SUGAR SITE - CSEM - Cruise MSM35 - January 20 - February 5, 2014 - Varna (Bulgaria) - Istanbul (Turkey) (English)

Cruise MSM35 was dedicated to conduct marine controlled source electromagnetic (CSEM) measurements in order to identify submarine gas hydrate deposits in the Danube delta fan, western Black Sea offshore Bulgaria and Romania. Like previous legs MSM34 1+2 the cruise is closely linked to the joint research projekct SUGAR - submarine gas hydrate deposits (www.sugar-projekt.de). The aim was to find suitable gas hydrate targets for a planned future drill test to produce methane from offshore hydrates. During MSM34 2D and 3D seismic data sets were acquired as well as OBS data, heat flow data, and sediment cores for pore water analyses. Two locations have been identfied with promising conditions to find gas hydrate in poreous sediments which are favorable for the production: a) a strong seismic reflector in 1400 m water depth within a buried canyon system points at possibly concentrated gas hydrates. b) The second location is at the edge of the gas hydrate stability field in about 600 m water depth, and shows anomalous upward warping of the bottom simulating reflector (BSR), and a lower thermal gradient. This could be caused by a sediment slump which can be clearly imaged in the bathymetry, and consequent dissociation of gas hydrates. During MSM35 2D and 3D CSEM measurements were conducted in both working areas using two types of CSEM instrumentation. The collected data will be analysed and inverted to obtain the subseafloor electrical resistivity structure which can be interpreted in terms of the local to regional gas hydrate distribution. The joint interpretation of CSEM with the seismic and geological data collected during MSM34 allows for a better evaluation of the gas hydrate potential.