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Gas Hydrates Potential of Makran Area, Offshore Pakistan

  • Aamir AliEmail author
  • Ihsan ul Haq
  • Matee Ullah
Chapter
Part of the Advances in Science, Technology & Innovation book series (ASTI)

Abstract

Gas hydrates are part of the unconventional energy resources called the gas clathrates. The present work focused on the assessment of gas hydrates potential of Makran area, Offshore, Pakistan. The presence of a clear bottom simulating reflector (BSR) is primary indicator for the occurrence of gas hydrates and generally referred to as base of gas hydrates stability zone. The gas hydrates zone in the study area was identified by the application of seismic attributes (sweetness, relative acoustic impedance and normalized apparent polarity) using major characteristics of BSR i.e. amplitude blanking, adopting the shape of seafloor, cross cutting the sedimentary structures and opposite polarity to seafloor. A low velocity layer was also interpreted beneath the hydrates layer due to the existence of free gas. Rock physics modelling for the two different geometrical distribution of hydrates was also applied to obtain effective elastic properties. The results of rock physics modelling showed that the hydrates as part of sediments have higher elastic properties compared to hydrates in pore spaces, and these properties were controlled by saturation of gas hydrates. Using the effective elastic properties, amplitude versus offset (AVO) forward modelling (Exact Zoeppritz + ray tracing) for different scenarios was performed to characterize the presence of BSR more efficiently.

Keywords

Gas hydrates Unconventional resources Bottom simulated reflection Rock physics AVO 

References

  1. 1.
    Johnson, H., Dore, A.G.: Unconventional oil and gas resources and the geological storage of carbon dioxide: overview. In: Geological Society, London, Petroleum Geology Conference series, vol. 7, issue 1, pp. 1061–1063. Geological Society of London (2010)Google Scholar
  2. 2.
    Aregbe, A.G.: Gas hydrate—properties, formation and benefits. Open J. Yangtze Oil Gas 2(01), 27 (2017)CrossRefGoogle Scholar
  3. 3.
    Riedel, M., Willoughby, E.C., Chopra, S. (eds.): Geophysical Characterization of Gas Hydrates. Society of Exploration Geophysicists (2010)Google Scholar
  4. 4.
    Chand, S., Minshull, T.A., Gei, D., Carcione, J.M.: Elastic velocity models for gas-hydrate-bearing sediments—a comparison. Geophys. J. Int. 159(2), 573–590 (2004)CrossRefGoogle Scholar
  5. 5.
    Chen, M.A.P., Riedel, M., Dosso, S.E.: Seismic AVO for gas-hydrate-related reflections. In: Geophysical Characterization of Gas Hydrates, pp. 73–93. Society of Exploration Geophysicists (2010)Google Scholar
  6. 6.
    Kadri, I.B.: Petroleum Geology of Pakistan. Pakistan Petroleum Limited (1995)Google Scholar
  7. 7.
    Roeser, H.A., Adams, J., Bargeloh, H.O., Block, M., Damm, V., Dohmann, H., Reichert, C., et al.: The Makran Accretionary Wedges off Pakistan: Tectonic Evolution and Fluid Migration-Part 1. SONNE Cruise SO-122 (7 Aug–6 Sept 1997). Operational Report and Preliminary Results: Published by BGR, Germany, 111 (1997)Google Scholar
  8. 8.
    Koson, S., Chenrai, P., Choowong, M.: Seismic attributes and their applications in seismic geomorphology. Bull. Earth Sci. Thai. 6(1), 1–9 (2014)Google Scholar
  9. 9.
    Mavko, G., Mukerji, T., Dvorkin, J.: The Rock Physics Handbook: Tools for Seismic Analysis of Porous Media. Cambridge University press (2009)Google Scholar
  10. 10.
    Katzman, R., Holbrook, W.S., Paull, C.K.: Combined vertical-incidence and wide-angle seismic study of a gas hydrate zone, Blake Ridge. J. Geophys. Res. Solid Earth 99(B9), 17975–17995 (1994)CrossRefGoogle Scholar
  11. 11.
    Krebes, E.S.: Seismic forward modelling. CSEG Rec. 30, 28–39 (2004)Google Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Quaid-i-Azam UniversityIslamabadPakistan

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