What type of charges and what shot density should be used prior to frac-packing?
For frac pack completions the operator must design the perforation shot density for a cased-hole gravel pack completion since reservoir fluid production will be through gravel packed perforation tunnels. Cased-hole gravel pack completions require large diameter perforations and high shot density to obtain the required inlet area and to minimize the convergent and linear flow restrictions associated with gravel pack completions. At the end of the fracturing treatment the perforation tunnels and casing-screen annulus must be packed with proppant to control formation sand production. Nodal analysis computer simulations can calculate the desired perforation shot density vs perforation diameter for the planned production rate. A 50% perforation efficiency factor should be applied to assure sufficient effective shot density i.e., if 6 spf are required then shoot 12 spf. In gravel pack completions the perforation inlet area is key to an efficient completion.
