The main use of guar and its derivatives in the oil-well industry is in oil exploration as a drilling agent. Its functions are to control viscosity and water loss of the mud to suspend the mud materials, to reduce friction and to lubricate and cool the drilling bit. Guar gum, which has high molecular weight, satisfies the requirements of an effective friction reducer.
In fact, friction reductions of as much as 70% are readily attainable with guar gum itself. However, depolymerised guar gel contains about 10% residue which can cause formation damages. A range of chemical derivatives of Guar gum has been synthesized and the modifications improve the solubility, rheology properties and reduce the number of undissolved residues of polymer in hydrofracking fluid after the breaking process.