Rigless Retrieval of a Stuck ESP Isolation Sleeve Using Real-Time Robotic E-Line Fishing Technology: A Case Study

This paper presents a case study on the successful retrieval of a mechanically stuck ESP isolation sleeve installed across a Y-tool in an offshore producer well. Multiple attempts to recover the sleeve using conventional fishing methods were unsuccessful. The objective of this operation was to restore well production and accessibility using a rigless, E-line solution capable of applying controlled, bi-directional force to overcome the mechanical lock-up. The methodologies, tools, and custom mechanical solutions employed in this intervention are discussed, offering practical insights for overcoming similar challenges. The operation demonstrates how advanced robotic E-line fishing systems, combined with custom mechanical adaptations, can be deployed to resolve complex downhole challenges and serve as a reliable alternative to traditional heavy interventions. An investigation following the failure to retrieve the isolation sleeve using conventional methods revealed a design flaw that caused the inner collet to move upward in unison with the outer collet when force was applied. This interaction prevented the shear pins from breaking, resulting in a mechanical lock-up. To overcome this, a custom-designed spring-activated sub (SAS) was incorporated below an electrically activated fishing tool (EAF) and deployed with an E-line Stroker—marking the first field application of this concept—to deliver a controlled downward force on the inner mandrel while simultaneously pulling at the fish neck. This differential loading enabled the shear pins to shear without engaging the upper no-go, allowing the collets to collapse and the sleeve to be retrieved without the risk of jamming. Furthermore, a potential hydraulic lock scenario was identified. Unlike jars, which deliver a sudden, short-duration impact, the E-line Stroker and spring activated sub applies a gradual and consistent force. This controlled application of force is more effective in bleeding off trapped pressure and overcoming the hydraulic lock. The isolation sleeve was successfully recovered in a single run. The EAF tool was able to latch onto the internal profile of the sleeve, which was confirmed using the surface read out measurement from the tool. The E-line Stroker was used to compress the SAS sub and provided the necessary force to shear the screws. Real-time data from the E-line stroker confirmed the stroke displacement and shear pin shearing, facilitating the collapse of the outer collets and subsequent release of the sleeve. Up to 35,000lbs of force were required to release the isolation sleeve. This confirmed the effectiveness of the spring actuated downward force mechanism in overcoming the collet interlock. The spring active sub (SAS) in combination with the EAF tool enabled us to provide a separation force against the sleeve release mandrel at the same time anchoring with the EAF grapples to the main latch sleeve. The successful retrieval of the isolation sleeve avoided a costly workover, resulting in substantial financial savings and a significant reduction in carbon emissions. This case demonstrates that robotic E-line fishing systems—equipped with real-time diagnostic capabilities— are not only effective but often superior to traditional fishing methods, enabling the successful recovery of various downhole obstructions that might otherwise be permanently stuck in the well.