Joint interpretation of geophysical field experiments in the danube deep-sea fan, Black Sea

Bialas, Jörg; Bohlen, Thomas; Dannowski, Anke; Eisenberg-Klein, G.; Gassner, Laura; Gehrmann, Romina; Heeschen, Katja; Hölz, Sebastian; Jegen, Marion; Klaucke, Ingo; Krieger, Markus H.; Mann, J.; Müller, Christine H.; Prüßmann, J.; Schicks, Judith M.; Schünemann, E.; Schwalenberg, Katrin; Sommer, Malte; Smilde, Peter L.; Spangenberg, Erik; Trappe, H.; Zander, Timo

doi:10.1016/j.marpetgeo.2020.104551

Cited by 19 publications

(25 citation statements)

References 63 publications

(113 reference statements)

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“…A summary of many of these activities and findings in the Black Sea was recently provided by Minshull et al (2020) as part of the European Union-funded project "Marine gas hydrate-an indigenous resource of natural gas for Europe" (MIGRATE). Bialas et al (2020) jointly summarized seismic and electromagnetic results achieved for the north-western margin within the SUGAR III project.…”

Section: Studies On Gas Hydrates and Gas Venting In The Black Seamentioning

confidence: 99%

“…A high-resolution subset of 2-D MCS lines was acquired but with a smaller-sized GI gun (1.5 L, 90 in 3 ) and shorter streamer (237.5 m active length, 76 channels). Additional high-resolution 3-D seismic data were acquired with the P-cable system in two regions linked to the SUGAR program activities (details see e.g., Zander et al, 2017;Hillman et al, 2018a;Hillman et al, 2018b;Bialas et al, 2020). Processing of the 2-D regional and high-res MCS data included geometry definition and sorting to common-mid-point locations, band-pass filtering (10-180 Hz), followed by velocity analysis with normal move-out (NMO) correction, and stacking.…”

Section: Multichannel Seismic Datamentioning

confidence: 99%

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Controls on Gas Emission Distribution on the Continental Slope of the Western Black Sea

et al. 2021

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The continental slopes of the Black Sea show abundant manifestations of gas seepage in water depth of <720 m, but underlying controls are still not fully understood. Here, we investigate gas seepage along the Bulgarian and Romanian Black Sea margin using acoustic multibeam water column, bathymetry, backscatter, and sub-bottom profiler data to determine linkages between sub-seafloor structures, seafloor gas seeps, and gas discharge into the water column. More than 10,000 seepage sites over an area of ∼3,000 km2 were identified. The maximum water depth of gas seepage is controlled by the onset of the structure I gas hydrate stability zone in ∼720 m depth. However, gas seepage is not randomly distributed elsewhere. We classify three factors controlling on gas seepage locations into depositional, erosional, and tectonic factors. Depositional factors are associated with regionally occurring sediment waves forming focusing effects and mass-transport deposits (MTDs) with limited sediment drape. Elongated seafloor depressions linked to faulting and gas seepage develop at the base between adjacent sediment waves. The elongated depressions become progressively wider and deeper toward shallow water depths and culminate in some locations into clusters of pockmarks. MTDs cover larger regions and level out paleo-topography. Their surface morphology results in fault-like deformation patterns of the sediment drape on top of the MTDs that is locally utilized for gas migration. Erosional factors are seen along channels and canyons as well as slope failures, where gas discharge occurs along head-scarps and ridges. Sediment that was removed by slope failures cover larger regions down-slope. Those regions are devoid of gas seepage either by forming impermeable barriers to gas migration or by removal of the formerly gas-rich sediments. Deep-rooted tectonic control on gas migration is seen in the eastern study region with wide-spread normal faulting promoting gas migration. Overall, gas seepage is widespread along the margin. Gas migration appears more vigorous in shallow waters below ∼160 m water depth, but the number of flare sites is not necessarily an indicator of the total volume of gas released.

