Application of gap element to nonlinear mechanics analysis of drillstring

Abstract

In order to describe the nonlinear contact between drillstring and hole wall, the multi-directional contact gap element (MCGE) is constructed and its formulas are derived. Through the MCGE connection with the beam element, the contact and geometric nonlinear finite element of drillstring is obtained in this paper. The application of this method to the GP1 well in the Daqing oil field shows that the contact friction force of the drillstring at any well depth can be obtained and the calculating error of the hole top load is below 10%. The results may provide a theoretical basis for the design and operation of drillstring.