OCTIO Gravitude will survey the Ormen Lange field during summer 2020. Ormen Lange is the second-largest gas field in Norway and has been in production since 2007. The operation is expected to last for four weeks and will produce measurements of water depth and gravitational field at the seabed above the gas reservoir.

Seabed gravimetry and subsidence measurements have been acquired every second year at Ormen Lange since 2012.  Gravimetry measurements detect mass changes in the subsurface and provide a picture of how fluids are moving in the reservoir. Seabed subsidence measurements indicate how reservoir rocks are responding to the pressure decrease caused by hydrocarbon production. These two measurements combined provide valuable  insight to improve reservoir management and support efficient hydrocarbon production with reduced cost and environmental impact.

For this survey, OCTIO Gravitude will utilize the new gWatch technology, introduced in 2018. gWatch features more efficient operation, lower costs and a largely improved sensitivity when compared with traditional gravimetry instrumentation.

At Ormen Lange, gravimetry and 4D seismic are combined to provide a robust and complete understanding of the reservoir, and hence to ensure optimal management of natural resources. Gravimetry and subsidence surveys are significantly less expensive than 4D seismic, and the monitoring strategy at Ormen Lange combines two-yearly monitoring with gWatch with less frequent 4D seismic acquisitions.