Effect of Human Factor on OCTG Collapse Testing

Well construction relies on metal pipes called casing to maintain its integrity during the life of the well. From surface to the target depths the inserted casings are used to prevent well collapse, hence being exposed to external pressure loads. Also the casing in place must hold the internal pressure during well operations, which is called burst resistance. During the past decades the manufacturing process of casing and tubing has been dramatically improved, but their testing has suffer very little changes. It is known to date that API calculation of collapse resistance is very conservative, most of the modern pipe mills being able to deliver pipes with higher collapse pressure than API calculated values. The paper will describe the actual testing procedure of collapse testing of pipes and critically discuss about the human error that is introduced during these measurements. The results shows that only through high quality laboratory standards, such errors can be mitigated, while automation must be carefully considered.