Study of Rheology and Flow Behavior of Magneto-Rheological Fluids Under the Influence of a Magnetic Field and Its Potential Applications for Drilling and Completion Operations

Abstract

The use of magnetorheological fluids (MRF) is presented as an alternative to overcome some of the problems encountered in the drilling and completion of a well. The magnetorheological fluids can modify their rheological properties instantaneously under the influence of a magnetic field. In this thesis, MRF consist of a base fluid, magnetizable particles and a polymer that supports the particles. The magnetizable particles align in the direction of the magnetic field, thus modifying the rheology of the mixture. Because of this characteristic, the use of this fluid can have advantages in controlling fluid losses while drilling in narrow operating windows, to provide a tunable sealing mechanism that could work as a packer, to provide a set-on-demand slurry, and as a novel mechanism for releasing stuck pipe. Using existing correlations for estimating the pressure drop in pipes and annuli and a model to estimate the yield stress of the fluid based on concentration of the magnetizable particles and the magnetic field strength, it is possible to determine the pressure drop caused by the fluid behavior when in presence of a magnetic field. The rheological properties of the MRF are measured in a rotational rheometer with two electromagnets attached to the measuring cup. The magnetic field is varied, and the shear stress and viscosity are measured at different shear rates and magnetic field strengths. The settling ratio is evaluated comparing different carrier fluids, magnetizable particle concentration and use of surfactants. On an experimental setup, different MRF samples are circulated on a flow loop resembling circulation geometry where the pressure drop of the fluid is measured in linear sections and compared to the models. The experimental setup also serves as a small-scale well where different applications for this type of fluid could be tested. The objective of the project is to determine if the pressure drop generated by these samples when magnetized can be high enough to control a fluid loss, to create a strong sealing mechanism as an open-hole packer or other potential mechanisms.