Keynote Speech - Ekofisk Permanent Seismic Monitoring - Results After first 4 years

In 2010, a full-field permanent seismic monitoring (PRM) system based on optical sensing technology was installed over the Ekofisk field.

Since installation, seven seismic surveys have been acquired with a plan to continue acquiring two new surveys each year.

Permanent sensor positioning combined with a high focus on quality during acquisition and processing have enabled achievement of NRMS values on the order of 4% resulting in detectable 4D seismic timeshifts less than 200s and amplitude changes of the order 2–3%.

The 4D seismic data from the system are routinely used for many different purposes including optimization of new well locations and trajectories, suggestion and prioritisation of well interventions, diagnoses of well mechanical issues and updating the reservoir model. In addition to reservoir applications, the data are used extensively for monitoring and surveillance of the impact of injection, production, compaction and subsidence on the overburden section.

In this paper, we will show a selection of cases where 4D seismic data from the Ekofisk PRM system have been used to impact business decisions related to injection and production from the Ekofisk reservoir.