Application of Novel Magnetic Surfactant-Based Drilling Fluids for Clay Swelling Inhibition

Abstract

Water-based drilling fluids are widely employed in the oilfield industry for the efficient and smooth drilling of wellbore reservoirs. In this study, a novel drilling formulation was prepared by mixing a magnetic surfactant in the base mud formulation. Several drilling fluid tests were conducted, which include steady shear and dynamic rheology, filtration, clay sedimentation, clay swelling, and particle size distribution analysis. Different analytical techniques─XRD, FTIR, and TGA analyses─were performed to study the interactions of magnetic surfactant with the clay platelets. The experimental results of the surfactant-modified formulations were compared to the base mud formulation. Thermal gravimetric analysis of the surfactant-modified mud showed improved thermal stability compared to the base mud. FTIR analysis results of the base mud and surfactant-modified mud were compared. In the steady shear rheology experiments, the flow curves of the base mud and surfactant-modified mud showed that the addition of surfactant in the base mud affects the shear stress of formulation. The shear stress data of rheology was fitted to the Herschel–Bulkley model, and model parameters trends were assessed with and without the addition of surfactant in the base mud. Shale inhibition tests showed that the incorporation of magnetic surfactant minimized the clay hydration of swelling, thus proving a superior shale inhibitor. The particle size analysis showed that the average particle size of clay particles increased with the increasing concentration of the magnetic surfactant. The linear swelling analysis of clay showed that the rate of swelling was 90% in the surfactant-modified mud as compared to the swelling rate in deionized water. According to the zeta potential, the combination of surfactants significantly affects the electrokinetic behavior of dispersion. Further, the XRD proved that the interlayer spacing of clay increasing while interacting with magnetic surfactant molecules indicates the ability of magnetic surfactant as a shale swelling and hydration inhibitor for water-based drilling formulations.