OptaSense demonstrated improved sensitivity of its distributed acoustic sensing (DAS) interrogator unit (IU).
The fourth generation IU will acquire higher quality vertical seismic profile (VSP) measurements, enabling geophysicists to see clearer images of the subsurface with the unique flexibility afforded by acquiring seismic measurement on an optical fiber deployed downhole. The improved IU is expected to improve microseismic monitoring with smaller events now detectable, and flow monitoring where the simultaneous use of more than one acquisition mode will extend the ability of DAS to accurately measure inflow and axial flow rates across the length of the well. These features, including a wider receive bandwidth and finer spatial resolution, will be implemented in the commercial release of the fourth generation IU due in summer 2015.
As part of its ongoing product development, a pre-production version of the fourth generation of the OptaSense DAS IU was used to acquire a VSP on a carbon capture and sequestration well during customer trials this month in North America. In these tests the new fourth generation IU achieved the targeted 6dB increase, a four times increase in sensitivity over the previous third generation system.
