Communications between the surface and the drill bit are problematical and yet they play a key role in downhole situational awareness and in applying real-time drilling optimization solutions. Currently most all communications are achieved through acoustic pulses in the mud column. This is reliable technology that does not require any particular kind of drill pipe. It is unfortunately also very low bandwidth. This can be fixed in two ways. If real time is not important, high frequency information can be recorded to downhole storage and replayed when the tool is pulled out of hole. But higher frequency, real time data mandates a special wired drill pipe. We take a look at some new offerings in the measurement-while-drilling space from Halliburton, NOV and AkerBP/TDE to see just how fast is fast in modern downhole comms.
Halliburton’s latest contribution to the MWD is QuickPulse, an automated directional gamma service that provides ‘quick and reliable downhole information at extended depths’. QuickPulse combines directional, vibration and gamma ray sensors with a strong transmission signal that overcomes most downhole interference. The system prioritizes critical measurements. Bandwidth as such has not been announced but a compete survey is said to take 24 seconds to transmit while ‘toolface updates’ can be delivered every 3 seconds. It is clear that we are talking a few bits per second here. This may be fine for many operations, but if you need higher real time sampling, you will likely need to look to a wired drill pipe.
Our first encounter with wired drill pipe was back in 2002 when Grant Prideco and Novatek announced IntelliPipe. IntelliPipe derived from a US Department of Energy funded experiment to offer ‘megabit bandwidth’ for MWD. (Incidentally mud pulse telemetry was likewise developed with help from the DoE, back in the 1970s.) Our next encounter with the technology was in 2006 when IntelliPipe had morphed into IntelliServ and was being marketed by Halliburton along with Grant Prideco. At the time the bandwidth was still quoted as ‘around a megabit’. But this had dropped to a more realistic 57 kbps in 2009 when we reported on Apache’s trials of IntelliServ offshore Australia. In the same year a new InteliServ joint venture kicked-off between Schlumberger and Prideco’s parent National Oilwell Varco. Today, it appears that NOV has repatriated the IntelliServ technology. It would not appear to have been the roaring success that was expected back in the early 2000s. By 2016, only around 130 wells had been drilled with wired drill pipe. But some successes have been reported, notably on the Norwegian Martin Linge field.
Most recently, interest in wired drill pipe has picked up with the announcement from Austria-based TDE Group of the ‘Powerline Drill String’ (PDS) that delivers both a high-speed data telemetry system and electrical power. TDE with joint venture partner AkerBP have tested the system in two weeks of drilling at the NORCE/Ullrigg test site in Stavanger. The tests demonstrated simultaneous transmission of data at 500 kbps (10x IntelliServ) and 300 watts of power. TDE Group’s Abdelrhani Lamik said, ‘Multivendor BHA tools can now be operated using electrical power from the surface without batteries or turbines. The quality of the downhole data streamed at 500,000 bit/s is unprecedented. A gap has been filled and the digital age can start!’
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