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Study of Sub Seafloor Gas Hydrates in Vestnesa Ridge Using Seismic Attributes

Sahoo, Sourav Kumar (2014) Study of Sub Seafloor Gas Hydrates in Vestnesa Ridge Using Seismic Attributes. Masters thesis, Indian Institute of Science Education and Research Kolkata.

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    Abstract

    Gas Hydrates are considered as a viable source of energy, especially in energy starved countries. The role of gas hydrates in climate change, geo hazard and energy source has led to its study in various countries. With present scientific understand the detection of gas hydrates is done quite accurately using various geophysical exploration methods but the volume estimation or distribution of gas hydrate in a particular site is not well understood. Bottom simulating reflector (BSR) is easily identified in seismic but the upper boundary is not clear due to low impedance contrast in the upper boundary. In this thesis an attempt has been made to identify the volume distribution of hydrates in Vestenesa Ridge using seismic attributes. P cable seismic data from University of Tromso were used and the attributes were calculated. Attributes like Instantaneous Quality, Bandwidth, RMS Amplitude, Envelope were able to differentiate the hydrate zone but there were other zones of low amplitude where it was also showing similar character. This may be related to the blanking effect of gas hydrates, where the amplitude of reflections from the gas hydrate zone is reduced. Chaos attribute could clearly differentiate the hydrate zone and chimneys. The other attributes which were all related to amplitude change were not able to differentiate between hydrate zone and other low amplitude zones, but chaos was able to differentiate it. But this finding has to be tested with the ground truth. As drilling has not been done in the study site, the results needs to be verified. Similar calculation may also be done in other areas to verify this method.

    Item Type: Thesis (Masters)
    Additional Information: Supervisors: Dr Manoj Jaiswal and Prof Bimalendu B Bhattacharya
    Uncontrolled Keywords: Gas Hydrates; Seismic Attributes; Sub Seafloor; Vestnesa Ridge
    Subjects: Q Science > QE Geology
    Divisions: Department of Earth Sciences
    Depositing User: IISER Kolkata Librarian
    Date Deposited: 08 Jan 2015 11:27
    Last Modified: 14 Jan 2015 17:14
    URI: http://eprints.iiserkol.ac.in/id/eprint/177

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