The productivity indices drop-versus-drawdown increase relationship has been fairly well known and described in the literature. This effect is most likely to be expected in the carbonate reservoirs with cavernous-fractured-matrix porosity and rock heterogeneity. It was observed to occur in the wells of Ardalin field and its satellites located in the north of the Timan-Pechora Oil and Gas Province during the well performance analysis. The discussed fields are highly prolific with the well flow rates as high as 1.500 m3 /day. The changes of productivity indices as an effect to increasing drawdown were not taken into account during well testing, modeling and production forecasts in the early phase of development. However, it becomes a necessity as the water production grows while the wells are converted from flowing to artificial lift with the electric submersible pumps, when the reservoir engineers need to achieve the optimal production rates and provide reliable production forecasts. Taking account of this factor will allow making the right choice of appropriate pumping equipment. The peak productivity of wells observed in the field appeared to be way below the original forecasts, which did not include the reservoir compressibility.

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