This paper was prepared for presentation at the 1999 SPE Annual Technical Conference and Exhibition held in Houston, Texas, 3–6 October 1999.

Slickline often plays a vital role in offshore plug and abandonment (P&A) operations, either used in the phases of the operation that require slickline conveyance, or because logistical, footprint, operational, economical, environmental or regulatory parameters of a P&A operation necessitate full reliance on this small, light, cost-effective conveyance offering. Today's evolving regulatory requirements are leading to an increasing demand on the scheduling and design of P&A activities. For activities such as barrier placement, proof that the work is being carried out to the prescribed high quality is increasingly required both by the operators and the authorities. In addition, as the time, costs, and risks involved in carrying out an offshore P&A operation are considerable, possible savings and risk reduction are highly sought after by the customer. P&A activities such as perforation, punching, cutting, device setting, and cement placement, previously done by electric line or with memory-based tools which required additional runs in the well and provided only post-job QC, can be carried out by digital slickline without any compromise to the efficiency and immediate certainty of the operation. Conducting these P&A activities with digital slickline enables efficiencies through equipment and logistics simplification, and people and equipment rationalization, as well as reductions in marine support requirements. Time and cost savings and process risk reduction or elimination, important in their own right on a single well abandonment operation, are increasingly relevant when applied on a full field abandonment scope of work. In addition, the suitability of slickline conveyance in such environments as riserless intervention P&A operations (negating the need for grease injection pressure seal), is another important feature that is part-and-parcel of a digital slickline operation. This paper will demonstrate, through actual field examples, the use of digital slickline's inherent surface read out and command and control capabilities, the operational value of precision and clarity delivered in real time, and the specific P&A job recordability and capabilities that have been absent from slickline operations of past. Also highlighted are digital slickline's facilitation of personnel and equipment reduction, and subsequent reduction in HSE exposure.

There are wells shut in because of damaged completion components which hinder their production control or integrity, or prevent a remedial intervention from being carried out. Often, the option to pull the completion has inherent risks from an operational, environmental and/or reservoir damage perspective and require extensive resources and time to execute. Rectifying completion component damage through a light but effective in-well intervention solution offers highly valuable options to reinstate production from such wells. This paper will discuss the rapid engineering development of an expander tool run in conjunction with an electric line deployed electrohydraulic mechanical stroker tool. Through a simple but highly-effective design, an expander tool was engineered to harness and magnify the axial force delivered by the stroker to generate a radial expansion with a force magnitude sufficient to prize out a defect in a completion component. Critical to the design was a precise measurement and control of the expansion extent and the radial force exerted, so the component in question and the other components of the completion were not damaged. This toolstring combination, coupled with real-time control and surface readout of key tool parameters, enabled a precise and measured high-magnitude expansion capability to be deployed in two different wells with ease, at pinpoint depth, and applied repeatedly across the length of the defect it was addressing. Furthermore, immediate validation of the repair was available through a drift verification pass. In both cases the in-well repair operation eliminated the need for a high cost, high risk completion retrieval and the repair operation was executed flawlessly in hours, enabling the subsequent intervention operations to be carried out and the wells be brought back on line with positive production results. The tool development was an exemplary case of rapid-response engineering, whose ingenuity stemmed from a direct customer request to solve a challenging completion defect. It resulted in a world first for an electric line deployed in-well expansion solution, the resulting value of which was well acknowledged by the customer.

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.

Real time digital slickline services have been used increasingly in the Gulf of Mexico by a number of customers. Through its telemetry enabled capabilities and the purpose built tools that complete the platform, digital slickline services can deliver a number of safety and efficiency gains to all types of slickline operations. Material presented in this paper will be from actual operations, examples being perforation, tubing punching and cutting, plug setting and cement dump bailing, and will demonstrate the operational efficiencies being delivered. Enhancement of the slickline service comes from real time surface readout of in situ tool operational status, the critical core measurements of downhole toolstring movement, deviation head tension and shock, and the depth precision now offered through gamma ray and CCL sensors. Optional tools such as a pressure / temperature gauge bring yet further visibility on the impact of the downhole actions undertaken. Expansion of the slickline service capabilities come from the telemetry enablement and core tools, coupled with a range of specific tools and sensors that have been developed to run on this slickline platform, namely a electro-hydraulic setting tool, an explosive triggering device, a monobore lock mandrel, and a production logging suite. The real time data that is delivered to the slickline operator removes the need for assumptions that often have to be made during conventional slickline operation, and allow for a more efficient and reliable slickline operation to be undertaken. This results in a reduction in operation time, and a reduction in unnecessary trips out of the well to check on the tool status or to validate depth. Furthermore, since digital slickline is able to carry out both slickline well preparation work and a range of remedial or measurement work often carried out on memory or eLine, these operations can often be conducted entirely utilizing digital slickline crew and equipment. This optimizes pre- and post-job logistics, equipment rig up and rig down, and the job execution itself. In addition to the obvious cost savings, with a slickline wire comes a simplification of the pressure control and a well control recovery situation.