شبیه‌سازی عددی اختلاط همرفتی ضمن ذخیره‌سازی دی‌اکسید‌کربن در مخازن آب شور

نوع مقاله: مقاله پژوهشی

نویسندگان

انستیتو مهندسی نفت، دانشگاه تهران، تهران، ایران

چکیده

ذخیره‌سازی دی‌اکسید‌کربن در مخازن آب شور به‌‌عنوان  روشی مؤثر برای کاهش گازهای گلخانه‌ای شناخته شده است. پیش‌بینی رفتار دراز‌ مدت دی‌اکسید‌کربن تزریقی نیازمند شناخت مکانیسم‌های حاضر در فرآیند می‌باشد. دی‌اکسید‌کربن تزریقی با نفوذ در آب شور، باعث افزایش چگالی آب شور و وقوع پدیده‌ اختلاط همرفتی می‌شود. در نتیجه نرخ انحلال افزایش می‌یابد. بنابراین شناخت فاکتورهای مؤثر بر اختلاط همرفتی در مخازن آب شور از اهمیت ویژه‌ای برخوردار است. در این مقاله یک مدل دو‌بعدی و تک‌فاز برای مدل‌سازی اختلاط همرفتی ارائه می‎گردد. آنالیز مقیاسی اختلاط همرفتی در مخازن آب شور بیان شده و پارامترهای همرفتی به صورت تابعی از عدد رایلی سیستم بیان می‌گردد. برای اولین بار در این مطالعه زمان افزایش انحلال ناشی از اختلاط همرفتی به عنوان یک پارامتر مهم در ارزیابی سایت‌های مناسب ذخیره‌سازی بر حسب عدد رایلی به صورت کمی مورد بررسی قرار گرفته است؛ نتایج نشان می‌دهد که افزایش انحلال ناشی از اختلاط همرفتی در زمانی حدود سه برابر زمان شروع ناپایداری‎ها شکل می‌گیرد. نتایج این مقاله شناخت و آگاهی لازم برای اجرای پروژه‌های ذخیره‌سازی دی‌اکسید‌کربن در مخازن آب شور عمیق را بدون نیاز به شبیه‌سازی‌های هزینه‌بر، افزایش می‌دهد.
 

کلیدواژه‌ها


عنوان مقاله [English]

Numerical Simulation of Convective Mixing during Carbon Dioxide Sequestration in Saline Aquifers

نویسندگان [English]

  • mohsen Pasdar
  • Behzad Rostami
  • Rasoul Nazari-Moghadam
Institute of Petroleum Engineering, University of Tehran, Tehran, Iran
چکیده [English]

The permanent storage of CO2 in deep saline aquifers is known as an effective method for reducing the greenhouse gas emissions. Predicting the long-term fate of the injected CO2 requires an understanding of the basic mechanisms involved in the storage process. CO2 injected in deep saline aquifers diffuses in resident brine, which increases the brine density and potentially leads to convective mixing raising the rate of dissolution. Hence it is important to realize the factors enhancing convection in deep saline aquifers. In this paper, a two dimensional, single-phase model is developed for modeling of the convective mixing. The scaling analysis of the convective mixing of CO2 in saline aquifers is presented and convection parameters are described as a function of system Rayleigh number. For the first time, in this study the start time of enhancement in CO2 dissolution due to convective mixing was studied quantitatively. The results indicate that the enhancement in CO2 dissolution due to convective mixing occurs at a time about three times of the onset time of instabilities. The results of this study increase our knowledge of the appropriate implementation of geological CO2 storage in deep saline aquifers, without the need for costly simulations.
 

کلیدواژه‌ها [English]

  • CO2 Sequestration
  • Convective Mixing
  • Departure Time
  • Numerical Simulation
  • Saline Aquifers
  • Scaling Analysis
 

[1]. Houghton J. T., Ding Y., Griggs D. J., Noguer M., Lindin P. J. v. d. and Dai X., Climate change 2001: The scientific basis, Contribution of working group I to the third assessment report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge. UK, 2001.

[2]. Keith D. W., Towards a strategy for implementing CO2 capture and storage in Canada, Oil, Gas and Energy Barnch, Environment canada, Ottawa, Onatrio, Canada, 2002.

[3]. Bachu S. and Adams J. J., “Estimating CO2 sequestration capacity in solution in deep saline aquifers”, Energy Conversion and Management, Vol. 44, No. 20, pp. 3151-3175, 2003.

[4]. Fellet M., Gurton R. and Taggart I., “The function of gas-water relative permeability hysteresis in the sequestration of Carbon Dioxide in saline formations”, SPE Asia Pacific Oil and Gas Conference and Exhibition, SPE paper 88485, Perth, Australia, 2004.

[5]. Gunter W., Perkins E. H. and McCann T. J., “Aquifer disposal of CO2- rich sequestration design for added capacity”, Energy Conversion and Management, Vol. 34, pp. 941-948, 1993.

