Contact states of tubular strings during sinusoidal buckling transitions in a horizontal wellbore

Abstract

Scholars working in the oil and gas industry have extensively researched the buckling behavior of downhole tubular strings. However, in most theoretical research, continuous contact between tubular strings and wellbores is assumed, which is not always true in experiments. To address this issue, a buckling model for a tubular string placed inside a horizontal wellbore using the beam-column model is built in this paper. Two contact states of the tubular string were considered: point contact and partial continuous contact. The model indicates that reducing the angular displacement of the wave peak position facilitates the tubular string's transition from point to partial continuous contact. Additionally, a higher gravity load or smaller radial clearance increases the likelihood of partial continuous contact. A new displacement calculation method has been proposed based on the buckling model. Using this method, the entire process of contact state changes of a tubular string is simulated under the sinusoidal buckling mode in this study. The results show that the contact state of the tubular string under sinusoidal buckling cannot be assumed to be a continuous contact state, and a theoretical foundation for various evaluations based on the buckling deformation of tubular strings is provided in this study.