scholarly journals Characteristics of Rock-Eval Analysis of Carbonates Source Rocks and of Petroleum Derived from Carbonate Source Rocks.

1991 ◽  
Vol 56 (3) ◽  
pp. 222-231
Author(s):  
Kenji HIRABAYASHI
2006 ◽  
Vol 51 (23) ◽  
pp. 2885-2891 ◽  
Author(s):  
Xinhua Geng ◽  
Ansong Geng ◽  
Yongqiang Xiong ◽  
Jinzhong Liu ◽  
Haizu Zhang ◽  
...  

Author(s):  
Sebastian Grohmann ◽  
Susanne W. Fietz ◽  
Ralf Littke ◽  
Samer Bou Daher ◽  
Maria Fernanda Romero-Sarmiento ◽  
...  

Several significant hydrocarbon accumulations were discovered over the past decade in the Levant Basin, Eastern Mediterranean Sea. Onshore studies have investigated potential source rock intervals to the east and south of the Levant Basin, whereas its offshore western margin is still relatively underexplored. Only a few cores were recovered from four boreholes offshore southern Cyprus by the Ocean Drilling Program (ODP) during the drilling campaign Leg 160 in 1995. These wells transect the Eratosthenes Seamount, a drowned bathymetric high, and recovered a thick sequence of both pre- and post-Messinian sedimentary rocks, containing mainly marine marls and shales. In this study, 122 core samples of Late Cretaceous to Messinian age were analyzed in order to identify organic-matter-rich intervals and to determine their depositional environment as well as their source rock potential and thermal maturity. Both Total Organic and Inorganic Carbon (TOC, TIC) analyses as well as Rock-Eval pyrolysis were firstly performed for the complete set of samples whereas Total Sulfur (TS) analysis was only carried out on samples containing significant amount of organic matter (>0.3 wt.% TOC). Based on the Rock-Eval results, eight samples were selected for organic petrographic investigations and twelve samples for analysis of major aliphatic hydrocarbon compounds. The organic content is highly variable in the analyzed samples (0–9.3 wt.%). TS/TOC as well as several biomarker ratios (e.g. Pr/Ph < 2) indicate a deposition under dysoxic conditions for the organic matter-rich sections, which were probably reached during sporadically active upwelling periods. Results prove potential oil prone Type II kerogen source rock intervals of fair to very good quality being present in Turonian to Coniacian (average: TOC = 0.93 wt.%, HI = 319 mg HC/g TOC) and in Bartonian to Priabonian (average: TOC = 4.8 wt.%, HI = 469 mg HC/g TOC) intervals. A precise determination of the actual source rock thickness is prevented by low core recovery rates for the respective intervals. All analyzed samples are immature to early mature. However, the presence of deeper buried, thermally mature source rocks and hydrocarbon migration is indicated by the observation of solid bitumen impregnation in one Upper Cretaceous and in one Lower Eocene sample.


2022 ◽  
pp. 1-42
Author(s):  
Xiaojun Zhu ◽  
Jingong Cai ◽  
Feng Liu ◽  
Qisheng Zhou ◽  
Yue Zhao ◽  
...  

In natural environments, organic-clay interactions are strong and cause organo-clay composites (a combination between organic matter [OM] and clay minerals) to be one of the predominant forms for OM occurrence, and their interactions greatly influence the hydrocarbon (HC) generation of OM within source rocks. However, despite occurring in nature, dominating the OM occurrence, and having unique HC generation ways, organo-clay composites have rarely been investigated as stand-alone petroleum precursors. To improve this understanding, we have compared the Rock-Eval pyrolysis parameters derived from more than 100 source rocks and their corresponding <2 μm clay-sized fractions (representing organo-clay composites). The results show that all of the Rock-Eval pyrolysis parameters in bulk rocks are closely positively correlated with those in their clay-sized fractions, but in clay-sized fractions the quality of OM for HC generation is poorer, in that the pyrolysable organic carbon levels and hydrogen index values are lower, whereas the residual organic carbon levels are higher than those in bulk rocks. Being integrated with the effects of organic-clay interactions on OM occurrence and HC generation, our results suggest that organo-clay composites are stand-alone petroleum precursors for HC generation occurring in source rocks, even if the source rocks exist in great varieties in their attributes. Our source material for HC generation comprehensively integrates the original OM occurrence and HC generation behavior in natural environments, which differs from kerogen and is much closer to the actual source material of HC generation in source rocks, and it calls for further focus on organic-mineral interactions in studies of petroleum systems.


