Developing the long-term seismic strategy for Azeri-Chirag-Gunashli, South Caspian Sea, Azerbaijan

摘要

At Azeri-Chirag-Gunashli (ACG), seismic activities have focused on static and dynamic imaging of the reservoir to reduce risk for appraisal and development drilling. Imaging and reservoir characterization constrain the "static" reservoir model, and 4D reservoir monitoring constrains the "dynamic" reservoir model. Over the last several years we have successfully tested and implemented prestack depth migration, 4-C OBS acquisition and processing, and towed-streamer 4D in various parts of ACG. Results from these technologies are being used to shape the longer-term (20+years) seismic strategy of the development—in particular, how 4D seismic surveillance should be implemented across ACG. Expected value delivered to ACG from 4D seismic surveillance has been based on proven benefits documented in other fields. Base production profiles and reserve estimates for Azeri and Gunashli include an expected benefit consistent with BP's global experience from 4D seismic surveillance. The 4D benefits being banked are generally related to identifying bypassed oil and unswept zones to assist in targeting development and infill drilling. Other potential benefits (production acceleration, cost savings, risk mitigation) from more frequent time-lapse monitoring ( > 1 survey/year) have been evaluated, but at this time there is not a sufficient industry track record to provide confidence in magnitude or likelihood that these benefits can actually be delivered.