Helical flow of non-Newtonian fluids, with reference to drilling fluid flow.

Morton, John Douglas

Abstract

This thesis Is motivated by a desire to understand better the complex flow of drilling fluids in oil wells. After an initial discussion of the flow and its complexities, mathematical models are considered, and a 'helical flow' model adopted as being a reasonable approximation to the flow which may be solved in practice. Rheological models for the fluids are discussed, and it is shown that, with helical flow, a shear rate dependent viscosity model is of considerable generality. Numerical methods for obtaining velocity profiles from these models are explored and it is suggested that an iterative finite difference procedure is the most suitable to the purpose of understanding better the flow of drilling fluids. The iterative finite difference procedure is implemented in a computer program 'MUDFLO' which can be operated using either a consistent dimensioned system of units, or using the dimensionless variables defined in the text. It is shown that three dimensionless parameter groups are sufficient to describe completely the helical flow of a power law fluid. A set of velocity profile graphs is presented, covering typical values of these three parameter groups. From this set of graphs, the velocity profiles for most practically occurring flows of power law fluids may be interpolated. Some computational difficulties are however reported in calculations using the Bingham plastic fluid model, and using the power law fluid model with very low fluid index. The results of the computer program withe the power law fluid model are supported by comparison with existing experimental data, and by discussion of the general characteristics of the set of dimensionless velocity profile graphs.

Citation

MORTON, J.D. 1978. Helical flow of non-Newtonian fluids, with reference to drilling fluid flow. Robert Gordon's Institute of Technology, MPhil thesis. Hosted on OpenAIR [online]. Available from: https://doi.org/10.48526/rgu-wt-1993278

• Thesis Type: Thesis
• Deposit Date: Oct 16, 2024
• Publicly Available Date: Oct 16, 2024
• DOI: https://doi.org/10.48526/rgu-wt-1993278
• Public URL: https://rgu-repository.worktribe.com/output/1993278
• Award Date: Nov 30, 1978