Research paper
Geologic implications of gas hydrates in the offshore of India: Results of the National Gas Hydrate Program Expedition 01

https://doi.org/10.1016/j.marpetgeo.2014.07.021Get rights and content

Abstract

The Indian National Gas Hydrate Program Expedition 01 (NGHP-01) is designed to study the occurrence of gas hydrate along the passive continental margin of the Indian Peninsula and in the Andaman convergent margin, with special emphasis on understanding the geologic and geochemical controls on the occurrence of gas hydrate in these two diverse settings. The NGHP-01 expedition established the presence of gas hydrates in the Krishna–Godavari and Mahanadi Basins, and the Andaman Sea. The expedition discovered in the Krishna–Godavari Basin one of the thickest gas hydrate accumulations ever documented, in the Andaman Sea one of the thickest and deepest gas hydrate stability zones in the world, and established the existence of a fully developed gas hydrate petroleum system in all three basins.

The primary goal of NGHP-01 was to conduct scientific ocean drilling/coring, logging, and analytical activities to assess the geologic occurrence, regional context, and characteristics of gas hydrate deposits along the continental margins of India. This was done in order to meet the long-term goal of exploiting gas hydrate as a potential energy resource in a cost effective and safe manner. During its 113.5-day voyage, the D/V JOIDES Resolution cored and/or drilled 39 holes at 21 sites (1 site in Kerala–Konkan, 15 sites in Krishna–Godavari, 4 sites in Mahanadi, and 1 site in the Andaman deep offshore area), penetrated more than 9250 m of sedimentary section, and recovered nearly 2850 m of core. Twelve holes were logged with logging-while-drilling (LWD) tools and an additional 13 holes were wireline logged. The science team utilized extensive on-board laboratory facilities to examine and prepare preliminary reports on the physical properties, geochemistry, and sedimentology of all the data collected prior to the end of the expedition. Samples were also analyzed in additional post-expedition shore-based studies conducted in leading laboratories around the world.

One of the specific objectives of this expedition was to test gas hydrate formation models and constrain model parameters, especially those that account for the formation of concentrated gas hydrate accumulations. The necessary data for characterizing the occurrence of in situ gas hydrate, such as interstitial water chlorinities, core-derived gas chemistry, physical and sedimentological properties, thermal images of the recovered cores, and downhole measured logging data (LWD and/or conventional wireline log data), were obtained from most of the drill sites established during NGHP-01. Almost all of the drill sites yielded evidence for the occurrence of gas hydrate; however, the inferred in situ concentration of gas hydrate varied substantially from site to site. For the most part, the interpretation of downhole logging data, core thermal images, interstitial water analyses, and pressure core images from the sites drilled during NGHP-01 indicate that the occurrence of concentrated gas hydrate is mostly associated with the presence of fractures in the sediments, and in some limited cases, by coarser grained (mostly sand-rich) sediments.

Section snippets

Editor's note

This report is part one of a two-report series that summarizes the results of the Indian National Gas Hydrate Program Expedition 01 (NGHP-01). This first report (Collett et al., this issue) in this series summarizes the overall operational and scientific accomplishments of NGHP-01, while the second report reviews the occurrence and geologic controls on gas hydrates in the Krishna–Godavari Basin, the Mahanadi Basin, the Andaman Sea, and the Kerala–Konkan Basin (Kumar et al., this issue).

Earlier investigations

The first indication of the presence of gas hydrates in the offshore India dates to 1984, when the Oil and Natural Gas Corporation Limited (ONGC) (Chopra, 1985) identified bottom-simulating reflectors (BSRs), which are often attributed to the presence of gas hydrate, on seismic lines in the Andaman Island offshore area. In 1997, the National Institute of Oceanography (NIO) generated the first gas hydrate resource map of India, which depicts the gas hydrate stability zone (GHSZ) in the Indian

Future research and direction

The occurrence of gas hydrate in mostly fracture-dominated systems in the offshore of India as documented during NGHP-01 is somewhat troubling when considering their energy resource potential. The prospects for economic recovery of natural gas from fracture-filling forms of gas hydrate occurring in mostly fine-grained sediments is likely limited with current technologies, and major improvements in extraction methods are required to enable commercial exploitation of such deposits (as reviewed by

Summary

NGHP-01 was among the most complex and comprehensive gas hydrates field ventures yet conducted. The successful recovery of a wealth of log and core data over a range of geologic environments has provided invaluable information on the geologic controls on the occurrence of gas hydrate in nature. The NGHP-01 expedition was an excellent example of the international spirit of collaboration that continues to infuse gas hydrates research.

