What is sinosoidal and helical buckling? And why do I have to think about it?

An episode from the series "Fun with Drilling Engineering" with Prof. Dr. Matthias Reich. Camera and cut : Susann Klein Made at the Institute of Drilling Engineering and Fluid Mining of the Technische Universität Bergakademie Freiberg, Germany. The education of Petroleum Engineers belongs to the program "Geo- Engineering", spezialization "Geo Energy Systems". Please feel free to visit our homepage on https://tu-freiberg.de/fakult3/tbt​​​... or send feedback, enquiries or suggestions to matthias.reich@tbt.tu-freiberg.de. Voiceover Artist: Bamisebi Joseph Adetiloye