The main objective of this paper is to present a practical interpretation of the pressure behavior of a hydraulically fractured vertical well located in a naturally fractured reservoir. The interpretation is based on analytical equations derived to determine permeability, fracture storage capacity ratio, interporosity flow coefficient, skin and wellbore storage from the pressure derivative plot without using type-curve matching technique. These parameters are obtained by making use of the characteristic lines and points found on the log-log plot of pressure and pressure derivative. The point of intersection of the straight lines corresponding to the different flow regimes are very useful in checking the parameters obtained from the slopes, when the pressure derivative curve is not smooth. The method of analysis is applicable to both drawdown and buildup tests in uniform flux, infinite conductivity or finite conductivity hydraulic fracture. A step-by-step procedure and Examples are included to illustrate the proposed technique.
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