Optimizing stimulated reservoir contact 

Halliburton X-Tend is the latest development in hydrochloric acid fluid system. It allows deeper penetration of live acid into the formation, increasing stimulated reservoir contact compared to conventional HCl systems. This innovative fluid system is applicable to matrix acidizing, acid fracturing, and wellbore cleanup treatments in carbonate formations. It’s the latest in advance fluid systems from Halliburton. 

Acid retarding properties 

Extensive laboratory testing has been performed using this new HCl fluid system and benchmarked against straight HCl and emulsified acid at different temperatures and permeability ranges. X-Tend delays the acid reaction on the carbonate surface almost independently of the pumping rate. Furthermore, this unique system can be injected below or above the optimum rate, even at 28% HCl acid strength.


  • The use of HCl as the calcite-dissolving component provides the best dissolution capacity available. Treatment fluid can be formulated using up to 28% HCl, when needed
  • Due to its chemically retarded properties, it can be pumped below the optimum injection rate with little to no the risk of NWB facial dissolution
  • With on-the-fly mixing, HCl retardation can be adjusted based on the concentration of the retarding agent
  • This is a polymer-free system
  • Due to the low viscosity, low friction pressures are expected, and the treatment can be bullheaded or pumped through coiled tubing or jointed pipe
  • Standard corrosion inhibitors for HCl can be used at similar dosages
  • This system has similar delayed characteristics as emulsified acid, but without the high friction pressure produced by the emulsion and with a safer environmental profile (no diesel or emulsifiers involved)
  • This fluid system can be integrated with Halliburton diversion technologies such as AccessAcid®  stimulation service or Guidon AGS™ acid diversion system to optimize fluid distribution along the pay zone

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