2-D and 3-D Pseudo-Seismic Transforms of Wireline Logs:
A Seismic Approach to Petrophysical Sequence Stratigraphy
Tim Carr, John Hopkins, Howard Feldman, Alan Feltz, John Doveton,
Dave Collins
Stratigraphic interpretation from wireline logs is typically drawn from
multiple
log traces or from crossplots of log data. Both techniques can readily
depict
vertical changes in lithology or reservoir quality, but lateral
relationships are
not readily visualized. Significant improvement in the geologic
interpretation of
wireline log data can be achieved through color image transformation
and treatment
of the transformed data as "seismic" traces for the purposes of
processing,
interpretation and display. Such a transform can combine data from
porosity.
gamma, and density tools generating a color coded "crossplot log' for
each well.
A well-designed color transformation of wireline log data from multiple
wells
maximizes both spatial and compositional information content, and
provides a
readily interpretable image of the subsurface geology. The transformed
image in,
either 2D or 3D, can be treated as "seismic" data easing the data
handling burdens
through use of computerized techniques designed for interpretation of
seismic data.
Various filters and transformations can be applied to emphasize
different aspects
of the subsurface geology. The color image transformation of wireline
log data
from multiple wells opens new dimensions in log interpretation and
provides
significant insight into complex stratigraphic geometries associated
with lithology,
reservoir quality, and fluids. Examples at both the regional and field
scale are
used to illustrate the utility of using the computer workstation to
integrate
petrophysical data into a seismic stratigraphic approach.
