Thermal maturity of the Upper Triassic–Middle Jurassic Shemshak Group (Alborz Range, Northern Iran) based on organic petrography, geochemistry and basin modelling: implications for source rock evaluation and petroleum exploration

AbstractOrganic petrography and geochemical analyses have been carried out on shales, carbonaceous shales and coals of the Shemshak Group (Upper Triassic–Middle Jurassic) from 15 localities along the Alborz Range of Northern Iran. Thermal maturity of organic matter (OM) has been investigated using vitrinite reflectance, Rock-Eval pyrolysis and elemental analysis of kerogen. Reflectance of autochthonous vitrinite varies from 0.6 to 2.2% indicating thermally early-mature to over-mature OM in the Shemshak Group, in agreement with other maturity parameters used. The shales of the Shemshak Group are characterized by poor to high residual organic carbon contents (0.13 to 5.84%) and the presence of hydrogen-depleted OM, predominantly as a consequence of oxidation of OM at the time of deposition and the hydrogen loss during petroleum generation. According to light-reflected microscopy results, vitrinite/vitrinite-like macerals are dominant in the kerogen concentrates from the shaly facies. The coals and carbonaceous shales of the Shemshak Group show a wide range in organic carbon concentration (3.5 to 88.6%) and composition (inertinite- and vitrinite-rich types), and thereby different petroleum potentials. Thermal modelling results suggest that low to moderate palaeo-heat flow, ranging from 47 to 79 mW m−2 (57 mW m−2 on average), affected the Central-Eastern Alborz basin during Tertiary time, the time of maximum burial of the Shemshak Group. The maximum temperature that induced OM maturation of the Shemshak Group seems to be related to its deep burial rather than to a very strong heat flow related to an uppermost Triassic–Liassic rifting. The interval of petroleum generation in the most deeply buried part of the Shemshak Group (i.e. Tazareh section) corresponds to Middle Jurassic–Early Cretaceous times. Exhumation of the Alborz Range during Late Neogene time, especially along the axis of the Central-Eastern Alborz, where maximum vitrinite reflectance values are recorded, probably destroyed possible petroleum accumulations. However, on the northern flank of the Central-Eastern Alborz, preservation of petroleum accumulations may be expected. The northern part of the basin therefore seems the best target for petroleum exploration.

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Characterization of organic matter in the fine-grained siliciclastic sediments of the Shemshak Group (Upper Triassic–Middle Jurassic) in the Alborz Range, Northern Iran

Geological Society London Special Publications ◽

10.1144/sp312.7 ◽

2009 ◽

Vol 312 (1) ◽

pp. 161-174 ◽

Cited By ~ 2

Author(s):

Ali Shekarifard ◽

François Baudin ◽

Johann Schnyder ◽

Kazem Seyed-Emami

Keyword(s):

Organic Matter ◽

Middle Jurassic ◽

Upper Triassic ◽

Northern Iran ◽

Fine Grained ◽

Alborz Range ◽

Siliciclastic Sediments

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Evaluation of the quality, thermal maturity and distribution of potential source rocks in the Danish part of the Norwegian–Danish Basin

Geological Survey of Denmark and Greenland Bulletin ◽

10.34194/geusb.v16.4989 ◽

2008 ◽

Vol 16 ◽

pp. 1-66 ◽

Cited By ~ 5

Author(s):

Henrik I. Petersen ◽

Lars H. Nielsen ◽

Jørgen A. Bojesen-Koefoed ◽

Anders Mathiesen ◽

Lars Kristensen ◽

...

Keyword(s):

