When CO2 is injected into deep saline aquifers, the resulting pressure build-up may cause micro-seismicity, fault reactivation, and induce damaging earthquakes. Continuous strain data are needed to measure vertical strain migration. Deploying a fiber-optic cable behind a well casing for subsurface geomechanical monitoring offers the opportunity to continuously track the deformation (strain) along the fiber-optic cable. 

 

We conducted water injection/production tests in both domestic and overseas sites and measured the strain profiles by using distributed fiber optic strain sensing (DFOSS) technique. Strain sensing based on Rayleigh scattering is focused on caprock deformation as well as well integrity monitoring due to the pressure build-up caused by CO2 injection, and the pressure communication between the injection/observation well and the ground water well when producing water for sampling following the regulation.