摘要
潜油电泵在高产油井中有着广泛应用,但频繁的检修大量增加了油田经营成本,不同大小的扁电缆接头处绝缘击穿是最常见的故障。为了分析潜油电缆失效原因,延长机组免修期,建立了潜油电缆工作时的电磁和热传导耦合模型,分析了电缆的热效应,模拟了电缆的工作状况;建立了电缆接头的电流守恒模型,分析了电缆接头的电场,并进一步分析接头的绝缘击穿;使用塔菲尔公式分析了拉伸应力影响下的铠装层腐蚀;使用灰色关联法分析了多种因素与电缆免修期的关联程度。结果表明,当环空为气体时,电缆感抗产生的热量不易散发,电缆温度可高出环境10°;电缆接头部位不光滑表面容易产生非均匀电场,最可能出现绝缘击穿;电缆拉伸越强,缺陷部位的腐蚀速率越快,特别是出现塑性应变时腐蚀速度大大加快;井下高温与电缆免修期的关联因素最高。选取电缆时,最高限温应留有一定余量,连接电缆时尽量保证接头的整齐光滑,并尽量减少拉伸应力,Agadem油田采取了针对性措施后,免修期延长了30%以上。
The electric submersible pump is widely used in high production oil wells,but frequent overhaul increases the operation cost,and the insulation breakdown of joint is the most common fault.In order to analyze the failure of the submersible cable and extend the time free period,an electromagnetic and heat conduction coupling model is established and the thermal effect of the cable is analyzed.The electric field of the cable joint is analyzed for reason of insulation breakdown of joint.The Tafel formula is used to analyze the armored layer corrosion in tensile stress.The grey correlation method is used to analyze the relationship between the various factors and the repair period of the cable.Results show that if the annular space is full of gas,the heat generated by cable inductance is not easy to distribute,the temperature can be 10 degrees higher than environment.The unsmooth surface at joint is most likely to produce non-uniform electric field lead to insulation breakdown.Stronger tension in cable brings higher corrosion rate at the defective position,especially,if plastic strain appears the corrosion rate is greatly accelerated.The correlation factor between temperature and repair period is the highest,so the ultimate temperature of cable should be appropriate and the joint is as smooth as possible,and the tensile stress is reduced as much as possible.After the pertinent measures taken,the repair period has been extended by more than 30%in Agadem oilfield.
作者
黄涛
HUANG Tao(Niger Project Department,China Petroleum International Petroleum Exploration and Development Technology Co.,Ltd.,Tianjin 300280,China)
出处
《科学技术与工程》
北大核心
2019年第13期71-76,共6页
Science Technology and Engineering
关键词
潜油电缆
热效应
绝缘击穿
腐蚀
灰色关联法
失效
对策
submersible cable
thermal effect
insulation breakdown
corrosion
grey correlation method
failure
countermeasure