Abstract

A new rigless stackable pipe system has been developed for running scab liners in damaged production liners or for improving well conformance. The system is designed to be lubricated and run through tubing under pressure and has been successfully deployed in Alaska. This paper details the development, testing and a field trial of this scab liner system. This system has a connection that snaps pipe sections together and is unique in that it allows a much larger internal diameter than other stackable systems. For regions where rig workovers are expensive such as offshore or the North Slope, using the stackable system for scab liners can save up to 90% of the cost of a rig workover. The snap latch pipe is deployed with a combination of slickline and coiled tubing for scab liners. The snap connection is available for use with 2-7/8″ and 3-1/2″ base pipe. Slickline sets a float assembly with a releasable anchor in the tubing then stacks the sections of float equipment and pipe for the required length of the scab liner. The final slickline run is to set a sleeve with a profile and polished bore for coiled tubing operations. Coiled tubing then picks up the entire scab liner and shears the anchor, then runs the liner to depth. On the second run, coil cements the liner in place. A field test of the system was performed in a well with a few sections of pipe prior to deployment in a well for an actual intervention. The target well for the intervention was an injection well on the North Slope. The well had a thief zone that was taking too much injection water and conventional cement squeeze techniques were unsuccessful at shutting off the thief. A cemented scab liner was proposed to isolate the thief zone. A 557′ scab liner was successfully deployed and cemented in place. Target intervals were perforated and the well was put on injection. Details of the design, testing and deployment of the scab liner are outlined in this paper.

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