DEVICE TO PREVENT MUD ACCUMULATION IN SIDE WELL HOLES Russian patent published in 2007 - IPC E21B33/12 

FIELD: oil well drilling and operation, particularly for selective well hole flushing to prevent mud accumulation therein.

SUBSTANCE: device comprises body 1, stem 8, sealing member 2, bush 4 and delivery unit. Device also has fixed bush 5 and spring-loaded differential disengaging bush 6 installed inside fixed bush 5. Additional differential bush 9 is arranged between body 1 and stem 8 so that the bush is spring-loaded relatively the body 1. The bush 9 has slots to receive stop 11 for bush fixation and for bush 9 movement limiting. Cap is arranged in lower body 1 part. Piston 15 is installed inside stem 8 and define oil chamber along with the stem 8. Radial channels 24 are made in body 1 and in additional differential bush 9. Engaging cone 16 comprising sealing sleeves 17 is installed at upper stem 8 end. The sealing sleeves 17 restrict device installed in collet clip from displacement in radial and longitudinal directions.

EFFECT: increased reliability of device installation and removal from well, extended conditions and possibility to perform technological operations due to possibility of repeated device installation and removal from well.

2 cl, 7 dwg