Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh
The offshore Bangladesh includes the northern Bengal fan, where sediment supply from the Ganges and Brahmaputra rivers has resulted in the accumulation of up to 20 km of shallow-marine, fluvio-deltaic and slope sediments that have accumulated during rapid tectonic subsidence since the late Miocene....
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2022
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Online Access: | http://nora.nerc.ac.uk/id/eprint/532659/ https://nora.nerc.ac.uk/id/eprint/532659/1/1-s2.0-S0264817222001684-main.pdf https://doi.org/10.1016/j.marpetgeo.2022.105690 |
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ftnerc:oai:nora.nerc.ac.uk:532659 2023-05-15T17:12:10+02:00 Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh Monteleone, Vanessa Marin Moreno, Hector Bayrakci, Gaye Best, Angus Shaon, Farhana Hossain, Mohammad Moinul Al Karim, Ahmad Alam, Md Khurshed 2022-04-15 text http://nora.nerc.ac.uk/id/eprint/532659/ https://nora.nerc.ac.uk/id/eprint/532659/1/1-s2.0-S0264817222001684-main.pdf https://doi.org/10.1016/j.marpetgeo.2022.105690 en eng https://nora.nerc.ac.uk/id/eprint/532659/1/1-s2.0-S0264817222001684-main.pdf Monteleone, Vanessa; Marin Moreno, Hector orcid:0000-0002-3412-1359 Bayrakci, Gaye; Best, Angus orcid:0000-0001-9558-4261 Shaon, Farhana; Hossain, Mohammad Moinul; Al Karim, Ahmad; Alam, Md Khurshed. 2022 Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh. Marine and Petroleum Geology, 141, 105690. https://doi.org/10.1016/j.marpetgeo.2022.105690 <https://doi.org/10.1016/j.marpetgeo.2022.105690> cc_by_4 CC-BY Publication - Article PeerReviewed 2022 ftnerc https://doi.org/10.1016/j.marpetgeo.2022.105690 2023-02-04T19:53:18Z The offshore Bangladesh includes the northern Bengal fan, where sediment supply from the Ganges and Brahmaputra rivers has resulted in the accumulation of up to 20 km of shallow-marine, fluvio-deltaic and slope sediments that have accumulated during rapid tectonic subsidence since the late Miocene. The high sedimentation rates, along with high organic matter content, make this area favorable for the formation of natural gas from both microbial and thermogenic sources. Here we use multichannel seismic reflection profiles and modelling of the gas hydrate stability zone (GHSZ) to present the first evidence for the occurrence of natural gas hydrate in the offshore Bangladesh. First, we analyze the sediments of the shelf and slope areas, which are characterized by downslope sediment transport features and by the presence, in places, of faults/fractures as well as widely distributed amplitude anomalies and seismic facies that we relate to the presence of gas. A high-amplitude reversed polarity reflection of variable continuity that mimics the seafloor and cross-cut stratigraphy is interpreted as a Bottom Simulating Reflector (BSR). The BSR is observed in several areas that are predominantly located in the E-SE of the study area, in water depths of 1300–1900 m and at depths below seafloor of 250–440 m. Sediments above BSR locations generally show higher seismic interval velocities reaching values of ∼1920–1940 m/s, which are consistent with the presence of gas hydrate in shallow marine sediments. Furthermore, the BSR lies at approximately the same depth as the theoretical base of the gas (methane) hydrate stability zone (BGHSZ), calculated assuming a 3.5 % wt pore water salinity and using existing geothermal gradient and seafloor temperature data from the study region. However, in places, the BSR lies deeper or shallower than the base of the modelled BGHSZ. These discrepancies include areas where faults/fractures and seismic evidence linked to fluid flow from deeper reservoirs reach the GHSZ disrupting its ... Article in Journal/Newspaper Methane hydrate Natural Environment Research Council: NERC Open Research Archive Marine and Petroleum Geology 141 105690 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
