Precise Deformation Monitoring by High Resolution Tiltmeters

摘要

Subsidence is typically thought to occur on long time scales relative to most field activities. Hence, monitoring subsidence in near real time has not been considered a priority. However, the availability of systems able to monitor and report ground movement to precise levels over both short and long time scales has generated new insights into field activities. One system currently in use employs tiltmeters for their low cost and extremely fine resolution, plus GPS for its long term stability. Fully automated data collection and analysis is a necessary step to obtaining near real time data, and also dramatically lowers the cost of the service. "Near Real Time" in this context may mean anywhere from a few seconds delay for a volcano project to a full day's delay in areas like oil and gas fields where the use of explosives precludes the use of radio data transmission during daylight hours. The data is published to a secure web site in a video format that allows visual assessment of the field motion.This paper discusses the development of combined tiltmeter and GPS subsidence monitoring arrays. In addition, the subsidence data is correlated to field activities to show how the monitoring can be used to correlate ground movement with reservoir events.