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Section: Studies On Gas Hydrates and Gas Venting In The Black Seamentioning

confidence: 99%

Section: Multichannel Seismic Datamentioning

confidence: 99%

Controls on Gas Emission Distribution on the Continental Slope of the Western Black Sea

et al. 2021

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“…Since then, a number of scientific research projects were conducted studying the general occurrence and distribution of gas hydrates along the continental margins of the Black Sea, e.g., [2][3][4][5][6][7][8]. Several seismic studies [9][10][11][12][13][14][15] were conducted to map bottom-simulating reflectors (BSRs), which are used as an indicator for the base of the structure I (sI) gas hydrate stability zone (GHSZ). However, BSRs are not widely distributed in the Black Sea [2,8,10,16] and occur in patches (Figure 1, see also e.g., [6,17]).…”

Section: Introductionmentioning

confidence: 99%

“…Figure15. Results from heat flow measurements at (a) the eastern edge of the horse-shoe-shaped slump-feature (along profile shown in Figure16a) and (b) crossing of the S2 channel (along profile shown in Figure16b).…”

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confidence: 99%

Heat Flow Measurements at the Danube Deep-Sea Fan, Western Black Sea

et al. 2021

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Seafloor heat flow measurements are utilized to determine the geothermal regime of the Danube deep-sea fan in the western Black Sea and are presented in the larger context of regional gas hydrate occurrences. Heat flow data were collected across paleo-channels in water depths of 550–1460 m. Heat flow across levees ranges from 25 to 30 mW m−2 but is up to 65 mW m−2 on channel floors. Gravity coring reveals sediment layers typical of the western Black Sea, consisting of three late Pleistocene to Holocene units, notably red clay within the lowermost unit cored. Heat flow derived from the bottom-simulating reflector (BSR), assumed to represent the base of the gas hydrate stability zone (GHSZ), deviates from seafloor measurements. These discrepancies are linked either to fast sedimentation or slumping and associated variations in sediment physical properties. Topographic effects account of up to 50% of heat flow deviations from average values. Combined with climate-induced variations in seafloor temperature and sea-level since the last glacial maximum large uncertainties in the prediction of the base of the GHSZ remain. A regional representative heat flow value is ~30 mW m−2 for the study region but deviations from this value may be up to 100%.

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“…The Black Sea has high gas hydrate potential. , By seismic, coring, and logging operations, this potential was proved recently. ,− In this study, hypothetical homogeneous and heterogeneous gas hydrate geological models were formed in the conditions of the Black Sea. Then, the effects of the horizontal well on gas production from these two gas hydrate reservoirs were investigated numerically by applying the depressurization method in different wellbore configurations (vertical and horizontal).…”

Section: Introductionmentioning

confidence: 94%

Gas Production from Methane Hydrate Reservoirs in Different Well Configurations: A Case Study in the Conditions of the Black Sea

Ubeyd

Merey

2020

Energy Fuels

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Gas hydrates are considered “near-future energy resources” due to their vast existence all around the world. Recently, China has tested gas production from methane hydrate-bearing clayey silts via horizontal well technology for the first time. This study aims to investigate the effect of well configuration on gas production from the Black Sea gas hydrates. Mainly, two different hydrate-bearing models (single-layer homogeneous hydrate-bearing sands and multilayer hydrate-bearing turbidite) were constructed in this study. Gas production numerical simulations were held using the TOUGH + HYDRATE simulator. Gas production via the horizontal well in single-layer homogeneous hydrate-bearing sand was higher compared to the vertical well case at early stages. However, fast depressurization via the horizontal well caused a rapid decline in reservoir temperature and hydrate dissociation rate. Then, local hydrate reformation was detected near the wellbore. In the later periods of gas production, higher gas production with the vertical well was obtained. The clay layers in the heterogeneous methane hydrate reservoirs (alternating sand and clay layers in turbidite) behave like a barrier to depressurization with a horizontal well.

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Joint interpretation of geophysical field experiments in the danube deep-sea fan, Black Sea

Cited by 19 publications

References 63 publications

Controls on Gas Emission Distribution on the Continental Slope of the Western Black Sea

Controls on Gas Emission Distribution on the Continental Slope of the Western Black Sea

Heat Flow Measurements at the Danube Deep-Sea Fan, Western Black Sea

Gas Production from Methane Hydrate Reservoirs in Different Well Configurations: A Case Study in the Conditions of the Black Sea

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