5PE 154/~ Sum......,. Analysis of field and laboratory data shows that variations in pressure drop caused by changing perforation-entry friction tends to influence the prediction of fracturing treatment performance. This paper presents experimental data on perforationentry friction as it affects fracturing treatment design.Prefracturing treatment planning practices include examination of numerous treating-pressure charts to determine formation type curves, which are used to anticipate fracturing treatment performance and screenout modes. Perforation-entry friction may vary greatly because of erosion of the perforation and near-wellbore fracture, and this changing friction pressure is often not properly accounted for in planning.This paper presents discussion and data (laboratory and field) that show the degree of perforation erosion encountered in fracturing operations and proposed guidelines to determine when to alter pumping schedules to account for proppant erosion to perforations, cement sheath, and formation.