膨胀管系统运动分析及腐蚀寿命计算

Study of Expandable Tubular System and its Longevity Calculation under Corrosion

膨胀管补贴套管技术的应用日益广泛,但是补贴套管过程中压力过高以及在腐蚀环境中寿命短是该技术的一个难题。研究了膨胀管在补贴套管时的受力状态及运动过程,指出膨胀坐封时需要的液压力明显高于膨胀管起胀的压力,此时膨胀锥不仅需要克服胀管做功,同时承受加压管柱的重力,因此,膨胀管坐封后应及时上提加压管柱以免膨胀压力过高而出现事故。建立了膨胀管在腐蚀影响下力学性能变化模型,将油套管强度校核理论运用于膨胀管的腐蚀剩余强度校核中,认为腐蚀对管体抗外挤强度影响更为严重,应考虑采取耐腐蚀措施。

It had been witnessed increasing application of expandable tubular in the oilfield, but problems, such as high expansion pressure and the longevity in the environment of corrosion, were clear. In this paper the characteristics during the expansion process was studied and the results demonstrated that the peak point of expansion pressure happened as the tubular was integrated with casing, at this point the expansion cone needed to expand the tubular while bearing the weight of the tubular string overhead, therefore it was quite necessary to pull up forward the string by the staff on the ground to avoid over high expansion pressure;meanwhile the model for longevity calculation in the environment of corrosion was established and the results indicated that the yield strength of the tubular was more vulnerable to corrosion and should be given additional attention while considering the protection measures.