Experimental analysis and predictive modelling of surge and swab pressure mitigation using graphene-based drilling fluid in shallow wells

Surge and swab pressures generated during tripping operations pose significant risks in shallow well drilling under narrow pressure margins. These uncontrolled pressure fluctuations can lead to formation fracturing or influx. Despite advances in nanoparticle-enhanced drilling fluids, most existing studies focus on static rheological and filtration properties, with limited experimental evaluation of transient pressure behavior. This study experimentally investigates the performance of graphene oxide-enhanced water-based drilling fluids (GO-WBDFs) in mitigating surge and swab pressures under dynamic conditions. Drilling fluids containing 0.0, 0.1 and 0.45 wt.% GO were formulated and characterized using rheological measurements, low-pressure low-temperature filtration tests and microstructural analysis (field emission scanning electron microscopy, X-ray diffraction and zeta potential). Surge and swab pressures were measured in a custom-built flow loop under varying annular diameter ratios (3.7–8.5 cm), eccentricities (0.0–0.9) and tripping speeds (0.45–0.54 m/s). The results show that the 0.1 wt.% GO formulation provides optimal performance, achieving up to 22.5% reduction in surge pressure compared to the base fluid. Filtration loss decreased by 16% at 0.1 wt.% GO, while rheological modelling using Yield Power Law and Herschel-Bulkley models yielded excellent agreement with experimental data (R 2 > 0.998). Microstructural analysis confirmed stable dispersion and nanosheet network formation, contributing to enhanced shear-thinning behavior and pressure damping. The findings demonstrate that low concentration GO effectively improves drilling fluid performance under dynamic conditions by linking microstructure, rheology and pressure responses. This study provides one of the first experimental validations of surge and swab pressure mitigation using GO-enhanced fluids and offers practical guidance for optimizing drilling fluid design and tripping operations in shallow wells.