BOREHOLE HYDRAULIC PERFORATION DEVICE Russian patent published in 2009 - IPC E21B43/114 

FIELD: mechanics.

SUBSTANCE: invention relates to oil industry and can be used in oil reservoir engineering using hydraulic fracturing. Borehole hydraulic perforation device consists of tubing string (1), casing (2) of perforator with axial channel (3) furnished with lateral holes (4) housing nozzles (5). The device incorporates also two-stage sleeve (6), assembly of centering devices arranged below aforesaid nozzles (5), coupling (7) fitted on sleeve (6) with the help of bearing (8) arranged between annular stop (9) of the coupling and larger stage (10) of sleeve (6). The assembly of centering elements consists of casing (11) with seat (12) at its top to accommodate working ball (13) with four centering ribs (14). One of the said ribs has slot (15) accommodating lengthwise axle (16) supporting holders (17) of rollers (18) jointed by torsion spring (19) that ensures constant contact of roller (18) with the wall of well casing (20). The angle with apex at the point whereat roller (18) touches the wall of well casing (20) and formed by the radius of well casing (20) and the line passing through the axis of turn of holder (17) of rollers (18) is smaller than the angle of friction.

EFFECT: higher reliability and efficiency.

2 dwg