The fluids commonly used in frac-pack treatments were initially designed for either fractruing low permeability formations or for conventional gravel pack operations. These fluids do not address the unique problems found when fracturing higher permeability formations. Conventional frac-pack fluids (borate crosslinked guars and HEC) undergo whole polymer leakoff, and create a deep invasion bank of concentrated polymer that is very difficult to break and can lead to high formation damage.
Viscoelastic surfactant (VES) fracturing fluids have been developed which exhibit excellent rheological properties and still maintain low formation damage characteristics even in high permeability formations. These fluids are completely polymer free and do not rely on internal chemical breakers to degrade the fluid viscosity.
This paper will detail the results of recent laboratory studies on viscoelasitic surfactant fracturing fluids, and will compare the rheological and formation damage properties to other conventional fracturing fluids. The laboratory findings will be substantiated by several field case studies.