Coordinators: Prof. Dr. Klaus Wallmann (GEOMAR), Prof. Dr. Magdalena Scheck-Wenderoth (GFZ), Prof. Dr. Mark Hannington (GEOMAR)

Scientific Questions 

The continually growing demand for energy and mineral resources is increasingly met by the exploitation of deep marine geological deposits of oil and gas, and potentially gas hydrates and seafloor massive sulphides. Waste products such as CO₂ can be stored in sub-seabed geological formations. The work package aims to address and answer the following key questions:

• How are oil and gas, gas hydrate and massive sulphide deposits formed and distributed in space and time below and on the seafloor?
• What is the resource potential of a slow-spreading ridge segment through time?
• What are the major environmental impacts of resource exploitation and sub-seabed CO₂ storage?
• How can these environmental impacts be reduced and mitigated by applying environmentally sound practices and new/advanced technologies for monitoring and resource utilization?

Contents and Goals

Research Highlight 1: Methane hydrate may be exploited as a new unconventional resource of natural gas in the coming decades with several countries supporting large-scale national research programmes (Japan, South Korea, India, China, Taiwan, Vietnam, USA, Canada, Germany). To better assess the resource potential, GEOMAR will further develop and apply its geophysical exploration techniques during several up-coming cruises to major gas hydrate provinces (Black Sea and offshore Norway and Taiwan). The fieldwork will be complemented by modelling studies applying new basin modelling tools developed within the SUGAR project (PetroMod 3-D with gas hydrate simulator). In a joint effort, GFZ and GEOMAR will use and further develop this new modelling software to simulate the build-up of gas hydrates in the Barents Sea under glacial conditions and their dissociation during interglacial periods in order to decipher the late Quaternary dynamics of seabed methane fluxes at high northern latitudes [link with Topic 2-WP3]. Moreover, GEOMAR will apply its in-house transport-reaction modelling tools to better constrain the global inventory of methane hydrates in marine sediments. 

Research Highlight 2: Storage of CO₂ in sub-seabed saline aquifers has been pioneered at the Sleipner site located in the Norwegian sector of the North Sea, where CO₂ has been injected into the seabed on an industrial scale since 1996. Recent studies within the ECO2 project show that formation waters are released at the seabed through a large fracture located 25 km north of the injection site. GEOMAR will quantify rates of formation water seepage and the associated emissions of dissolved chemicals at this newly discovered fracture using its advanced sea-going instrumentation while GFZ will apply its modelling capabilities to simulate the pressure build-up in the Sleipner storage complex, the displacement of formation waters and the reactive transport of CO₂. These joint studies will be used to evaluate potential links between CO₂ injection at Sleipner and the observed formation water seepage and to constrain the likelihood and extent of future CO₂ leakage through the studied seabed fracture. They will contribute significantly to the evaluation of leakage potentials and environmental risks associated with the storage of CO₂ in geological formations. 

Research Highlight 3: Hydrothermal metal accumulations are a potential metal resource, but basic information on their size and distribution, the percentage of total metal actually deposited as massive sulphide (rather than being dispersed in the water column and subsequently in seafloor sediments) and how the geological setting of the specific venting affects this process are still unknown. Most importantly, our knowledge of the variability and possible resource potential of seafloor hydrothermal systems is hampered by the lack of high-resolution data on the lateral distribution of fluid pathways and the location of inactive and presently active deposits on a regional scale. No statistically representative model presently exists of how seafloor mineral deposits are distributed in space and time. We will focus on this problem by targeting one major hydrothermally active province in the central Atlantic (a mid-ocean spreading segment). Here, we will carry out high-resolution regional AUV surveys, targeted geophysical studies and complementary numerical simulations at GEOMAR and GFZ covering the on- and off-axis regions with the goal of assessing the regional metal distribution and economic potential and to determine the important resource-forming control variables. This will require an international effort involving partners from InterRidge and various oceanographic institutions (e.g. National Oceanography Centre Southampton (NOCS), Woods Hole Oceanographic Institution (WHOI), Japan Agency for Marine-Earth Sciences and Technology (JAMSTEC)). Furthermore, size calculations of individual deposits based on interpretation of surface outcrop thickness and extent generally overestimate their size and tonnage. At the same time, inactive or buried deposits are under-sampled leading to significant underestimation of the resource potential of explored areas. New geophysical techniques and numerical modelling tools to better explore hidden deposits will be developed at GEOMAR and tested in areas of buried hydrothermal products, both in the Atlantic and in the Tyrrhenian Sea. Overall, these studies will lead to a better understanding of the variability of metal deposition in space and time as well as of the influence of the geological setting, water depth and magmatic volatiles on metal contents, resource potential, and depositional processes of seafloor massive sulphide deposits.

