Overcoming a Challenging Casing Stuck Situation Through the Cutting and Recovery of a 1.2 Million-lbs 18-5/8 in. Casing String: A Breakthrough in KOC Deep Drilling Operations

Abstract This paper presents the successful cutting and recovery of a stuck 18-5/8 in. casing string weighing more than 700,000 lb (after cut buoyant weight) from a depth of 6,900 ft in open hole, representing the first and heaviest casing recovery operation of its kind ever executed onshore by Kuwait Oil Company (KOC). The recovery was essential because, in KOC's deep Jurassic wells, the casing design provides no contingency options if the 18-5/8 in. casing is landed prematurely in the Shuaiba formation. A failure to recover would have led to well abandonment and loss of a critical drilling slot in a high-value gas development project. The stuck casing incident resulted from an uncontrolled descent of the travelling block caused by a drawworks failure, followed by extended static time during repairs, which led to mechanical sticking in the Shuaiba formation. Given the depth, casing size, and extreme weight, conventional fishing and recovery options were deemed unfeasible. An engineered solution was developed that relied on a hydraulically actuated pressure pipe cutter equipped with high-strength, wear-resistant knives and a positive-return mechanism to provide clear confirmation of a complete cut at surface. The operation required unique rig- site adaptations, including cutting the casing stick-up, installing a false rotary, and fabricating a custom returns flow line. A staged procedure was executed, using real-time surface pressure, torque, and hook-load diagnostics to verify cutting progress. Following the cut, a multi-step recovery operation was performed using heavy-duty retrieval tools and specially designed handling procedures to lift the massive string safely to surface. The operation marked a historic first for KOC in terms of casing size, depth, and weight recovered. The multidisciplinary team executed the cut and recovery without compromising safety or well integrity. The open hole was preserved for sidetracking, enabling continuation of the gas development plan and safeguarding a critical drilling slot. The methodology and lessons learned established a new internal benchmark for well restoration operations and contribute to global best practices for high-risk casing interventions in deep, high-value assets.