SLOT FORMING PROCESS IN THE WALL OF THE CASING STRING AND IN THE CEMENT ROCK AT WELL PERFORATION Russian patent published in 2008 - IPC E21B43/112 

FIELD: oil and gas industry.

SUBSTANCE: invention is referred to a mining industry, in particular, to oil extracting field. At process realisation the diametrical moving out of two serrated milling cutters is made with imposition to them of a radial load. Then by pulling through the mentioned milling cutters are compulsory longitudinal moved along a treated material upwards-downwards for a slot length with simultaneous over-rolling in a direction of a longitudinal movement course. At this time a treated material is planned off by a dent of a milling cutter to the subsequent milling. At a turn of pulling through the gradual accretion of a radial load is made which is in a range from 0.1 tons to 10 tons. Milling cutter teeths are executed in the form of a wedge with a sharpening angle at top of 50-110°, containing the major cutting edge, placed along a milling cutter direct axis, from which side walls get off to milling cutters body with bending off from a direct axis. Each of side walls consists at least of two drawing up surfaces which have been placed under an angle to each other with formation of side cutting edges. It provides increase of a slot forming process efficiency.

EFFECT: increasing of slot forming process efficiency.

9 cl, 3 dwg, 1 ex