Dynamic overburden interpretation using pre-stack time-shifts

Dynamic changes in the overburden such as geomechanical variation and hydrocarbon migration which occur between the acquisition of 4D surveys influence reservoir monitoring programs and are typically not compensated for with current industry time-lapse workflows. We utilize pre-stack time-shift analysis for the Central North Sea Shearwater field to interpret observed dynamic overburden signatures in these attributes and propose a relation to 4D anisotropy due to production related stretching and extension. An inversion of the pre-stack time-shift data delineates velocity perturbations in the overburden associated with structural extension effects.