V.H. Forgenie, SPE, Amoco Trinidad Oil Company and now Hydrocarbon Outsource Limited, E.M. Heiberger, SPE, Amoco Trinidad Oil Company now Amoco Exploration and Production, L.K. Kelso, SPE, Amoco Trinidad Oil Company now Amoco Egypt and R.E. Roeth, Amoco Trinidad Oil Company
Coil tubing was utilized to perform a modified strip over operation and recover 9500 ft. of stuck slickline (0.108 in.) wire. The technique, thought to be an industry first, eliminated the risky option of recovering the wire piecemeal via conventional wireline fishing operations. This paper documents the background that lead to the development of the technique. An operational summary details its implementation and illustrations are included of the special tools and techniques employed.
Amoco operates the A-17 well in its Samaan field offshore the east coast of Trinidad. The well is selectively completed in two Miocene age consolidated sandstones. The wellbore configuration is complicated by gas lift valves, multiple packers, and several tubing internal diameter changes. Gas lift mandrels have historically created difficulty with wireline operations and the well has a moderately high deviation which hits a maximum of 60 degrees at the perforations. (See Figure 1).
Slickline operations necessary to recomplete the A-17 well were suspended when a shifting tool became lodged in a nipple profile at 9426 ft. MD. Several attempts to release the tool and then cut the wire at the rope socket were unsuccessful. Continued work resulted in the slickline parting at the surface and being lost to the hole. The well was secured and a plan was developed to recover the wire.
It was recognized early that a coil tubing unit could be utilized to circulate the well and fish the stuck shifting tool. However, the biggest obstacle was first the recovery of the wire. A first time technique was utilized to strip over and fish the wire in one trip. This technique and associated specialty tools are discussed. The operation went smoothly and successfully recovered the slickline the first time. The effort paid off by allowing the eventual recompletion of the well to a zone that is now producing 300 BOPD and 2.5 MMCFD.
Prior to the discussed operation the well was producing 2 MMCFD and 1000 BWPD with a 1000 psi FTP from a non gravel packed upper selective zone. Flow was entering the tubing through a sliding sleeve. A decision was made to move downhole and recomplete back to a previously produced zone approximately 100 ft. below the upper zone. A previous workover had set an isolation packer between the two zones and had installed 100 ft. of bull plugged tail pipe for isolation. Additionally, a mechanical release sub was installed to allow the release of the tail pipe and permit the future adding of through tubing perforations to the lower zone.
From the onset of the planned recompletion the operation ran into difficulties. Relatively large pieces (1 in. × 1 in. × 1 in.) of packer or hydril rubber were required to be fished from the tubing to get access to the sliding sleeve. Coil tubing washing operations were necessary to wash sand fill and a thick tarry substance from the sliding sleeve to the end of the bull plugged tailpipe.