Casing exit operations are a common technique in the well intervention domain due to many technical purposes as accessing more reservoirs (re-entry drilling) or bypassing downhole obstructions (remedial operations). The casing exit is a complex operation that involves milling through the well casing to create an exit path and then drilling a rathole for accommodating any subsequent drilling bottom hole assembly (BHA) such as mud motor or rotary steerable system. Accurate tracking of the casing exit process is essential to ensure the operation's success and save extra runs to check passing through the window. This abstract presents two successful field trials for a novel approach using advanced sensing technology to track the casing exit window.
Many factors impact successful window milling in terms of operation parameters, penetrated formation, casing and cement integrity, wellbore inclination and dogleg severity, subsequent BHA, etc. To date, there is no standardized application for tracking window milling, leaving a critical gap in the industry's ability to track this crucial process. Through this paper, innovative sensing technology was tested through two field trials to track the casing exit window through providing the angle change above the window and at the window end along the window profile. The innovative approach showcases the developed technology's remarkable capability to accurately assess the window quality, thereby effectively reducing additional run costs and time.
The field trials conducted on two wells have demonstrated the system's robustness and effectiveness in accurately tracking the milling window during casing exit. The two trials were conducted through casing exit jobs while the sensor was assembled with the milling string. The results obtained from the two jobs through angle differences measurements showed the good window quality to pass the BHA from the technical engineering and operation aspects. The subsequent BHA runs confirmed passing the window milling successfully and the next section was drilling within the same run. The successful implementation of this novel application represents a significant advancement in the field of casing exit operations. It offers tangible benefits to the oil and gas industry by tracking the window profile quality. The remarkable outcomes obtained from the successful field trials unlock opportunities for further advancements in downhole monitoring tools and subsequent real-time log data, leading to a path of increased automation and optimization in casing exit operations.