Abstract: High Precision Reservoir Volumetric Computation
SATTLEGGER, JOHANN, HOLGER ZIEN and ROBERT KONIG
Integration of well information and information derived from three-dimensional seismic data allows one to predict parameters like porosity, seismic velocity and net/gross ratio with considerable detail. Also, reservoir boundaries like horizons and fault planes may be mapped at depth with high precision. Computation of hydrocarbon in place should take full advantage of all this information.
Values of porosity, net/gross
ratio, velocity, depth and other are usually obtained at the meshpoints
of a regular grid. Three-dimensional computation of hydrocarbon in place
has to be performed on a (sub-)grid cell basis where:
The reservoir
is split up into vertical prisms whose cross
sections are grid cells
Volumes
are cut out from these prisms by reservoir bound-
aries represented by horizons, faults and concession boundaries
Values
of porosity and net/gross ratio are interpolated for
points inside a grid cell
Saturation
is computed as a function of local porosity and
elevation above fluid/fluid or fluid/gas contact, net pore volume
from local porosity and net/gross ratio values
Contribution
of hydrocarbons in place is obtained by inte-
gration over saturation and net pore volume, both as a function
of depth.
Not only does this way of computation take full advantage of all information and detail available, it also allows to display contour maps of local net pore volume and hydrocarbons in place which are helpful for field development.
AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria