Understanding bottom-hole assembly (BHA) dynamic phenomena remains a c
ritical drilling systems issue due to the cost of potential failures.
Many studies have provided ARCO Exploration and I useful insight into
drillstring dynamics. This study extends previous efforts by providing
a novel BHA model which accounts for several critical response factor
s and can be augmented to address a variety of other effects; new data
from art experimental study regarding damping are presented. The prop
osed model represents the transfer function of the drillstring in term
s of its natural modes and properly incorporates several factors criti
cal to BHA dynamic response prediction, including frequency-dependent
fluid added mass, and nonlinear wellbore constraints. Results from per
tinent numerical studies are presented.