30th International Meeting on Organic Geochemistry (IMOG 2021)

This study aim to investigate the structural changes of a lacustrine Type-II kerogen, by taking the seventh Member of the Triassic Yanchang Formation in the Ordos Basin (Chang 7 Shale) as an example. Integrated analysis including elemental analysis, programmed pyrolysis (Rock-Eval), FT-IR, and 13C NMR were conducted on the unheated and post-pyrolysis rocks and kerogens.

Results show that before the peak hydrocarbon-generating stage (Ro < 0.6%), defunctionalization of oxygen-containing functional groups, which generates water, CO2 and NSOs, occurs simultaneously with the detachment of short aliphatic side chains and small aromatic rings, which generates volatile fractions (C6-C14, C15+ sat and C15+ aro), suggesting that the Chang7 kerogen is highly branched. During the peak hydrocarbon-generating stage (0.6–1.09 %Ro), the concurrent breakage of weak cross-link bonds and long aliphatic chains lead to the simultaneous peak generation of liquid hydrocarbons and NSOs, indicating the highly cross-linked features of the Chang7 kerogen. After the peak hydrocarbon-generating stage (Ro > 1.09%), the reactions in the previous two stages produce a highly aromatic kerogen. The increased aromaticity of the highly matured kerogen is likely to be caused by aromatization or dehydrogenation of hydroaromatics and coking of aromatic bitumen, not by fusing or condensation of aromatic rings.

This report highlights the following aspects of the trace element (TE) composition of naphthides: 1. genetic relationships of bitumoids with the composition of generated oils; 2. dynamics of changes in the TE composition of naphthides during catagenic and hypergenetic transformations; 3. correlation dependences of the TE compositions of naphthides with the composition of various substances. The composition of the TE of oils and bitumoids has long been successfully used in petroleum geochemistry for solving various geological and geochemical problems. That is why the use of data on the TE composition of naphthides is relevant and well-grounded.

The recent availability and property determination of petroleum-derived higher diamondoids has led to a number of applications and potential applications both within and outside of the petroleum industry. These include: correlation of highly-mature fluids, correlation of mixed-maturity oils, photo-emitters, field emitters, seeds for growing small diamonds with color centers for quantum information, pharmaceuticals, components in new polymers, components in lithium-ion batteries and catalysts. This presentation is an overview of these applications and the physical properties leading to them

The studied Bovanenkovskoye oil-gas-condensate field is located at the Yamal Peninsula – in the north of West Siberia, where a new gas-production centre is being formed. The aim of the study is to conduct geochemical type assignment of oil (5) and condensate (10) samples from the Lower Cretaceous (K₁al – 2, K₁a – 3, K₁g – 3), Middle (J₂bt – 3, J₂b – 3), and Lower Jurassic (J₁p – 1) deposits, using data about their properties and composition (distribution of n-alkanes, i-alkanes, steranes, terpanes, arenes, and, mainly, of light hydrocarbons C₄–C₈). In the presented research, the use is made of GC and GC/MS analyses of crude oils (condensates) and their hydrocarbon fractions. The obtained results suggest the hydrocarbon formation in the Bovanenkovskoye field from a single center of oil and gas generation due to the terrestrial organic matter of the Lower and Middle Jurassic strata (Malyshevka, Layda formations) and a significant contribution of the aquatic organic matter from the Upper Jurassic strata (Bazhenov formation) to the generation of the Aptian condensates.

The Early Palaeozoic Alum Shale Formation in northwestern Europe is rich in uranium up to several hundreds of ppm. Despite the absence of higher land plant precursors, the primary Type II kerogen in the Alum Shale has an abnormally strong aromatic character even at low thermal maturities, probably due to α-particle bombardment.

FT-ICR-MS data reveal that the macromolecules in the uranium-rich Alum Shale samples are less alkylated than less irradiated counterparts, and that oxygen containing-compounds are enriched in the uranium-rich samples but are not easily degradable into low-molecular-weight products due to irradiation-induced crosslinking.

Despite strong organic matter alteration, CO2 and CH4 are formed using U-rich samples in incubation experiments, and DNA-based high-throughput sequencing allows a detailed phylogenetic characterization of the indigenous microbial communities with implications of an uranium-adapted biosphere.

The alteration of macromolecular organic matter in the Alum Shale Formation is suggested as an Earth analogue of the Martian surface, in response to α-particle irradiation. Especially a comparison of potential habitats on the Martian surface with Kolm nodules of the Alum Shale in terms of irradiation dosage and organic geochemical characteristics reveals that they have received similar levels of irradiation.

Determination of oil maturity is of great significance for understanding the origin and evolution stage at which the oil is generated, and is one of major topics in petroleum geochemistry research. Due to oil migration, oils in reservoirs most likely are mixtures of oils generated at different thermal maturities or by different source rocks, and it is usually hard to establish relationship between source rock and oil with respect to thermal maturity. In this paper, source rock maturity was compared with that of intra-source oil (i.e. shale oil), providing preliminary implications for further study.

Light non-aqueous phase liquids (LNAPLs) are one of the most common sources of soil pollution worldwide. The Intergovernmental Panel on Climate Change (IPCC) predicts a significant increase of groundwater level fluctuations' intensity by 2100 that may greatly favor the remobilization of these contaminants in the environement. Yet, the effect of groundwater tables fluctuations on the LNAPL mobilization is not fully understood. To this aim, a new original experimental system combining in situ physical-chemical, geochemical, and indirect geophysical measurements was developed at the GISFI station, Homécourt, France to assess the effect of the groundwater level variations dynamic, under current and climate change conditions, on the LNAPL remobilization. Attention will be paid, especially, to the evolution of the concentration and composition of the dissolved LNAPL phase over time. Measurement, and monitoring of the pure LNAPL phase thickness and chemical composition variation will be also monitored. Numerical simulations of the LNAPL transport through the contaminated soil will also be carried out. These experiments should provide a better understanding of the fate of these hydrocarbons at contaminated soils and thus, a better assessment of the environmental risks associated with these contaminated sites and their evolution in the climate change context.

Dayangshu Basin is located in Eastern Inner Mongolia Autonomous Region, China. It is a late Mesozoic basin that is covered by volcanic rocks. The tectonic movement is violent. Fault activities control the formation and development of the basin. Volcanic activity runs through the whole process of basin formation. It is of great significance that study on the characteristics of source rocks and oil-gas sources in the Dayangshu Basin for evaluating the oil-gas exploration potential, understanding the oil-gas generation and evolution of the volcanic strata in the eastern basin of China.

a geochemical study on source rocks found in the eastern flank of Oman Ghaba Basin and effort to correlate this source rock to Oman oils families. we believe that this source rocks is the source for the well known Q oil family in Oman which has been known since 40 years but no source rocks were linked to it.