Source Rock ◽

Early Cretaceous ◽

Middle Jurassic ◽

Upper Cretaceous ◽

Vitrinite Reflectance ◽

Lower Jurassic ◽

Source Rocks ◽

Thermal Maturity ◽

Potential Source ◽

Petroleum Generation

The quality, thermal maturity and distribution of potential source rocks within the Palaeozoic–Mesozoic succession of the Danish part of the Norwegian-Danish Basin have been evaluated on the basis of screening data from over 4000 samples from the pre-Upper Cretaceous succession in 33 wells. The Lower Palaeozoic in the basin is overmature and the Upper Cretaceous – Cenozoic strata have no petroleum generation potential, but the Toarcian marine shales of the Lower Jurassic Fjerritslev Formation (F-III, F-IV members) and the uppermost Jurassic – lowermost Cretaceous shales of the Frederikshavn Formation may qualify as potential source rocks in parts of the basin. Neither of these potential source rocks has a basinwide distribution; the present occurrence of the Lower Jurassic shales was primarily determined by regional early Middle Jurassic uplift and erosion. The generation potential of these source rocks is highly variable. The F-III and F-IV members show significant lateral changes in generation capacity, the best-developed source rocks occurring in the basin centre. The combined F-III and F-IV members in the Haldager-1, Kvols-1 and Rønde-1 wells contain 'net source-rock' thicknesses (cumulative thickness of intervals with Hydrogen Index (HI)> 200 mg HC/g TOC) of 40 m, 83 m, and 92 m, respectively, displaying average HI values of 294, 369 and 404 mg HC/g TOC. The Mors-1 well contains 123 m of 'net source rock' with an average HI of 221 mg HC/g TOC. Parts of the Frederikshavn Formation possess a petroleum generation potential in the Hyllebjerg-1, Skagen-2, Voldum-1 and Terne-1 wells, the latter well containing a c. 160 m thick highly oil-prone interval with an average HI of 478 mg HC/g TOC and maximum HI values> 500 mg HC/g TOC.The source-rock evaluation suggests that a Mesozoic petroleum system is the most likely in the study area. Two primary plays are possible: (1) the Upper Triassic – lowermost Jurassic Gassum play, and (2) the Middle Jurassic Haldager Sand play. Potential trap structures are widely distributed in the basin, most commonly associated with the flanks of salt diapirs. The plays rely on charge from the Lower Jurassic (Toarcian) or uppermost Jurassic – lowermost Cretaceous shales. Both plays have been tested with negative results, however, and failure is typically attributed to insufficient maturation (burial depth) of the source rocks. This maturation question has been investigated by analysis of vitrinite reflectance data from the study area, corrected for post-Early Cretaceous uplift. A likely depth to the top of the oil window (vitrinite reflectance = 0.6%Ro) is c. 3050–3100 m based on regional coalification curves. The Frederikshavn Formation had not been buried to this depth prior to post-Early Cretaceous exhumation, and the potential source rocks of the formation are thermally immature in terms of hydrocarbon generation. The potential source rocks of the Fjerritslev Formation are generally immature to very early mature. Mature source rocks in the Danish part of the Norwegian–Danish Basin are thus dependent on local, deeper burial to reach the required thermal maturity for oil generation. Such potential kitchen areas with mature Fjerritslev Formation source rocks may occur in the central part of the study area (central–northern Jylland), and a few places offshore. These inferred petroleum kitchens are areally restricted, mainly associated with salt structures and local grabens (such as the Fjerritslev Trough and the Himmerland Graben).

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Petrology, rank and evidence for petroleum generation, Upper Triassic to Middle Jurassic coals, Central Alborz Region, Northern Iran

International Journal of Coal Geology ◽

10.1016/j.coal.2005.11.002 ◽

2006 ◽

Vol 67 (4) ◽

pp. 249-258 ◽

Cited By ~ 15

Author(s):

L.D. Stasiuk ◽

F. Goodarzi ◽

H. Bagheri-Sadeghi

Keyword(s):

Middle Jurassic ◽

Upper Triassic ◽

Northern Iran ◽

Central Alborz ◽

Petroleum Generation ◽

Alborz Region

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THE SUPPRESSION OF VITRINITE REFLECTANCE IN SOME NORTH WEST SHELF WELLS: BARROW-1, JUPITER-1 AND FLAMINGO-1

The APPEA Journal ◽

10.1071/aj91024 ◽

1992 ◽

Vol 32 (1) ◽

pp. 300 ◽

Cited By ~ 3

Author(s):

R.W.T. Wilkins ◽

J.R. Wilmshurst ◽

G. Hladky ◽

M.V. Ellacott ◽

C.P. Buckingham

Keyword(s):

Organic Matter ◽

Vitrinite Reflectance ◽

Accurate Determination ◽

Petroleum Exploration ◽

Thermal Maturity ◽

North West ◽

The North ◽

The Individual ◽

Reflectance Data

The sediments of the North West Shelf pose several problems for the accurate determination of thermal maturity by vitrinite reflectance. There are some serious discrepancies between the results of different workers; in some wells there is a surprisingly small increase of reflectance with depth, and it is sometimes difficult to honour these data in thermal maturity modelling. There appear to be two major sources of error in the reflectance data. These are firstly, the effect known as 'suppression' of vitrinite reflectance, and secondly, the difficulty of identifying the vitrinite population in dispersed organic matter.These problems may be addressed by the fluorescence alteration technique which is closely related to vitrinite reflectance but has two special advantages. Firstly, it depends on an analysis of the fluorescence alteration response of a small representative population of organic matter in which the individual macerals need not be identified. Secondly, anomalous vitrinites with suppressed vitrinite reflectance are readily characterized, and the corrected equivalent reflectances determined.The technique has been tested on three North West Shelf petroleum exploration wells, Barrow-1, Jupiter-1 and Flamingo-1. Major discrepancies between measured and equivalent vitrinite reflectance appear to originate in part from the difficulty of identifying the vitrinite population in dispersed organic matter from marine sediments. There is also evidence of suppression of vitrinite reflectance in most samples from Barrow-1, in the Flamingo Group and Plover Formation of Flamingo-1, and in the upper part of the Mungaroo Formation of Jupiter-1.A model is proposed to facilitate the assessment of measured vitrinite reflectance data from Carnarvon or Bonaparte Basin wells. Suppression effects are likely to have influenced measured vitrinite reflectance results from wells for which the strongest data are obtained from the Lower Cretaceous fluvio-deltaic Barrow Group sediments or their equivalents.

