Marine CSEM gas hydrate exploration in the Danube Delta, Black Sea

Begin of project: August 1, 2013

End of project: December 31, 2016

Status of project: September 1, 2016

Maria S. Merian Cruise MSM 35

19 January – 08 February, 2014

Varna, Bulgaria – Istanbul, Turkey

In late 2013 and early 2014 the German research vessel Maria S. MERIAN will stay in the western Black Sea to conduct two cruises (MSM 34 and MSM 35) dedicated to investigate the distribution of submarine gas hydrates in the Danube Delta Fan. Anaerobic conditions in the Black Sea are ideal to generate natural hydrocarbons. Gas flares have been frequently observed along the shelf outside the gas hydrate stability field. The presence of submarine gas hydrates has been inferred from mapping the bottom simulating reflector (BSR), and through direct sampling. Around the Danube Fan offshore Romania the sedimentation rate has been particularly high. Particularly the data from the Danube Fan show multiple BSRs which are believed to be caused by climate related sea level changes in the past.

Research vessel Maria S. MERIAN Source: http://www.maria-s-merian.de/index.php?id=24

On MERIAN voyage MSM34 GEOMAR Kiel conducts high resolution seismic and acoustic measurements along with a coring program for geochemical analysis in known gas hydrate areas on the Danube Delta Fan. During cruise MSM35, this will be complemented by marine controlled source electromagnetic (CSEM) (link) experiments carried out by teams from BGR Hannover and GEOMAR Kiel. CSEM data contain information of the electrical properties of seafloor sediments. Gas hydrates are electrically insulating and replace conductive pore fluid. Thus, the formation resistivity derived from CSEM data is elevated where gas hydrate form in sufficient quantities.

As a result, the joint interpretation of data will allow a more accurate evaluation of the gas hydrate situation and choice of a suitable drill site for a planned methane production test.

Seafloor-towed electrical dipole-dipole system, and stationary EM seafloor receivers and mobile CSEM source Source: BGR

Two marine CSEM systems will be used: a seafloor-towed electrical dipole-dipole system deployed along selected seismic lines, and stationary ocean bottom electromagnetic receivers and a mobile CSEM signal source to acquire detailed 3D data in small-scale survey areas.
CSEM profiles and 3D survey areas will be selected on the basis of the seismic data collected during MSM34 which already show indications of gas hydrate accumulations within the sediments.

Survey map of the western Black Sea showing planned seismic and CSEM profiles and target areas Source: GEOMAR/BGR

Seismic (high resolution structural information) and CSEM data (volume information) contain complementary information. Thus, the joint interpretation of all information available will allow a more reliable assessment of the gas hydrate situation in the Danube Delta.

Partner:

Dr. Marion Jegen, Dr. Sebastian Hölz, GEOMAR Kiel