EXPANDABLE PIPING SYSTEM FOR FIXING TROUBLE ZONES WHILE DRILLING WELLS Russian patent published in 2022 - IPC E21B7/20 E21B33/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, and in particular to the drilling of oil and gas wells while isolating the zones of shedding and landslides when drilling with a string of expandable casing pipes. An expandable pipe system for fastening problem zones during well drilling consists of a drill string and a casing string, a rock-breaking element made in the form of a drillable bit screwed on a conical thrust thread. In the upper part of the casing there is a hermetically sealed sub with keys inserted into the mating grooves made on the upper end of the casing. The sub is equipped on the bottom with a bit with a hole for the passage of the ball, and on top with a groove inserted into the narrowing of the casing string and a thread for connecting to the drill string. The lower part of the casing string is provided with an expandable anchor branch pipe with fixing elements, which consists of a branch pipe with sockets at the ends, attached by welding to the lower end of the casing string. The lower socket is equipped with a thrust conical thread for the bit to be drilled, provided with a multifaceted hole. An expanding punch made of a polymeric material is hermetically installed in the upper socket, equipped with a seat for a ball and a multi-faceted protrusion for a multi-faceted hole of the bit being drilled. The fixing elements are made in the form of strips of triangular section in such a way that the diameter of the circle described around the fixing elements is 1.5-3% less than the diameter of the drilled bit, and are connected by welding on the outer surface of the anchor pipe between the upper and lower sockets.

EFFECT: increased reliability of drilling, minimal narrowing of the passage diameter after the installation of the device in the well, elimination of emergency situations associated with the separation of the drill string from the sub during the installation of the device, the possibility of drilling a drilled bit with flushing to remove cuttings.

1 cl, 4 dwg