4D Seismic in the Southern North Sea - Reducing Cost, Maximising Value

摘要

In 2006 the Nederlandse Aardolie Maatschappij (NAM) kicked off a 4D seismic acquisition campaign, targeting the remaining volumes of the Jurassic and Triassic reservoirs in the Southern North Sea. The main driver to acquire time-lapse seismic over these fields was to identify additional development opportunities by imaging hydrocarbon drainage patterns or pressure depletion. As feasibility studies did not promise major 4D signals over these reservoirs and dynamic versus static volume discrepancies indicated that the remaining opportunities are relatively small in volume, the urge to design a cost-effective solution led to the decision to acquire 4D seismic swaths. The reduced extend of these acquisitions and the achieved synergies with other seismic acquisitions have lead to significant cost reductions. Although the potential of technical success of the 4D data interpretation is reduced with the swath acquisition, the field examples to date have greatly contributed to further field development with the potential to unlock significant value. Hence this selective and cost effective approach is to be viewed as a serious alternative in cases where full field time-lapse acquisition does not meet economic screening criteria.