On any open or perforated interval longer than 30 ft, the natural tendency is for acid to take the highest-permeability path and ignore the rest. Diversion forces coverage — and decides whether the treatment affects 20% or 90% of the pay.
Three families, three jobs
- Chemical diverters (gels, polymers, VES) raise viscosity in high-perm streaks until acid finds the next zone.
- Foam diversion creates a high apparent viscosity using gas–liquid mixtures; effective in long intervals and high-rate coiled tubing operations.
- Mechanical diversion (straddle packers, ball sealers, CT bottomhole assemblies) physically isolates the target.
Sequence matters more than choice
Most successful long-interval treatments combine all three across a multi-stage schedule — pre-flush + main acid in stage 1, diverter, main acid in stage 2, and so on. The right sequence depends on skin distribution, completion type and rate envelope, which is exactly what the matrix acidizing software pumping-schedule optimizer is built to find.