Utilizing PRM Systems for Injection Monitoring

Seismic ocean bottom monitoring solutions can contribute with useful information both for monitoring the caprock integrity as well as fluid movement and pressure build ups, avoiding unwanted events. For decades active 4D seismic has given excellent results in mapping changes in the reservoir parameters. Recent developments, mainly driven by the unconventional reservoirs, show that there is also a significant potential in real time monitoring using the seismic sensors in passive mode. Many of the challenges with injection are related to the lack of frequent active seismic 4D monitor surveys. 4D towed surveys are costly, hence in some cases the injection operations are carried out without sufficient information to take the right management decisions for optimal results. Existing field examples from the NCS are ranging from injection for IOR failing to provide the expected result due to flood barriers under seismic resolution to more dramatic examples of cap rock failure leading to surface leakage. If passive microseismic methods can be utilized on a permanent or semi-permanent monitoring system, issues like fluid movement or cap rock failure can be mapped in real time, providing information for the asset team to take action.