BISCHKE, R. E., W. FINLEY and D. J. TEARPOCK*, Subsurface Consultants and Associate, LLC, Lafayette, LA; Rozel Energy, Lafayette, LA
Abstract: Growth Analysis (dd/d): Case Histories of the Resolution of Correlation Problems as Encountered while Mapping around Salt
We present the dd/d Growth Plot Analysis,
and show examples of how the technique can solve mapping or correlation
problems around salt, where you lack confidence in correlating the well
logs or 3-D seismic. The quantitative growth history of a structure is
employed to resolve correlation problems. Growth structures form
as sediments
are deposited near active faults, mobile salt or in subsiding basins. The
law
of superposition requires that the growth sediments be deposited in
a systematic manner. We demonstrate that growth sediments obey nonrandom
processes, and that growth sediments record the history of deposition along
with the dynamic processes that affect the deposition of sediments. Accordingly,
correlations obtained from the growth sediments record the progressive
histories of structures. In order to study the growth history using Dd/d,
the correlations are usually presented in the
form
of a graph. Surprisingly,
on the plots of Dd/d the correlations often
plot along monotonic or linear curves. Although growth plots confirm that
sediments are deposited systematically, growth typically changes abruptly
across sequence boundaries, disconformities, and active faults. Abrupt
changes in growth on the plots indicate abrupt tectonic or stratigraphic
changes. Correlation data points that deviate from the
general
linear trends
may represent stratigraphic miscorrelations. The Dd/d
Growth Plot Analysis is a powerful technique. The high-resolution Dd/d
technique graphically displays the growth history of an area in a manner
that is readily interpreted.
AAPG Search and Discovery Article #90924©1999 GCAGS Annual Meeting Lafayette, Louisiana