Comparative Analysis of Well Deliverabilities Through Different Perforation Strategies in a Mature Field, Deployment of Completion Conveyed Underbalance Perforation – A Case Study

Abstract Wellbore deliverability impairment caused during drilling, testing, and completion operations remains an inevitable operational challenge. The TCP Shoot and Pull perforation method is widely deployed in the country; however, the requirement of kill cycle afterward ultimately hinders the perforation performance. On the other hand, underbalance perforations post well completion presents their challenges with limited IDs, compromised penetration (smaller gun size), and most importantly; maintaining underbalance in subsequent perforation runs. Therefore, the Operational Best Practices developed throughout the years needs to be tailored as per individual well requirement. The performance of the existing perforation methodology of TCP Shoot & Pull (Overbalanced) and Thru-Tubing (Underbalanced / Balanced) were evaluated for recently completed wells in a mature gas field. The well test interpretation indicated near wellbore damage in wells completed overbalance across the sandstone formation, significantly affecting the deliverability of the wells. Unlike most carbonates, Acid Stimulation is not readily adopted for clastic formations due to its associated risks, therefore, it becomes quintessential to identify suitable perforation techniques to improve well deliverability. Completion Conveyed Perforation guns were successfully deployed at the newly drilled development well, which showed significant improvement in the well's deliverability compared to the existing methods of perforation. This paper presents the successful application of Completion Conveyed Underbalance Perforations (CCUP) in development wells along with well performance improvement compared to previous strategies. The CCUP technique was risk assessed and selected for the new development wells in a mature gas field. The 4-1/2" casing guns were conveyed with a drop-sub assembly in the permanent packer tail. Following well completion operation, underbalance was induced in the wellbore. The guns were successfully activated and dropped in rat-hole through Slickline.