Investigating the influence of fluid rheology and multiphase flow on pressure and flow dynamics in non-Newtonian wellbore systems

Abstract

This thesis investigates the influence of fluid rheology and multiphase flow on pressure and flow dynamics in non-Newtonian wellbore systems, with a specific focus on the parameters affecting pressure losses. One of the major parameters examined in this study is eccentricity, which refers to the offset between the wellbore and the drill string. Non-Newtonian fluids, characterized by their complex viscosity behavior, present unique challenges in wellbore operations, particularly in drilling, production, and completion processes. Key parameters such as fluid viscosity, shear rate, flow velocity, pipe geometry, and especially eccentricity are systematically analyzed. The findings reveal that eccentricity significantly affects pressure losses by altering flow patterns and increasing frictional forces within the annulus. Eccentricity leads to asymmetric flow distribution, which in turn impacts the overall pressure gradient and efficiency of fluid transport. Results highlight the necessity for accounting for eccentricity in the design and operation of wellbore systems. The study provides practical insights into optimizing drilling and extraction processes, aiming to minimize pressure losses and improve operational efficiency. By enhancing the understanding of how eccentricity and other parameters influence pressure dynamics, this research contributes to safer and more cost-effective wellbore operations.