BMWi-Project SUGAR

joint project:
SUGAR - Submarine gas hydrate resources
SUGAR-B: Submarine gas hydrate stores - investigation, excavation and transport


SUGAR Subproject A3 (Professor Dr. Gerhard Bohrmann):

Development of a pressure core sampler and adjustment to the sea floor drill rig (MeBo)

Gashydrates in the marine subsurface are considered to contain substantially higher amounts of methane than all known conventional deposits of natural gas. The global quantity of methane carbon in submarine hydrates is estimated at approx. 1000 - 10,000 Gt C and thus in the same order of magnitude as the C-quantity in well-known coal occurrences. The joint project SUGAR aims on developing new technologies for the investigation and excavation of submarine hydrate resources and new concepts for gas transport. The possible impact on the environment of the hydrate removal is considered in the project. Therefore, the hydrate extraction is coupled with a reposition (sequestration) of CO2 in sea sediments.

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 hydrate decomposes 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 quantification of gas hydrate is possible.

Two lines of development using autoclave technology, which allow for recovery of gas hydrate bearing drilling cores under in situ pressure, are pursued in the framework of SUGAR. The lines aim on different operating conditions.

In the first line an autoclave technology is to be developed and integrated into the transportable sea floor drill rig (MeBo) developed at the MARUM in Bremen.
The MeBo, which can be launched from conventional ships without boring platform into water depths of up to 2000 m, is used to recover cores from unconsolidated sediments and rocks of 50 m length, so far.

The second line aims on the development of an autoclave system with associated drilling technology, for sampling of soft sediments and gas hydrates. This system is not limited with respect to water depth and thickness of sediments to be sampled. The employment of this system will be restricted to drilling ships.

Both approaches provide new technologies, which can be adapted to specific conditions and requirements of sediments to be drilled during gas hydrate sampling.

Structural units of the MeBo

A prerequisite for investigations of natural gas hydrates under in situ conditions, is the maintenance of pressure and temperature conditions as present at and within the seafloor during recovery. The processing of pressure cores after recovery includes

- non destructive visualization of the sediment by means of computer tomographic visualization
- controlled gas release for quantification of the natural gas inventory
- sampling of the gas released for subsequent analyses

Two autoclave sampling devices, the Multi-Autoclave Corer (MAC) and the Dynamic Autoclave Piston Corer (DAPC), were designed in the frame of the former projects OMEGA (2000 - 2003) and METRO (2004 - 2007). The devices were successfully deployed on several expeditions.

Computer tomographic imaging of a sediment core

CT scanning results of a pressure core

Working area in the Black Sea

Prakla Bohrtechnik GmbH
Technische Universität Clausthal
Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. (FhG)

GeoForschungsZentrum Potsdam (GFZ)
Wirth Maschinen- und Bohrgeräte-Fabrik GmbH
BASF Aktiengesellschaft