Refrigerated Foundation Monitoring in a Grind and Inject Facility - Case Study
A new grind and inject (G&I) facility was recently completed for Hilcorp at Milne Point in northern Alaska. The geotechnical consultant for the facility brought BeadedStream on-board for monitoring purposes related to the unique thermal environment of the G&I structure’s foundation.
Relatively warm drilling fluid (~50° F) is a primary issue in G&I applications in that it would offload to a subgrade wash pit less than a foot above ice-rich permafrost. The potential for ground thaw and subsequent settlement under these conditions presents various design challenges that must be managed to meet design criteria for the facility.
Design solutions included insulation layers and passive thermosyphons to block and route heat from permafrost soils. Concurrently, active thermal monitoring using BeadedStream instrumentation allows engineers and site operators to ensure that design methods are effective and operational. Further, the monitoring system allows facility managers to remain pro-active against any unprecedented changes within the structure’s refrigerated foundation, which can often incur heavy costs in remediation.
Custom BeadedStream DTCs (Digital Temperature Cables) were routed to various subfloor locations around the structure and integrated with a BeadedStream D405 Datalogger for long-term, foundation monitoring. In this case the satellite capability of the D405 was left untapped to meet a less frequent schedule for data extraction. On-site collection of new temperature data from the memory of the logger is done wirelessly, over Bluetooth via BeadedStream’s AuroraLink iOS application. The foundation temperature monitoring system is set to match or exceed the 20 year design life of the G&I facility.
Milne Point is located on the North Slope of Alaska – an arctic hub of petroleum extraction activity. More information on the region can be found here.