Improved Rheological Properties and Lubricity of Drilling Fluids at Extreme Temperatures and Pressures Using Graphene Oxide and Flowzan

Summary The use of graphene-based lubricants in water-based drilling fluids (WDFs) has emerged as a promising avenue for enhancing their tribological properties, particularly under high-temperature (HT) conditions, by incorporating inorganic-material-based additives. For this study, we used a green and adsorption-based approach to prepare highly-dispersed graphite for modification, utilizing a cationic surfactant. Our research demonstrated the effective dispersion of the prepared graphite in water, characterized by low sedimentation rates and small contact angles in distilled water. The concentration dosage of Flowzan® on graphite was determined to be 0.02 g/g. To assess the effectiveness of modified graphite as a lubricating additive in water-based drilling, we conducted rheological studies and measured viscosity coefficients. The results revealed a significant decrease in the viscosity coefficient of the drilling fluid by 68% at 300°F when incorporating 0.05% modified graphene. Furthermore, the study investigated the thickness of six WDFs under high-temperature, high-pressure (HTHP) conditions. The addition of 3% graphene expansion resulted in a notable reduction in the volume of HTHP liquid filtrate by up to 30% compared with the control. These experimental findings underscore the advantageous effects of nanoparticle addition on properties such as lubricity, rheology, fluid loss, and thermal stability, potentially revolutionizing the drilling process. In addition to evaluating the performance of modified graphite, we analyzed its primary, crystalline, and morphological properties using various techniques, including particle size tests, zeta potential tests, Fourier transform infrared (FTIR), powder X-ray diffraction (XRD), and scanning electron microscopy (SEM). These analyses elucidated the lubrication mechanism, demonstrating that graphite modification primarily occurred through physical adsorption without altering the crystal structure. These insights provide valuable guidance for the development of high-performance WDFs tailored to endure the challenges of drilling operations.