... not always agree with pressures predicted by fracture design models. They listed five factors that had the potential for causing this disagreement: (1) high perforation friction pressure, (2) high friction pressure in the fracture, (3) the generation of multiple parallel fractures, (4) higher actual fracture...

... crosslinking is an equilibrium process which can produce very high fluid viscosities under conditions of low shear. While this property is very desirable once the fluids enters the fracture, it can cause high frictional pressure to be developed in the tubular under certain flow conditions. A crosslink...