PDC Bit Hydraulic and Mud Rheological Simulation to Model Pressure Drop across Bit

When fluid flow from larger into smaller diameter pipes, it experiences a drop in
pressure. High pressure drop across bit is an indication of high energy loss in the
hydraulic system and also a setback to ROP performance. This is inefficient and
pressure pumps would have to be of bigger sizing to make up for the losses. Present
form of pressure drop models are in terms of mud density, flow rate, and total flow
area. No study on mud rheological parameters specifically the Yield Stress,
Consistency Index, and Power Index have been done with respect to pressure drop
across bit. The objective of this research is focused on the analysis of CFD simulation
and to propose optimized parameters for improved ROP. Single phase flow study of
Yield Power Law mud rheology was simulated at bottom hole of horizontal section.
For accuracy of simulated results, a mesh independence test was carried out to justify
the validity of the simulated results. Preliminary simulation on Yield Power Law Muds
showed about 50% reduction of pressure drop across bit as flow rate increase.
Parametric study on mud rheology was carried in Design of Experiment.