MILLING MACHINE Russian patent published in 2023 - IPC E21B29/06 

FIELD: drilling and repairs of oil and gas wells.

SUBSTANCE: drilling and major repairs of oil and gas wells for milling the casing string during drilling a lateral wellbore. Device includes a housing, the blades of which are fully milled and coated with a wear-resistant cutting-abrasion coating. The end part is made in the of a crown with welded cutting elements. The housing has a central channel and flushing holes in the end part. Between the blades in the grooves of the housing there are movable blades equipped with cutters, which are fixed in the transport position by a shear pin and are moved into the working position by a piston installed in the central channel of the housing, connected to the movable blades by means of rods with hinges. In the working position, the cutting part of the movable blades protrudes forward relative to the milled blades. There are at least three flushing holes in the end part, spaced evenly relative to the central axis, while the total cross-sectional area of the flushing holes is not less than the cross-sectional area of the piston hole.

EFFECT: reliable and durable design is provided that allows drilling a direction pocket along the rock formation after cutting out the window, the speed of window milling is increased, and the wear of cutting elements is reduced.

1 cl, 4 dwg