Rig-Less Restoration of Wellbore Integrity Using an Innovative Resin-Cement System via Coiled Tubing

Abstract Restoring legacy wells is a strategic priority for Operators, particularly in hydrocarbon-rich regions where they continue to deliver high productivity. In one such case, a well drilled in 1977 experienced annular barrier failure due to a deteriorated production packer, presenting a significant restoration challenge. This paper presents a rig-less intervention that successfully re-established annular isolation by deploying a specially formulated resin-cement system through coiled tubing - effectively replacing the failed packer, eliminating sustained casing pressure, and enabling production rates of up to 6,500 barrels of oil per day (bpd). The well intervention was conducted 46 years after the well's original completion. A series of rig-less operations - including well killing, logging, and tubing integrity evaluation - were carried out to investigate the pressure in the tubing-casing annulus. These diagnostics confirmed the presence of sustained casing pressure, attributed to a failed production packer. To address this, industry experts proposed a novel approach: opening the Sliding Sleeve Door (SSD) in the completion string and placing cement through coiled tubing to form a new annular barrier. A custom-designed resin-cement system, characterized by low viscosity and high compressive strength, was formulated for this purpose. The operation was executed safely and efficiently through close coordination among the Fluids, Well Testing, Cementing, and Coiled Tubing service teams. Following the designated wait-on-resin-cement (WORC) period, the tubing-casing annulus was opened to safely bleed off trapped pressure and monitor for any signs of sustained casing pressure. With the resin-cement effectively placed, a strong and durable annular barrier was established, and the annulus pressure was observed to be zero. The integrity of the barrier was further validated through a successful pressure test up to 500 psi, in compliance with local regulatory standards. While traditional workover rig operations are often more costly, this rig-less intervention demonstrated a more economical and efficient alternative. The successful deployment of the resin-cement system via coiled tubing not only restored wellbore integrity but also introduced a viable method for rejuvenating legacy wells in southern Iraq. The resin-cement system presented in this paper is a novel formulation that synergistically combines traditional cement hydration with a polymer chain reaction, resulting in a high-performance sealing material. Designed specifically for restoring wellbore integrity, it is particularly effective in remedial cementing applications. This paper outlines the system's fluid properties, pump schedule, hydrostatic fluid balancing, and techniques for isolating wellbore fluids from the resin-cement during placement. It also details the deployment methodology via coiled tubing and the post-operation evaluation procedures used to verify barrier integrity.