Finite element analysis of drill pipe-slip system

Abstract

As an important tool for tripping of a drill-string, a drill-pipe (DP)-slip system directly affects both the service life of a DP and the target depth it can reach. In this paper, a finite element (FE) model programmed in ABAQUS is used to simulate interactions within a DP-slip system. For this model, materials, geometric dimensions, loads, and boundary conditions were determined from an actual DP-slip system. A special attention has been paid on the stress field of the slip insert and the DP focusing on the geometric parameter optimization of the slip insert with regards to the stress distribution, wherein factors like a longitudinal groove number in slip insert, a number of slip inserts, and a number of row spacing of slip inserts are considered. Numerical results show that the circumferential stress distribution and stress distribution in the direction of DP axis change for both the DP and slip insert and that the stresses of the inner surfaces are higher than that of the outer surfaces. Effects of geometric parameters of the slip insert on the stress distributions of both DP and slip insert are studied and the corresponding optimized values are obtained, which can be used when designing slip insert tools.