A Study of Non-Darcy Effects in Retrograde Gas Reservoirs

by
Kassim Mohamed Al-Riyamy, M.S.E.

University of Texas at Austin, 1995
Supervisor: Mark A. Miller

The non-Darcy effect is mainly experienced in high-rate gas and volatile oil wells. This effect arises from the fact that fluid flow near the wellbore has a turbulence component due to the convergence of flow at the wellbore resulting in high flow velocities. This phenomenon is particularly prominent in gas wells due to the low viscosity and high expandability of gases.

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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