Advanced Dual Electro-Optical Telemetry System Enhances Reliability in Coiled Tubing Electrical Plug Setting and Retrieval Operations

This study introduces an innovative solution that utilizes a hybrid electro-optical cable within a coiled tubing (CT) pipe to enable the concurrent operation of fiber-optic and electrical telemetry systems. The goal is to facilitate the deployment of electrical tools below the smart CT bottomhole assembly (BHA), with both downhole tool and smart CT BHA having real-time telemetry communication to surface. The new CT conveyance system and methodology involve a dedicated power line on the hybrid cable that supplies uninterrupted telemetry for the downhole tools while other downhole sensors use fiber-optic telemetry and draw power from a downhole battery module. This integrated system allows the application, for example and not limited to, of precise correlation of plugs that are used with electrical setting tools and eliminates the need for flagging the CT pipe, resolving depth offset uncertainties. Other applications include downhole cameras or linear actuators below the smart CT, providing an array of tooling that traditionally is not conveyed with correlation capability, tension and compression monitoring, or pressure and temperature measurements. The study underscores a successful trial conducted after extensive preparations and yard tests. Subsequently, 10 isolation plug setting and retrievals were performed using this method. The downhole data allowed for improved latching, reduction of no-latch runs, observation of equalization pressures downhole, and the tension and compression data also helped to identify when the plugs are in a neutral weight for safe retrieval after the elastomer retracts and pressure is fully equalized. The acquired downhole data significantly contributed to the well operator's ability to make informed decisions, enhancing operational safety and reliability. This technology led to substantial time and cost savings, reducing rig time by up to 30 hours per well in an offshore environment. Additionally, it lowered operational and safety risks by eliminating the need to switch conveyance methods. The study underscores the innovative nature of combining dual electrical and optical telemetry systems for maximum downhole data retrieval and its potential applications in various CT downhole operations involving electrically operated tools or diagnostic instruments.