提高非调质套管抗射孔开裂能力的重要措施

Ways to improve perforation cracking resistance of hot rolled casing.

油层套管射孔开裂失效事故往往造成巨大的经济损失。套管材质是影响套管射孔开裂的重要因素,其中冲击韧性是决定套管抗射孔开裂能力的关键。通过对采用不同钢种成分、轧制工艺、热处理工艺生产的J55、N80油层套管的试验研究,提出了提高非调质套管抗射孔开裂能力的重要措施:(1)成分设计应降碳、增锰,并严格控制硫含量。对N80套管则应在此基础上添加少量钒来提高韧性并弥补因降碳引起的强度不足;(2)轧管时应注意再加热前的缓冷及温度控制,同时采用张力减径方法进一步提高材料韧性;(3)用在线常化或正火热处理来保证套管具有足够的强韧性配合。

Perforation cracking of production casings may cause a vast economy losing. Material property is a main factor causing casing perforation cracking, while the impact toughness is the most important. Based on a research of J55 casing and N80 casing produced by different rolling processes and heat treatment technologies, this article presents a few ways to improve perforation cracking resistance of the hot rolled casing, that is: (1)decreasing C content, increasing Mn content and controlling S content in designing compositions of steel, and adding a little vanadium to advance the toughness of N80 casing and to compensate the low strength resulted from the decrease of C content; (2)paying an attention to the slow cooling and the temperature control in the process of rolling, and adopting the strain sizing method to improve the material toughness; (3)applying online normalizing or normalizing to assure the enough strength and toughness of the casing.