A new semi-analytical model for vertical or horizontal wells in heterogeneous elongated linear reservoirs is presented. In fluvial environments, such reservoirs can be formed due to the effect of low sinuosity river channels.

Transient pressure response or fractional flow rate from well segments can be calculated using the model. To obtain the solution, semi-permeable wall model and strip-wellbore model are used. A wellbore may penetrate several different permeability zones and skin factor can be different along the wellbore. It is shown that early-time linear flow behavior, which can be often seen in acidized carbonate reservoirs, can be approximated by the strip-wellbore model.

Type-curves for the heterogeneous elongated linear reservoirs, which may be used directly in well test analysis, can be generated using the model developed in this study. If the results of production logging are available, they are useful for the analysis since the transition of fractional flow rate from each well segment can be calculated. Such analyses become important to determine the size and rock properties of each heterogeneous zone, which is critical for future production forecast.

The validity of the model is confirmed by comparison with the results of numerical simulation. This study provides a new tool for studying and analyzing the pressure behavior of wells completed in fluvial environments as well as acidized carbonate reservoirs.

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