FLOW ANALYSIS IN A ROLLER DRILL BIT DURING DRILLING USING WATER-BASED AND HYDROCARBON-BASED MUD

Abstract

Drilling is the main type of increase in hydrocarbon production. Bits of various types are used as a rock-destroying tool during drilling. When drilling any wells for oil and gas, drilling fluids are used as a working fluid. The flow of these types of liquids differs from the flow of water, which is an incompressible medium. The purpose of this work is to study the flow of the Newtonian fluid of water and two types of water-based drilling fluids, which is described by the power-law model of a non-Newtonian fluid and the hydrocarbon-based fluid of the Herschel-Bulkley type. In the work, the construction of the geometric model of the square bit was carried out, and the estimated unstructured grid of the liquid volume filling the internal area of the bit and the space behind the bit was constructed. Calculations of the three-dimensional flow of water, drilling fluids on water and hydrocarbon bases were carried out using the open platform OpenFOAM. It was found that during the flow of liquids described by non-Newtonian models, the kinematic viscosity of the liquid changes depending on the velocities and shear stresses. Another important factor in the use of non-Newtonian fluids when drilling wells is the reduction of hydraulic losses during their flow. This is achieved due to the presence of a certain structure of the liquid, non- zero values of shear stresses, lubricating properties even with their viscosity, which is ten times higher than the viscosity of water. Visualization of the flow of three types of fluids: Newtonian, non-Newtonian power-law and non-Newtonian Herschel-Bulkley type is presented. The use of non- Newtonian fluids makes it possible to reduce the formation of vortices and, as a result, also affects the amount of hydraulic losses in the direction of their reduction.