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Using Ambient Noise for Real-time (Hourly) Overburden Monitoring
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Third EAGE Workshop on Permanent Reservoir Monitoring 2015, Mar 2015, Volume 2015, p.1 - 5
Abstract
For monitoring of an injection well we use 172 permanent 4 component nodes on the seafloor close to the Oseberg C platform. By using the platform noise as a permanent seismic source we obtain virtual shot gather for each hour. As an example, these hourly vintages are analysed for 10 days, providing 240 vintages. Time lapse changes for the acoustic guided waves (mulitiples) have been observed with time shifts up to 10 ms related to tidal variations. Time-lapse analysis of Scholte waves reveals time shifts of up to 100 ms within only 4 hours. Observed shear wave velocity decreases correlate well with atmospheric weather variations and changes in wave heights.
The high sensitivity to natural variations caused by tides and weather indicates that early detection of a leak from the injection well is possible with the installed system at the Oseberg C platform.