Establishment of dynamic model of suck rod string of 3D bending well bores and its simulation

The directional well is a 3D curvature hole with buckling and contorting. The complexity of borehole makes the suck rod string, which moves up and down in the borehole, endure complex alternate stresses, which frequently result in the rod's uneven abrasion and break-off. On the basis of existing dynamic analysis model of the sucker-rod pumping system, a dynamic analysis model in 3D deviated wells has been established in this paper. Based on the theoretical research, an applied software is developed with Visual Basic 6.0 and Matlab 6.0. A systemic study has been carried out in the influence of three dimension curvature hole on the suck rod string's stresses and life-span. The simulation results are very useful to releasing abrasion between the rod strings and tubes, cutting down the break-off of rod strings, prolonging production maintenance period and reducing the production cost.