1982 ◽  
Vol 22 (1) ◽  
pp. 5
Author(s):  
A. R. Martin ◽  
J. D. Saxby

The geology and exploration history of the Triassic-Cretaceous Clarence-Moreton Basin are reviewed. Consideration of new geochemical data ('Rock-Eval', vitrinite reflectance, gas chromatography of extracts, organic carbon and elemental analysis of coals and kerogens) gives further insights into the hydrocarbon potential of the basin. Although organic-rich rocks are relatively abundant, most source rocks that have achieved the levels of maturation necessary for hydrocarbon generation are gas-prone. The exinite-rich oil-prone Walloon Coal Measures are in most parts relatively immature. Some restraints on migration pathways are evident and igneous and tectonic events may have disturbed potentially well-sealed traps. Further exploration is warranted, even though the basin appears gas-prone and the overall prospects for hydrocarbons are only fair. The most promising areas seem to be west of Toowoomba for oil and the Clarence Syncline for gas.


1992 ◽  
Vol 32 (1) ◽  
pp. 289 ◽  
Author(s):  
John Scott

The main potential source rock intervals are generally well defined on the North West Shelf by screening analysis such as Rock-Eval. The type of product from the source rocks is not well defined, owing to inadequacies in current screening analysis techniques. The implications of poor definition of source type in acreage assessment are obvious. The type of product is dependent on the level of organic maturity of the source rock, the ability of products to migrate out of the source rock and on the type of organic material present. The type of kerogen present is frequently determined by Rock-Eval pyrolysis. However, Rock-Eval has severe limitations in defining product type when there is a significant input of terrestrial organic material. This problem has been recognised in Australian terrestrial/continental sequences but also occurs where marine source rock facies contain terrestrially-derived higher plant material. Pyrolysis-gas chromatography as applied to source rock analysis provides, by molecular typing, a better method of estimating the type of products of the kerogen breakdown than bulk chemical analysis such as Rock-Eval pyrolysis.


1984 ◽  
Vol 24 (1) ◽  
pp. 66 ◽  
Author(s):  
John D. Gorter

The quantity of organic matter in the source beds within the Horn Valley Siltstone, as defined by the Total Organic Carbon content, increases westward from low values in the south and east of the Basin to maximum values in the Mt Winter and Mereenie areas. This westerly enrichment trend is paralleled by an improvement in source rock quality, as defined by the Hydrogen Index and Tmax crossplot of samples analysed by Rock-Eval pyrolysis.Earlier attempts to measure thermal maturation levels of source rocks in the Basin relied on the reflectivity of coalified graptolites but this method was only applicable to unweathered material obtained from the few and scattered bore holes in the Basin. In this study, conodont colour alteration is used to define organic maturation levels. This technique, newly applied in Australia, was used principally on samples collected from the Horn Valley Siltstone and has the practical advantage of being applicable to samples from both outcrop and subsurface localities.The study indicates that the conodont colour alteration isograds in the Amadeus Basin are primarily related to events of the Alice Springs Orogeny, when the thick mass of molasse sediments (Pertnjara Group) resulting from erosion of the uplifted Arunta Block was deposited. Anomalies in the conodont colour isograds are closely related to timing of structural growth during the orogeny and also possibly to the growth of salt structures.In addition, the study shows that burial at depths below 1500 m will have led to the catagenetic breakdown of reservoired oil and the production of only gaseous hydrocarbons from source beds.In combination, these two factors lead to the conclusion that the most prospective area for oil sourced by the Horn Valley Siltstone is north and west of the Mereenie Oil Field in areas of shallow burial.


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