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.