Novel approaches to cross-linking high molecular weight polysaccharides: Application to guar-based hydraulic fracturing fluids

We report on recent work carried out using computational chemistry techniqu es which is aimed at suggesting novel ways of improving upon current method s of handling guar-based fracturing fluids. We describe generic methods ava ilable for modelling macromolecular, polysaccharide systems and apply these methods to building representative sections of the guar polysaccharide mol ecule, and to study its conformations in vacuo and in aqueous solutions usi ng molecular dynamics. We then propose some novel cross-linking agents whic h differ from most of those currently under consideration in that they are extended, linear molecules related to polyethers. Representative cross-link ing agents are then prepared and tested with various guar preparations. Thi s study shows that with the correct choice of cross-linking agent, the over lap concentration C* can be reduced below the expected level for particular guars.