Improvement of the methodology for measuring plastic viscosity and dynamic shear stress of drilling fluids

Abstract This article focuses on developing a methodology for measuring the rheological properties of drilling fluids using the Marsh funnel, an essential tool for analyzing drilling fluids. The primary objective is to determine plastic viscosity and dynamic shear stress based on apparent viscosity measurements, facilitating the assessment of fluid behavior under mechanical loads. The study systematically analyzes scientific and technical literature on determining the rheological properties of fluids, particularly drilling fluids. A detailed analysis of the flow process in the Marsh funnel examines the relationship between apparent viscosity, plastic viscosity, and dynamic shear stress. To implement the methodology, standard geometric dimensions of the funnel were utilized, and calculations of parameters influencing rheological characteristics were performed. The described experimental stages encompass measuring the outflow time of the fluid from the funnel and analyzing the obtained results, which allows for the determination of plastic viscosity and dynamic shear stress values. The presented methodology facilitates the simplification of the measurement process and allows for its application in field conditions, making it particularly useful for monitoring drilling fluid parameters. The conclusions drawn from this research may contribute to enhancing drilling efficiency, improving the quality of drilling fluids, and reducing preparation costs.