SPE Journal
Volume 16,
Number 4,
December 2011,
pp. 812-827
Summary
The amount of wetting phase that is recovered by gravity drainage when the
displacing fluid is not in chemical equilibrium with the initial fluid involves
a complex interplay of gravitational, diffusive, and capillary forces.
Previously, in Part 1 in a series of papers, we proposed analytic solutions for
capillary/gravity equilibrium (CGE) in compositional gravity drainage and
estimated the total recovery of wetting phase (DiCarlo and Orr 2007). In Part
2, we presented the results of experiments in an analog brine/isopropanol
(IPA)/isooctane (IC8) system in which the vertical profile of the
components was measured destructively after 3 weeks of drainage (DiCarlo et al.
2007). Here, we present numerical simulations of compositional gravity
drainage. We find that the CGE solutions are approached asymptotically as the
simulation grid is refined for a simplified phase diagram. For vaporizing
drainages, a bank of wetting fluid is found to be created from early times in
the drainage because of wetting fluid imbibing back into swept regions. We show
that including hysteresis in the capillary pressure curve limits the creation
of the wetting-fluid bank. We compare the numerical simulations to the
experimental observations and find that the simulations match well for
condensing drainages but not for vaporizing drainages, similar to what is seen
for the CGE solutions.
© 2011. Society of Petroleum Engineers
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History
- Original manuscript received:
2 August 2007
- Meeting paper published:
11 November 2007
- Revised manuscript received:
6 October 2010
- Manuscript approved:
11 October 2010
- Published online:
4 April 2011
- Version of record:
23 December 2011
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