DEVICE FOR WELL CEMENTING Russian patent published in 2000 - IPC

FIELD: well construction; applicable in stage and basket cementing of wells, first of all inclined wells and wells with horizontal end of wellbore. SUBSTANCE: device includes body with central through channel, radial circulation holes and internal surface made with circular projections and depressions. Installed in body and telescopically interconnected by means of shear members are two-way bushing and ring. Bushing and ring are made with circular separation into which conical stops are installed for engagement with body internal surface and simultaneous advance into central channel or going out of it. Bushing is locked in body by means of shear screw. Bushing has mechanical limiter of its first motion which is installed for its bringing out of its working position by displacement of ring relative to bushing. Bushing is made with radial circulation holes located above body holes and separated from them with possibility of communication with them and repeated separation in the first and second motions of bushing downward. Circular depression of body internal surface under circular projection is stepped one, narrowing from top downward. Limiter includes sector retainers. Two-way bushing has individual reducing valve and made to form hydraulic brake together with body. Hydraulic brake is in the form of closed circular hollow communicated with reducing valve after repeated separation of circulation holes of bushing and body. Bushing and body are made with adjacent depressions below circulation holes. Depressions are located with possibility to form simultaneously with formation of hydraulic brake bypass channel from bushing circulation holes to additional reducing valves radially located in body and separated from central channel by gate with members forming seat. Bushing lower part has circular check valve including rubber collar installed on bushing for closing of its radial holes. EFFECT: provision of device versatility as through one due to possibility of withdrawal of residual grouting mortar from its central channel into annular space after cementing of wells. 2 cl, 4 dwg