2118/1340-PA.
Mahmoud, M.A. and Al-Majed, A.A. 2012. New Model to Predict Formation Damagedue to Sulfur Deposition in Sour Gas Wells. Paper SPE 149535 presented at theNorth Africa Technical Conference and Exhibition, Cairo, Egypt, 20-22 February.http://dx.doi.org/10.2118/149535-MS.
Maston, R.F., Freeport Sulfur Co., un published report, and Kellas, A.M.,J. Chem. Soc., Vol. 113, 1918, pp. 903-22.
Mei, H., Zhang, M. and Yang, X. 2006. The Effect of Sulfur Deposition on GasDeliverability. Paper SPE 99700 presented at the SPE Gas Technology Symposium,Calgary, Alberta, Canada, 15-17 May. http://dx.doi.org/10.2118/99700-MS.
Roberts, B.E. 1997. The Effect of Sulfur Deposition on Gas Well InflowPerformance. SPE Res Eng 12 (2): 118-123. http://dx.doi.org/10.2118/36707-PA.
Roof, J. G. 1971. Solubility of Sulfur in Hydrogen Sulfide and CarbonDisulfide at Elevated Temperature and Pressure. SPE J. 11(3): 272-276. http://dx.doi.org/10.2118/3264-PA.
Shedid, A. S. and Zekri, A. Y. 2002. Formation Damage due to SulfurDeposition in Porous Media. Paper SPE 73721 presented at the InternationalSymposium and Exhibition on Formation Damage Control, Lafayette, Louisiana,20-21 February. http://dx.doi.org/10.2118/73721-MS.
Shedid, S. and Zekri, A.Y. 2006. Formation Damage Caused by SimultaneousSulfur and Asphaltene Deposition. SPE Prod & Oper 21(1): 58-64. http://dx.doi.org/10.2118/86553-PA.
Shuai, X. and Meisen, A. 1995. New Correlations Predict Physical Propertiesof Elemental Sulfur. Oil Gas J. 93 (42): 50-55.
Standing, M.B. and Katz, D.L. 1942. Density of Natural Gases. Trans.AIME 146 (1): 140-149. http://dx.doi.org/10.2118/942140-G.
Steudel, R. 2003. Elemental Sulfur and Sulfur-Rich Compounds, Topics inCurrent Chemistry, Vol. 1. New York City, New York: Springer.
Xiao, G., Zhimin, D., Yong, Z., et al. 2006. Laboratory and SimulationInvestigation of Sulfur Deposition in Sour Gas Reservoir. Paper SPE 103810presented at the International Oil & Gas Conference and Exhibition inChina, Beijing, China, 5-7 December. http://dx.doi.org/10.2118/103810-MS.