Development of CPA EOS Model for the Analysis of Phase Behavior of Water-CO2-Hydrocarbon Mixture

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2009 Vol.46, Issue 1 Preview Page Next Page

Development of CPA EOS Model for the Analysis of Phase Behavior of Water-CO2-Hydrocarbon Mixture 물-CO2-탄화수소 혼합물간의 상거동 해석을 위한 CPA 상평형 모델 개발: 하세훈, 이영수, 이태훈, 권순일, 성원모
Sehun Ha, Youngsu Lee, Taehun Lee, Sunil Kwon and Wonmo Sung

28 February 2009. pp. 28-35

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Abstract

The CO2 miscible flooding as one of the tertiary recovery methods is applied to produce additional oil that still remains remarkably in reservoir after primary and secondary recovery processes. CO2 miscible flooding has proliferated due to its advantages of enhances in the oil recovery as well as CO2 sequestration. Therefore, recently numerous researches on phase behavior of CO2-oil have been conducted at the underground reservoir condition. In petroleum development industry, water is not generally considered in phase behavior analysis since water does not react with hydrocarbon. However, when water saturation is very high, water does affect in phase behavior of the mixture due to association effect of the water itself. And hence, in chemical process industry, the equation of state considering the association effect of polar compound such as water and alcohol have been developed. In this study, CPA-EOS model together with SRK cubic equation has been developed in order to conduct phase behavior analysis of water-CO2-hydrocarbon system that contains polar compound like water. In order to validate the developed model, we have performed phase behavior analysis for single-component as well as two-component systems. The results show the excellent matches with the experimental data. Also, we have characterized phase boundary and their volume fraction according to pressure and temperature by conducting the phase behavior analysis for multi- component mixture of water-CO2-hydrocarbon. Finally, the model was utilized for the phase behavior analysis of oil mixture sampled in Captain producing oil field located at NW offshore, Scotland. With the aid of the result of phase behavoir analysis, minimum miscible pressure was calculated. Its result indicates that oil and CO2 mixture in the reservoir condition is found to be immiscible when CO2 flood is planning to be applied to Captain field.

Keywords

CO2 miscible flooding

EOS model

CPA

Phase behavior analysis

MMP

일반적으로 유전에서는 1, 2차 회수 이후에도 많은 양의 오일이 저류층에 잔류하게 되는데, 이러한 잔류오일의 상당부분은 3차 회수과정을 통해 생산증진이 되며, CO2 miscible 공법은 그 중 한 공법이다. CO2 miscible 공법은 오일의 추가 회수뿐만 아니라 지구온난화의 주범인 CO2를 처리할 수 있다는 장점을 가지고 있어서 최근에 급격히 증가하는 추세이다. 이에 따라 지하 저류층의 조건에서 CO2와 오일간의 보다 정확한 상거동 해석을 위한 많은 연구가 진행되고 있다. 상거동해석시, 물은 탄화수소와 반응을 하지 않으므로 석유개발 분야에서는 일반적으로 물을 고려하지 않았다. 그러나 물의 포화도가 높은 경우 물과 물간의 association 현상으로 인하여 혼합물의 상거동에 영향을 미치게 되므로 화학공정분야에서는 물이나 알코올과 같은 극성화합물의 association 현상을 고려한 상태방정식들이 이전부터 개발되어 왔다. 이에 본 연구에서는 물과 CO2 및 탄화수소 혼합물간의 상거동 해석을 실시하기 위해 Soave-Redlich-Kwong(SRK) 3차 상태방정식과 함께 물과 같은 극성화합물이 포함된 혼합물시스템에서의 상평형 계산이 보다 더 정확하다고 알려져 있는 Cubic-Plus-Association(CPA) 상태방정식을 이용하여 상평형 모델을 개발하였다. CPA 상태방정식은 3차 상태방정식인 SRK 식에 Statistical Associating Fluid Theory(SAFT) 모델의 association 항을 결합한 것으로 이 모델을 활용하여 단일성분과 2성분 시스템에 대한 타당성 검증을 수행한 결과 실제 데이터와 잘 일치함을 확인할 수 있었다. 또한 물과 CO2 및 탄화수소의 다성분 혼합물간의 상거동 해석을 실시하여 압력과 온도에 따른 상의 경계와 부피비를 규명하였다. 본 연구의 상평형 모델을 적용하여 현재 생산 중인 유전인 스코틀랜드 북서부 해상에 위치한 캡틴유전의 오일 성분에 대해서도 상거동 해석을 수행하였으며, 이를 활용하여 Minimum Miscible Pressure(MMP)를 산출한 결과 캡틴유전에 CO2 공법 적용 시에는 immiscible 유동이 발생함을 알 수 있었다.

