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AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain

Heuristic Model of Hydrocarbon Reservoir Related Microtremors

Erik H. Saenger1

(1) Geological Institute, ETH Zurich, Zurich, Switzerland.

A number of surveys over different oil and gas fields throughout the world have reported the presence of spectral anomalies in the passive seismic wavefield (between about 1 Hz and 6 Hz), with a high degree of correlation to the location of hydrocarbon reservoirs. If these microtremors originate from the reservoirs, they can be used as a reservoir indicator and for reservoir characterization. A preliminary model is presented to explain the potential source mechanism of microtremors generating the spectral anomalies. Poroelastic effects due to wave induced fluid flow and oscillations of different fluid phases are significant processes in the low-frequency range which can modify the earth’s omnipresent seismic background spectrum. These processes only occur in partially saturated rocks. We assume that hydrocarbon reservoirs are partially saturated whereas the surrounding rocks are fully saturated. Real data observations are in general agreement with this conceptual model.