The goal of acid-stimulation treatments is to remove or bypass formation damage from the near-wellbore area. The success of matrix treatments depends on the uniform distribution of the treating fluids over the entire production (or injection) interval.

Acid placement methods should not cause formation damage, should be compatible with the treating fluids (over flush or displacement fluids) and formation brines. It should clean-up rapidly and completely when the well is put back on production, and should be stable at the bottom hole treating conditions.

Viscoelastic surfactants (VES) have been used in the industry for stimulation applications. VES acids exhibit remarkable viscoelastic character, which can significantly increase the viscosity of the fluid. Therefore, VES fluids can be used to improve the fluid’s diverting ability in acidizing treatments. VES acid systems have been successfully applied in the oilfield industry as fracturing fluids and matrix acidizing fluids. A VES based in-situ gelled acid system can be prepared by adding surfactant to the acid.