19th World Petroleum Congress Madrid 2008, June 29th to July 3rd.
Geospectra Infrasonic Passive Differential Spectroscopy (IPDS)®:
an Optimized Technology for Direct Detection of Hydrocarbon Reservoir in Structural and Non-Structural Traps, Efficient Tool for a Well-Founded Enhanced Oil Recovery and reservoir monitoring.
Non-structural traps result from litho-facies variation, angular unconformities, differential compaction of sediments and others.
The stratigraphic traps are resulting from a variety of sealed geologic container capable of retaining hydrocarbons; they are formed by pinch-outs unconformities. Lithological traps are issued from facies variations or sedimentary features. Traps resulting from differential compaction may lead to the trapping of oil on mid-flank of the structures in the crevasse-splay sandstones with sloping aquifers whereas the top of the structure could turn out to be completely lixiviated and dry.
However, disclosing non-structural traps requires a detailed geological work and acquiring high quality 2D/3D seismic principally oriented on structural features and could turn out to miss non-structural traps. Stratigraphic traps are always associated with high exploration drilling risk.
In this connection, Passive Seismic-IPDS® is a technology for direct Reservoir Hydrocarbon Indication (RHI) independently of the reservoir type: structural or not. This technique is based on the principles that the hydrocarbon reservoir as a multi-fluids system in porous medium has an unconventional (non linear) transfer characteristic for acoustic waves. Hydrocarbon fluid in porous system can be detected as a characteristic deformation of the natural earth noise spectra in the acoustic low frequency range between 0.2 and 10 Hz.
Drilled test wells have shown that, the results of about 80% of them were in line with the IPDS (RHI) predictions. The correlation coefficient between cumulative Net Pay Zone thickness and IPDS (RHI) is often in the order of 80-90%. The IPDS technology provides also detailed aerial hydrocarbon distribution, reservoir delineation and monitoring and reliable estimation of hydrocarbon potential reserves or resting unproduced oils. It is well evident how the IPDS® technology could be promising for any EOR/IOR project.
Finally, IPDS® monitoring allows best orientation for horizontal and vertical well drilling in the framework of injection/production operations.