scholarly journals Análisis geoquímico y petrográfico de las formaciones Los Cuervos y Molino, Subcuenca Cesar (Colombia): implicaciones en la evolución del sistema petrolero

2021 ◽  
Vol 43 (2) ◽  
Author(s):  
Gladys Marcela Avendaño-Sánchez ◽  
Mario García-González ◽  
Luis Enrique Cruz-Guevara ◽  
Luis Felipe Cruz-Ceballos
Keyword(s):  
Organic Matter ◽  
Vitrinite Reflectance ◽  
Geochemical Modelling ◽  
Maturation Stage ◽  
Petrographic Analysis ◽  
Hydrocarbon Generation ◽  
Thermal Maturation ◽  
Reflectance Analysis ◽  
Rock Eval

A geochemical characterization of Los Cuervos and Molino formations in the Cesar Sub-Basin was carried out using core samples obtained from the ANH-La Loma-1 Well. A total of 113 Rock-Eval pyrolysis analysis, total organic carbon (TOC), total sulphur content (TS) analysis, 13 vitrinite reflectance analysis (%Ro) and 30 thin-section petrographic analysis were performed. Based on these new data, it was possible to classify the quality of organic matter and the current thermal maturation of Los Cuervos and Molino formations. Additionally, a petrographic characterization of 30 samples allowed the correlation of the lithology with the geochemical results. Also, one-dimensional geochemical modelling was implemented in order to contribute to the knowledge of the evolution of the oil system in the Cesar Sub-Basin. The spatial distribution of the formations used in the modelling was obtained from 2 seismic lines two-way time. The results obtained indicate that Los Cuervos Formation presents TOC values from 0.29 to 66.55%, TS values from 0.02 to 11.29%, their organic matter consisted of type III kerogen which is consistent with an immature thermal maturation stage. In contrast, the Molino Formation presents TOC values from 0.23 to 2.28%, TS values from 0.001 to 1.39%, their organic matter consisted of type II/III kerogen this suggests an early entry to the oil window with a maximum pyrolysis temperature (Tmax) value of 442°C. The geochemical modelling tunes better with measured data from palaeo-geothermometers (%Ro and Tmax). The geochemical modelling shows that, between 60 - 40 million years ago (mya), the Cretaceous formations entered in the oil generation window and it is expected that, between 40 - 30 mya, the Lagunitas, Aguas Blancas, and La Luna formations will be at their peak of hydrocarbon generation.

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.

scholarly journals Characterization of Organic Matter from Bituminous Coals of Lafia-Obi, Middle Benue Trough, Nigeria

2021 ◽  
Vol 25 (5) ◽  
pp. 701-717
Author(s):  
M.U. Uzoegbu ◽  
C.U. Ugwueze ◽  
J.I. Nwosu
Keyword(s):  
Organic Matter ◽  
Vitrinite Reflectance ◽  
Atomic Ratio ◽  
Carbonaceous Shale ◽  
Hydrocarbon Generation ◽  
Oxic Condition ◽  
Gaseous Hydrocarbon ◽  
Benue Trough ◽  
Type Iii ◽  
Rock Eval

The present work deals with a study based on the geochemical techniques such as biomarkers, Rock-Eval pyrolysis, and detailed petrographic study to evaluate hydrocarbon generation potential of coal by collecting nine coal and carbonaceous shale samples from boreholes in Awgu Formation of Middle Benue Trough, Nigeria. The values vitrinite reflectance (0.94–1.15%VR) and Tmax (446–469°C) confirmed that samples are matured enough to generate liquid and gaseous hydrocarbon in coal. The coal samples also contain sufficient quantity of vitrinite and liptinite macerals varying from 70.28% to 74.10 wt%, which confirm the production of liquid hydrocarbon. The cross-plot between H/C and O/C atomic ratio indicates that samples were predominant in the bituminous rank and having kerogen Type III makes it suitable for hydrocarbon generation. Similar results were found in Rock-Eval pyrolysis analysis (Types II-III and Type III kerogen). The homohopane index (C35/C31 - C35) and homohopane ratio (C35αβS/C34αβS) range from 0.02 to 0.12 and 0.15 to 0.92 indicates oxic condition during organic matter deposition from Lafia-Obi samples. The Moretane/Hopane, Hopane/Hopane + Moretane, Ts/Ts + Tm, 22S/22S + 22RC32homohopane ratios range from 0.06 to 0.14; 0.88 to 0.94; 0.34 to 0.66; and 0.53 to 0.62 and 20S/20S+20R and αββ/αββ+ααα C29 ratios range from 0.43 to 0.58 and 0.42 to 0.55 indicate samples ar e within the late oil window/gas phase. Plots of 22S/22S+22R C32hopanes against C29αββ/αββ+ααα steranes show that Lafia-Obisamples are thermally mature.

