In this work a semi-analytical solution method is elaborated to obtain the transient behavior of a vertical well intersected by a finite conductivity horizontal ("pancake") fracture. Both the constant production rate and the constant drawdown cases are considered. Permeability anisotropy and non-homogeneous formation structure are incorporated into the model formulation. The results can be used to evaluate pressure transient testing and/or to forecast the production increase. Comparison with the uniform flux and infinite conductivity solutions brings light to the effects neglected in those approximations. Late time pseudoradial behavior is interpreted in terms of pseudo-skin factor and the issue of optimal fracture conductivity is addressed.