Determining the Hole Interval to Run Anti-eccentric Lined Tubing in Directional Oil Wells

The purpose of this paper is to overcome the drawbacks that only hole deviations and experiences are based in determining the hole interval where to run the anti-eccentric lined tubing. A general type mathematical model is to be built based on the characteristics that the hole interval to run the lined tubing is random and time-varying on a macro level. To do this, first we need to determine the friction between the down hole sucker rod and tubing, then determine the stress on the representative element volume (REV) of the sucker rod, and finally determine the hole interval to run the lined tubing: according to the calculated axial force on the nodal points, the hole interval between the two nodal points where the axial stress becomes greater is the interval to run the lined tubing. After this technology has been used in over 1400 directional oil wells, the pump inspection period for oil wells has extended by over 512 days, and is still going on, which provides technical reference for application in other domestic oilfields.