Vitrinite Reflectance as a Tool To Assess Thermal Maturity

1991 ◽  
Author(s):  
J. T. Senftle ◽  
Charles R. Landis
Keyword(s):  
Vitrinite Reflectance ◽  
Thermal Maturity

scholarly journals 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

2011 ◽  
Vol 149 (1) ◽  
pp. 19-38 ◽  
Author(s):  
ALI SHEKARIFARD ◽  
FRANÇOIS BAUDIN ◽  
KAZEM SEYED-EMAMI ◽  
JOHANN SCHNYDER ◽  
FATIMA LAGGOUN-DEFARGE ◽  
...  
Keyword(s):  
Middle Jurassic ◽  
Vitrinite Reflectance ◽  
Upper Triassic ◽  
Petroleum Exploration ◽  
Thermal Maturity ◽  
Northern Iran ◽  
Carbonaceous Shales ◽  
Petroleum Generation ◽  
Central Eastern ◽  
Alborz Range

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.

STABLE HYDROGEN ISOTOPE RATIOS OF SEDIMENTARY HYDROCARBONS: A POTENTIAL METHOD FOR ASSESSING THERMAL MATURITY?

2005 ◽  
Vol 45 (1) ◽  
pp. 253
Author(s):  
D. Dawson ◽  
K. Grice ◽  
R. Alexander
Keyword(s):  
Vitrinite Reflectance ◽  
Potential Method ◽  
Source Rocks ◽  
Crude Oils ◽  
Thermal Maturity ◽  
Peak Oil ◽  
Data Set ◽  
High Maturity ◽  
The Difference ◽  
Hydrogen Isotope Ratios

A relationship has been identified between the maturity level of source rocks and the stable hydrogen isotopic compositions (δD) of extracted saturated hydrocarbons, based on the analysis of nine sediments and five crude oils from the Perth Basin (WA). The sediments cover the immature to late mature range. Distinct δD signatures are observed for the immature sediments where pristane and phytane are significantly depleted in deuterium (D) relative to the n-alkanes. With increasing maturity the difference between the δD values of n-alkanes and isoprenoids reduces as pristane and phytane become progressively enriched in D. The n-alkane–isoprenoid δD signature of the crude oils, including one from a different source facies, is similar to mature–late mature sediments representative of the peak oil–generative window. Enrichment of D in isoprenoids is attributed to isotopic exchange associated with thermal maturation. Average δD values of pristane and phytane correlate well with vitrinite reflectance, as does the biomarker maturity parameter Ts/Tm. The limited data set suggests that δD values of aliphatic hydrocarbons may be useful for establishing thermal maturity, particularly when other maturity parameters are not appropriate. Furthermore, we suggest δD values may be useful over a wider maturity range than traditional parameters, particularly at very high maturity where biomarker parameters are no longer effective.

scholarly journals Organic geochemical and palynological studies of the Maastrichtian source rock intervals in Bida Basin, Nigeria: implications for hydrocarbon prospectivity

2020 ◽  
Vol 10 (8) ◽  
pp. 3191-3206
Author(s):  
Olusola J. Ojo ◽  
Ayoola Y. Jimoh ◽  
Juliet C. Umelo ◽  
Samuel O. Akande
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Vitrinite Reflectance ◽  
Source Rocks ◽  
High Yield ◽  
Thermal Maturity ◽  
Hydrocarbon Source Rock ◽  
Moderate Amount ◽  
Oxic Condition ◽  
Freshwater Swamp

