SHOE FOR INSTALLATION OF SHAPED SHUTOFF DEVICES IN WELLS Russian patent published in 2001 - IPC

FIELD: construction and repair of wells, particularly, means for installation of shaped shutoff devices for isolation of zones of drilling complications or sections with disturbed seal of casing strings. SUBSTANCE: shoe has assembling bolt with left-hand and right-hand taper threads ands top nut screwed on thread. Nut has conical surface and knurling. There is bead between bolt threads. Installed under bead is additional stop with conical surface and funnel with locking ring. Sealing member in form of several cylindrical segments with conical surface on ends is located between stop nut and additional stop. Segments are interconnected to form ring by means of flexible material, for instance, rubber after is vulcanization. Flexible material is located, mainly, on segment end faces on side of additional stop. Shoe is secured in lower end of shutoff device, and after its expansion by hydraulic pressure, it is rolled out. When expander reaches the shoe, it is screwed with its end onto bolt thread and fixed with ring. Further rotation of expander and bolt results in nut screwing down on left-hand thread to free sealing member which is radially compressed to ensured free coming out of shoe from shutoff device. EFFECT: higher sealing reliability of shutoff device bottom due to use of shoe and repeated use of shoe. 5 dwg