The Synergistic Effect of Algerian Na-Bentonite/Potato Starch/Grass Powder on the Enhancement of Aged Water-based Drilling Fluids

Abstract

Nowadays, the use of eco-friendly additives in drilling fluids to improve rheological properties is widespread. This work aims to examine and assess the rheological characteristics and fluid loss of drilling fluid suspensions containing Algerian Na-Bentonite (NaB) and potato starch (PS) as viscosifier upon the addition of grass powder (GP). The obtained results indicate that the aging tests applied on different drilling fluid suspensions during 192 h at (20 °C) reduce the values of apparent viscosity by an average of (14.3%), plastic viscosity (22.2%), yield point (6.7%), and shear stress (47.3%) when varying the (PS) concentration in the suspensions (0.6, 1.2, 2%) as well as the values of fluid loss (9.5%); meanwhile, the values of initial and final gel strength are increased (32.6% and 19.6%, respectively). Subsequently, the possibility to further improve the rheological properties of drilling fluid suspensions using an environment eco-friendly additive (GP) has been studied. The introduction of (3, 6, 9 g) GP in the aged suspensions increases the values of rheological properties, i.e., the highest efficiency of 18.4% has been achieved by adding 9 g of GP to 2% (PS) aged suspension. The fluid loss test indicates that increasing the (GP) concentration in the (NaB+PS) suspension reduces the fluid loss volume by 36.42%. This study demonstrates the synergy of combining cost-effective GP to (NaB+PS) in aged drilling fluids by enhancing significantly its rheological properties besides a better environmental protection.