Marine Biogeochemistry

Subproject A1- Hydroacuostics
The generation of gas hydrates requires the presence of free gas. Consequently, the presence of rising gas bubbles from the seafloor or gas flares in the water column is a strong indicator for the presence of gas hydrates in the subsurface. Gas bubbles in the water column can best be detected by hydro-acoustic methods. Very efficient tools for that purpose are multibeam echosounder. Traditionally these systems were optimized for the precise detection of the seafloor which means that signals from the water column are suppressed or disregarded. The aim of subproject A1 is to develop data processing methods and enhanced visualisation techniques to allow for a better and faster detection and localisation of gas flares in the water column using portable multibeam systems.


Subproject A2- Geophysics

The subprojects A2 explore hydrate accumulations for gas extraction and CO2 storage using geophysical methods. 

For this purpose both seismic

SP A2.1: Exploring hydrate accumulations for CO2 storage using deep-towed multichannel seismics (DTMCS)

and electromagnetic

SP A2.2: Controlled Source Electromagnetic (CSEM) for Gas Hydrate Evaluation and Quantification

methods will be optimized and applied.


Subproject A3- Autoclave Drilling

In the frame of subproject A3 drilling tools are to be equipped with autoclave technology and used for sampling of hydrate deposits. To evaluate the quality of gas hydrate deposits, while considering hydrate distribution and concentration to be determined within the occurrences, application of drilling technology is essential. Since gas hydrates decompose while decompressed or heated during drilling and the gas released is lost, a combined autoclave drilling technology is necessary to preserve the in situ pressure. Using this approach accurate quantification of gas hydrate is possible.


Subproject A4- Numerical Modelling

The formation of submarine gas hydrates and their spatial distribution in the subsurface depends on a variety of sensitive control parameters, e.g. the in-situ production of methane, the advection of dissolved and gaseous methane, the existence of fluid pathways as well as the porosity and permeability of sediments. Hence, the quantification of gas hydrate inventories is still largely unconstrained in most regions. This project aims at the numerical simulation of potential gas hydrate reservoirs for selected, well-known locations to predict their 3D-distribution within the sedimentary sequence. In addition, we plan to give constraints on the long-term stability of gas hydrate reservoirs in order to get a better understanding of their temporal dynamics.


Subproject B1- Reservoir Modelling

In the frame of sub-project B1 a 3D numerical model for describing the process of winning methane from hydrates with simultaneous CO2 sequestration is to be developed. Various extraction techniques and types of deposits in sediments will be regarded and their efficiency will be verified. Validated mathematical simulation models enable the up-scaling of data obtained from laboratory experiments as well as from literature.


Subproject B2- Laboratory Experiments

Methane hydrates will be exposed to CO2 to gain natural gas (methane) and to store CO2 in hydrates. Gas swapping in hydrates is possible since CO2 hydrates are thermodynamically more stable than methane hydrates under the pressure and temperature conditions prevailing below the seafloor.


Subproject B3- Pellet Transport of Natural Gas

Natural gas extracted from clathrate deposits offshore needs to be stored and later transported in a reasonably efficient, inexpensive way. We explore a possibility to utilize a clathrate cage structure as a highly efficient storage medium and the phenomenon of so called “self-preservation” for its stabilization. During the decomposition at the ambient pressure and several degrees below the melting point of ice in the “self-preservation” region, clathrate pellets will be coated by an ice film that is able to retard any further transformation from minutes to weeks/months time scale. In this state, gas hydrates would be transported to costal facilities for further processing.