An operator required straddle related interventions to be carried out on one of their platforms in the North Sea, for both straddle retrieval and straddle deployment purposes. For these they were seeking innovative solutions to deliver more efficient and effective operations providing time and cost savings. The first operation described in the paper was a straddle packer deployment, which, done conventionally using coiled tubing, would have required nine runs to install the 100-meter assembly. This was due to the limited rig up height available. The second operation was to pull a shallow set straddle before setting a plug and punching the tubing as part of a plug and abandon operation. Here, scale had accumulated above the straddle which first needed to be removed to enable the removal of the straddle itself. For both operations, a solution was devised that overcame the challenges and inefficiencies of the more traditional methods, be that using coiled tubing or slickline. In the first (straddle packer deployment), an electric line tractor was used to aid in-well straddle assembly. The tractor's real-time tension/compression readings would provide accurate and controlled deployment and a precise measurement of the over-pull verification once set. The solution provided more rig up height, enabling surface assembly of spacer pipe sections, hence fewer runs for the full straddle system deployment. For the second (straddle packer retrieval), historically such scale removal would be performed by slickline broaching—a time consuming multi-run method. Instead, an electric line powered debris removal tool string was used, removing the scale in hours instead of days. Critical toolstring space-out through the blowout preventer (BOP) stack was managed. Furthermore, an electric line powered stroker was used to retrieve the straddle sections. The application of electric line based intervention technologies provided direct and indirect efficiencies. In the first operation, the electric line deployment of the straddle packer assembly was completed in only six runs compared to the nine runs required if coiled tubing was used, which delivered a time saving of almost two days. Pre-job simulations were carried out to optimise the deployment tool string design. During the second operation, the cleanout mill string, with collection chambers added purely to manage the string space out through the BOP stack, also provided better centralisation for the milling operation. With this operation occurring within the marine riser section, hydraulic oil specification was optimised for 1 °C operation. Advantages brought about through the use of electric line deployed powered mechanical tools were apparent in both operations. The depth resolution, coupled with the real-time surface read-out toolstring command—provided by electric line—enabled fast, precise and controlled operations, including delicate straddle tagging without risk of damage. Both operations were executed successfully.

A plug needed to be set in a well located in the Norwegian Continental Shelf to shut off an existing production interval, followed by the opening of several pre-installed reservoir control sliding sleeves, in order to optimise oil production from the well. It was suggested by the service company that such a two- run operation could be combined into a single run to save time and cost. An electric line deployed solution was designed to ensure high accuracy and control across the combined operation, providing power to both the plug setting and sleeve shifting tools, along with real- time command and toolstring status readout at surface. The combined setting and shifting functionality required the use of a through-wired shifting tool to enable real-time activation of the plug setting tool, which was positioned below. A bi-directional shifting tool was used, which, in conjunction with a bi- directional stroker, would enable sliding sleeve shifting in both directions, if required, during the operation. Furthermore, its dogs were retractable on command to ensure no inadvertent shifting occurred while traversing the multiple sleeve positioned in the well. Pre-job system integration testing was done at the service company location using a mock up completion comprised of two sleeves rigged up with a tubing joint in a horizontal set-up. This tested that there was no incompatibility between the plug setting and sleeve shifting components of the combined tool string, and that no inadvertent tool hang up occurred within the completion. The toolstring was run in hole, depth correlated and the plug set and released. Subsequent correlation was then done for the sleeve section. The real-time control and surface readout of stroker force and position enabled a precise sleeve shifting operation, and all sleeves were shifted successfully as per requirements. The stroker also provided a means of pulling the plug when it got inadvertently stuck whilst running to set depth and the electric line winch was unable to pull the string free. Multiple release subs were also positioned in the toolstring to enable independent recovery of the plug and stroker assembly if required. In addition, a memory pressure/temperature gauge was run, which provided further validation of sleeve shifting upon download and analysis. A tractor was used to convey the toolstring across the highly deviated section of the well. This single-run combined service solution delivered flawless operation with considerable time savings.