A new simplified method is presented for analyzing wells with wellbore storage and skin in double porosity systems. The method applies to damaged, acidized and fractured wells in fissured reservoirs, and it is based on the mathematical properties of the solutions (Bourdet et al. 's solutions1,2 ).

By taking the second derivative of the dimensionless pressure solution for a well with wellbore storage and skin in a homogeneous system a locus is defined which contains the maximun of the curve of p/tp/Cp) vs. tD/CD, for each value of the parameter CD exp(2S). The use of the maximun points curve together with the derivative value for radial flow of the total system (fracture and matrix) is used to define a Match Point on the log-log field data graph. This Match Point is also defined on the Type Curve and allows the calculation of C and k, without the neccessity of using the conventional Type Curve Analysis, nor a computer program for pressure transient analysis.

Further properties of the solutions are used to determine S, ω and X, making use of the transition curve minimun (for the pseudo-steady interporosity flow model) and the late transition data (for the interporosity flow model). The simplified analysis presented in the paper is illustrated with actual field examples from several different fissured reservoirs; it is accurate enough for engineering purposes (average relative errors less than 10%) and only requires a few calculations, using the log-log field data graph and a hand held calculator. It can be used as a screening method of analysis. It can also be implemented in more advanced programs of analysis.

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