Study On Eccentric Wear Prevention Technology Of Rod Pumped Well In Shenyang Oilfield

Study on Eccentric Wear Prevention Technology of Rod Pumped Well in Shenyang OilfieldAbstract: Shenyang oilfield is in the middle-later stage of water flooding development, with the development of the oilfield, composite water cut is increasing continuously, because of the produced fluid with a high water cut, lubrication condition between pumping rods and oil tubes became worse, thus eccentric wear get serious. There were426oil wells with eccentric wear via on-site follow up in2009, which accounted39%of all production wells. Currently, there are about12000pumping rods,4000oil tubes and50000rod collars scrap because of eccentric wear. For this situation,on the basis of force analysis on rods and tubes, binding the distribution law of eccentric wear, by laboratory test, pump diameter, water cut, submergence depth, and swabbing parameters are analysed, and then the eccentric wear mechanism is obtained. Fluid supply capacity decreases due to the formation pressure decreases in some block,and then the submergence depth should be deepened. If the pumping rods work in high water cut and low submergence depth, it will happen "liquid hammer". Eccentric wear will happen more easily with larger vibration load. Larger pumps are installed in some oil wells that have a better injection effect. Eccentric wear will happen easily when larger swabbing parameters are used. Working condition become worse due to water cut rise constantly. With the development of the oilfield,the degree of eccentric wear become serious, the number of eccentric wear wells increase continuously. Controlling and preventing eccentric wear is the effective way to control the production cost.The measure to prevent eccentric wear is using centralizer and injection molding rod to constrain the rods and tube. Wear resistant materials is used to improve the wear resistance of rod collars and oil tubes. Optimize the working condition to change the pressure in pumping rods and tubes.