In the process of window milling in the
casing wall for sidetracking using rotary system, the drillstring is subject to
bending moment in the window zone and torque from the rotary table.
The objective of the work was to determine critical bending loads at certain wedge
angle and the number of cycles
in terms of drill pipes safety.
Materials and methods
Based on theoretical studies of the
technique of determining the
permissible value of the deflection
angle of the wedge, which allows
to exclude the emergency
demolition of the drill
string for sidetracking
1. Theoretical methods of analysis values of the deflectionangleofthewedge,which influencesthefatiguestrengthof drill pipe when cutting a "window" in the wall of the casing and kickoffrotary.
2. To prevent the destruction of the elements of the layout of BHA to heavy weight drill pipe to push the interval "window", and between them and the arrangement of cutters to establish more flexibledrillpipeor a specially made sub.
3. Create an axial load on the cutter when cutting a "window" and kickoffwithintheaxial stability of the bottom of the drill pipe or a special sub.
4. Should be a requirement for an echo-pulse studies of drill pipe within the layout of BHA [10, 11] before use in a well to cut
ultimate tensile strength of pipe material