Effect Of Wellbore Storage And Damage On The Transient Pressure Behavior Of Vertically Fractured Wells

A model recently presented by Cinco et al. for the transient pressure behavior of wells with finite conductivity vertical fractures was modified to include the effects of well-bore storage and fracture damage. An infinitesimal skin was considered around the fracture and it was handled as a dimensionless factor defined as (pi/2)(w/sub d//x/sub f/)(k/k/sub d/ - 1). It was found that the well behavior is importantly affected by the fracture damage. When plotted as a function of log p/sub wD/ vs. log t/sub D/ for short times, results show flat, almost horizontal lines that later become concave upward curves asymptotically approaching the curve for undamaged fractures. This behavior is shown even by slightly damaged fractures. Also, it was found that important information about the fracture characteristics may not be determined when well-bore storage effects are present. (24 refs.)