Further highlights of our future work include:

Oil and gas deposits: Natural hydrocarbon deposits are exploited to satisfy society´s ever-growing energy demand and are increasingly used to store CO₂ from coal power plants and other industrial sources. In a joint approach, cutting-edge geological models of the sedimentary basins in the central North Sea and the Barents Sea will be applied by our contributing programme partner GFZ to assess regional controlling factors for temperature and pressure and to simulate the formation of oil and gas, the emplacement of hydrocarbon deposits and the seepage of hydrocarbons into bottom waters through geological time. These model studies will then be augmented by field studies conducted by GEOMAR on the seabed above the GFZ model domains to locate seepage sites and to quantify gas and oil seepage rates using hydro-acoustic techniques, lander deployments, ROV sampling and in-situ mass spectrometry. Modelling and observation results will be combined to develop a hydrocarbon system model consistent with seepage observations. This should allow us for the first time to balance hydrocarbon formation, accumulation and leakage rates and to quantify the impact of deep geological processes on the marine environment in an integrated systems approach. These coherent model and field studies will also improve the quantification of oil and gas inventories in the North Sea and Barents Sea and will help to evaluate CO₂ storage and leakage potentials of major oil and gas deposits. 

Monitoring and environmental impact studies: Leakage of gases and fluids from oil, gas, gas hydrate reservoirs and CO₂ storage sites and turbidity plumes caused by seafloor mineral extraction constitute potential threats for the marine environment. Mass wasting triggered by gas hydrate exploitation may threaten seabed installations [link with Topic 4-WP1]. GEOMAR will develop protocols to use a wide range of geophysical, hydro-acoustic, chemical and visual methods linked to statistically robust ground truthing and GIS data base management to design strategies for the efficient monitoring and surveillance of hydrocarbon production, CO₂ storage and mining activities. Geotechnical and geophysical studies will be conducted to evaluate the effects of gas hydrates and gas hydrate dissociation on slope stability [link with Topic 4-WP1], oceanographic models will be applied to simulate the spread and fate of emitted contaminants [link with Topic 1], while the response of biota to exploitation-induced stresses will be studied in-situ and experimentally [links with Topics 2 & 3]. Guidelines for deep-sea monitoring and the environmentally sound operation of production and storage sites will be disseminated nationally and internationally through the Kiel Cluster of Excellence “The Future Ocean.” 

Minimizing the environmental impact: New technologies are currently being developed at GEOMAR to use CO₂ for methane production from gas hydrates, stabilizing the sedimentary fabric and reducing the likelihood of slope failure. Storing CO₂ at water depths >250 m reduces leakage risks as rising CO₂ forms solid CO₂ hydrate clogging high permeability conduits for gas and fluid escape. These new approaches will be further developed in the lab and on the computer within the GEOMAR-led SUGAR project. If successful, these new technologies may provide more natural gas for the global market and important economic incentives for the implementation of CCS at a global scale. Moreover, GEOMAR and GFZ will participate in a field production test at a gas hydrate deposit located off South Korea at 2000 m water depth in close cooperation with the South Korean gas hydrate programme and Statoil.