3D rod mechanics research and application in deep deviated well conditions

With the development of deep reservoirs and promotion of green oilfields, there is an increasing number of deep wells, highly-deviated wells, cluster wells, etc. The rod pump wells under complex wellbore conditions have such problems as severe eccentric wear, short pump inspection period and that the rod eccentric wear mechanism has not satisfactorily addressed. Based on the effects of wellbore trajectory, fluid viscous resistance and centralizers, a 3D rod mechanic model was built, and the dynamic distribution regularity of 3D lateral force was solved. The calculations show that the direction of lateral force below the neutral point on the rod is prone to periodic change, which explains the rod eccentric wear. The periodic change in lateral force may cause rod collision, which is a key reason for severe rod eccentric wear below the neutral point. Quantitative analysis was conducted to the effect of a number of parameters on the lateral force, providing theoretical basis for the design of anti-eccentric production parameters.