Study On Trajectory Design Optimization And Drillstem Vibration Analysis Of Extended Reach Well

Extended reach well of Drilling technology has a good applied prospect in such a time that drilling technology highly developed. This paper gives the calculating formula for angle of hold angle section of wellbore curve through studying the optimized design of extended reach well's wellbore trajectory. Based on the principle of determining the build point, it deducts the calculating formula for cycloid, catenary, amended catenary, quasi- catenary, lateral catenary and parabola of various curvature methods. Using weighted coefficient estimation method, the optimist curve was found accord to the facts of length of borehole, length of build section, build rate and all kinds of friction and torque. By researching drillstring vibration, in view of the complexity of drillstring vibration of extended reach well, this paper establishes entire vibration model and vibrating equation of entire drillstring composition, and it gives concrete solution, which can quantitatively calculate and predict fatigue resistance of extended reach well drillstring.