Modified locally derived graphene nanoplatelets for enhanced rheological, filtration and lubricity characteristics of water-based drilling fluids

Abstract

Drilling fluid rheology, filtration, and lubricity are fundamental parameters that influence the efficiency and ease of drilling operations. The drilling industry is constantly exploring different research areas for stabilizing and improving these parameters at high temperatures. The use of drilling fluid additives, especially synthetic polymers, poses a threat to the environment. Herein, rice husk char (RHC) was used to synthesize graphene Nanoplatelets (GNP) whose surface is modified with triton-X100 nonionic surfactant. Field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR), Particle size distribution (PSD), Energy Dispersive X-Ray Analysis (EDX), and Zeta potential analysis are performed on the synthesized nanomaterials to verify their morphology, functional groups, particle size, elemental composition, and material stability. Synthesized GNP from RHC (GNP-RHC) along with surface-modified GNP-RHC (GNP-TXT) were examined critically and their properties compared using a water-based mud (WBM) formulation. The rheological and lubricity characteristics of all the mud samples were determined before and after hot rolling (AHR), and the filtration properties were determined under API and high pressure high temperature (HPHT) conditions. The TGA results indicate that GNP-TXT nanomaterial resists thermal degradation with 10% weight loss at 300 °C, while the zeta potential analysis indicates the materials are stable. Since the GNP-TXT particles are so well dispersed, the GNP-TXT-based muds worked better than the GNP-RHC-based muds and was more stable at controlling filtration and improving rheological properties. For example, at 1.5 g AHR, the plastic viscosity of GNP-TXT-based mud decreased by 22.2% from 9 to 7 cP, while that of GNP-RHC-based mud decreased from 17 to 7 cP by 59%. Also, the API and HPHT FL of WBM of 11 and 24.8 mL, respectively, were reduced by GNP-TXT-based muds to the range of 8.6 and 9.8 mL for API and 18.6 and 22.3 mL for HPHT. However, GNP-RHC-based drilling muds showed a lower fluid loss control of the WBM between 9.6 and 10.2 mL for API and between 19.6 and 23.6 mL for HPHT. Furthermore, the coefficient of friction of the WBM of 0.45 was decreased with GNP-RHC concentrations between 0.47 and 0.32, while GNP-TXT demonstrated a higher decrease between 0.26 and 0.20.