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  • Passive low frequency spectral analysis: Exploring a new field in geophysics

    N. Al Araimi, B. Gedge, K. Burns and M. Mahajan

    In 2003, a group of scientists in Switzerland set out to answer some intriguing questions with implications for the way oil and gas reserves are discovered and produced. Research conducted by Dr. Stefan Dangel at the University of Zurich had highlighted a strong and consistent empirical relationship between low-frequency spectral anomalies in seismic background wavefields and geological characteristics of a collection of reservoirs, mainly in the Middle East. Similar observations have also been reported in the Russian literature since the early 1990s. Dangel's research was robust by any standard, but focused on one feature in particular: curious amplitude peaks clustered around 3 Hz in surface velocity data measured above hydrocarbon reservoirs.1 The possibility of a universal hydrocarbon-indicator, while attention-grabbing, did not sit well with the real-world complexities that the industry confronts day-to-day. Moreover, the reasons for such features were left largely open.

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2013 Fracturing Technology

2013 Fracturing Technology