키워드

도시가스산업

투입산출분석

외생화

References

Ayirala, S.C., Rao, D.N. and Jerry Casteel, 2003, “Comparison of Minimum Miscibility Pressure Determined from Gas-Oil Interfacial Tension Measurements with Equation of State Calculations,” SPE Annual Technical Conference and Exhibition, Oct, pp. 5-8.
Gasem, K.A.M. et al., 1993, “Experimental Phase Densities and Interfacial Tensions for a CO2/Synthetic-Oil and a CO2/Reservoir-Oil System,” SPERE, Aug, pp. 170-174.
Kanji Kato, 1981, “Generalized Interaction Parameters for The Peng-Robinson Equation of State: Carbon Dioxide-n-Paraffin Binary Systems,” Fluid Phase Equilibria, pp. 219-231.
Kontogeorgis, G.M., Yakoumis, I.V., 1998, “Prediction of Phase Equilibria in Binary Aqueous Systems Containing Alkanes, Cycloalkanes, and Alkenes with the Cubic-plus-Association Equation of State,” Ind. Eng. Chem. Res. Vol. 37, pp. 4175-4182.
Kuan, D.Y. et al., 1986, “Multicomponent CO2/Water/Hydrocarbon Phase Behavior Modeling: A Comparative Study,” SPERE Jan., pp. 61-77.
Mehra, R.K., Heidemann, R.A. and Aziz, K., 1983, “An Accelerated Successive Substitution Algorithm,” Cdn. J. Chem. Eng., Aug., pp. 590-596.
Ohgaki, K., and Takashi Katayama, 1977, “Isothermal Vapor -Liquid Equilibrium Data for the Ethane-Carbon Dioxide System at High Pressure,” Fluid Phase Equilibria, pp. 27-32.
Sahimi, M., Davis, H.T., and Scriven, L.E., 1985, “Thermodynamic Modeling of Phase and Tension Behavior of CO2/Hydrocarbon Systems,” SPEJ, April, pp. 235-254.
Shinta A.A. and Firoozabadi, Abbas., 1997, “Predicting Phase Behavior of Water/Reservoir -Crude systems With the Association Concept,” SPERE, May, pp. 131-137.
Smith, J.M., Ness, H.C. Van. and Abbott, M.M., 1949, “Introduction To Chemical Engineering Thermodynamics,” Sixth Edition, McGraw-Hill Higher Education, NY, pp. 91-99, 329-367.
Soave, G., 1972, “Equilibrium Constants from a Modified Redlich-Kwong Equation of State,” Chem, Eng. Sci., Vol. 27, pp. 1197-1203.
Tarek Ahmed, 1989, “Hydrocarbon Phase Behavior,” Contributions in Pertroleum Geology & Engineering; Volume 7., Gulf Publishing Company, Houston, Texas, pp. 287-347.

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society for Geosystem Engineering
Journal Title(Ko) :한국지구시스템공학회지
Volume : 46
No :1
Pages :28-35

[1] Ayirala, S.C., Rao, D.N. and Jerry Casteel, 2003, “Comparison of Minimum Miscibility Pressure Determined from Gas-Oil Interfacial Tension Measurements with Equation of State Calculations,” SPE Annual Technical Conference and Exhibition, Oct, pp. 5-8.

[2] Gasem, K.A.M. et al., 1993, “Experimental Phase Densities and Interfacial Tensions for a CO2/Synthetic-Oil and a CO2/Reservoir-Oil System,” SPERE, Aug, pp. 170-174.

[3] Kanji Kato, 1981, “Generalized Interaction Parameters for The Peng-Robinson Equation of State: Carbon Dioxide-n-Paraffin Binary Systems,” Fluid Phase Equilibria, pp. 219-231.

[4] Kontogeorgis, G.M., Yakoumis, I.V., 1998, “Prediction of Phase Equilibria in Binary Aqueous Systems Containing Alkanes, Cycloalkanes, and Alkenes with the Cubic-plus-Association Equation of State,” Ind. Eng. Chem. Res. Vol. 37, pp. 4175-4182.

[5] Kuan, D.Y. et al., 1986, “Multicomponent CO2/Water/Hydrocarbon Phase Behavior Modeling: A Comparative Study,” SPERE Jan., pp. 61-77.

[6] Mehra, R.K., Heidemann, R.A. and Aziz, K., 1983, “An Accelerated Successive Substitution Algorithm,” Cdn. J. Chem. Eng., Aug., pp. 590-596.

[7] Ohgaki, K., and Takashi Katayama, 1977, “Isothermal Vapor -Liquid Equilibrium Data for the Ethane-Carbon Dioxide System at High Pressure,” Fluid Phase Equilibria, pp. 27-32.

[8] Sahimi, M., Davis, H.T., and Scriven, L.E., 1985, “Thermodynamic Modeling of Phase and Tension Behavior of CO2/Hydrocarbon Systems,” SPEJ, April, pp. 235-254.

[9] Shinta A.A. and Firoozabadi, Abbas., 1997, “Predicting Phase Behavior of Water/Reservoir -Crude systems With the Association Concept,” SPERE, May, pp. 131-137.

[10] Smith, J.M., Ness, H.C. Van. and Abbott, M.M., 1949, “Introduction To Chemical Engineering Thermodynamics,” Sixth Edition, McGraw-Hill Higher Education, NY, pp. 91-99, 329-367.

[11] Soave, G., 1972, “Equilibrium Constants from a Modified Redlich-Kwong Equation of State,” Chem, Eng. Sci., Vol. 27, pp. 1197-1203.

[12] Tarek Ahmed, 1989, “Hydrocarbon Phase Behavior,” Contributions in Pertroleum Geology & Engineering; Volume 7., Gulf Publishing Company, Houston, Texas, pp. 287-347.

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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