Spoolable coiled tubing completion system

Abstract

A coiled tubing completion system is provided with a plurality of completion apparatus, all of which is designed flush with the diameter of the coiled tubing outside diameter for avoiding upsets and are flexible, spoolable on a coiled tubing reel and having through bores large enough to pass wireline tools for performing other operations. The spoolable coiled tubing system may use standard coiled tubing well control equipment and can be used in live wells. The flush, flexible, spoolable and through bore completion equipment may include a tubing retrievable safety valve, an annular control valve, concentric gas lift valves, a zone packer, a landing nipple, a sliding sleeve, and may include at the end a non-flexible but flush and open bore production packer and pump out plug. The completion system may be retrieved through a retrieval system.

Description

BACKGROUND OF THE INVENTIONThe present invention is directed to a method and apparatus for completion or recompletion of oil and / or gas wells with spoolable, flexible coiled tubing and retrieving the same.In place of conventional drilling rigs or workover rigs, completions or recompletions of conventional oil and gas wells by coiled tubing have been disclosed in U.S. Pat. No. 4,844,166. However, the various completion equipment utilized, such as safety valves, gas lift mandrels and packers are rigid tools placed in the coiled tubing while the coiled tubing is being inserted into the well. In addition, the various completion equipment components are of a larger diameter than the coiled tubing (called upset). Since the completion equipment is rigid and has a larger outside diameter than the coiled tubing, these characteristics prevent the completion equipment from being run through a coiled tubing injector head. Therefore, equipment including windows must be provided to couple and spl...

AI Technical Summary

Benefits of technology

The present invention is directed to a spoolable, flexible coiled tubing completion system which includes a flexible coiled tubing having an outer wall and a bore therethrough in which the outer wall has a continuous outer diameter without upsets and the bore is adapted to pass wireline tools. The system may include one or more of the following completion components: a longitudinally flexible safety valve, a longitudinally flexible annular control valve positioned in the coiled tubing, one or more longitudinally flexible gas lift valves positioned in the coiled tubing, a longitudinally flexible isolation packer positioned in the coiled tubing, a longitudinally flexible landing nipple positioned in the coiled tubing, a longitudinally flexible sliding sleeve positioned in the coiled tubing, a production packer and a pump out plug. All of the above include a bore therein for passage of wireline tools and have an outside diameter flushed with the outside diameter of the coiled tubing. The safety valve and annular control valve each have a hydraulic control line extending upwardly within the outer wall of the coiled tubing but adjacent the outer wall for avoiding interference with the passage of wireline tools through the coiled tubing bore.

Still a further object of the present invention is the provision of a coiled tubing safety valve having a housing secured to the coiled tubing, a valve closure means in the passageway moving between open and closed position for controlling the fluid flow through the passageway, a flow tube telescopically moving in the housing for controlling the movement of the valve closure member, hydraulic piston and cylinder fluid actuating means positioned above and connected to the flow tube with a biasing spring means positioned about the flow tube and connected thereto for moving the valve to a closed position. The spring means and the flow tube are longitudinally flexible for allowing bending about the longitudinal axis of the valve for allowing the valve to be spooled on a coiled tubing reel. Preferably, the hydraulic actuating means is connected to the flow tube by a flexible connection. Preferably, a downstop is connected to the inside of the coiled tubing for limiting the movement of the flow tube. In one embodiment, the coiled tubing includes a wall and a hydraulic control line is connected to the hydraulic piston and cylinder actuating means and is positioned in the wall of the coiled tubing. The longitudinally flexible valve is provided longitudinal flexibility by having a housing which includes first and second separated parts secured to the inside of the coiled tubing, and includes a plurality of separated longitudinally extending ribs.

Problems solved by technology

Furthermore, various specialized well control equipment, such as pack-offs and BOP stacks, were required because of the external upsets in the installation.

Such installations were much more complicated to operate and required additional equipment when used with live wells which need to be pressure balanced.

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