Heat flow and quantity of methane deduced from a gas hydrate field in the vicinity of the Dnieper Canyon, northwestern Black Sea

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%.

Download Full-text

Do marine gas hydrate deposits create heat flow anomalies on the seabed?

Review of the Bulgarian Geological Society ◽

10.52215/rev.bgs.2020.81.3.181 ◽

2020 ◽

Vol 81 (3) ◽

pp. 181-183

Author(s):

Atanas Vasilev ◽

Nikola Botoucharov ◽

Petar Petsinski ◽

Rositsa Pehlivanova ◽

Ivan Genov ◽

...

Keyword(s):

Heat Flow ◽

Black Sea ◽

Gas Hydrates ◽

Gas Hydrate ◽

Basin Analysis ◽

Average Heat ◽

Heat Flows ◽

Marine Gas Hydrate ◽

Gas Hydrate Deposits ◽

Stage 1

The aim of Stage 1 of the FNI project GEOHydrate is to prove the hypothesis that gas hydrates deposits (GHDs) create measurable temperature and heat flow (T&HF) anomalies on the seafloor. We use a PetroMod™ model for 98 Ma basin analysis of the Western Black Sea basin, developed in GEOMAR, FRG. The model was run 2 times – with and without GH formation. The resultant difference of the heat flows on the seabed shows average heat flow anomaly above GHDs of 7 mW/m2 and a maximum of 15 mW/m2.

Download Full-text

Research into Dissociation Zones of Gas Hydrate Deposits with a Heterogeneous Structure in the Black Sea

Energies ◽

10.3390/en14051345 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1345

Author(s):

Oleg Bazaluk ◽

Kateryna Sai ◽

Vasyl Lozynskyi ◽

Mykhailo Petlovanyi ◽

Pavlo Saik

Keyword(s):

Black Sea ◽

Gas Hydrate ◽

Computer Modelling ◽

Interpolation Method ◽

Methodological Approach ◽

The Black Sea ◽

Heterogeneous Structure ◽

Offshore Area ◽

Gas Hydrate Deposits ◽

Hydrate Deposit

Ukraine is an energy-dependent country, with less that 50% of its energy consumption fulfilled by its own resources. Natural gas is of paramount importance, especially for industry and society. Therefore, there is an urgent need to search for alternative and potential energy sources, such as gas hydrate deposits in the Black Sea, which can reduce the consumption of imported gas. It is necessary to refine the process parameters of the dissociation of gas hydrate deposits with a heterogeneous structure. The analyzed known geological–geophysical data devoted to the study of the offshore area and the seabed give grounds to assert the existence of a significant amount of hydrate deposits in the Black Sea. An integrated methodological approach is applied, which consists of the development of algorithms for analytical and laboratory studies of gas volumes obtained during the dissociation of deposits with a heterogeneous structure. These data are used for the computer modelling of the dissociation zone in the Surfer-8.0 software package based on the data interpolation method, which uses three methods for calculating the volumes of modelling bodies. A 3D grid-visualization of the studied part of the gas hydrate deposit has been developed. The dissociation zone parameters of gas hydrate deposits with different shares of rock intercalation, that is, the minimum and maximum diameters, have been determined, and the potentially recoverable gas volumes have been assessed. The effective time of the process of gas hydrate deposit dissociation has been substantiated. The obtained research results of the dissociation process of gas hydrate deposits can be used in the development of new technological schemes for gas recovery from the deep-water Black Sea area.

Download Full-text

Deep faults, heat flow and gas leakage in the northern Black Sea

Geo-Marine Letters ◽

10.1007/s00367-004-0172-3 ◽

2004 ◽

Vol 24 (3) ◽

Cited By ~ 14

Author(s):

R.I. Kutas ◽

S.I. Paliy ◽

O.M. Rusakov

Keyword(s):

Heat Flow ◽

Black Sea ◽

Gas Leakage ◽

Deep Faults

Download Full-text

Gas hydrate stability and the assessment of heat flow through continental margins

Geophysical Journal International ◽

10.1046/j.0956-540x.2001.01404.x ◽

2001 ◽

Vol 145 (3) ◽

pp. 647-660 ◽

Cited By ~ 76

Author(s):

Ingo Grevemeyer ◽

Heinrich Villinger

Keyword(s):

Heat Flow ◽

Gas Hydrate ◽

Continental Margins ◽

Flow Through ◽

Hydrate Stability

Download Full-text

Control of the geomorphology and gas hydrate extent on widespread gas emissions offshore Romania

BSGF - Earth Sciences Bulletin ◽

10.1051/bsgf/2017182 ◽

2017 ◽

Vol 188 (4) ◽

pp. 26 ◽

Cited By ~ 11

Author(s):

Vincent Riboulot ◽

Antonio Cattaneo ◽

Carla Scalabrin ◽

Arnaud Gaillot ◽

Gwénaël Jouet ◽

...

Keyword(s):

Water Column ◽

Black Sea ◽

Gas Hydrate ◽

Accumulation Rate ◽

Sediment Accumulation ◽

The Black Sea ◽

North East ◽

Bottom Simulating Reflectors ◽

Gas Flares ◽

Sea Fan

The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediments offshore the Danube delta is rich in gas and thus shows Bottom Simulating Reflectors (BSR). The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a geomorphological analysis of the continental slope north-east of the Danube canyon compared with the spatial distribution of gas seeps in the water column and the predicted extent of the gas hydrate stability zone. This analysis provides new evidence of the role of geomorphological setting and gas hydrate extent in controlling the location of the observed gas expulsions and gas flares in the water column. Gas flares are today considered an important source of the carbon budget of the oceans and, potentially, of the atmosphere.

Download Full-text