Helical Pipe Viscometer System for Automated Mud Rheology Measurements

Abstract

Abstract Optimum well construction operations require frequent and accurate measurements of drilling fluid properties. Optimized hydraulics, hole cleaning and well control requires proper management and characterization of fluid rheology and density. Currently, the methods by American Petroleum Institute (API) standards are used for drilling fluid property measurements. However, these methods are sporadic, labor-intensive and the data quality is highly dependent on the practicing engineer. These dated methods need to be replaced and improved by an automated, continuous and practical way of measuring and monitoring drilling fluid properties. In this paper, we introduce a helical-pipe viscometer system for automated mud measurements. An automated flow-loop was constructed to perform experiments with Newtonian and non-Newtonian fluids. Flow tests were conducted in two straight- and two helical-pipe test-sections. Frictional pressure loss data was obtained from each section simultaneously. Flow rate, density and temperature data were obtained using a Coriolis flow meter. It was observed that the toroidal geometry results in secondary flow due to the centrifugal forces. Therefore, elevated frictional pressure losses and delayed transition to turbulent flow were observed in the experiments from the helical-pipe test-sections. A machine-learning regression model was trained using the results from the experimental data for friction factor predictions by the helical pipe pressure loss measurements. The proposed approach was compared with both the experimental data and other theoretical equations reported in the literature. It was observed that the existing correlations in the literature for non-Newtonian fluids are not accurate for the characterization of Herschel Bulkley fluids. Using the trained machine learning model, an algorithm was developed and tested to prove the applicability of the system for automated rheological property determination. Very good accuracy was observed when comparing helical pipe viscometer measurements with standard API measurements. Helical pipe viscometers offer distinct advantages over standard pipe viscometers, such as compact size and more versatile frictional pressure loss profiles. They are also of interest for the hydraulic design of coiled tubing and slim-hole operations, where the maximum allowable flow rate is often limited by frictional pressure loss.