The type of mechanism used to create the perforations. The total number of perforations in the interval. The shot density of the perforated interval in number of perforations per length. The diameter of the perforation entrance holes. The average length of the perforations measured from the casing to the end of the perforation. The angular range of perforations created by a perforating gun set up for directional shooting, expressed clockwise from north. If perforations are from due north to due east, the angle is 90 degrees. The angle between perforations with respect to the centerline of the wellbore. Examples are 120 deg. for perforations oriented at 0, 120 and 240 deg., and 180 deg. for perforations oriented at opposite sides of the wellbore. The assumed diameter of the crushed zone in each perforation in the interval. The ratio of the crush zone permeability to the damaged zone permeability around the perforations. The length of the gun. The type of gun used to create the perforation. The size of the explosive charge. The type of explosive charge. Name of formation penetrated. Name of formation, regionally dependent.