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Burial and Thermal History Modeling of the Paleozoic–Mesozoic Basement in the Northern Margin of the Western Outer Carpathians (Case Study from Pilzno-40 Well, Southern Poland)

Minerals ◽

10.3390/min11070733 ◽

2021 ◽

Vol 11 (7) ◽

pp. 733

Author(s):

Dariusz Botor

Keyword(s):

Heat Flow ◽

Thermal History ◽

Middle Jurassic ◽

Source Rocks ◽

Petroleum Exploration ◽

Late Triassic ◽

Hydrocarbon Generation ◽

Thermal Maturity ◽

Northern Margin ◽

Outer Carpathians

Hydrocarbon exploration under thrust belts is a challenging frontier globally. In this work, 1-D thermal maturity modeling of the Paleozoic–Mesozoic basement in the northern margin of the Western Outer Carpathians was carried out to better explain the thermal history of source rocks that influenced hydrocarbon generation. The combination of Variscan burial and post-Variscan heating due to elevated heat flow may have caused significant heating in the Paleozoic basement in the pre-Middle Jurassic period. However, the most likely combined effect of Permian-Triassic burial and Late Triassic–Early Jurassic increase of heat flow caused the reaching of maximum paleotemperature. The main phase of hydrocarbon generation in Paleozoic source rocks developed in pre-Middle Jurassic times. Therefore, generated hydrocarbons from Ordovician and Silurian source rocks were lost before reservoirs and traps were formed in the Late Mesozoic. The Miocene thermal overprint due to the Carpathian overthrust probably did not significantly change the thermal maturity of organic matter in the Paleozoic–Mesozoic strata. Thus, it can be concluded that petroleum accumulations in the Late Jurassic and Cenomanian reservoirs of the foreland were charged later, mainly by source rocks occurring within the thrustbelt, i.e., Oligocene Menilite Shales. Finally, this work shows that comprehensive mineralogical and geochemical studies are an indispensable prerequisite of any petroleum system modelling because their results could influence petroleum exploration of new oil and gas fields.

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Geochemistry of siliciclastic rocks from the Shemshak Group (Upper Triassic–Middle Jurassic), northeastern Alborz, northern Iran: implications for palaeoweathering, provenance, and tectonic setting

Geological Quarterly ◽

10.7306/gq.1433 ◽

2018 ◽

Vol 62 (3) ◽

Cited By ~ 1

Author(s):

Azizollah TAHERI ◽

Mahdi JAFARZADEH ◽

John S. ARMSTRONG-ALTRIN ◽

Seyed Reza MIRBAGHERI

Keyword(s):

Middle Jurassic ◽

Tectonic Setting ◽

Upper Triassic ◽

Northern Iran ◽

Siliciclastic Rocks

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THE CURRENT STATUS OF THE FAMM THERMAL MATURITY TECHNIQUE FOR PETROLEUM EXPLORATION IN AUSTRALIA

The APPEA Journal ◽

10.1071/aj97020 ◽

1998 ◽

Vol 38 (1) ◽

pp. 421 ◽

Cited By ~ 4

Author(s):

R.W.T. Wilkins ◽

C.P. Buckingham ◽

N. Sherwood ◽

N.J. Russell ◽

M. Faiz ◽

...

Keyword(s):

Organic Matter ◽

Vitrinite Reflectance ◽

Petroleum Exploration ◽

Current Status ◽

Thermal Maturity ◽

North West ◽

Intensity Measurements ◽

Organic Matter Oxidation ◽

Working Set

The fluorescence alteration of multiple macerals (FAMM™) technique was developed in 1989-91 to overcome problems encountered by existing techniques applied to the thermal maturity determination of North West Shelf organic matter. Subsequently it has been widely used in Australia, SE Asia and elsewhere. This paper reviews the present status of the FAMM technique.Since its inception, the methodology of the FAMM technique has undergone some changes. The most important is a closer integration with vitrinite reflectance (VR) resulting in expansion of the capacity of the technique to solve complex maturity problems. The accumulated data indicate that shales and mudstones are most suitable for FAMM analysis for the reason that more porous lithologies are potentially more susceptible to organic matter oxidation. There is extensive evidence that organic matter in cores and well-protected cuttings samples of shales remain unaffected by oxidation during decades of storage because clay is extremely effective in limiting access of oxygen. Adhering to sampling guidelines can greatly reduce the risk of errors from this source. Of the two recently described thermal maturity techniques based on combining VR with fluorescence intensity measurements (Quick, 1994; Newman, 1997), FAMM is more closely related to Quick's method. As the fluorescence alteration ratio which acts as the thermal maturity indicator in the FAMM method is independent of VR, it is possible to cross check results for consistency using suppression iso-correction curves-a possiblity which does not exist with the other thermal maturity techniques based on fluorescence. A working set of suppression iso-correction curves has been determined specifically for Australian Jurassic vitrinite. Whether from coal or dispersed organic matter (DOM), Australian Jurassic vitrinites are commonly perhydrous and this should be borne in mind when modelling thermal histories of North West Shelf sequences.

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