Passive Observations - Surface Deformations, Gravity and Microseismics

This presentation reviews state-of-the-are for some options of passive geophysical observations above a producing reservoir. These are surface deformations (mostly subsidence or uplift), gravity and microseismic data. A wide range of technologies exist for high-precision measurements of changes in these properties. The data can be used for understanding the reservoir, and can complement each other, 4D seismic measurements, production data and well pressure measurements. Some of the installations are best made permanent in a field-life perspective.