Jakub Siemek, Rafał Wiśniowski, Stanisław Stryczek
Faculty of Drilling, Oil and Gas, AGH-UST
Poland, 30-058 Kraków, al. Mickiewicza 30,
Drilling muds used for oil drilling are described with various rheological models (Newtonian,
Bingham, Ostwald de Waele, Herschel-Bulkley). The Herschel-Bulkley model (Yield Power
Law) which best describes the rheological parameters of drilling fluids needs modifications.
Principles of determining rheological parameters of drilling mud described with a model of
Generalized Yield Power Law (GYPL) fluid were presented in the paper. The functions of shear
stresses and shear rate were given. Then the conditions of laboratory measurement of rheological
parameters of Generalized Yield Power Law fluids were introduced and the respective
mathematical dependences derived. On this basis, the rheological model parameters were
determined. When elaborating the block diagrams, the numerical methods for solving the
dependences were introduced. On this basis, rheological parameters of an exemplary drilling
mud were calculated.