When tubing is freely suspended, it can be buckled by an upward force applied at the bottom of tubing. A section of tubing exposed to compression force will have a chance of being buckled. However, a part which is under tension will not face a buckle issue.
The neutral point is the boundary below which buckling can possibly be occurred and above which buckling will not happen.
Figure 1 – Wellbore Diagram with Tubing Buckling Due to Compression Force
