DEVICE FOR STEPPED CEMENTATION OF WELL Russian patent published in 1997 - IPC

FIELD: well drilling technology. SUBSTANCE: device ensures higher quality of cementation of vertical, incline and horizontal wells and simplifies round-trip operations with pump-compressor tubes. Device has body and housing with cementation holes. They create annular space. Seated in this space are locking spool and bush. Locking spool is spring-biased by its upper end to bush. This thrust bush is located in upper part of space. Locking spool is fixed in housing. Cementation holes in housing are located above upper end of spring-loaded locking spool. Seated in lower part of device are annular piston and packing member. Annular piston is positioned beyond housing and combined with bush which is installed on body. Above-piston space of annular piston communicates with in-tube space. EFFECT: high efficiency. 3 dwg