Seismic
Characterization And Emplacement - Process Modelling Of the Volund 0.5 Km3
Sandstone Laccolith, Offshore
Szarawarska, Ewa
Paulina1, Mads Huuse1, Andrew
Hurst1,
A spectacular subsurface example of sand injectite is the Volund giant
complex that is located in the Paleogene of the South
Viking Graben (Norwegian North Sea). The sand injectite complex, which is essentially a large sandstone laccolith with associated wing-like edges, measures tens of
metres in thickness, crosscuts 250+m of upper
Paleocene and lower Eocene strata and covers an area of some 8 km2.
Its total sand volume is estimated at 0.5km3. This complex is
believed to be the first sand injectite to be
deliberately (and successfully) targeted by exploration drilling and the
success of the discovery added several tens of millions of barrels of oil
reserves to the operator's portfolio. The studies of mechanics of sand
intrusions include the modelling of post-depositional
sand remobilization using the Discrete Particle Method for sand grains coupled
with Finite Element modelling to describe fluid flow.
Combining these methods with analogue observational data from key outcrop
analogues and selected sand injectite complexes known
from oil fields is essential to form a robust understanding of the mechanical
processes active during sand injection. The modelling
is far from non-trivial as a full description of the process involves fluid and
fracture mechanics combined with reservoir engineering to understand the
fracture propagation, fluidized flow and pressure depletion within the source
bed. However, both intermediate results and a final coupled model may be used
to infer process, predict occurrence and perhaps even reservoir distribution in
sand injectite fields, and hence should be of
significance for hydrocarbon exploration in the
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California