BOTTOM-HOLE ASSEMBLY MODELING AND DYNAMIC-RESPONSE DETERMINATION

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.