Borehole microseismic in deep live oil wells: an example

Passive seismic monitoring of development activities at reservoir level is a challenging activity. Seismic signals of very low energy are emitted, and only few are detectable from surface tools. To improve quantity and quality of detected signals, the sensors must be deployed deep in the Earth, close to the sources. The instrumentation of a well is costly from both the economic and the technical point of view but can give useful information for the understanding of the reservoir dynamics. A dedicated well to install the microseismic sensors is rarely available, so that, the possibility to use a live well is very attractive. The field test performed by Eni successfully demonstrated the possibility to record microseismic events during well activity, with a smooth integration into well completion. The clear correlation between well operations and microseismic events helped to improve the reservoir model close to the well.