Limitations of current MOC (Method of Characteristic) methods to predict MMPs for complex gas/oil displacements

Kaveh Ahmadi, Russell Taylor Johns, Kristian Mogensen, Rashed Noman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

An accurate minimum miscibility pressure (MMP) is one of the key factors in miscible gas flood design. There are a variety of experimental and analytical methods to determine the MMP, but the most reliable methods are slim-tube experiments, 1-D slim-tube simulations, mixing-cell models, and the key tie-line approach using method of characteristics (MOC). Direct comparisons of all these methods generally agree well, but there are cases where they do not. No explanation has yet been given for the anomalies, although the MMP is critically important to recovery. The focus of this paper is to explain when current MOC results may not be reliable and how to identify when this is the case. We demonstrate using fluid characterizations from Middle Eastern oils that the MMPs using the MOC method can be over 6500 psia greater than those calculated using a recently developed mixing-cell method. The observed differences in the MMP increase substantially as the API gravity of the oil decreases. We show that the key tie lines determined using MOC methods do not control miscibility for such cases. We explain the reasons for these differences using simplified pseudoternary models and show how to determine when an error exists. We also offer several ways to correct the MMP predictions using the MOC for these complex gas/oil displacements.

Original languageEnglish (US)
Title of host publication17th SPE Improved Oil Recovery Symposium 2010, IOR 2010
Pages516-524
Number of pages9
StatePublished - Jul 9 2010
Event17th SPE Improved Oil Recovery Symposium, IOR 2010 - Tulsa, OK, United States
Duration: Apr 24 2010Apr 28 2010

Publication series

NameProceedings - SPE Symposium on Improved Oil Recovery
Volume1

Other

Other17th SPE Improved Oil Recovery Symposium, IOR 2010
CountryUnited States
CityTulsa, OK
Period4/24/104/28/10

Fingerprint

Gas oils
Solubility
oil
gas
Application programming interfaces (API)
method
Gravitation
design flood
Recovery
Fluids
miscibility
analytical method
Gases
gravity
anomaly
Experiments
fluid

All Science Journal Classification (ASJC) codes

  • Energy Engineering and Power Technology
  • Geotechnical Engineering and Engineering Geology

Cite this

Ahmadi, K., Johns, R. T., Mogensen, K., & Noman, R. (2010). Limitations of current MOC (Method of Characteristic) methods to predict MMPs for complex gas/oil displacements. In 17th SPE Improved Oil Recovery Symposium 2010, IOR 2010 (pp. 516-524). (Proceedings - SPE Symposium on Improved Oil Recovery; Vol. 1).
Ahmadi, Kaveh ; Johns, Russell Taylor ; Mogensen, Kristian ; Noman, Rashed. / Limitations of current MOC (Method of Characteristic) methods to predict MMPs for complex gas/oil displacements. 17th SPE Improved Oil Recovery Symposium 2010, IOR 2010. 2010. pp. 516-524 (Proceedings - SPE Symposium on Improved Oil Recovery).
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abstract = "An accurate minimum miscibility pressure (MMP) is one of the key factors in miscible gas flood design. There are a variety of experimental and analytical methods to determine the MMP, but the most reliable methods are slim-tube experiments, 1-D slim-tube simulations, mixing-cell models, and the key tie-line approach using method of characteristics (MOC). Direct comparisons of all these methods generally agree well, but there are cases where they do not. No explanation has yet been given for the anomalies, although the MMP is critically important to recovery. The focus of this paper is to explain when current MOC results may not be reliable and how to identify when this is the case. We demonstrate using fluid characterizations from Middle Eastern oils that the MMPs using the MOC method can be over 6500 psia greater than those calculated using a recently developed mixing-cell method. The observed differences in the MMP increase substantially as the API gravity of the oil decreases. We show that the key tie lines determined using MOC methods do not control miscibility for such cases. We explain the reasons for these differences using simplified pseudoternary models and show how to determine when an error exists. We also offer several ways to correct the MMP predictions using the MOC for these complex gas/oil displacements.",
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Ahmadi, K, Johns, RT, Mogensen, K & Noman, R 2010, Limitations of current MOC (Method of Characteristic) methods to predict MMPs for complex gas/oil displacements. in 17th SPE Improved Oil Recovery Symposium 2010, IOR 2010. Proceedings - SPE Symposium on Improved Oil Recovery, vol. 1, pp. 516-524, 17th SPE Improved Oil Recovery Symposium, IOR 2010, Tulsa, OK, United States, 4/24/10.

Limitations of current MOC (Method of Characteristic) methods to predict MMPs for complex gas/oil displacements. / Ahmadi, Kaveh; Johns, Russell Taylor; Mogensen, Kristian; Noman, Rashed.

17th SPE Improved Oil Recovery Symposium 2010, IOR 2010. 2010. p. 516-524 (Proceedings - SPE Symposium on Improved Oil Recovery; Vol. 1).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Ahmadi K, Johns RT, Mogensen K, Noman R. Limitations of current MOC (Method of Characteristic) methods to predict MMPs for complex gas/oil displacements. In 17th SPE Improved Oil Recovery Symposium 2010, IOR 2010. 2010. p. 516-524. (Proceedings - SPE Symposium on Improved Oil Recovery).