| Popis: |
A world-leading extended reach drilling (ERD) project in the UAE has successfully made a breakthrough, drilling several of the longest wells in the world from artificial islands offshore Abu Dhabi. A key enabling technology for efficiently delivering such wells has been the use of a single size string of ultra-high torque drill pipe throughout the entire well construction process. The drill pipe incorporates specially designed threads and tubular geometry to overcome technical challenges and enable ERD depths beyond 40,000 feet (12,000 m). The drill pipe design is fit for purpose, incorporating the latest in thread technology to enable ultra-high operational torques. The connection pushes the limits of thread design with make-up torques (MUT) in excess of 70,000 ft-lbs for a 6½-in. connection and 5½-in. tubular body. Design considerations allow for fishability in an 8½-in. hole while accounting for equivalent circulating density (ECD) and standpipe pressure restriction that might otherwise limit the achievable drilling depths. The drill pipe design was successfully used to drill more than 1,000,000 ft (300 km) across seven rig lines since the tubular entered service in early 2018. As of February 2020, zero failures related to the drill pipe have occurred. The incredibly high operational torque is continuing to allow wells to reach out further and further, with multiple wells now among the top 10 longest worldwide. The drill pipe being of a single size has tremendously reduced the amount of tubular handling that must occur as it is no longer necessary to lay down and pick up other tubular sizes on each well. Hydraulic design considerations have proven to be sufficient. This paper details the comparative evaluation of two drill pipe designs that enabled the operator to drill wells that are among the longest in the world. Insight into the operational benefits obtained by shifting to the new tubular design are also detailed. |
