Extended-reach wells with narrow pressure margins are complicated with respect to maintaining accurate pressure control during drilling. The high compressibility of the drilling mud that is typically used in such wells result in large pressure transients that need to be handled by the Managed Pressure Drilling (MPD) system. Also, limitations in sampling interval and delay in transmission time for downhole pressure measurements using mud pulse telemetry affects the ability to use the data.
This paper presents results showing the benefit of using wired drill pipe for transmitting pressure measurements when drilling with back-pressure MPD in an Extended-Reach Drilling (ERD) operation. It is shown how minutes can be saved each connection by using wired drill pipe in combination with state-of-the-art MPD control algorithms. It is also shown how a combination of traditional back-pressure MPD, and wired drill pipe can significantly improve the ability to control down hole pressure. Measurements are generated synthetically by an advanced transient well flow model. The example cases are based on a real ERD well drilled recently in the North Sea.
Benefits by this approach are the ability to minimize downhole pressure variations that will occur in ERD wells and, in particular, save time during connections, and also more accurate pressure control, and thereby safer drilling operations.