Print this pageEffects of Burial Rate on Hydrocarbon Generation: Results of Comparative Modeling of Tectonically Active Basins
CREWS, STEVEN G., and ZHINYONG HE
The extreme burial rates characteristic of rapidly subsiding basins (RSBs),
typically associated with convergent plate boundaries, can affect petroleum
system evolution in several ways. Depressed thermal gradients caused by
transient heat flow, increases in generation temperature due to the kinetic
effects of high heating rates, and excess fluid pressure due to compaction
disequilibrium are all increasingly likely as burial rates increase above about
1 kilometer/million years. In this study we compare the burial, thermal, and
hydrocarbon generation histories of both rapidly and nominally subsiding basins
from a variety of tectonic settings around the world, including: the South
Caspian basin, the Qiong Dong Nan basin of the South China Sea, the Ventura and
LA basins of Califomia, the Cook Inlet of southern Alaska, and the Gulf of
Mexico (offshore Texas). We contrast tectonic setting/subsidence 
mechanisms
,
sedimentation rates, and the effects of rapid sedimentation in each of the study
areas, and present techniques and model capabilities that are useful in
simulating geohistory and hydrocarbon generation in RSBs.
The presence or absence of overpressure, transient heat flow, and high
heating rates is predicted for each of the RSBs in this study, using "Genesis",
ARCO's proprietary 1-D basin model. The sensitivity of predicted timing,
temperature and depth of hydrocarbon generation to each of these factors is
evaluated and discussed, and related to tectonic setting, basin age, and
probable subsidence mechanisms
.