Perforation is a special operation to crease an efficient communication path between a wellbore and a reservoir by creating tunnels. The effective paths allow reservoir fluid to flow into the well with minimum pressure loss (less skin as much as possible).
The process of perforation involves lowering a perforating gun into a wellbore to a planned depth and energizing the gun to be safely fired. When perforating a well, shape charges are fired and then energy from the explosion will create tunnels through casing, and cement and then into a reservoir. Length and diameter of perforation hole are dependent on the objectives which will be discussed later. Figure 1 shows the cross sectional of perforation.