Study On Ultra-short Radius Turning Track And Matched Drill Pipe

The Ultrashort Radius Radial System (URRS) is an advanced technology for the post-developing of oil fields. It has the features of low developing cost, extensive compatibility, and great effect on improving recovery of deposed or ended wells. At present, the key problem to puzzle domestic wide application of URRS is that the reaming space is difficult to meet whipstock construction requirement. So this research task is focused on the study on turning track and matched drill pipe.It will reduce conditional reaming diameter from 600mm to 300-450mm,and search the drill pipe which outer diameter between 14 and 25mm and thickness between 1.0 to 2.5mm which can pass through the radius less than 200mm track on the condition of high internal pressure and no instability.Theory analysis, finite element method and laboratory experiment are all used in the drill pipe bending and turning research. The material of drill pipe which can meet the under-ground working condition is evaluated and optimized. Designed the turning track which needed space is in the range of 300mm to 450mm. Simulated and analyzed the track and matched drill pipe by finite element analysis. Through the finite element simulation of the drill pipe turning and bending,the result shows that the plastic deformation of selected drill pipes is less than the plastic limit. The resistance increases with the change of the curvature of the slideway trajectory, and its magnitude depends on the magnitude of the change of the curvature; The radius of the cross-section deformed adds up because of the plastic deformation. The drill pipe matching experimental research of turning radius to be 150mm shows that slideway factors and drill pipe factors are the main factors impacting drill pipe resistance and cross section deformation, including the drill pipe thickness, diameter, roller wheel shape and the clearance between the pipe,roller wheels and structure of straightening segment.The basic rules are consistent with that of finite element analysis. According to different turning angle experimental study, it is concluded that the increase of the resistance to the drill pipe is not added with the increases of turning angle. The resistance is smaller than the others in near 70°and 100°, maximum can reduce by 20%.The rolling reduction is increasing with the increasment of turning angle,and its maximal value is 3.5mm. The conclusion can be used to guide the drill pipe specifications and new whipstock design, and lay a certain foundation for URRS applying to other types of well.