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Potential Impacts of Gas Hydrate Exploitation on Slope Stability - A Study from the Danube Fan, Black Sea
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Near Surface Geoscience 2016 - Second Applied Shallow Marine Geophysics Conference, Sep 2016, Volume 2016, p.1 - 5
Abstract
Summary
We created a two-dimensional geomechanical model to analyse the hazard of hydrate production induced slope failures in a channel-levee system of the Danube paleo-fan in the Black Sea. Gas hydrates presumably have accumulated in coarse-grained sediments at the base of a paleo channel. The exploitation scenario is based on depressurization of the reservoir along a vertical drill hole. The model geometry is based on high resolution reflection seismic data. Initial results estimated the failure surface at the steepest part of the levee slope (>8° dip) with a Factor of Safety of 1.254, which is considered to be critically affected by seabed subsidence. Preliminary results show that the estimated subsidence at the seafloor after pore pressure depletion of the gas hydrate reservoir is only in the order of centimeters. The effect of production-induced subsidence on the stability of critical slopes will be minor. However, the inherent stability of the slope is still under marginal ranges, and the material properties and production scenario still have big uncertainties due to lack of information.
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