1. Gas Condensate Blockage
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
3700
3900
4100
4300
4500
4700
4900
5100
5300
Reservoir pressure, psi
Productivity Index
rb = f(CGR)  ft
Krgb = f(CGR,rock,Nc) 
Nc = f(qg,pwf)
sb  (100)
Condensate blockage is the build-up of liquid around the wellbore, reducing the effective gas permeability and lowering well deliverability.
Condensate saturations in the near-well region can reach 50%, reducing the gas permeability in the near-well region by a factor of 2 to 20.
Condensate blockage is only important when there is a significant pressure drop between the deep reservoir and the well perforations, and when the well is on decline (tubing-pressure limited).
Condensate blockage is more important at low kh. It is likely to be a major issue when kh < ~ 1,000 md-ft. It is unlikely to be significant when kh > ~10,000 md-ft.
The primary relative permeability relationship affecting condensate blockage is krg as a function of krg/kro in the near-well region. Saturation does not enter the calculation.
The impact of condensate blockage can be reduced by an increase in krg at high velocities (capillary numbers, Nc) in the near-well region. Considerable evidence for this effect exists from lab experiments and well tests.
November 23, 2018
e-notes (c) Curtis H. Whitson, Robert E. Mott

2. e-notes (c) Curtis H. Whitson, Robert E. Mott
References
Arun SPE paper
Gas Condensate Relative Permeability for Well Calculations
Measurement and Correlation of Gas Condensate Relative Permeability
Engineering Calculations of Gas Condensate Well Productivity
Examples
Condensate blockage skin estimation – a simple spreadsheet
Condensate blockage – single well simulation calculations and example
Single well simulations to demonstrate the fundamental rel perm relationship for condensate blockage.
Notes
November 23, 2018
e-notes (c) Curtis H. Whitson, Robert E. Mott