Innovative Approaches and Lessons Learned from Longest Slim Hole Smart Completion Wells with Hybrid Cable: Twin Fraternal Well Monobore Case Study

Abstract This case study aims to break down the engineering and operational strategies, along with the challenges faced in deploying the longest slim hole smart completion wells, with hybrid cable in a monobore configuration. The slim hole monobore smart completion design with twin fraternal were required as part of the Reservoir Monitoring Plan (RMP) in the Simultaneous Injection of Miscible Gas and Polymer (SIMGAP) project. It is a pilot concept to perform Enhanced Oil Recovery (EOR) with the purpose of increasing recovery factor (RF). The twin fraternal wells, equipped with water injector and oil producer, have been presented with challenges due to material availability for 7" liner, 3.5" tubular, and completion accessories. These requires for a slim open hole size of 6" for a monobore, a completion made of carbon steel (L-80) and chrome resistance alloy (CRA P-110), additional line and completion accessories for the oil producer, and a targeted total depth (TD) of 13,000 feet measure depth (MD) in water-based mud. Slim hole monobore deployment and smart completion in one trip are challenging due to the risk of longer stationary time in the open hole that can lead to differential sticking. Additionally, the risk of buckling with the small size of the tubing, and well tortuosity itself. It opted for a hybrid cable to improve the completion process and reduce the number of installed lines. Critical steps included open-hole preparation, operational strategy, and detailed execution, all defined by a comprehensive approach. The first well completion installation as a successful case for the water injector, using carbon steel (L-80) material without a centralizer in the open hole, Limited Entry Liner (LEL) configuration in the lower part, successfully reached over 12,000 feet. The second installation was unsuccessful for the oil producer, which used CRA (Alloy SM2535) with a feed-through centralizer, additional lines for chemical injection, gas lift mandrels, and a tubing hanger groove. Despite the unsuccessful landing and completion to the planned TD, the second well reached over 12,700 feet MD. This application represents the longest monobore slim hole smart completion as a journey in the UAE onshore field, The fraternal wells reveal successes and lessons learned from the other case, emphasizing adaptability and continual learning for similar applications in the future and successful deployment.