Introducing a Rheology Model for Non-Newtonian Drilling Fluids
Masoud Rashidi, Ahmad Sedaghat, Biltayib Misbah, Mohammad Sabati, Koshy Vaidyan, Ali Mostafaeipour, Seyyed Shahabaddin Hosseini Dehshiri, Khalid Almutairi, Alibek Issakhov
Abstract
An API standard drilling fluid was investigated from laminar to turbulent flow conditions using an in-house-built viscometer at speeds from 200 to 1600 RPM. A power-based method was applied to obtain the apparent viscosity and the shear stress of the water-based drilling mud (WBM) in the annulus of the viscometer. Then, a MATLAB optimization program was developed to obtain model parameters for five rheology models integrated in a generalized Herschel-Bulkley-Extended (HBE) model and two widely used 4-parameter models in drilling industry. It is found that the Bingham, Cross, and HBE rheology models have precisely matched the WBM measurements in the viscometer. A generalized Reynolds number was applied to determine the Darcy friction factor although the PL (power law model) and the HB (Herschel-Bulkley model) exhibited a nonrealistic negative shift from the laminar friction factor.