Quantitative Geophysics for Exploration and … datahseets/flyer agr... · Quantitative Geophysics...
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www.agr.com Quantitative Geophysics for Exploration and Reservoir Characterisation Eyvind Aker Principal Rock Physics [email protected] Mob: +47 47 90 77 02 Quantitative geophysics can reduce exploration risks by identifying subtle traps, lithology type and pore fluid content. AGR Reservoir Management is utilizing inversion of seismic data, seismic attribute analysis and rock physics to obtain reservoir properties like lithology, porosity, pore fluid and pressure. Spectral decomposition The seismic signals are analysed with respect to their frequency content to reveal geological patterns that may be difficult to observe. The attribute map to the right shows the seismic amplitude within three frequency bands centred around 10, 18 and 36 Hz. For visualization purposes the filtered amplitudes are plotted using the RGB colour map. A sand channel containing all three frequencies is therefore revealed as light colours. Simultaneous inversion Seismic inversion is transforming the seismic reflection data into quantitative properties of the subsurface rock. Simultaneous inversion solves for both shear impedance (SI) and acoustic impedance (AI). Combined with rock physics models we can predict lithology and fluid content. In the lower left plot sands with increasing gas saturation shows up as points in the blue triangle. The sand points are overlaying the spectral decomposition attribute map to the lower right. A clear pattern of channelling sands is observed. Sigurd Harald Sande Schmidt Senior Geophysicist [email protected] Mob: +47 98 28 20 97 John Erick Battié Chief Geoscientist [email protected] Mob: +47 91 55 70 54 Spectral decomposition of seismic signal Sand points coloured according to porosity
Transcript of Quantitative Geophysics for Exploration and … datahseets/flyer agr... · Quantitative Geophysics...
www.agr.com
Quantitative Geophysics for Exploration and Reservoir Characterisation
Eyvind AkerPrincipal Rock [email protected]: +47 47 90 77 02
Quantitative geophysics can reduce exploration risks by identifying subtletraps, lithology type and pore fluid content. AGR Reservoir Management isutilizing inversion of seismic data, seismic attribute analysis and rockphysics to obtain reservoir properties like lithology, porosity, pore fluid andpressure.
Spectral decompositionThe seismic signals are analysed with respectto their frequency content to reveal geologicalpatterns that may be difficult to observe. Theattribute map to the right shows the seismicamplitude within three frequency bandscentred around 10, 18 and 36 Hz. Forvisualization purposes the filtered amplitudesare plotted using the RGB colour map. A sandchannel containing all three frequencies istherefore revealed as light colours.
Simultaneous inversionSeismic inversion is transforming the seismic reflection data into quantitative properties ofthe subsurface rock. Simultaneous inversion solves for both shear impedance (SI) andacoustic impedance (AI). Combined with rock physics models we can predict lithology andfluid content. In the lower left plot sands with increasing gas saturation shows up aspoints in the blue triangle. The sand points are overlaying the spectral decompositionattribute map to the lower right. A clear pattern of channelling sands is observed.
Sigurd Harald Sande SchmidtSenior [email protected]: +47 98 28 20 97
John Erick BattiéChief [email protected]: +47 91 55 70 54
Spectral decomposition of seismic signal
Sand points coloured according to porosity
www.agr.comAGRKarenslyst allé 40213 OsloNorway
The AVO cross-plot of intercept versus gradient is dividing the AVO response in differentclasses and is very helpful when analysing AVO data. The lower left plot is showing theAVO respond of the seismic data from the previous page. The dark green squarecorresponds to Class III gas sands and are coloured as pink points in the seismic attributemap to the right. By combining the inversion, rock physics modelling and AVO analysis wereduce the uncertainty of the fluid and lithology interpretation.
AVO analysis
Amplitude versus offset (AVO) analysis has become very popular in the oilindustry and can be used to determine fluid content and rock properties likeporosity and density from pre-stacked seismic data. The technique is basedon the relationship between reflection amplitude and incident angle ofseismic waves.
Related services
• Seismic attribute analysis for detecting geological features
• Fluid interpretation based on seismic amplitude data and inversion.
• Forward modelling as way of understanding the seismic response.
• Estimating the effect of pore fluids on the seismic signature
• Evaluation of seismic anomalies in prospect evaluation.
• Part of 4D feasibility and interpretation study.
Seismic attribute map with AVO Class III in pink points
