DOWNHOLE HYDRAULIC PULSATOR Russian patent published in 2001 - IPC

FIELD: equipment for hydraulic pulse treatment of formations in wells. SUBSTANCE: downhole hydraulic pulsator has a drive unit including immovable stator and hollow movable rotor, and flow interrupter located on external surface of rotor. Stator includes upper and lower coaxial parts each has internal spiral teeth with different direction of threading in each part. Rotor has external spiral teeth of left and right direction for engagement with corresponding spiral teeth of stator. Number of rotor teeth is less than that of stator teeth by one unit. Rotor axis is displaced relative to stator axis through value of eccentricity equaling half of tooth height. Made between upper and lower parts of stator is radial hole for communication of pulsator internal cavity with well cavity. Flow interrupter is made on rotor external surface and located between rotor teeth of left and right direction in zone of holes for communication of pulsator internal cavity with well cavity. The plug is connected to stator lower part. Working fluid getting into pulsator upper part is separated into two flows. One flow entering stator upper part moves downward to give rotary motion to rotor upper part. The other flow passes through central hole and side holes of hollow rotor, enters stator lower part and rises to rotate rotor lower part. Hydraulic resistance to flow motion periodically varies to produce fluid pressure pulsation. EFFECT: higher oil recovery from producing formation in operating wells and improved injectivity of water injection wells. 5 cl, 8 dwg