悬点载荷变化对抽油杆断裂的影响

Effect of Suspension Center' s Loading Change on Sucker Rod Break

运用工程力学原理、采油工程原理,结合对现场断杆井的统计,对萨北油田抽油机井抽油杆断裂原因、抽油杆疲劳破坏产生原因进行了分析,结果表明,抽油杆断裂的主要原因是非对称循环应力作用产生的疲劳损坏。原油含水上升、抽油机工作参数变大、结蜡等因素,都将导致抽油机井悬点载荷增加,引起抽油杆的疲劳损坏。通过合理优化管柱结构、应用高强度抽油杆确定合理的油井热洗周期、改进刮蜡抽油杆加工工艺等措施可有效防治和减缓抽油杆断裂的发生。

Based on the fundamentals of engineering mechanics and production engineering, and the statistics of rod broken wells in the field, the reasons for sucker rod break in rod pumped wells and for the rod' s endurance failure are analyzed. The analytical results suggest that the fatigue breakdown caused by asymmetry circulating stress effect is the main reason for sucker rod break. Some factors, such as the increase of water cut, the enlargement of the operation parameters for well pumping unit and paraffin deposit, will result in the increase of suspension center loading of rod pumped well and fatigue breakdown of pump rod. Some measures, such as reasonable optimization of string structure, the application of high endurance pump rod, determination of reasonable hot flushing cycles for producers and improvement of paraffin cutting pump rod technology, can be used to effectively control well pumping unit break.