Amine-functionalized graphene oxide in polyamine based drilling fluids for nanosized pore plug filter cake

Abstract

Water-based muds (WBM) is widely used in oil and gas wells drilling industry due to its environmental friendliness and lower operational cost implication. However, WBM drilling process has severe shale swelling problems caused by the hydration due to the shale minerals affinity to water from the WBM which reduces WBM technical performance. Thus, additives that fitted to its function should be added in WBM formulations to enhance overall drilling performance to achieve the target depth. In this study, graphene oxide (GO) is selected as the additive due to its excellent physico-chemical properties could benefit as an option to mitigate the above challenges. GO was synthesized via Modified Hummers' method where the average thickness obtained was ±46 nm. The GO additive was then modified with Octadecylamine (ODA) to alter the surface hydrophobicity. The contact angle of GO changed from 25° ± 0.5 to 98.9° ± 1.8 after the ODA modification. The hydrophobic GO (HGO) was then added in the drilling fluid formulation and the drilling fluid performance was evaluated based on filtration characteristics. The filter cake showed a thickness of 0.832 mm and a filtrate volume of 5.09 ml at 150 psi/30 min after the filtration with drilling fluid treated with HGO. The filter cake formed was the thinnest and the least filtrate volume was produced which are 30% and 20% reductions compared to drilling fluid without GO, which signify the remarkable reduction of fluid loss. On top of that, the drilling fluid with HGO demonstrated a good rheology property over wide shear rate scheme and enhanced thermal stability. Hence, GO was highly recommended as a potential fluid loss control nano-additive in drilling fluid formulation.