METHOD OF PRODUCING FORMATION PERFORATING Russian patent published in 2003 - IPC

FIELD: methods of secondary tapping of oil and gas formations. SUBSTANCE: method includes preliminary making of holes in casing string wall and cement ring, and subsequent hydraulic perforating of formation. Working fluid is pumped by pumps from surface through erosion perforator lowered on pipes. Holes in casing string wall are made with help of drilling perforator lowered on cable. Erosion perforator with hard-alloy nozzles is used for search of perforated holes. For this purpose, 25-30% of working fluid is supplied with registration of its flow rate and pressure. Jet hitting or nonhitting of perforated hole is detected by variation of working fluid flow rate and pressure. After hitting, working flow rate and pressure are increased up to designed value, and channel is further deepened by hydraulic perforating. EFFECT: higher efficiency of perforating operations by making perforated channel of large length with preservation of cement stone integrity. 3 cl, 1 dwg