In the contact element, not only transverse friction force but also the longitudinal friction forces are taken into account. The element stiffness and damping matrices are derived explicitly. This element is implemented in general and powerful multi-body dynamics analysis software, namely Mecano module of Samcef. Therefore, many computational aspects of the Mecano software, for example the nonlinear beam element, the implicit time integration method, can be directly applied. | Vietnam Journal of Mechanics , NCST of Vietnam Vol. 25, 2003, No 3 (97 - 112) APPLYING THE CONTACT ELEMENT FOR SIMULATION OF INTERACTION BETWEEN DRILLSTRING AND HOLEWALL LE PHUOC HAO, TA Quoc DUNG Drilling and Production Department, Faculty of Geology and Petroleum Ho Chi Minh City University of Technology ABSTRACT. The purpose of research is to create a contact element in order to simulate the dynamics contact phenomenon of drillstring and drillhole. The contact element is located at some selected node along the drillstring. In the contact element, not only transverse friction force but also the longitudinal friction forces are taken into account. The element stiffness and damping matrices are derived explicitly. This element is implemented in general and powerful multi-body dynamics analysis software, namely Mecano module of Samcef. Therefore, many computational aspects of the Mecano software, for example the nonlinear beam element, the implicit time integration method, can be directly applied. 1. Introduction The equipment for oil well drilling consists basically of five distinct subsystems: hoisting, circulating, rotating components, well control and power system. These five subsystems make a complete drilling system which is located over a wellhead for the sole purpose of making a hole in the ground. Among the five subsystems, the rotating components, or drillstring system, play an important role during drilling. The main purpose of this paper is to research a contact element for the simulation . when drillstring contacts to holewall. The contact element is located at some selected node along the drillstring. If t~e contact at one node occurs, the contact element at this node _is introduced. In this way, all the contact points along the drillstring can be determined. The contact force analysis can be used for two purposes: *To study the mechanical behavior of the bottom hole assembly (BHA), such as the position of the BHA in the wellbore, contact forces,
