During the development of the San Francisco field near Neiva, Colombia, South America, significant reductions in productivity indexes were encountered when wells were put on artificial lift after being perforated. These wells were completed in the Caballos formations, which typically span over 400 gross ft with 110 ft of net pay and appear to become damaged when exposed to water. Tubing conveyed perforating is the preferred technique due to its advantage of better inflow performance. When retrieving the tubing conveyed guns, aqueous control fluids were used to control some wells prior to running a sucker rod pump. Thus, these high volume wells usually suffered an increase in formation damage which lowered their productivity indexes.
A workable solution to this problem was developed and called a seating nipple bypass assembly. This tool enables conventional tubing conveyed perforating guns and a differential firing head to be attached to the bottom of a tubing string. The tool also contains an 3-½ in. API seating nipple so that a rod pump can be seated and operational when the guns are activated. Thus, a well can be completed with the benefits of using tubing conveyed perforating and immediately commence artificial lift. This achieves greater production rates without damaging the producing formation, as could have happened when controlling the well with aqueous based fluid while reconfiguring the bottom hole assembly.