4D Case Study at Ringhorne, Ringhorne East, Balder and Forseti - Integrating OBC with Streamer Data

Time-lapse (4D) seismic data at Ringhorne, Ringhorne East, Balder and Forseti in the Norwegian North Sea are used to monitor water and gas movement within the reservoirs and improve reservoir simulation models, enabling cost-effective field operations. The structural complexity of the reservoirs, their proximity to the high-impedance Cretaceous chalk, and a modest predicted 4D signal required significant effort in seismic acquisition and processing to achieve a successful final product. The 4D repeatability of the data was significantly improved at the processing stage through the use of robust quality control measures (QCs) analyzed in collaboration between CGGVeritas seismic processing specialists, ExxonMobil geophysicists and business unit geoscientists. Analysis was followed by targeted seismic processes which removed as much of the 4D noise as possible while retaining the true 4D signal amplitudes and the 4D resolution. The final result is a 4D dataset of outstanding quality that has had a major business impact.