Crosslinked guar gel

From Wikimarcellus

Injecting borate-crosslinked guar gel is one of the techniques used to increase fracturing fluid viscosity. Guar, or derivatives of guar gum, from the guar beam plant (seeds) is crosslinked with borate ions to create a polymar for this purpose.

The pulp of the guar plant seed is dissolved in a fluid such as mineral oil and then rehydrated by water. It is called linear gel at this stage. By adjusting the pH, and using a metal substrates such as Borate, the gel can be cross linked. It produces much higher viscosity in the gel.

Oil, diesel or propane can also be used as a base fluid instead of water depending upon the water sensitivity of the formation. They can be gelled or pumped with a friction reducer according to need for viscosity.