Monitoring surface deformation induced by hydrocarbon production using satellite radar interferometry

The start of hydrocarbon production in the 1960s in the northeastern part of the Netherlands has resulted in subsidence of the ground level, which has been estimated from periodic leveling campaigns. Although leveling is a precise and reliable technique for subsidence monitoring, it is labor intensive, expensive and poses a safety risk since measurements are taken along roads. Hence, the application of satellite radar interferometry (InSAR) is investigated for subsidence monitoring, coupled with the potential improvement of reservoir behavior monitoring due to the InSAR observation frequency. The main focus lies on the Groningen gas field, which has a diameter of ∼30 kilometers, at ∼3 kilometers below surface. Complicating factors for the application of InSAR for subsidence monitoring in the Groningen area are surface changes in time due to its agricultural character (temporal decorrelation), atmospheric disturbances, and the low subsidence rates (< 1 cm/year) over a large spatial extent. Hence, the applicability of Persistent Scatterer InSAR (PSI) is investigated. PSI utilizes objects with a coherent phase behavior in time for the estimation of deformation and other phase contributions. Since the subsidence monitoring period exceeds the lifetime of a satellite (5–10 years), multiple sensors are required: ERS-1, ERS-2 and Envisat phase observations have been used.