METHOD FOR FORMING A MONOLITHIC DRILL STRING FROM CASING PIPES BY ORBITAL LASER WELDING Russian patent published in 2022 - IPC E21B17/00 E21B7/20 B23K101/06 

FIELD: mining industry.

SUBSTANCE: invention relates to the field of drilling with laser-welded steel pipes, namely, to the formation of a drill string by laser welding of casing steel pipes during vertical or inclined drilling of a well during oil, gas or water production, as well as during the construction of bore piles. The drill string is formed from casing pipes with the possibility of attaching a drill bit at its lower end. The upper casing pipe is brought to the lower casing pipe from above freely suspended. The welding machine is pre-installed and fixed at the free end of the lower casing pipe. The welding machine is mounted on the casing pipe by means of a two-segment annular lower girth in such a way as to provide a coaxially mounted laser single-segment orbital module of the welding machine rotating non-contact with the casing pipe above this girth at least a complete revolution around the lower girth at a distance from the edge along the casing pipe, providing partial alignment on the edge of the filler wire and radially supplied laser beam in the area of beam tightening during welding. The upper casing pipe is lowered until it comes into contact with the end face of the lower one. The girth and fixation of the end of the upper casing pipe is carried out with a two-segment upper girth, coaxial with the lower one and rigidly attached to it with a steel power arc-shaped structure, which is located outside and outside the orbital module to prevent restriction of its rotation and ensure its alignment with the grips. The winding of the energy protective cable channel hanging sideways on the body of the power structure is carried out onto the drum of the mentioned module for at least one full turn and in this position laser welding is carried out with the formation of a solid weld in at least one pass. In the process of fully automatic reverse rotation of the orbital part of the welding machine, the cable channel is unwound from the drum. At the end of the process of forming a solid weld, at least in one pass, the casing pipes are freed from the girths of the welding machine, which is taken aside.

EFFECT: improvement of the quality and strength characteristics of a monolithic drill string, an increase in its reliability, drilling speed and depth, and service life is ensured.

1 cl, 1 dwg