Gas Condensate Blockage

1
Gas Condensate Blockage
A worked example using a simplified simulation
model to demonstrate the fundamental relative
permeability relationship affecting condensate
blockage. The fundamental relationship which
determines condensate blockage is krg as a
function of the ratio krg/kro. In the condensate
bank, the ratio krg/kro (a sort of fractional
flow) can be determined from the flowing OGR (rp)
and the PVT properties
2
Rel perms for Condensate Blockage
Consider two different sets of gas-oil rel perm
curves. The blue curves have a critical
condensate saturation of 20 The blue curves have
a critical condensate saturation of 10
3
Rel perms for Condensate Blockage
But both sets of rel perm curves have the same
krg vs krg/kro behavior
4
Simulation calculations

• Run 1D Sensor model for 10 md reservoir with
  these two sets of rel perms

1. Original (blue) rel perms
2. Modified (red) rel perms

Or use these output files for Case A and Case B.
Compare oil saturations at 4 years and gas
production profiles.
5
Oil saturations after 4 years production
Different rel perms give different saturations in
the condensate bank
6
Gas production profiles
but the different rel perms give almost
identical gas production profiles.
krg vs krg/kro is the primary relationship which
determines the effect of condensate blockage.
Saturations (including critical condensate
saturation) are much less important,
7

• References
• Modeling Gas Condensate Well Deliverability
• Gas Condensate Relative Permeability for Well
  Calculations
• Measurement of Relative Permeability for
  calculating Gas Condensate Well Deliverability

Notes