Orientated Perforating in a Large Diameter Wellbore Using Tubing Conveyed Perforating in Conjunction with Fiber Optic Cable

Abstract Objectives/Scope This abstract presents a case study on the successful completion of a monitoring well in Mclean County, North Dakota. The well, completed in 2023, is designed to monitor the changes in the reservoir while its counterpart well is injecting up to 200,000 tons of CO2 annually into the Broom Creek Formation. The scope of this paper focuses on well construction design, fiber optic monitoring, and overcoming challenges during perforation. Methods, Procedures, Process The project utilized a digital temperature sensor (DTS) fiber optic line installed along the 5,000- foot intermediate casing to monitor temperature and fluid movement throughout the well's life. The design of this well posed two challenges: The casing diameter and the alloy material used across the injection zone. Due to these two design requirements, several techniques used to detect fiber optic line and subsequently perforate the well were deemed unsuitable for this challenge. To avoid damage to the monitoring system during perforation, a high-resolution acoustic downhole evaluation system was selected to map the fiber optic line's orientation, which would work both in the large diameter casing and through the large diameter alloy casing section. Based on this data, a tubing-conveyed perforating system was deployed, precisely aligned using a surface-readout gyro. This method ensured that the perforation gun was accurately positioned to protect the fiber optic line. Results, Observations, Conclusions The Monitoring Well was successfully perforated while maintaining the integrity of the DTS fiber optic system. Despite challenges arising from the large borehole diameter and corrosion-resistant alloy casing, the mapping of the fiber optic cable before perforation and the use of the tubing-conveyed perforating system allowed for accurate alignment. The project demonstrated that the well could safely manage the injection of CO2 without risking misfire or damage to the monitoring system. This workflow also prevented potential failure and unnecessary re-drilling, ensuring operational readiness and well functionality for CO2 sequestration monitoring. Novel/Additive Information This paper introduces new techniques for integrating DTS fiber optic monitoring systems with large- diameter well perforation. It demonstrates an innovative solution for maintaining the integrity of monitoring equipment during complex operations, providing valuable insights for future CO2 injection and Class VI well projects.