Cellulose nanofibrils as a replacement for xanthan gum (XGD) in water based muds (WBMs) to be used in shale formations

"In this work, the potential replacement of xanthan gum (XGD) by cellulose nanofibrils in the composition of water based muds (WBMs) was studied. Bleached (B-CNF) and unbleached (L-CNF) cellulose nanofibrils, mainly differentiated by their lignin content, were tested and their performances were compared with that of XGD. The effects of cellulose nanofibrils on the rheological and filtration properties of WBMs were investigated. Rheometric analysis showed a shear-thinning behavior more noticeable for fluids containing B-CNF and XGD, while filtration properties were improved using L-CNF. The Sisko model was used to determine rheological parameters. Finally, it was found that by replacing XGD by double concentration of L-CNF in a WBM for Argentina shale, similar rheological properties were obtained. Structural changes were assessed by using Scanning Electron Microscopy (SEM). Particles agglomeration and good film formability were observed. Furthermore, WBMs with lignin-containing cellulose nanofibrils exhibited a better thermal stability after aging."