Achieving Brazilian Extended Reach Drilling Records on Polvo Project with Ultra-High Torque Connection

The Polvo project is a platform based drilling rig located ~95km off the Brazilian coast in the Campos Basin. The field consists of two distinct reservoirs, a carbonate reservoir to the southwest, and a sandstone reservoir to the east. The Polvo project began drilling in March 2007 and has since drilled a total of 32 wellbores. The wells range in difficulty from “short reach” to “very extended reach” wellbores. The deviation is from 3-7º DLS at angles of 30-92º. Wellbores are 3-dimensionally designed in order to improve total reservoir exposure. Extended reach, deep and high deviation wells require the use of a drill string that has both higher torsional yield strength drill pipe body and greater torque capacity tool joints than are afforded by standard API connections. VAM Express double shoulder connection has been designed in order to address the drilling challenges linked to the development of such complex wells. This proprietary high torque connection incorporates four major design features allowing pushing further the drilling envelope limits: quick rig make-up, high torque performance, user friendly and durability. After beginning the project and platform placement, it was discovered that sandstone reservoir targets further to the east had higher productivity than expected. After drilling 12 wells and numerous lessons learned, the furthest extended reach well in the history of Brazil was attempted and successfully completed. The Pol-O wellbore was drilled to a total measured depth of 6,489 m (2,429 m TVD) and a vertical section step out of 5,615 m. This wellbore was and continues to hold the record for furthest reach wellbore in the history of Brazil. In addition to obtaining this extended reach record, Polvo also attained the record of fastest 24 hours drilling in an 8 ½” hole with 1,610 m in 24 hours. To obtain this drilling record, it was not only critical to have high on bottom ROP, but also to optimize connection time. The high torque connection helped to achieve this fast connection time and also prevented any drillstring failure. Having drilled over 100,000m of total hole in highly deviated wellbores using the same drillstring, there has not been any twist-offs or back-offs on the Polvo project. By being able to drill these further reach wellbores successfully and more economically, the Polvo Platform has proved up further reserves that can be produced without requiring installation of another platform or subsea tiebacks. The rig is not limited by connection strength and plans are in place to improve the top-drive to deliver more torque, while staying with the same double shoulder connection size.