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Title: Correlation of minimum miscibility pressure for impure CO/sub 2/ streams

Conference · · Soc. Pet. Eng. AIME, Pap.; (United States)
OSTI ID:6554781

The displacement efficiency of oil by carbon dioxide is highly pressure dependent and miscible displacement efficiency is only achieved at pressures greater than a certain minimum. This minimum miscibility pressure (MMP) is a function of temperature and composition of the injection gas. The study presented in this paper examines the effect on MMP of up to 55 mole percent impurities in the CO/sub 2/-rich injection gas. A correlation of these data was developed based on the mole average pseudocritical temperature (TCM) of the gas and the minimum miscibility pressure of pure CO/sub 2/ with the same oil at the same conditions. In general, it was found that increasing the TCM of the gas lowered the MMP and decreasing the TCM increased the MMP. Injection gases with the same TCM but very different compositions were found to have the same MMP. Various correlating parameters were tried but TCM was found to be the most suitable. This correlation is compared to others in the literature and found to be superior in the case where the drive gas contained both light and intermediate components. The correlation indicates that miscibility in a field-wide CO/sub 2/ flood may be maintained by reinjection of impure CO/sub 2/ streams if sufficient intermediate hydrocarbons are present in the produced gas to offset the effects of lighter gases. Since CO/sub 2/ cleanup is one of the major costs in fieldwide CO/sub 2/ flooding, reduction or complete elimination of produced gas cleanup will have a significant positive impact on process economics. The operational and regulatory aspects of injecting an impure CO/sub 2/ stream must be considered, however, in order to optimize the recycling scheme.

Research Organization:
Amoco Production Co.
OSTI ID:
6554781
Report Number(s):
CONF-8304162-
Journal Information:
Soc. Pet. Eng. AIME, Pap.; (United States), Vol. SPE/DOE 12648; Conference: 4. SPE/DOE symposium on enhanced oil recovery, Tulsa, OK, USA, 16 Apr 1983
Country of Publication:
United States
Language:
English