LOW-PERMIABILITY RESERVOIR BOTTOMHOLE CLEANING DEVICE Russian patent published in 2009 - IPC E21B37/00 E21B43/18 E21B28/00 

FIELD: oil-and-gas production.

SUBSTANCE: invention related to oil-and-gas production, particularly to equipment which creates hydrodynamic shock while operating, creating positive influence on low-permeability reservoir bottomhole. Device consists of operating pipe, which forms bottomhole zone together with production string, parker, separating bottomhole zone from under parker zone, running on fluid energy supplying from operating pipe, jet pump, equipped with increasing space and discharge head, communicating with bottomhole zone, chamber, divided on two parts by valve, one of those parts is hydraulically connected to under parker zone, the valve consists of piston with end-to-end channel installed inside barrel with string and triggers at certain pressure drop, throttle element. Throttle element installed inside end-to-end channel of piston. Pressure drop created between under parker zone and zone formed by another part of chamber, hydraulically connected to jet pump increasing space. Barrel and piston are stepped. Greater barrel's step equipped with side windows, hydraulically connecting under parker zone to jet pump increasing space, while pistol is in very left position. End-to-end channel located in the greater step of the pistol, flushing hole connected to radial channel performed in a smaller step of the pistol. Greater step of the pistol and smaller step of the barrel form circular chamber. Smaller step of the barrel contains end-to end channel, which consists of radial and axial parts and connected to circular chamber. Barrel's string located over pistol, with the gap equal to distance between its smaller step top of end-to-end channel radial part and top of the pistols radial channel. In pistol's lower position its radial channel hydraulically disconnected with radial part of barrels end-to end channel smaller part.

EFFECT: effectiveness increase in low-permeability reservoir bottomhole cleaning.

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