SLEEVE FOR STEP-BY-STEP CEMENTATION OF CASING STRINGS Russian patent published in 1999 - IPC

FIELD: oil and gas production industry. SUBSTANCE: sleeve is used in technique and technology of constructing oil and gas wells. Device has following components: body with side-located circulation holes, upper bush and lower bush, blowing separating plug and locking separating plug, and closing device in the form of falling plug. Upper bush in its lower part is provided with split diaphragm. Diaphragm can be bent out with pressing its components against internal surface of body when separating plug is passing through it. Falling plug is provided with detent and core with shear members. Circulation holes are closed with stoppers. Locking separating plug is of larger fitting interference in comparison with blowing plug and is provided with breakable diaphragm. Aforesaid embodiment of cementation sleeve is characterized by simple design, enhanced reliability, and high quality of cementation of wells. EFFECT: higher efficiency. 4 dwg