This work investigates the effects of initial reservoir pressure on the computation of effective permeabilities for homogeneous and heterogeneous solution-gas-drive reservoirs which are initially above the bubble-point pressure. The heterogeneous system considered is that of a two-zone composite reservoir with different absolute permeability and/or relative permeability curves in the two regions. It is shown that the initial effective oil permeability may be estimated from drawdown and buildup pressure data. It is also shown that one can obtain accurate estimates of computed effective permeabilities as pointwise functions of wellbore pressure from drawdown data during the time period that the wellbore pressure is less than the initial bubble-point pressure. From the estimates of effective permeabilities obtained, it is shown that for the case of homogeneous solution-gas-drive systems one can construct approximate effective (or relative) permeability curves by nonlinear regression analysis techniques. For the case of heterogeneous solution-gas-drive reservoirs it is shown that if the initial reservoir pressure is above the reservoir bubble-point pressure then the effective oil permeability of the inner or the outer zone might be obtained from the analysis of drawdown and/or buildup pressure data.

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