Geophysical reservoir monitoring is an important tool for increased production as well as safety. We have developed new methods within this theme that has been tested on field examples. 4D refraction seismic is not a standard today, however, we have demonstrated that there is a potential for using this technology as a complementary tool, especially for fields equipped with permanent sensors at the sea bed.
The project has developed new research results within seismic inversion (the process where properties of subsurface layers are determined from seismic data). We have also made progress within seismic anisotropy research, which enable us to include that the seismic velocity varies with angle.
Within the field of CO2-monitoring, the project has delivered more than promised. We have published many papers within this field, including a recent book entitled "Geophysics and Geosequestration" published by Cambridge University Press this year.
Vi har forsket på seismisk inversjon og avbildning, spesielt full waveform inversion som nå er vanlig i bruk. Innenfor seismisk anisotropi har vi bidratt med mange artikler og dypere forståelse.
For geofysisk reservoarmonitorering har utviklet nye metoder og utført flere felteksempler. Betydningen av en bedre monitorering av lagene over reservoaret er viktig, og våre metoder egner seg godt til dette formål. For seismiske kilder har vi gjort laboratoriearbeid feltforsøk som har resultert i ny innsikt.
Innen CO2-forskning har prosjektet bidratt med mer enn planlagt. To bøker: Geophysics and Geosequestration og Introduction to Exploration Geophysics with Recent Advances. Den siste boka ble delt ut gratis til alle norske studenter innen geofag.
Vi har publisert 114 artikler i tidsskrifter, hvorav en artikkel i Nature. Vi har presentert mer enn 160 foredrag på konferanser og workshops i løpet av prosjektperioden, og publisert 33 populærvitenskapelige artikler, de fleste i GeoExpro.
Geophysical methods have been and will still be a crucial tool for for hydrocarbon exploration and production offshore Norway. We propose to develop new geophysical methods aiming for reducing the risk in exploration as well as increased oil recovery. Wi thin seismic imaging we will focus on effective 3D seismic modeling, further development and testing of full waveform inversion methods. We expect that the success of full waveform inversion depends on the acquisition geometry. Therefore, we propose to te st the sensitivity of this technique for various acquisition geometries. We know that the earth is anisotropic, and methods for estimation of various seismic anisotropic parameters will therefore be developed and tested.
We propose to further develop the time lapse seismic method into a more quantitative approach. The future within 4D seismic will probably be a combination of permanent receiver systems, semi-permanent receivers or exploiting the new broadband streamer technology. We will develop methods that exploit this richness in data, and especially test if 4D refraction methods can be used to monitor overburden changes. Another area for further research is to explore why the contribution from converted waves is limited, and suggest methods to improv e the use of such data both in exploration and in a 4D seismic setting. There is a close link between time lapse geophysical methods and geomechanics and rock physics, which will be explored. Both measurements and combined seismic-geomechanical modeling a re crucial areas for research. The preferred marine seismic source is the air gun, and there has been only minor developments during the past decades. Environmental issues related to the use of air guns will be in focus, as well as new concepts for develo pment of a seismic low frequency (1-5 Hz) source. We have established international cooperation with 5 international universities, closely linked to these research topics.