Analysis of destruction causes of drill string elements

• Main Authors: Василь Михайлович Івасів, Ярослав Степанович Гриджук, Лідія Романівна Юрич
• Format: Article
• Language: English
• Published: PC Technology Center 2014-12-01
• Series: Tehnologìčnij Audit ta Rezervi Virobnictva
• Subjects: drill string elements; fatigue; fracture; accident analysis
• Online Access: http://journals.uran.ua/tarp/article/view/31838

The results of published material relating to failures of drill string are shown in the article. It is established that the accidents which occur with drill pipes usually has a fatigue character. The fatigue phenomenon is occurred at alternating bending, torsion collision, fluctuation of the drill string and variable loads. The main factor that causes variable strains and alternating bending is the rotation of the string. The highest percentage of destruction falls on drill pipe fracture in the thickened ends. The main loads occur in screw joints, so screw joint destruction are divided into two groups during exploitation: chipping of some turns and cone fracture of nipple or coupling. The results of this analysis can be used in developed of technical and technological measures to improve the resource and safe operation of the drill string.