Effects of formation damage and high-velocity flow on the productivity of perforated horizontal wells

A comprehensive semianalytical model has been built to investigate the effects of drilling and perforating damage and high-velocity flow on the performance of perforated horizontal wells. The model incorporates the additional pressure drop caused by formation damage and high-velocity flow into a sermanalytical coupled wellbore/reservoir model. The reservoir model considers the details of flow in the vicinity of the wellbore, including 3D convergent flow into individual perforations, flow through the damaged zone around the wellbore and the crushed zone around the perforation tunnels, and non-Darcy flow in the near-wellbore region. The wellbore flow model includes the effect of frictional pressure drop. Both oil and gas wells are considered. The expressions provided in this paper for additional pressure losses caused by perforating damage, drilling damage, and high-velocity flow can be used to optimize perforating parameters and decompose the total skin into its components (perforation pseudoskin, damage skin, and non-Darcy skin).