Nonlinear analysis on the impact wear characteristics of casing based on drillstring dynamics

Casing integrity is significant for subsequent drilling and production and prediction of casing wear accurately helps to reduce casing damage. Thus, this study aims to represent the casing impact wear characteristics more intuitively and accurately during drilling. The vibrating drillstring when drilling will collide with casing frequently and increase the casing wear. The drillstring nonlinear dynamic model is established using beam finite element method in this work, and the drillstring dynamic characteristics are obtained using generalized-& alpha; method. Subsequently, the friction coefficient and wear factor are obtained through the casing wear test. On this basis, the casing impact wear characteristic combined with the casing wear efficiency model is described, and the residual strength of casing is analyzed. In addition, the effects of drilling depth, weight on bit (WOB), rotation speed and the eccentric distance of the drillstring on the casing wear are discussed. We hope that our research will aid in designing drilling parameters and reducing casing damage.