DEVICE FOR STIMULATION OF FORMATION BY PRESSURE DIFFERENTIAL Russian patent published in 2003 - IPC

FIELD: mining industry, particularly, oil and gas production; applicable in well completion and operation. SUBSTANCE: device is designed for inducing of inflow of fluids from permeable formation to well in its completion and for maintenance of high well production rate, reduction of expenditures and increase of safety of operations at stages of well completion and operation. Device has downhole assembly including pipe string run into well and packer and shutoff device with gate located in pipe string lower part. Gate is installed for opening inlet of string. Shutoff device installed above gate has movable bushing with ring piston to form together with body, closed chamber whose cavity is communicated through throttle hole with through channel above gate location. Bushing is connected with gate for its changing to closed position with piston moving to direction for increase of chamber volume, and to open position with moving back. Made in shutoff device body wall, above chamber are radial holes closed by bushing in its uppermost position. Device has valves for discharge of fluid from string. Check valve opened for intake is installed in string bottom. Installed in shutoff device above chamber is hollow float filled with light fluid and provided with gate which is closed for fluid passage to chamber with float in upper position. Device produces sharp deep drawdown with pressure drop in a fraction of the second in bottom-hole zone from value of formation pressure to pressure close to atmospheric one to induce inflow of fluids to oil and gas wells, both, with use of pump and compressor equipment, and without said equipment, by intensification of inflow of oil and gas with periodic stimulation of formation by deep pressure differential. Device also makes it possible to remove plugs and prevent their formation and to clean bottom-hole formation zone from impurities. EFFECT: higher efficiency of use. 3 cl, 11 dwg