SPE 159636; World First Riserless Light Well Intervention (RLWI) Technique to Mill and Clean Hard-Packed Debris, and Then Pull a Bridge Plug From a Live Subsea Well Using Electric Wireline

Background

A subsea production well in the North Sea was being serviced with a riserless intervention which inadvertently resulted in fill atop a temporary bridge plug. Riserless slickline and traditional e-line attempts to remove the debris and pull the plug were unsuccessful. A rig or intervention vessel with riser for coiled tubing cleanout was unavailable for approximately a year. The operator requested innovative solutions and selected a unique riserless light well intervention consisting of an e-line cleaning tool with a reverse circulating bit and bailer sections to break through the hard-packed debris, vacuum it into the bailers, and retrieve it to surface.

The remaining debris in the internal fishing neck of the plug was sucked up by a high-powered e-line cleaning tool and the plug was pulled in the same run. The job was executed without incident from a small, dynamically positioned, vessel with a moon pool and a subsea lubricator, saving the operator about one year’s deferred production versus waiting for the coiled tubing solution. This paper discusses the operation of the downhole tools and procedure for riserless deployment to achieve the objectives and create this value.

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