Foringsröranordning og fremgangsmåte for å tilveiebringe tilgang til en formasjon gjennom en sementert foring

An apparatus and method for producing through a casing without perforation are disclosed. The casing can be rotated while it is cemented and includes a multiplicity of sliding sleeve valves. Each of the valves selectively covers a plurality of pistons, each of which preferably has a rupture disc mounted therein. A pressure-regulating device is provided in association with each rupture disc to ensure retention of sufficient internal pressure in the tubing such that all discs eventually burst without any short circuiting through the discs which ruptured earlier. The outward movement of the pistons acts to assist in fracturing the formation. Thereafter, the pressure used to rupture the discs aids in further channeling the fluid energy of the fluid rupturing the discs, as well as putting additional pressure on the movable pistons to further stress fracture the formation. As the piston is pumped outward, the grease that is held captive within the piston assembly is forced outward through a bladder. As the grease is pumped out, it displaces the cement slurry and flushes the face of the formation directly in front of the piston. Serrations on the end of the piston assembly concentrate the stresses, causing the piston assembly to bite into the formation. As the piston continues to penetrate the formation, the grease is ejected through the serrations, which helps to further flush the face of the formation. The ejected grease also tends to act as an inhibitor which prevents the cement from setting up in the area around the piston. The interior of the piston assembly will still contain grease which helps prevent the temporary restriction from dissolving.