{HEAD ~ Compositions} and methods are given for {TAIL ~ delayed breaking} of viscoelastic surfactant gels inside formation pores, particularly for use in hydraulic fracturing 
{ HEAD ~ Compositions } and methods are given for { TAIL ~ delayed breaking } of viscoelastic surfactant gels inside formation pores , particularly for use in hydraulic fracturing
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH