What is the Benefit of Using
Prestack Attributes
By
Charles Bertrand1, Thierry Tonellot2, Frederique Fournier2
(1) Beicip Franlab, Rueil Malmaison, France (2) Institut Francais du Petrole, Rueil Malmaison, France
It is becoming coming common practice to perform 3-D prestack inversion of
iso-offset or iso-angles cubes, in order to estimate elastic parameters such as
P- and S- impedances at the reservoir level. In particular , S- attributes
should provide information on the reservoir parameters complementary to the
information derived from P-
attributes
.
In the context of prestack attributes
, four question arise. (1) What is the
amount of non redundant information provided by the S-
attributes
? (2) What are
the best parameters (such as impedances and Lame parameters) for interpreting
prestack
attributes
in terms of reservoir properties ? (3) How to define
reservoir properties that are significantly related to the P- or S- information
? (4) What is the impact of the limited bandwidth of the prestack
seismic
attributes
on the reservoir property estimation ?
These questions will be examined in this presentation through a deep-water
case study. A general workflow has been proposed to quantitatively exploit the
pertinent prestack attributes
in relation to the reservoir properties, while
assessing the uncertainties of such an interpretation. The workflow involved
segmentation algorithms and estimation techniques in a probabilistic frame. It
allowed for the derivation of maps or cubes of average reservoir properties,
such as porosity or shale volume, and their associated uncertainties. It was an
efficient tool for quantifying the benefits of prestack
attributes
.