Enhanced Rheological and Filtration Properties of Water-Based Mud Using Iron Oxide and Polyanionic Cellulose Nanoparticles

The unstable wellbore created by the infiltration of drilling fluids into the reservoir formation is a great challenge in drilling operations. Reducing the fluid infiltration using nanoparticles (NPs) brings about a significant improvement in drilling operation. Herein, a mixture of iron oxide nanoparticle (IONP) and polyanionic cellulose nanoparticle (nano-PAC) additives were added to water-based mud (WBM) to determine their impact on rheological and filtration properties measured at 80 °F, 100 °F, and 250 °F. Polyanionic cellulose (PAC-R) was processed into nano-PAC by wet ball-milling process. The rheological behaviour, low-pressure low-temperature (LPLT), and high-pressure high-temperature (HPHT) filtration properties performance of IONP, nano-PAC, and IONP and nano-PAC mixtures were compared in the WBM. The results showed that IONP, nano-PAC, and synergy effect of IONP and nano-PAC in WBM at temperatures of 80 °F and 250 °F improved the density, 10-s and 10-min gel strength (10-s Gs and 10-min GS), plastic viscosity (PV), and the yield point (YP), while the pH was constant at 9.0. The mixture of 1.5 wt.% IONP + 0.25g nano-PAC in the WBM unveiled the most promising and optimal properties. At LPLT, the mixture improved the YP by 11% and reduced the LPLT fluid loss volume (FL) by 32.4%. At HPHT, the mud density increased by 3%, 10-s GS by 56%, 10-min GS by 52%, and the YP by 33.3%, while the HPHT FL decreased by 21%. With 1.0 g concentration at 100 °F, the nano-PAC achieved the greatest reduction in the FL of the WBM by 63%, followed by PAC-R by 57% before IONP that showed 36% reduction. Overall, the impact of IONP and nano-PAC in the WBM is evident and while the IONP showed more improved PV, the nano-PAC is more desirable for fluid loss control when 1.0 g at 100 °F was used. The use of combined IONP and nano-PAC could be beneficial for mitigating fluid loss and averting wellbore problem.