Sub‐sample time shift and horizontal displacement measurements using phase‐correlation method in time‐lapse seismic

Hydrocarbon production and fluid injection affect the level of subsurface stress and physical properties of the subsurface, and can cause reservoir-related issues, such as compaction and subsidence. Monitoring of oil and gas reservoirs is therefore crucial. Time-lapse seismic is used to monitor reservoirs and provide evidence of saturation and pressure changes within the reservoir. However, relative to background velocities and reflector depths, the time-lapse changes in velocity and geomechanical properties are typically small between consecutive surveys. These changes can be measured by using apparent displacement between migrated images obtained from recorded data of multiple time-lapse surveys. Apparent displacement measurements by using the classical cross-correlation method are poorly resolved. Here, we propose the use of a phase-correlation method, which has been developed in satellite imaging for sub-pixel registration of the images, to overcome the limitations of cross-correlation. Phase correlation provides both vertical and horizontal displacements with a much better resolution. After testing the method on synthetic data, we apply it to a real dataset from the Norne oil field and show that the phase-correlation method can indeed provide better resolution.