SPE Reservoir Evaluation & Engineering
Volume 12,
Number 1,
February 2009,
pp. 88-95
Summary
One of the tools used for the characterization of gas reservoirs is the
geochemistry of gas condensates. The fingerprinting of gas condensates by gas
chromatography, in particular, may provide information regarding reservoir
compartmentalization, which can be a major uncertainty at the
early-field-appraisal stage. An important concern is the capture of suitable
liquid samples. When the flowing bottomhole pressure falls below the dewpoint
pressure, for example, condensate will drop out near the wellbore and the
captured sample may not be representative of the formation fluid.
We conducted two sets of tests simulating the effect(s) of gas-/liquid-phase
fractionation on fingerprinting analyses: (1) at different pressures (all below
the dewpoint) at reservoir temperature (RT) region in order to simulate dropout
of liquids in the near-wellbore area and (2) to investigate the effect of
variations in separator temperature and pressure.
Geochemical fingerprints obtained on our laboratory-fractionated samples
show that condensates obtained from gas wells with flowing bottomhole pressures
below dewpoint may not be suitable for compartmentalization studies.
Differences in separator pressure and temperature affect the fingerprints of
gas condensates, but the effects are small and unlikely to alter conclusions
regarding potential fluid-flow barriers. We suggest a number of best practices
for the collection and analysis of gas condensates for fingerprinting
studies.
© 2009. Society of Petroleum Engineers
View full textPDF
(
900 KB
)
History
- Original manuscript received:
24 July 2007
- Meeting paper published:
11 November 2007
- Revised manuscript received:
16 March 2008
- Manuscript approved:
10 June 2008
- Published online:
2 March 2009
- Version of record:
26 February 2009
View Cart
