粘弹性流体法向应力对抽油杆偏磨的影响机理

大庆油田实施聚合物驱油以后,出现了抽油杆受力状况恶化、抽油杆柱严重偏磨的现象,为此开展了粘弹性流体水动力学理论和试验研究,得出了粘弹性流体在抽油机井筒内的流动规律及对抽油杆柱法向应力的影响规律,定量测出了粘弹性流体对抽油杆柱的法向应力值和抽油杆柱产生的偏心率.提出了粘弹性流体的法向力是造成抽油机井杆管偏磨的主要原因,建立了法向力作用下抽油杆纵向横向弯曲模型,并提出了抽油杆加扶正器和底部加重的综合防止偏磨措施,应用于大庆油田获得了较好的经济效益.

Partial abrasion mechanism of sucker rod caused by normal stress of viscoelastic fluid

The working condition of sucker rod under force action became worse,and the partial abrasion of sucker rod has resulted in the break and drop of sucker rods,after polymer flooding put into effect in Daqing Oilfield.The visco-elastic fluid hydrodynamic theory was applied to the wear-resistance experiment on sucker rods.The values of normal stress in suck string generated by visco-elastic fluid and eccentricity brought out by sucker string were measured quantitatively.The partial abrasion of sucker string and tube in oil well was caused from the normal stress of visco-elastic fluid.A module for bending analysis of sucker rod in cross direction and wire direction was developed. Some integrated measures to avoid partial abrasion of sucker string and tube were provided.To add a centralizer between sucker rods and increase of weight at bottom of sucker are beneficial to protect the sucker rods.The use of this method has gained a great economic effect in Daqing Oilfield.