The development of new oil production techniques such as extracting via long deviated wells and drilling in ultra-deep water, requires improvements in the performance of conventional drilling fluids. It is essential to design new recipes of drilling fluids that possess improved properties both at rest and in dynamic. Seeding nanoparticles into a drilling fluid is a recent development aiming to improve the drilling fluid’s performance. However, it is still in its infancy, and many inconsistent results have been reported. Understanding the influences and the mechanisms of nanoparticles with regards to different drilling fluid functions could provide the information required for designing novel receipts. This project aims to explore and assess the influence of various nanoparticles and their mixtures on the performance of water-based muds (WBM), including rheological, filtration, swelling, lubrication properties, and corrosion inhibition, as well as lifting capacity improvement.
A number of nanoparticles (SiO2, CNT, CB, Gr and Al2O3) and their mixtures were employed in two WBMs, both with and without biopolymers. The particles and nanofluids were characterized by scanning electron microscope (SEM), dynamic light scatting (DLS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermal-gravimetric analysis (TGA). The rheological properties of the formulating drilling fluids were examined by an Anton Parr rheometer and Fann 35 Viscometer. The filtration and lubrication properties of different hybrid nanoparticle and nanofluid based WBMs were conducted by using a differential sticking tester. A novel simple method to simulate pipe erosion-corrosion in a reservoir-like environment under both static and dynamic conditions was developed, and the influence of wellbore temperature, pressure and salinity of WBMs on the corrosion behaviour of the drill pipe was examined. The lifting capacity of the drilling fluid flow was simulated by a four-way coupling scheme to take into consideration particle-particle interactions.
The results show that the addition of nanoparticles generally increased the performance of WBMs both under stationary and dynamic conditions, due to the formation of an appropriate gel structure and easy break under low shear stress. In addition, these nanoparticles increased the degree and the speed of the structural recovery by reducing the relaxation time, which is desirable to prevent the sedimentation of the cuttings and weighting materials. In particular, using appropriate hybrid nanoparticles allowed for enhancements in rheology, filtration, lubrication and thermal features, leading to an overall performance improvement. For WBM with biopolymers, the addition of nanoparticles was found to increase the thermal and mechanical stability of the biopolymer, leading to less filtrate loss and improved performance.
The addition of SiO2/Xanthan nanoparticles was found to inhibit the erosion-corrosion rates of the drill pipe, which is also affected by the cuttings morphology and concentration. The simulation results showed that the cutting’s transport process and fluid viscosity were significantly enhanced by adding nanomaterials.
The present work suggests that using appropriate nanoparticles mixtures could improve the overall performance of conventional drilling fluids, leading to improved rheology, filtration, and transport properties.
