Natural Black Sea Oil Source Study
Location of the source was determined based on the analysis of oil spills detected on 14multi-temporal radar images of ENVISAT and RADARSAT-1 satellites, acquired within 2003-2011. The GeoMixer web-mapping application was used in the study. The spot with coordinates 41°09'10''N and 40°41'06''E, being the centre of a group of spills is quite a precise indicator of the location of the oil source on the sea floor. The source is located in the deepwater part of the sea at the depth of 1,100 metres at the foot of the continental slope.
This oil seep has been known since XIX century, studied applying different methods, however this is next to no information available about it. Therefore a decision was made to study it using space radars and geoinformation technology. Oil seepage volumes can be assessed by measuring spills acreage on radar images and based on simple physical considerations, connecting the thickness of oil film with its color that varies from rainbow in the place of surfacing to silver-grey on the circumference of the slick, - explains Senior Researcher of the Shirshov Institute of Oceanology Andrei Ivanov.
The area of the sea, covered by oil sheen, depending on the hydrometeorological conditions constitutes from 3 to 21 sq.km (9.7 sqkm on average), which enables to assess natural oil seepage volumes.
According to estimates of the institute specialists the oil-in-place relief in south-eastern part of the Black Sea only from this source (if recurrent discharge trend remains) may constitute on average from 0.3 to 2.5 tons of oil per day or 140 to 1,000 tons per year. The maximum possible estimates of volumes of natural oil seepage in this place according to space radar data may reach 2,300 tons of oil per year.
The use of multi-temporal radar images enables to considerably increase the probability of natural oil sources detection at seas. For analysis and research of natural oil seeps, detected using radar images, the method developed at the Institute of Oceanology was applied. The geoinformation approach was used, which was also used to study and even to detect natural oil sources in the Caspian Sea, on the north-eastern shelf of the Sakhalin Island and in Lake Baikal, in the Georgian sector of the Black Sea.
