ropellant-boosted perforating has proven to affordably increase completion and recompletion performance in a wide variety of saltwater disposal (SWD) wells and producers. Advances in integrating propellants with traditional shaped-charge perforating technology have enabled perforating and stimulation operations to be performed in one trip at lower cost than traditional two-step, shoot-and-treat methods. The critical success factor is the adoption of a progressively burning, solid propellant designed to increase penetration, eliminate clogged perforations and overcome near-wellbore damage from compaction caused by traditional shaped-charge perforators.
Standard perforating gun systems enhanced with propellant boosters create multiple 10-ft or longer radial fractures that remove skin to enhance the injectivity index. After the shaped charge fires and penetrates the casing, the slower progressively burning propellant breaks down the formation to lower treating pressures, reduce acid volume and improve rates.
Compared to offset wells, this 71% increase in injection volume was achieved at the same pressure. Compared to status quo offset SWD well completions, the propellant-enhanced SWD required 50% less acid, rig time decreased by an average of five days, and the lower pressure needed to achieve permitted rates reduced the horizontal pump size and associated power consumption.
In the two perforating tests with a shaped charge assisted by propellant boosters, propellant ignition occurred immediately after the explosion of the shaped charge. The burning of the propellant boosters generated high-pressure gas inside the gun and exited out into the perforation tunnel. This process creates a dynamic-overbalance event that enhances the perforation and creates fractures past the compacted rock (skin) produced by conventional shaped charges, thereby improving access to the formation.
When completion engineers consider the following four factors they become more willing to adopt propellants:
- Propellant boosters are safe to handle and transport;
- They are compatible with deep-penetrating, big-hole and equal-hole entry charges;
- Tools are assembled and verified away from the well site to lower operations risk; and
- Gun systems enhanced with propellant boosters can be conveyed and fired by all standard methods and with customized shot densities and phasings.