[6]. Perkins E. H. and Gunter W., A users manual for PATHARC.94: a reaction path-mass transfer program, in:  Alberta Research Council Report ENVTR 95-11, 1995.

[7]. Bachu S., Nordbotten J. M. and Celia M. A., “Evaluation of the spread of acid gas plumes injected in deep saline aquifers in western Canada as an analogue to CO2 injection in continental sedimentary basins, Proceedings of 7th International Conference on Greenhouse Gas Control Technologies, IEA Greenhouse Gas Programme,

Cheltenham, UK, 2004.

[8]. Bachu S., Gunter W., Overview of acid-gas injection operations in western Canada, Proceedings of the 7th International Conference on Greenhouse Gas Control Technologies, IEA Greenhouse Gas Programme, Cheltenham, UK., 2004.

[9]. Lindeberg E., “Escape of CO2 from aquifers”, Energy Conversion and Management”, Vol. 38, pp. 235-240, 1997.

[10]. Lindeberg E., Wessel-Berg D., “Vertical convection in an aquifer column under a gas cap of CO2,” Energy Conversion and Management, Vol. 38, pp. 229-234, 1997.

[11]. Ennis-King J. and Paterson L., “Rate of dissolution due to convective mixing in the underground storage of carbon dioxide”, 6th International Conference on Greenhouse Gas Control Technologies 2002, Kyoto, Japan., 2002.

[12]. Ennis-King J., Pretson I. and Paterson L., “Onset of convection in anisotropic porous media subject to a rapid change in boundary conditions”, Physics of Fluids, Vol. 17, 2005.

[13]. Hassanzadeh H., Pooladi-Darvish M. and Keith D. W., “Modeling of convective mixing in CO2 storage”, Journal of Canadian Petroleum Technology, Vol. 44, No. 10, pp. 43-51, 2005.

[14]. Xu X., Chen S. and Zhang Z., “Convective stability analysis of the longterm storage of carbon dioxide in deep saline aquifers”, Advances in Water Resources, Vol. 29, pp. 397-497, 2006.

[15]. Hassanzadeh H., Pooladi-Darvish M. and Keith D. W., “Stability of a fluid in a horizontal saturated porous layer: Effect of non-linear concentration profile initial and boundary conditions”, Transport in Porous Media, Vol. 65, pp. 193-211, 2006.

[16]. Hassanzadeh H., Pooladi-Darvish M. and Keith D. W., “Scaling behavior of convective mixing, with Application to Geological Storage of CO2”, American Institute of Chemical Engineers AIChE, Vol. 53, pp. 1121-1131, 2007.

[17]. Lidenburgm E. and Bergmo P., “The long-term fate of CO2 injected into an aquifer”, Proceedings of the 6th International Conference on Greeenhouse Gas Technologies, 2003.

[18]. Hesse M. A., “Mathematical modeling and multiscale simulation of CO2 storage in saline aquifers”, PhD Thesis, Department of Energy Resources Engineering, Stanford University, 2008.

[19]. Horton C. W. and Rogres F. T., “Convection currents in porous media”, Journal of Applied Physics, Vol. 20, pp. 367-369, 1945.

[20]. Elder J. W., “Steady free convection in a porous medium heated from below”, Journal of Fluid Mechanics, Vol. 27, pp. 29-50, 1967.

[21]. Voss C. I. and Souza W. R., “Variable density flow and solute transport simulation of regional aquifers containing a narrow freshwater-saltwater transition zone”, Water Resources Research, Vol. 23, No. 10, pp. 1851-1866, 1987.

[22]. Kolditz O., Ratke R., Diersch H.-J. and Zielke W., “Coupled groundwater flow and transport: 1. Verification of variable density flow and transport models”, Advances in Water Resources, Vol. 21, No. 1, pp. 27-46, 1998.

[23]. Simpson M. J., Clement T. P., “Theoretical analysis of the worthiness of Henry and Elder problems as bench

marks of density-dependent groundwater flow models”, Advances in Water Resources, Vol. 26, No. 1, pp. 17-31, 2003.

[24]. Hassanzadeh H., Mathematical Modeling of Convective Mixing in Porous Media for Geological CO2 Storage, PhD Thesis, Department of Chemical and Petroleum Ebgineering, University of Calgary, Calgary, Alberta, 2006.

[25]. Carslaw H. S. and Jaeger J. C., Conduction of heat in solids, Oxford University Press, 1959.

[26]. Bachu S. and Carroll J. J., “In-situ phase and thermodynamic properties of resident brine and acid gases (CO2 & H2S) injected in geological formations in western Canada”, Proceedings of the 7th International Conference on Greenhouse Gas Control Technologies, Vancouver, B.C. Canada, pp. 5-9, September 2004.