The operational highlights of NGHP-01 included the following:

Acknowledgment

The editors wish to thank those that contributed to the success of the Indian National Gas Hydrate Program Expedition 01 (NGHP-01). NGHP-01 was planned and managed through collaboration between the Directorate General of Hydrocarbons (DGH) under the Ministry of Petroleum and Natural Gas (India), the U.S. Geological Survey (USGS), and the Consortium for Scientific Methane Hydrate Investigations (CSMHI) led by Overseas Drilling Limited (ODL) and FUGRO McClelland Marine Geosciences (FUGRO). The

References (58)

  • D.I. Ashford et al.

    Overview of engineering and operations activities conducted as part of the JOGMEC/NRCan/Aurora Mallik 2007-2008 Gas hydrate production research well program, Part A: 2007 field program, in scientific results from the JOGMEC/NRCan/Aurora Mallik 2007-2008 Gas hydrate production research well program, Mackenzie Delta, northwest Territories, Canada

    Geol. Surv. Can. Bull.

    (2012)
  • R. Boswell et al.

    Current perspectives on gas hydrate resources

    Energy Environ. Sci.

    (2011)
  • R. Boswell et al.

    Geohazards Associated with Naturally-occurring Gas Hydrate

    (2012)
  • K. Chandra et al.

    Gas hydrate potential of Indian offshore area

  • N.N. Chopra

    Gas hydrate an unconventional trap in forearc regions of the Andaman offshore

    Bull. Oil Nat. Gas Corp.

    (1985)
  • Resource and Hazard Implications of Gas Hydrates in the Northern Gulf of Mexico: Results of the 2009 Joint Industry Project Leg II Drilling Expedition

    Marine Pet. Geol.

    (2012)
  • T.S. Collett et al.

    Geologic implications of gas hydrates in the offshore of India: results of the National Gas Hydrate Program Expedition 01

    J. Mar. Pet. Geol.

    (2014)
  • T.S. Collett et al.

    Natural Gas hydrates – a review

  • T.S. Collett et al.

    Well log characterization of natural gas hydrates

    Petrophysics

    (October 2012)
  • T. Collett et al.

    Indian National Gas Hydrate Program Expedition 01 Initial Reports

    (2008)
  • T. Collett et al.

    Indian National Gas Hydrate Program Expedition 01 Downhole Log Data Report

    (2008)
  • A.E. Cook et al.

    Electrical anisotropy due to gas hydrate-filled fractures

    Geophysics

    (2010)
  • A.E. Cook et al.

    Extent of gas hydrate-filled fracture planes: implications for in situ methanogenesis and resource potential

    Geophys. Res. Lett.

    (2008)
  • A.E. Cook et al.

    Natural gas hydrates occupying fractures: a focus on non-vent sites on the Indian continental margin and the northern Gulf of Mexico

    J. Mar. Pet. Geol.

    (2014)
  • S. Dai et al.

    Sampling natural hydrate-bearing sediments: pressure core technology used in the Krishna–Godavari Basin

    J. Mar. Pet. Geol.

    (2014)
  • Directorate General of Hydrocarbons

    Gas Hydrate: Road Map

    (2014)
  • C. Hadley et al.

    Gumusut-Kakap Project: geohazard characterization and impact on field development plans

  • M. Holland et al.

    Comparison of methane mass balance and X-ray computed tomography for calculation of gas hydrate content of pressure cores

    J. Mar. Pet. Geol.

    (2014)
  • T.L. Inks et al.

    Seismic prospecting for gas hydrate and associated free-gas prospects in the Milne Point area of northern Alaska

  • Cited by (152)

    View all citing articles on Scopus
    View full text