Reconstruction of burial and thermal history, oil generation and migration in the Songliao Basin, Northeastern China

The Songliao Basin in northeastem China is a Zarge nonmarine petroliferous basin. The sedimentary sequence in the basin is up to 10000 m thick and is predominated by Cretaceous fluvial and lacustrine strata with interlayed volcanic and volcaniclastic rocks. The constructed 270 km-long profile across the Songliao Basin reveals a rift architecture. The early grabenhorst systems were filled by volcanic and volcaniclastic rocks and alluvial and lacustrine sediments of the Upper Jurassic Huoshiling Formation and the Lower Cretaceous Shahezi and Yingchenzi Formations. The graben-horst systems were covered by basin-wide fluvial and lacustrine deposits of the Lower Cretaceous Denlouku, the Quantou, the tipper Cretaceous Qingshankou, the Yaojia, the Nenjiang, the Sifangtai and the Mingshui Formations. At the top part of the sequences was truncated by a regional unconformity between the Cretaceous and the Tertiary. Basin structure and basin fill indicate that the Songliao Basin was formed by rifting during the Latz Jurassic and Early Cretaceous (154 Ma - 127 Ma), followed by thermal subsidence during the Cretaceous and late-stage compression. The late-stage compression was initiated in the southeastem part of the basin at the end of Nenjiang tune (72.5 Ma). During the Early Tertiary the compression reached its maximum. An integrated organic geochemistry - basin modelling approach was applied to reconstruct the burial and thermal history, oil generation and rnigration in the Songliao Basin. Basin modelling was conducted along the constructed regional profile using the two-dimensional modelling programme PETROMOD$^{TM}$ as well as the one-dimensional modelling programme PDI-PC both developed by IES Jülich, Germany. Organic geochemical data were integrated into the basin model, and provided valuable constraints on the simulated results. Organic maturity parameters are widely used as calibration data for simulation of burial and thermal bistories of sedimentary basins. A review of the related case studies shows that facies and lithology influence the organic maturity parameters . However, the degree of the diese influences differs from parameter to parameter, from lithofacies to lithofacies, and fron basin to basin. A detailed investigation on maturity parameter variability with lithofacies in the Upper Cretaceous lacustrine deltaic sequence of the western Songliao Basin provided a preliminary evaluation of the applicabiiity of different maturity parameters in the basin. 23 samples of black shale, grey siltstone, fine-grained sandstone and limestone were collected from the lacustrine deltaic sequence. These different lithofacies are characterized by a different bulk geochemistry. The organic-rich shales contain Type I kerogen of mostly algal origin, whereas the organiclean sandstones and limestones contain mostly Type III/IV kerogen of terrestrial origin. Molecular geochemistry indicates that the extracted bitumen is generated from the algal-rich shale. Within the studied sequence (from 1380 m to 1720 m depth), vitrinite reflectance values range, from 0.60% to 0.82% and show an overall trend of increase with depth. No systematic [...