Abstract The Patti Formation which consists of sandstone and shale offers the best potential source beds in the Bida Basin. This inland basin is one of the basins currently being tested for hydrocarbon prospectivity in Nigeria. Fresh samples of shale from Agbaja borehole, Ahoko quarry and Geheku road cut were analysed using organic geochemical and palynological techniques to unravel their age, paleoecology, palynofacies and source bed hydrocarbon potential. Palynological data suggest Maastrichtian age for the sediments based on the abundance of microfloral assemblage; Retidiporites magdalenensis, Echitriporites trianguliformis and Buttinia andreevi. Dinocysts belonging to the Spiniferites, Deflandrea and Dinogymnium genera from some of the analysed intervals are indicative of freshwater swamp and normal sea conditions. Palynological evidence further suggests mangrove paleovegetation and humid climate. Relatively high total organic carbon TOC (0.77–8.95 wt%) was obtained for the shales which implies substantial concentration of organic matter in the source beds. Hydrocarbon source rock potential ranges from 0.19 to 0.70 mgHC/g.rock except for a certain source rock interval in the Agbaja borehole with high yield of 25.18 mgHC/g.rock. This interval also presents exceptionally high HI of 274 mgHC/g.TOC and moderate amount of amorphous organic matter. The data suggests that in spite of the favourable organic matter quantity, the thermal maturity is low as indicated by vitrinite reflectance and Tmax (0.46 to 0.48 Ro% and 413 to 475 °C, respectively). The hydrocarbon extracts show abundance of odd number alkanes C27–C33, low sterane/hopane ratio and Pr/Ph > 2. We conclude that the source rocks were terrestrially derived under oxic condition and dominated by type III kerogen. Type II organic matter with oil and gas potential is a possibility in Agbaja area of Bida Basin. Thermal maturity is low and little, or no hydrocarbon has been generated from the source rocks.

Assessing thermal maturity beyond the reaches of vitrinite reflectance and Rock-Eval pyrolysis: A case study from the Silurian Qusaiba formation

2017 ◽  
Vol 180 ◽  
pp. 29-45 ◽  
Author(s):  
Stephen Cheshire ◽  
Paul R. Craddock ◽  
Guangping Xu ◽  
Bastian Sauerer ◽  
Andrew E. Pomerantz ◽  
...  
Keyword(s):  
Vitrinite Reflectance ◽  
Thermal Maturity ◽  
Rock Eval

scholarly journals Thermal and structural modeling of the Scillato wedge-top basin source-to-sink system: Insights into the Sicilian fold-and-thrust belt evolution (Italy)

2019 ◽  
Vol 131 (11-12) ◽  
pp. 1763-1782 ◽  
Author(s):  
Martina Balestra ◽  
Sveva Corrado ◽  
Luca Aldega ◽  
Maurizio Gasparo Morticelli ◽  
Attilio Sulli ◽  
...  
Keyword(s):  
Short Range ◽  
Vitrinite Reflectance ◽  
Sediment Provenance ◽  
Hydrocarbon Generation ◽  
Thermal Maturity ◽  
Thrust Belt ◽  
Ordered Structures ◽  
Source To Sink ◽  
Fold And Thrust Belt ◽  
Basin Fill

Abstract Temperature-dependent clay mineral assemblages, vitrinite reflectance, and one-dimensional (1-D) thermal and three-dimensional (3-D) geological modeling of a Neogene wedge-top basin in the Sicilian fold-and-thrust belt and its pre-orogenic substratum allowed us to: (1) define the burial history of the sedimentary succession filling the wedge-top basin and its substratum, (2) reconstruct the wedge-top basin geometry, depocenter migration, and sediment provenance through time in the framework of a source-to-sink system, and (3) shed new light into the kinematic evolution of the Apennine-Maghrebian fold-and-thrust belt. The pre-orogenic substratum of the Scillato basin shows an increase in levels of thermal maturity as a function of stratigraphic age that is consistent with maximum burial to 3.5 km in deep diagenetic conditions. In detail, Ro% values range from 0.40% to 0.94%, and random ordered illite-smectite (I-S) first converts to short-range ordered structures and then evolves to long-range ordered structures at the base of the Imerese unit. The wedge-top basin fill experienced shallow burial (∼2 km) and levels of thermal maturity in the immature stage of hydrocarbon generation and early diagenesis. Vitrinite reflectance and mixed-layer I-S values show two populations of authigenic and inherited phases. The indigenous population corresponds to macerals with Ro% values of 0.33%–0.45% and I-S with no preferred sequence in stacking of layers, whereas the reworked group corresponds to macerals with Ro% values of 0.42%–0.47% and short-range ordered I-S with no correlation as a function of depth. Authigenic and reworked components of the Scillato basin fill allowed us to unravel sediment provenance during the Neogene, identifying two main source areas feeding the wedge-top basin (crystalline units of the European domain and sedimentary units of the African domain), and to detect an early phase of exhumation driven by low-angle extensional faults that predated Neogene compression.

