Successful Perforation of Fiber Glass Casing for the 1st Time in KOC to Convert Idle Observation Well to Producer, A Case Study

As part of the Wellbore Utilization and Asset's idle well reactivation initiative in KOC, Fields Development S&EK evaluated several Saturation Observation wells completed with Fiber Glass casing across the Wara reservoir, currently under waterflood. The existence of brittle fiber glass casing was a major challenge that could jeopardize the well integrity during Work Over or Production life of the well. After reviewing all potential risks during recompletion, a well was successfully perforated and completed with substantial oil production gain. The subject well completed with fiber glass casing was monitored for saturation changes with time-lapse resistivity surveys between 2017 and 2023. The latest diagnostic resistivity survey recorded in 2023 confirmed good oil potential in Wara sands. A thorough investigation of cement integrity prior to perforations was performed to evaluate the zonal isolation. The perforation was done with 4-1/2″ high Speed perforation gun and production logging with noise diagnostic log was recorded right after the perforations, to confirm the fiber glass casing integrity. As a final verification, a downhole camera log confirmed the good condition of the casing and its integrity. The resistivity diagnostic time-lapse survey results confirmed no depletion across the target Wara sands in the well with initial hydrocarbon saturation. The offset producers/injectors were reviewed as well to confirm the potential and saturation profile. Cement evaluation prior to re-completion has revealed very good cement bond behind the fiber glass casing, with no indication of any channeling or poor bonding. The 4-1/2″ HMX gun was pre-selected to ensure deep penetration with maximum reservoir contact. The returns from the re-circulation post perforation job during the wellbore cleanup have indicated no traces of any debris from the fiber glass. A production logging (PLT) along with HPT-SNL noise log recorded confirmed no movement of fluid behind casing and above the producing Wara formation, ensuring the reservoir and casing integrity. The downhole camera log revealed a very clear insight on the perforation entry holes, integrity associated with the perforation and the overall fiber glass condition, which was observed to be fully intact during the whole completion process. The well became the first ever successful conversion of a fiber glass casing observation well to an oil producer in KOC. The direct conversion meant a substantial cost reduction for KOC by avoiding a liner cost or even sidetracking the well. The downhole camera log has confirmed the completion process as a success and paved the way for monitoring downhole well conditions for many other applications including corrosion and well integrity management for the asset.