WELL REAMER Russian patent published in 2013 - IPC E21B7/28 

FIELD: oil and gas industry.

SUBSTANCE: well reamer includes a housing with inclined slots on outer side and a stock arranged in it, a piston interacting with the stock, which has an annular shape and is arranged in a chamber formed with a stock outside wall and a housing inside wall, which are fixed on inclined slots of the housing and hinged by means of tie-rods to a piston of a lug with cutters on working surface, and a lower adapter with an internal converging channel, which is connected from below to the housing. The piston is equipped from below with a hollow bushing with side channels, below which inside the hollow bushing there is a constriction and a cylindrical outer surface that has the possibility of sliding interacting with the converging channel of lower adapter and with possibility of leaving the above convergent channel when the piston is moving relative to the housing. Lugs with rows of cutters are located uniformly along the perimetre of the housing and arranged with distance along the perimetre between lugs, which exceeds the width of lugs at least by two times, provides a gap between them, walls and of the well and the housing in working position for creation of liquid lifting speed, which is sufficient for carryover of slurry from those gaps and cooling of cutters.

EFFECT: invention allows increasing operational life owing to providing similar work load of cutters during a reaming process, improved resistance of vibration and stabilisation at destruction of mine rocks, improving quality of formation of the well shaft, and providing the liquid lifting speed, which is sufficient for cooling of cutters and carryover of slurry.

2 dwg