Monitoring horizontal and vertical surface deformation over a hydrocarbon reservoir by PSInSAR

We study surface deformation monitoring over a hydrocarbon reservoir in the Middle East with permanent scatterer interferometric synthetic aperture radar (PSInSAR). By combining data from two different observation angles, it is possible to disentangle horizontal and vertical deformation of the Earth’s surface. We benchmark the PSInSAR data against an existing GPS network and find good agreement in both vertical and horizontal displacements. In order to relate the surface data to the reservoir, we invert the surface deformations using an analytical geomechanical model and obtain reservoir strain. Assuming linear poroelasticity, we relate the strain to pressure depletion. The areal extent of the reservoir strain is in good agreement with predictions from reservoir simulation. By considering velocity gradient maps, we find intriguing relationships between major faults in the reservoir and the surface data. We conclude that surface deformation monitoring and geomechanical inversion can provide valuable information on dynamic reservoir behaviour.