The offshore Bangladesh includes the northern Bengal fan, where sediment supply from the Ganges and Brahmaputra rivers has resulted in the accumulation of up to 20 km of shallow-marine, fluvio-deltaic and slope sediments that have accumulated during rapid tectonic subsidence since the late Miocene. The high sedimentation rates, along with high organic matter content, make this area favorable for the formation of natural gas from both microbial and thermogenic sources. Here we use multichannel seismic reflection profiles and modelling of the gas hydrate stability zone (GHSZ) to present the first evidence for the occurrence of natural gas hydrate in the offshore Bangladesh. First, we analyze the sediments of the shelf and slope areas, which are characterized by downslope sediment transport features and by the presence, in places, of faults/fractures as well as widely distributed amplitude anomalies and seismic facies that we relate to the presence of gas. A high-amplitude reversed polarity reflection of variable continuity that mimics the seafloor and cross-cut stratigraphy is interpreted as a Bottom Simulating Reflector (BSR). The BSR is observed in several areas that are predominantly located in the E-SE of the study area, in water depths of 1300–1900 m and at depths below seafloor of 250–440 m. Sediments above BSR locations generally show higher seismic interval velocities reaching values of ∼1920–1940 m/s, which are consistent with the presence of gas hydrate in shallow marine sediments. Furthermore, the BSR lies at approximately the same depth as the theoretical base of the gas (methane) hydrate stability zone (BGHSZ), calculated assuming a 3.5 % wt pore water salinity and using existing geothermal gradient and seafloor temperature data from the study region. However, in places, the BSR lies deeper or shallower than the base of the modelled BGHSZ. These discrepancies include areas where faults/fractures and seismic evidence linked to fluid flow from deeper reservoirs reach the GHSZ disrupting its ... |
format |
Article in Journal/Newspaper |
author |
Monteleone, Vanessa Marin Moreno, Hector Bayrakci, Gaye Best, Angus Shaon, Farhana Hossain, Mohammad Moinul Al Karim, Ahmad Alam, Md Khurshed |
spellingShingle |
Monteleone, Vanessa Marin Moreno, Hector Bayrakci, Gaye Best, Angus Shaon, Farhana Hossain, Mohammad Moinul Al Karim, Ahmad Alam, Md Khurshed Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh |
author_facet |
Monteleone, Vanessa Marin Moreno, Hector Bayrakci, Gaye Best, Angus Shaon, Farhana Hossain, Mohammad Moinul Al Karim, Ahmad Alam, Md Khurshed |
author_sort |
Monteleone, Vanessa |
title |
Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh |
title_short |
Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh |
title_full |
Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh |
title_fullStr |
Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh |
title_full_unstemmed |
Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh |
title_sort |
seismic characterization and modelling of the gas hydrate system in the northern bay of bengal, offshore bangladesh |
publishDate |
2022 |
url |
http://nora.nerc.ac.uk/id/eprint/532659/ https://nora.nerc.ac.uk/id/eprint/532659/1/1-s2.0-S0264817222001684-main.pdf https://doi.org/10.1016/j.marpetgeo.2022.105690 |
genre |
Methane hydrate |
genre_facet |
Methane hydrate |
op_relation |
https://nora.nerc.ac.uk/id/eprint/532659/1/1-s2.0-S0264817222001684-main.pdf Monteleone, Vanessa; Marin Moreno, Hector orcid:0000-0002-3412-1359 Bayrakci, Gaye; Best, Angus orcid:0000-0001-9558-4261 Shaon, Farhana; Hossain, Mohammad Moinul; Al Karim, Ahmad; Alam, Md Khurshed. 2022 Seismic characterization and modelling of the gas hydrate system in the northern Bay of Bengal, offshore Bangladesh. Marine and Petroleum Geology, 141, 105690. https://doi.org/10.1016/j.marpetgeo.2022.105690 <https://doi.org/10.1016/j.marpetgeo.2022.105690> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.marpetgeo.2022.105690 |
container_title |
Marine and Petroleum Geology |
container_volume |
141 |
container_start_page |
105690 |
_version_ |
1766068955126956032 |