The 4D Seismic Response of a Compacting Reservoir - Examples From the Valhall Field, Norway. Available to Purchase

We present a summary of seismic time-lapse observation from a compacting oil field. Due to the compressibility of the reservoir rock, the production induced changes propagates up into the overburden and results in subsidence at the seafloor. The seismic waves appear to be very sensitive to these changes. The conventional 4D seismic analysis is aiming at isolating the production induced effects at the reservoir, to match reservoir performance and improve predictions. In the case of a compacting reservoir, the induced effects in the overburden complicate these analyses. However, the seismic responses also bring new insights to how the compaction is propagating to the surface as well as important information about the reservoir. Rock mechanical modeling is essential in understanding the 4D seismic observations of a compacting reservoir, and a screening tool for translating rock deformation into seismic attributes has been implemented to set the interpreters expectation and to help facilitate quantitative use of the seismic 4D data.