This paper summarizes the work for developing and deploying the world's first deepwater long-term monitoring system which is designed for the methane hydrate production test in Nankai Trough in the first quarter of 2013.
The system is targeting to record temperature profiles through the methane hydrate reservoirs. One of the most challenging requirements is this downhole monitoring system must be self-operated by battery without cable connection from the sea surface for the period of 18 months. Therefore, the reliability and redundancy of the monitoring system are the key design challenges on top of the measurement data quality and offshore deployment tasks.
The monitoring system was developed and the installations for the monitoring wells were successfully completed in offshore Japan of 1000m water depth in February and March, 2012. The valuable data were also recorded by temperature sensors during the cementing.