Structural styles of the External Rif and Flysch Domain (Rif belt, northern Morocco) through thermal maturity and structural data

2020 ◽  
Author(s):  
Andrea Schito ◽  
Achraf Atouabat ◽  
Sveva Corrado ◽  
Faouziya Haissen ◽  
Geoffroy Mohn ◽  
...  
Keyword(s):  
Vitrinite Reflectance ◽  
Methodological Approach ◽  
Structural Evolution ◽  
Structural Data ◽  
Thermal Modelling ◽  
Thermal Maturity ◽  
North African ◽  
Data Set ◽  
The North ◽  
Rif Belt

<p>Located in northern Morocco, the Rif belt represents the western edge of the Maghrebides system. This domain underwent a significant Cenozoic alpine compressional deformation, due to the collision between the North African margin and the south-western margin of the exotic Alboran Domain. This collision led to the development of a nappe stack during the Miocene.</p><p>This contribution aims to characterize the main tectonic mechanisms driving the evolution of the Rifain wedge, its burial-exhumation paths and to understand the former architecture of the North African paleo-margin. The work focuses mainly on the Flysch domain, originated from the Maghrebian branch of the Tethys and on the External domain (namely Intrarif, Mesorif and Prerif) that belong to the former north African margin. To define the thrust sheet stacking pattern and their burial-exhumation paths, a regional transect from Chefchaouen and Ouezzane towns (Central Rif), crossing the orogenic wedge from the Flysch to the Prerif Units is constructed.</p><p>The methodological approach consists in combining petrography and Raman micro-spectroscopy on organic matter and 1D thermal modelling, together with field structural data.</p><p>A new paleo-thermal data set of vitrinite reflectance (Ro%) and Raman micro-spectroscopy displays levels of thermal maturity between early and deep diagenetic conditions (Ro% ranges from 0.50% to 1.15%).</p><p>Preliminary results show an abrupt change in the thermal maturity and the rate of shortening in the Loukkos sub-unit (Intrarif Domain) that is structurally squeezed between Tangier sub-unit (Intrarif Domain) and the “Izzaren Duplex” (Mesorif).</p><p>Furthermore, previous studies show that the thickest crust below the Rif fold-and-thrust belt is located below the Izzaren area, suggesting a deep crustal imbrication at the transition between the Intrarif and the Mesorif. These observations joined with the thermal maturity data and 1D thermal modelling allow revisiting the structural evolution of the central part of the Rif belt, by defining the rate of shortening and proposing a new geological restoration with respect to the Mesozoic North African margin structural original setting.</p>

scholarly journals Evaluating Molecular Evolution of Kerogen by Raman Spectroscopy: Correlation with Optical Microscopy and Rock-Eval Pyrolysis

Energies ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 1406 ◽  
Author(s):  
Seyedalireza Khatibi ◽  
Mehdi Ostadhassan ◽  
David Tuschel ◽  
Thomas Gentzis ◽  
Humberto Carvajal-Ortiz
Keyword(s):  
Raman Spectroscopy ◽  
Organic Matter ◽  
Structural Information ◽  
Vitrinite Reflectance ◽  
Nondestructive Method ◽  
Thermal Maturity ◽  
Shale Formations ◽  
Reflectance Analysis ◽  
Rock Eval ◽  
Maturity Parameters

Vitrinite maturity and programmed pyrolysis are conventional methods to evaluate organic matter (OM) regarding its thermal maturity. Moreover, vitrinite reflectance analysis can be difficult if prepared samples have no primary vitrinite or dispersed widely. Raman spectroscopy is a nondestructive method that has been used in the last decade for maturity evaluation of organic matter by detecting structural transformations, however, it might suffer from fluorescence background in low mature samples. In this study, four samples of different maturities from both shale formations of Bakken (the upper and lower members) Formation were collected and analyzed with Rock-Eval (RE) and Raman spectroscopy. In the next step, portions of the same samples were then used for the isolation of kerogen and analyzed by Raman spectroscopy. Results showed that Raman spectroscopy, by detecting structural information of OM, could reflect thermal maturity parameters that were derived from programmed pyrolysis. Moreover, isolating kerogen will reduce the background noise (fluorescence) in the samples dramatically and yield a better spectrum. The study showed that thermal properties of OM could be precisely reflected in Raman signals.

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