Advances in MWD, LWD, SWD continue to give drillers ever-clearer downhole pictures
For decades, the industry has been chasing the “look-ahead” dream – being able to see ahead of the bit as we drill. Whether that’s still an unfulfilled dream with current measurement-while-drilling (MWD), seismic-while-drilling (SWD), and logging-while-drilling (LWD) tools is up for debate.
According to Schlumberger, its newest SWD tool, seismic-VISION, can send up to two seconds of partially processed stacked waveform data to the surface in relevant drilling time, allowing for a limited look-ahead potential. The primary technological breakthrough enabling the system was building a downhole clock accurate enough to measure milliseconds and rugged enough to survive downhole, the company said.
At the same time that we’re trying to look ahead of the bit, we’re getting significantly better at looking near the bit at what’s already been drilled.
Baker Hughes INTEQ says that its MagTrak LWD tool, based on magnetic resonance technology, is the first to measure the T2 distribution spectrum successfully. Real-time applications include identifying borehole problems, identifying missed pay in low-resistivity formations and geosteering into high-production zones.
Halliburton’s Sperry Drilling Services is launching the InSite Generation of LWD sensors, which includes a resistivity device that has 14 depths of investigation up to 18 ft out in 32 directions around the borehole. Compared with legacy tools that can detect a resistivity change but can’t tell the driller what direction to drill, the InSite sensor can tell not only what direction a formation change is but also how far away it is.
Weatherford’s True Vibration Monitor (TVM) sensor, part of its Hostile Environment Logging (HEL) MWD system, can alert the driller in real time when excessive shock or vibration is occurring downhole. It can even tell what type of vibration is occurring, whether whirl or stick-slip, so rig personnel will know what parameters to change to alleviate the vibration.
PathFinder’s Survivor series of MWD/LWD tools can withstand temperatures up to 350ºF and pressures up to 25,000 psi. It includes a slim density neutron standoff caliper (SDNSC) tool that uses a Californium 252 neutron source, which the company says is considered more environmentally friendly than the traditional Americium-Beryllium sources.
The following articles highlight recent “innovating while drilling” advances made by five service companies. The industry may not have fully realized its “look-ahead” dream yet, but with innovations like these and more on the way, we can’t be too far away.