At present,there are about 300,000 oil Wells being exploited and unexploited in China.According to statistics,the average service life of nylon sucker rod centralizer is often less than one year.The failure of sucker rod centralizer is mainly caused by partial wear with the tubing and corrosion caused by the liquid media in the well.Moreover,partial wear and corrosion are not simply superimposed,they interact with each other,and the combination of them is very destructive.
(1)Influence of comprehensive water cut:With the increasing of comprehensive water cut,the degree of corrosion of oil Wells is becoming more and more serious.The reason is that when the water content of the produced fluid is greater than 74.02%,the produced fluid changes phase and changes from water-in-oil type to oil-in-water type,that is,the rod and pipe gauge,and loses the protection effect of crude oil.The produced water directly contacts the sucker rod and tubing,and the corrosion rate increases.The lubricant of friction changes from crude oil to produced water,and loses the lubricating effect of crude oil,so the wear rate of sucker rod and the inner wall of tubing is accelerated and severely worn.
(2)Partial wear increases corrosion:Partial wear and corrosion do not simply add up to each other,but work together to further accelerate the reduction of rod cuttings and tubing wall thinning,with serious consequences.