Mechanism Analysis Of Flexible Pipe-Progress In Drilling Deep Stratum Radial Horizontal Well

The technology of ultrashort radius radial jet-drilling is conducive to production recovery of shut-down wells,improving the well utilization rate.Based on the mechanism analysis of flexible pipe and redirector in 5.5" casing,carry conceptual design on non-radial expand steering technology;the steering process and effect of trajectory and flexible drill pipe mechanical characteristics were analyzed,optimized the parameters of turning radius and flexible drill pipe,making the foundation for the implementation of the whole process.Drill pipe is the critical component which is used to make the jet bit turn 90°.In order to determine the parameters of the drill pipe,a large number of laboratory experiments are implemented to study the effect of the flexible pipe size,material on the steering resistance.The results showed that without internal pressure,the smaller outer diameter,the smaller steering resistance;the smaller wall thickness,the smaller steering resistance;the smaller plastic strength,the smaller steering resistance.By comparison,stain less steel pipe of 0Cr17Ni12Mo2,?12x2.0mm is the finishing material.With Finite Element Analysis,the influence factor of steering resistance was analyzed.It is found that geometric parameters of steering trajectory and material and size of drill pipe have a great influence on steering resistance.In order to reduce the steering resistance,the process of drilling pipe go through steering track is numerical simulated and the stress distribution of drill pipe is discovered.By analysis the variation of resistance and feed distance,it is found that steering resistance in creased where track curvature change.Orbital trajectory was optimized by numerical simulation,the optimized internal diameter is 14 mm and outer diameter is 12 mm,in order that flexible pipe is bending in steering track with a security and high efficiency way.Theoretical analysis is used to analysis the drilling pipe buckling phenomenon and the size matching of the drill pipe length and centering cylinder inner diameter.Through the calculation of the systemic circulatory pressure consumption,the parameters of the flexible pipe and coiled tubing are obtained.