With the increase of water content,the lubricity of crude oil to the contact surface of pipe rod is reduced,and the neutral point position of oil rod is moving up,and the eccentric wear section is lengthening.
1.Corrosion and scaling make eccentric wear of oil rod worse.Corrosion and scaling reduce the surface smoothness of tube rod and increase the friction coefficient,resulting in intensified eccentric wear.At present,there are 568 corroded and scaled Wells,accounting for 78.7%of the number of Wells(722).With the increase of the number of corroded and scaled Wells,the number of eccentric wear Wells is increasing year by year,which puts forward higher requirements for rod wear prevention.According to the distribution area of eccentric wear of oil well in the whole plant,rod eccentric wear is common in Badangtai block,Yingdong Saertu Block,Yingdong Gaotaizi block and 152 block.
2.Theoretical research basis of centralizing technology
(1)Acoustic wave test quantitative analysis of eccentric wear of oil rod
The echo instrument reflects the smooth characteristics of the stopped acoustic wave curve,which is different from that in the open pumping.The internal reason is that the rod and tube bend seriously in the open pumping,resulting in the increase of the local radial area of the rod and tube and irregular arrangement,which makes the sound waves reflect violently and reveal the peristalsis and eccentric wear area of the tube and tube.The scientific analysis of acoustic wave curve provides a basis for making effective technical measures to prevent eccentric wear of rod and tube.Quantitative calculation of rod and pipe eccentric wear section,for example,the acoustic wave test curve of well 10-12 shows that there is a sharp fluctuation between 360 meters and 850 meters,which is consistent with 7 rod breaks and 8 pipe leaks in this area.
