Case Study of Successful Identification of Hydrocarbon Reservoirs by Microtremor Analysis (HyMAS)

Holzner, Reto¹, Patrik Eschle¹, Hannes Zurcher¹, René Graf², Stefan Dangel³, Peter F. Meier³ (1) Spectraseis Technologie AG, Zurich, Switzerland (2) Proseis AG, Zurich, Switzerland (3) University of Zurich, Zurich, Switzerland

Hydrocarbon Microtremor Analysis (HyMAS) is an innovative passive technology iden­tifying the hydrocarbon content of geological structures by analyzing low frequency seismic signals. Hydrocarbon indicating information is extracted from spectral modifications of nat­urally occurring seismic background noise waves in the 0.01 – 10 Hz range passing through hydrocarbon bearing porous structures. The mechanism underlying HyMAS technology can be summarized as “selective absorption and hydrocarbon induced amplification of low fre­quency seismic background noise”. As a direct hydrocarbon indicator, HyMAS is an ideal complement to 2D and 3D seismic structural imaging technologies. It allows fast and envi­ronmentally safe screening of prospects as well as cost and time saving optimization of an operator’s investment in 3D acquisition and optimized well placement during exploration, appraisal and production. Its relevance has been proven at more than 15 sites worldwide [S. Dangel et al “Phenomenology of tremor-like signals observed over hydrocarbon reservoirs” J.Volcan.Geotherm.Res.Vol128(2003)135-158). During a recent onshore commercial trial in Brazil, HyMAS data was acquired over an area of 120 km² (by a crew of 20 people operat­ing ultra-sensitive broadband seismometers), processed and interpreted within five months. The results were displayed as HyMAS hydrocarbon potential maps. A subsequent compari­son with the integrated thickness of the hydrocarbon containing layers identified by log data of 30 wells confirmed comparably good correlations as reported for the first time for sever­al sites in the Middle East (S. Dangel et al) where a linear relationship between measured signals and the total hydrocarbon layer thickness was established.