Research And Application Of Technology For Preventing Eccentric Wear Of Oil Well In Putaohua Oilfield

With the development of Putaohua oilfield in the middle and late stage,the water content of the oilfield is increasing continuously,and the rod pipe eccentric wear and polished rod wear are more serious.In the Putaohua oil field,413 wells were deviated and 47 wells were severely deviated from each other due to high water cut.197 wells were operated due to the abrasion of polished rod,accounting for 18%,2.04% and8.8% of the total wells respectively.In recent years,tools such as external coating coupling,comprehensive protector and pouring centralizer have been applied to solve the problem of eccentric wear of rod and pipe,and some results have been achieved.However,there are still three problems: first,the application method of anti eccentric wear measures lacks theoretical guidance,and the design of application location lacks scientific analysis;second,the existing anti eccentric wear measures have a better effect on the treatment of high water cut serious eccentric wear wells The third is that the research of polished rod wear protection technology has not been carried out,and the polished rod is worn more than 180 wells per year.According to the investigation,at present,the centralizer arrangement and the application of anti eccentric wear measures in Daqing oil field are mainly based on the production experience and big data statistics.The centralizer is applied to the vertical well pump of 400 m and the whole well of the inclined well,and the centralizer is added to the eccentric wear part of 50 m,but there are some problems in this method,such as the eccentric wear part is not in the protection of the anti eccentric wear measures,the eccentric wear section moves up and the non eccentric wear well resists the flow Lack of specific theoretical basis.In high water cut wells with serious eccentric wear,the composite lined pipe is mainly used to reduce the friction coefficient and reduce the degree of eccentric wear of the rod and pipe.However,the technology adopts the combination of high polymer lining material and mechanical pressure sealing of the oil pipe,which is easy to cause the problem of lining falling off due to high temperature during chemical cleaning.Therefore,this paper studies the technology of oil well anti eccentric wear,through the study of the mechanism of the formation of eccentric wear,starting with the production conditions and reservoir characteristics,carries out the modeling analysis of the stress on the rod string,and provides the scientific basis for the application of anti eccentric wear measures;solves the high water cut production well from two aspects: the internal treatment of the tubing to reduce the friction coefficient and the increase of the bottom of the sucker rod to reduce the bending deflection To solve the problem of serious eccentric wear,the outer wall of polished rod should be treated to improve the hardness of polished rod,reduce the friction coefficient,solve the problem of polished rod wear,and achieve the purpose of reducing the degree of eccentric wear of oil well.The test application of the above-mentioned anti eccentric wear measures in Putaohua oilfield has achieved certain results.