The Board of Appeal of the European Patent Office in Munich has found that EMGS’s patent for the use of CSEM for the direct detection of hydrocarbons in submarine reservoirs is valid.
The patent (EP 1256019) was the subject of an Opposition in the European Patent Office, but has successfully overcome that opposition at the final appeal level.
Controlled source electromagnetic (CSEM) surveying
Wellbore resistivity has long been the fundamental formation evaluation measurement. Marine CSEM surveying uses the same principles to map resistive bodies such as commercial-scale hydrocarbon reservoirs from the seabed.
As pore fluid resistivity largely determines the EM response, CSEM surveying is the perfect partner for seismic techniques, which generally provide structural information. Together, and with other subsurface information, these methods form a valuable set of exploration tools.
In CSEM surveying, a powerful horizontal electric dipole is towed about 30 m above the seafloor. The dipole source transmits a carefully designed, low-frequency electromagnetic signal into the subsurface.
EM energy is rapidly attenuated in conductive sediments, but it is attenuated less and propagates faster in more resistive layers such as hydrocarbon-filled reservoirs.
Grids of seabed receivers measure the energy that has propagated through the sea and the subsurface. Data processing, post-modelling and inversion are performed to produce 3D resistivity volumes. These datasets are integrated with other subsurface information to enable you to make important drilling decisions with greater confidence.
About EMGS
EMGS, the marine EM market leader, uses its proprietary electromagnetic (EM) technology to support oil and gas companies in their search for offshore hydrocarbons. EMGS supports each stage in the workflow, from survey design and data acquisition to processing and interpretation. The company’s services enable integration of EM data with seismic and other geophysical and geological information to give explorationists a clearer and more complete understanding of the subsurface. This improves exploration efficiency, and reduces risks and the finding costs per barrel.
EMGS has conducted more than 600 surveys to improve drilling success rates across the world’s mature and frontier offshore basins. The company operates on a worldwide basis with main offices in Trondheim and Stavanger, Norway; Houston, USA; and Kuala Lumpur, Malaysia.
[mappress] Subsea World News Staff , December 13, 2011; Image: EMGS