DEVICE FOR BUILDING-UP DIFFERENTIAL PRESSURE ONTO FORMATION Russian patent published in 2002 - IPC

FIELD: oil producing industry. SUBSTANCE: device may be used as equipment for cleaning of bottom-hole formation zone from drillings, sand, paraffin, resins and other deposits difficult to remove by washing-out. The device has body with cylinder, depression chamber with valve, hollow piston with bottom and two rows of radial channels, and packer. Installed in main row of radial channels are detents in the form of balls engageable with hollows in cylinder and branch pipe. Branch pipe is telescopically located in internal cavity of hollow piston. Piston and branch pipe are connected by a shear member. Container for drillings is used in the form of perforated and plugged from bottom tubing pipes. The shear member is broken at impact against bottom hole. Rope is used for lowering and lifting of the device. Claimed device may be multiply used in operation. EFFECT: simplified design, reduced material expenditures. 3 cl, 2 dwg