RESEARCH ON THE DISTRIBUTION CONTACT PRESSURE BETWEEN SUCKER ROD AND TUBING STRING OF ROD PUMPING SYSTEM IN DIRECTIONAL WELLS

With the sucker rod string separated into some elements, and the spring elements of two directions used to describe the contact states between the sucker rod and tubing string, the mix finite simulation models are setup to study the bend deformation of the sucker rod string in the tubing string and the contact pressure between the sucker rod and tubing string. In the models, the difference of contact conditions between the sucker rod and tubing string is resulted in by the diameter difference within the sucker rod body, rod coupling and the rod guiders. According to the finite simulation results of the supporting forces, the internal forces and displacements at the nodal points, and the simulation models of the distribution contact pressure between the sucker rod and tubing string are setup. The simulation results of the distribution contact pressure can be used to predict the wear life of the sucker rod and tubing string, and to calculate the friction power of the sucker rod string and the system efficiency of the rod pumping wells.