A Study of Non-Darcy Effects in Retrograde Gas Reservoirs

by
Kassim Mohamed Al-Riyamy, MSE

University of Texas at Austin, 1996
Supervisor: Mark A. Miller

Retrograde gas wells producing from tight reservoirs (i.e. with permeability below 10 md) are susceptible to a region of high condensate saturation buildup near the wellbore when the bottom-hole flowing pressure drops below the dewpoint. The buildup of liquid saturation near the wellbore causes the well to lose deliverability.

Apparent non-Darcy flow may appear in well tests due to any mechanism which causes the well skin to be flowrate dependent. This study evaluates apparent non-Darcy flow in a rich retrograde gas condensate reservoir using the VIP commercial reservoir simulator. This case study shows that there is little correlation between condensate accumulation near the wellbore and the non-Darcy effect. This study also shows the effects of condensate accumulation near the wellbore on the interpretation of drawdown and buildup responses.

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