A Comprehensive Overview on Inefficient Events and Key Technologies of Multi-Branched Well Drilling and Completion: Cases in the Middle East

Abstract

Abstract Multi-lateral wells are widely utilized by exhibiting enhanced productivity and reduced drilling costs in comparison to traditional vertical well technology, due to the shared upper casing section and production process equipment. Nevertheless, a systematical evaluation of the key technologies of the multi-lateral wells is currently absent, resulting in frequent inefficiencies occurring during the drilling and completion process and having a negative influence on drilling efficiency. Based on the statistical data sourced from an oilfield in the Middle East, this paper undertaken a comprehensive assessment of the inefficiencies from three perspectives of geological factor, design factor and drilling optimization. The key technologies for enhancing the efficiency of drilling and completion are identified. Results indicate that inefficient events related to geological factors are primarily formation losses, while design-related inefficiencies include intricate trajectory for which control is difficult, as well as a long horizontal section with difficulties in cut carrying and a propensity for the formation of rock beds. From a viewpoint of drilling optimization, inefficiencies involve stuck pipes during drilling, particularly in water-sensitive formations, causing issues such as hole shrinkage, key seat sticking, and long operation time. In addition, an ease of swabbing during retrieve Whipstock in 7″ liner results in a heightened risk of well control, and shear pin may snap if the driller slacks off extra weight during run in hole (RIH), leading to the Whipstock to plummet into the hole. In order to address the three types of factors, the strategy of abandoning total loss hole and using high-performance drilling fluids is adopted to save costs and time. Collision avoidance is considered to prevent unintended intersection or interference and distance among window to window is optimized around 200 ft. In addition, the multi-window one-time scraping method is used to enhance operational efficiency by minimizing the number of trips. During the drilling process in the 6-1/8″ wellbore, employing the fast drilling method reduces the time required by half compared to traditional controlled-speed drilling. This research provides both practical and theoretical guidance for contributing to multi-lateral well construction efficiency, modulating non productive time (NPT) and ensuring safety during operation.