DOWNHOLE DRIFT FOR PIPES Russian patent published in 2003 - IPC

FIELD: construction and repair of oil, gas and other wells. SUBSTANCE: invention can be used for communication of space of casing with environment to stimulate inflow of product from pool, for pumping of various fluids while acting on bottom and conducting insulation work when it is necessary to punch aggregate of holes in wall of casing string. Proposed drift is run in well on working string. It includes hollow body with side conduits filled with fluid and communicating with space of body. Piston with working tool is located in side conduit of body. Hollow cylinder is made fast to body. Rod is mounted in spaces of body and cylinder for axial movement. Hollow plunger is coupled to rod. It is installed in space of cylinder and forms working chamber together with it. Sub is made fast to cylinder. Pipe string with hydraulic conduit to feed power fluid-energy carrier from pump is used in the capacity of working string. Its space is hydraulically coupled to working chamber and space of well through chokes. Rod chamber communicates with space of well through holes in cylinder. Plunger has through conduit communicating working and rod chambers and carries normally open valve. Rod is made fast to plunger and they both are spring-loaded to ensure rod with position of extension from body and to secure shutting off of valve across conduit in plunger. Rod is provided with piston for interaction with fluid contained in body while rod extends from it. Normally closed control valve is installed in sub. It communicates working chamber with space of well. Shut-off element of control valve is tied up to piston of hydraulic relay of time delay. Relay is provided with non-return valve, conduits and return spring to secure opening of control valve after certain specified time delay and to accelerate its shut-off with return of relay to initial position. EFFECT: capability to punch aggregate of holes in casing string in process of single run through extended interval of well shaft. 4 dwg