ABSTRACT: Extension and Oil Maturity in the Pearl River Mouth Basin, China

Su Da-Quan, Nicky White, Dan McKenzie

The uniform stretching model has been applied to seismic reflection profiles and well-log information from the Pearl River Mouth basin on the northern flank of the South China Sea. Stretching factors were calculated from subsidence curves determined from the stratigraphy by using the backstripping technique to remove the effects of compaction and sediment loading. Variations in rift topography, paleobathymetry, and global sea level were taken into account. We argue that the Pearl River Mouth basin formed by lithospheric extension by a factor of about 1.8, lasting from Late Cretaceous to late Oligocene times. Stretching factors calculated from subsidence agree with those determined from the geometry of normal faulting and from crustal thinning.

Based on the stretching model, it is straightforward to calculate the time-temperature history of any sedimentary horizon within the basin. The temperature of any stratum as a function of depth and time can be used to calculate oil abundance, vitrinite reflectance, and the maturity of sterane by the method of chemical reactions. The results are consistent with each other and in good agreement with observations from wells.

AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990