Thermal regime of the northwest Indian rifted margin – Comparison with predictions

Calvès, Gérôme; Schwab, Anne M.; Huuse, Mads; Clift, Peter D.; Inam, Asif

doi:10.1016/j.marpetgeo.2010.02.010

Cited by 13 publications

(8 citation statements)

References 81 publications

(117 reference statements)

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“…In addition, new techniques have extended the domains of measurements on contintental margins, with the use of Bottom Simulating Reflectors observations along high‐resolution seismic profiles (Hyndman et al, ; Kaul et al, ; Lucazeau et al, ; Yamano et al, ), and on mid‐ocean ridges, with the use of short probes operated by submarine engines (Becker et al, ; Johnson et al, ) or thermal blankets (Johnson & Hutnak, ; Johnson et al, ; Salmi et al, ). In the 2000s, the depletion of conventional oil reserves has stimulated the research on deep continental margins, including acquisition of new heat flow measurements (Calvès et al, ; Lucazeau et al, ; Lucazeau et al, ; White et al, ); processing of oil exploration data to derive heat flow has also been improved by new techniques for estimating thermal conductivity from geophysical logs (Fuchs & Förster, ; Goutorbe et al, ; Hartmann et al, ) or correcting bottom hole temperatures (Goutorbe et al, ). On land, several teams have maintained measurements activity (Mareschal & Jaupart, ), and several regional compilations have identified heat flow data not included in Pollack's compilation (Blackwell & Richards, ; Hu et al, ; Jiang et al, ; Jiang et al, ; Tanaka et al, ).…”

Section: Introductionmentioning

confidence: 99%

Analysis and Mapping of an Updated Terrestrial Heat Flow Data Set

Lucazeau

2019

Geochem Geophys Geosyst

173

169

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The number of heat flow measurements at the Earth surface has significantly increased since the last global analysis (Pollack et al., 1993, https://doi.org/10.1029/93RG01249), and the most recent of them provide insights into key locations. This paper presents a new compilation, which includes approximately 70,000 measurements. Continental heat flow (67 mWm−2) does not change significantly, but the differences are more important for oceanic heat flow. The divergence with conductive cooling models is reduced significantly for young ages of the seafloor, since the most recent measurements (92 mWm−2) are significantly higher on average than the older ones (79 mWm−2). This is related to a better quality and a better sampling of measurements in regions affected by hydrothermal circulation. The total Earth heat loss derived from these most recent measurements is estimated to ∼40–42 TW and represents only 3–5 TW less than with a conductive cooling model (∼45–47 TW). Hydrothermal heat loss in the oceanic domain is estimated with a new method based on the ruggedness of the seafloor and represents ∼1.5 TW more than previous estimates. The heat flow variability on continents is so large that defining a trend with stratigraphic or tectono‐thermal age is difficult and makes extrapolation from age a poor predictor. On the other hand, additional geological and geophysical information can be combined with age for better predictions. A generalized similarity method was used here to predict heat flow on a global 0.5° × 0.5° grid. The agreement with local measurements is generally good and increases with the number and quality of proxies.

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Section: Introductionmentioning

confidence: 99%

Analysis and Mapping of an Updated Terrestrial Heat Flow Data Set

Lucazeau

2019

Geochem Geophys Geosyst

173

169

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“…The workflow consists of the following steps (e.g. Calvès et al, 2010): (1) picking of seabed and regional BSR horizons, (2) conversion from two-way time (TWT) to depth, based on a P-wave velocity of m/s in seawater and 1800 m/s in sediments, (3) conversion from BSR depth to temperature using a phase boundary diagram, 4determination of the thermal gradient computed by dividing the temperature difference between the seabed and the BSR by the subbottom depth.…”

Section: Methodsmentioning

confidence: 99%

Seismic evidence of gas hydrates, multiple BSRs and fluid flow offshore Tumbes Basin, Peru

et al. 2017

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International audienceIdentification of a previously undocumented hydrate system in the Tumbes Basin, localized off the north Peruvian margin at latitude of 3°20′—4°10′S, allows us to better understand gas hydrates of convergent margins, and complement the 36 hydrate sites already identified around the Pacific Ocean. Using a combined 2D–3D seismic dataset, we present a detailed analysis of seismic amplitude anomalies related to the presence of gas hydrates and/or free gas in sediments. Our observations identify the occurrence of a widespread bottom simulating reflector (BSR), under which we observed, at several sites, the succession of one or two BSR-type reflections of variable amplitude, and vertical acoustic discontinuities associated with fluid flow and gas chimneys. We conclude that the uppermost BSR marks the current base of the hydrate stability field, for a gas composition comprised between 96% methane and 4% of ethane, propane and pure methane. Three hypotheses are developed to explain the nature of the multiple BSRs. They may refer to the base of hydrates of different gas composition, a remnant of an older BSR in the process of dispersion/dissociation or a diagenetically induced permeability barrier formed when the active BSR existed stably at that level for an extended period. The multiple BSRs have been interpreted as three events of steady state in the pressure and temperature conditions. They might be produced by climatic episodes since the last glaciation associated with tectonic activity, essentially tectonic subsidence, one of the main parameters that control the evolution of the Tumbes Basin

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“…5) is crucial to understanding the interplay between heat flow, thermal conductivity, and geothermal gradient. Establishing a shallow linear geothermal gradient using BSRs is well established (Calvès et al, 2010;Serié et al, 2017) and studies have extrapolated this shallow geotherm for traditional basin modelling workflows.…”

Section: Figurementioning

confidence: 99%

“…It has been shown that gas hydrate identification on seismic reflection data through detection of bottom simulating reflectors (BSRs) at the base of gas hydrate stability zone (GHSZ), can be used for geothermal gradient estimation (Yamano et al, 1982;Calvès et al, 2010;Hodgson et al, 2014;Serié et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Subsurface temperature from seismic reflections: application to the post break up sequence offshore Namibia

Sarkar¹,

Huuse²

2022

Preprint

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Accurate estimations of present-day subsurface temperatures are of critical importance to the energy industry, in particular with regards to geothermal energy and petroleum exploration. This paper uses seismic reflection observations of bottom-simulating reflections and subsurface velocities coupled with an empirical velocity to thermal conductivity transform to estimate subsurface temperature in a process dubbed reflection seismic thermometry. The case study is a frontier passive margin extending from the shelf edge to deep water in the central Lüderitz Basin, offshore Namibia. The bottom simulating reflector is used to derive surface heat flow. The thermal conductivity model was applied to seismic processing velocities to determine the subsurface thermal conductivity. Knowledge of surface heat flow and thermal conductivity structure allowed us to estimate subsurface temperatures across the study area. The results suggest the Lüderitz Basin has a working hydrocarbon system with the inferred Aptian Kudu source interval within the gas generation window.

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Thermal regime of the northwest Indian rifted margin – Comparison with predictions

Cited by 13 publications

References 81 publications

Analysis and Mapping of an Updated Terrestrial Heat Flow Data Set

Analysis and Mapping of an Updated Terrestrial Heat Flow Data Set

Seismic evidence of gas hydrates, multiple BSRs and fluid flow offshore Tumbes Basin, Peru

Subsurface temperature from seismic reflections: application to the post break up sequence offshore Namibia

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