19th International
CODATA Conference
Category: Gas Hydrates
3D Modeling for Defining
Gas Hydrate Potentialities
Jean-Jacques Royer (Jean-Jacques.Royer@ensg.u-nancy.fr)
Computer Science Department,
ENSG-CRPG, France
Gas hydrates (GH), a mixture
of solid water and gas (usually methane in natural GH), are central in the debates
on energy and global change issues. They may offer an alternative energy resource
for future generations (as recently mentioned in Science, Kerr, 2004
[13]). The amount of hydrated energy is twice
that of all other fossil fuel energy sources combined. Several scientific research
programs have been launched both at National level (Japan, 1995,
2001; India, 1996;
China, 2002; USA 1982,
2002; Russia; Europe, 1996)
and international level. The understanding of this unconventional gas deposit,
is essential to resolve major societal questions such as energy reserve and
recovery, climate change, global carbon budget, and seafloor hazard stability.
However, it appears that
there is a lack of information for defining gas hydrates potential zones, especially
in marine environment. This paper investigates the possibility of using 3D
modeling at the basin scale in order to estimate the potential stability window
of gas hydrates in a marine environment. This methodology includes (i) a full
3D geometrical model of the
geological formation; (ii) the estimation of the 3D thermal field of lithologies solving the temperature
equation; (iii) the calculation of the pressure in 3D at depth. This various 3D models are then used to define the stability
conditions of gas hydrates using a standard equation of state for gas hydrates
assuming a given composition for natural gas hydrates. The methodology has been
implemented in Gocad, a 3D modeler developed for modeling complex natural object
in geosciences. This methodology has been applied on several illustrative case-studies
such as margins including the Angola
basin, the off-shore Brazil
margins and the New Caledonia Farewell
Basin. These examples illustrates
the lack of data and references values in the field of gas hydrates, a question
recently addressed by the Codata Task group on Gas Hydrates. With the support
of ICSU and several national committees, Codata has launched a task group on
Gas hydrates in 2000 to fill the gap of scientific information lacking,
and especially of databases on standard values. One of the unexpected results
of this activity is the increase in international cooperation programs.