When drilling long horizontal wells, buckling is a common issue that drilling engineers are facing in designing and operations. The general perception is that when drill strings or casing strings exceeding helical buckling, they cannot be operated safely in the hole as the risk of failure or lock-up is too high. However, some experience and field studies have shown that tubular may be run in the hole even in a buckling state, within safe limits. Thus it is a dilemma that drilling engineers often have to deal with whether allowing buckling to occur or redesigning the system to prevent it from happening.

The talk will present a case study of multiple liner failures in the Bakken field in early 2012. A torque and drag study was conducted to investigate if buckling has contributed to the liner failures.  Field data was gathered, analyzed and used to run the conventional torque and drag model as well as performing post-buckling simulations in an advanced model. The author will present the finding and results from an operator perspective and also share some guidelines on torque/drag and buckling.