Abstract A high-resolution three-dimensional (3D) numerical basin model, incorporating the eastern part of the Lower Saxony Basin (LSB), the Gifhorn Trough and parts of the southern Pompeckj Block, was built to reconstruct the thermal and structural evolution of this area. The estimation and calculation of the unconventional oil and gas resource density within the Posidonia Shale source-rock unit was the main objective of this study. Incorporating organic–geochemical data for the Posidonia Shale source-rock units, such as compositional petroleum generation kinetics data, allowed a more accurate prediction of hydrocarbon potential compared to large-scale models of the area, as well as a better prediction of bulk adsorption capacity and adsorbed gas content. For the accurate calculation of oil and gas contents within the source-rock lithologies, mineralogy and physical properties of the rocks, such as compressibility, sorption capacity and porosity, are important as well as organic matter quantity, quality and thermal maturity. These properties in turn are strongly dependent on the vastly different burial/uplift histories within the LSB, Gifhorn Trough and the Pompeckj Block. The Gifhorn Trough, large parts of the Pompeckj Block and the flanks of the LSB are interesting concerning the unconventional oil potential, with current source-rock maturities between 0.65% and 1.2% vitrinite reflectance. Central parts of the LSB and small parts of the Pompeckj Block show inherent unconventional gas potential. Methane adsorption capacity is influenced by the burial/uplift history of the basin, which stresses the importance of structural and geochemical interlocking in understanding unconventional hydrocarbon systems.

Abstract A detailed 3D petroleum system model was constructed for the Schleswig-Holstein area in northern Germany. Salt movement and the Quaternary ice episodes were implemented in order to reconstruct their impact on temperature, maturity and pressure. Burial, temperature and maturity histories were calculated for the Jurassic troughs and the Glueckstadt Graben showing both differences and similarities. For example, all locations reached (almost) deepest burial at present day, whilst subsidence and long-term sedimentation rate was highest in Glueckstadt Graben during the Triassic. The Jurassic troughs received their major subsidence and sedimentation pulse later, and were strongly affected by a later salt movement. The implementation of Quaternary glacial episodes does not have a strong impact on petroleum generation from the major source rock (Lower Toarcian Posidonia Shale). In the case of the Posidonia Shale reaching the stage of petroleum expulsion (outside of the study area), the effect of ‘glacial pumping’(i.e. the development of high pore pressures during glaciation followed by expulsion and subsequent pressure release during deglaciation) can be deduced from the model. Petroleum accumulations in the reservoir layers (Dogger sandstones) are also seen to have been affected. This finding is of interest for exploration, as it might control petroleum composition, biodegradation and leakage through cap rocks.

Abstract Structural modeling combined with basin modeling was used to demonstrate the influence of the structural history on hydrocarbon generation. For this purpose, a tectonic setting in the Netherlands was selected that shows large-scale tectonic inversion, associated erosion, and later subsidence. On the basis of a 300-km (186-mi) two-dimensional section that crosses the main tectonic features of this setting, a structural model consisting of 21 paleosections was created. The results generated by the structural model show that the Late Cretaceous inversion affected the basins the most, whereas the erosion in the Jurassic had the strongest influence on the structural highs. This can be seen from the amount of erosion associated with these erosion phases. Using the structural model as input for the basin model allowed the temperature and maturity of the sediments to be calculated. A temperature profile at 2000-m (6562-ft) depth along the section shows that the present-day temperature distribution is also strongly influenced by the inversion. In the inverted basins, highly conductive layers, such as overcompacted sediments or salt, are closer to the surface, which results in higher temperatures than in the noninverted. Finally, the timing of hydrocarbon generation from the Posidonia Shale source rock was found to be related to the structural history within the basin. In strongly inverted parts of the basin, present-day burial is insufficient to restart hydrocarbon generation, but in less inverted parts, hydrocarbon generation resumed during the Tertiary.

Abstract Apetroleum system modeling (PSM) study was performed on the Jeanne d’Arc Basin, offshore eastern Canada, to study the constraints and reliability of the reconstruction of petroleum reservoir filling histories. Petroleum generation and phase behavior were analyzed using phase-predictive compositional kinetic models (PhaseKinetics) determined by pyrolysis of Egret Member source rock samples. Various additional calibration data (well, rock, and fluid data), such as porosity, permeability, temperature (bottom-hole temperature, apatite fission tracks, fluid inclusions), maturity (vitrinite reflectance), and petroleum properties, such as API, gas-oil ratio, formation volume factor, and saturation pressure were integrated into this model. Different charge scenarios were tested for the effects of open and closed faults in the carrier system to reconstruct the most likely migration pathways for the petroleum that is trapped in the Terra Nova (TN) oil field. The most probable filling history includes charge to the reservoir from a local kitchen and a second kitchen located between Hibernia and TN that was responsible for the long-range migration. In the model, the hydrocarbons migrate from this kitchen in the northwest part of the study area along pathways defined by closed transbasin faults from the north into the field. This new migration concept differs from the traditional explanation based on geochemical measurements only von der Dick et al., 1989 ), which infers that local generation was solely responsible for filling the TN field. The latter can be disproved based on a simple mass balance calculation.

Abstract Detailed organic geochemical investigations were performed on organic-carbon-rich sediments from Baffin Bay (ODP-Site 645) and the upwelling area off Northwest Africa (ODP-Site 658). Main objectives of this study were (1) to reconstruct the depositional environment of these sediments and (2) to point out factors controlling the formation of organic-carbon-rich sediments. Sediments with high total organic carbon contents of up to more than 3% were deposited at both Site 645 and Site 658. Mass accumulation rates of total organic carbon are also similar, ranging from 0.05 to 0.4 gC cm -2 ky -1 . The types of organic matter, however, differ between Site 645 and Site 658, reflecting different depositional environments. In the narrow Baffin Bay, climate-controlled changes in terrigenous carbon supply have been the prime influence on organic-matter accumulation at Site 645 throughout the last 20 Ma, with maximum rates of input in the middle Miocene and the late Pliocene/Pleistocene. During the former period, additional quantities of marine organic carbon accumulated. These are thought to reflect a phase of higher productivity caused by the first inflow of cold Arctic water masses. In the upwelling area off Northwest Africa, variations in marine organic carbon input, caused by changes in surface-water productivity, were the primary control on organic-carbon accumulation at Site 658. Nevertheless, terrigenous organic carbon may still represent a significant proportion of the total organic carbon. Estimated paleoproductivity values are in the same range as those measured in the area today. Between 3.6 and 3.1 Ma, the supply of terrigenous organic carbon reached its maximum, probably due to a phase of dominantly humid climatic conditions in Northwest Africa. The higher oceanic productivity also recorded for this interval may have been caused by increased fluvial nutrient supply.