DBPapers
DOI: 10.5593/sgem2012/s14.v3004

GAS HYDRATES AND BOTTOM INSTABILITY: BLACK SEA, BULGARIA

A. VASILEV, E. KOZHUHAROV
Wednesday 1 August 2012 by Libadmin2012

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 3, 957 - 964 pp

ABSTRACT

In the continental slope of Bulgarian Exclusive Economic Zone (BEEZ) of the Black
Sea, where large volumes of gas hydrates (GH) could be concentrated in sediments near
the seafloor, bottom water temperature varies periodically. This for example is due to
seasonal changes or can be affected by aperiodic factors. The process of heat transfer
from seawater to bottom sediments and thus on gas hydrate and slope stability is
modeled. The results of modeling indicate that long time (50 years), seasonal and shortterm
variations of bottom water temperature may affect gas hydrate stability only in the
upper 1-2 m of sediments. However, the zone where repetitive gas hydrate formation
and decomposition occur because of bottom water temperature change is extensive in
the area with water depths range 300-500 m mainly and up to 1000 m. Examples are
shown from new seismic records received in 2011 from the consortium of scientists
from all Black Sea countries in the frame of the project BLACK SEA SPAN.

Keywords: gas hydrates, bottom instability, Black Sea, Bulgaria