GEOLOGY, SOURCE ROCKS AND HYDROCARBON GENERATION IN THE CLARENCE-MORETON BASIN

1982 ◽  
Vol 22 (1) ◽  
pp. 5
Author(s):  
A. R. Martin ◽  
J. D. Saxby
Keyword(s):  
Vitrinite Reflectance ◽  
Source Rocks ◽  
Geochemical Data ◽  
Hydrocarbon Potential ◽  
Hydrocarbon Generation ◽  
Tectonic Events ◽  
History Of ◽  
Rock Eval ◽  
Coal Measures ◽  
Migration Pathways

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.

Biomarker Geochemistry and Hydrocarbon Generation Potential of the Evaporites in Dongying Lacustrine Basin

2012 ◽  
Vol 616-618 ◽  
pp. 1042-1047
Author(s):  
Zhong Hong Chen
Keyword(s):  
Organic Matter ◽  
Hydrocarbon Generation ◽  
Lacustrine Basin ◽  
Hydrocarbon Generation Potential ◽  
Deep Wells ◽  
Generating Capacity ◽  
High Maturity ◽  
Different Response ◽  
Hydrocarbon Expulsion ◽  
Rock Eval

To investigate hydrocarbon potential of the evaporites, some deep wells such as Haoke-1 well and Fengshen-2 well were intensively cored, tested by TOC, Rock-Eval, and chromatography and mass spectrometry and evaluated using geochemistry of biomarker and hydrocarbon generation. High content of gammacerane and low Pr/Ph was exhibited in the evaporite system compared to the non-evaporite system. Different response of biomarkers parameters for the different sedimentary systems was exhibited, such as C19/(C19+C23) terpanes, C29/(C27+C28+C29) steranes, C24/C23 and C22/C21 tricyclic terpane. The evaporites and mud stones have the capacity to generate and expel hydrocarbons. The tested samples were mostly typeⅠand typeⅡ1 of organic matter, and their original generating capacity can reach 40 mg/g rock and 20 mg/g rock respectively. The efficiency of hydrocarbon expulsion reached 60%, but the distribution of organic matter and its generative potential was highly variable. In general, the mudstones show greater generative potential than the evaporites. High maturity severely reduced the capacity of their rocks to generate and expel petroleum.

scholarly journals Organic geochemistry and mineralogical characterization of the Paleocene Ranikot Formation shales in selected areas of Southern Indus Basin Pakistan.

2021 ◽  
Author(s):  
Hussain Asghar ◽  
◽  
Saeed Abbas ◽  
Muhammad S. Khan ◽  
Samina Jahandad ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Organic Geochemistry ◽  
Vitrinite Reflectance ◽  
Xrd Analysis ◽  
Indus Basin ◽  
Gas Chromatography Mass Spectrometry ◽  
Mineralogical Characterization ◽  
Type Iv ◽  
Rock Eval

Southern Indus Basin is one of the promising regions in Pakistan as a commercially producing oil and gas perspective. The current research presents the geochemical characterization of the Ranikot Formation shales from Southern Indus Basin based on total organic carbon (TOC), Rock-Eval (RE) pyrolysis, organic petrography, gas chromatography-mass spectrometry (GC-MS), and x-ray diffraction (XRD) analyses. The average TOC of Ranikot shale is 4.6 wt. %, indicating very good hydrocarbon potential. Types III/IV kerogens were identified in Ranikot shale. The maceral data also suggest that the Type of kerogen present in Ranikot shale is dominantly Types II-III, with the minor occurrence of Type IV. The vitrinite reflectance, pyrolysis Tmax and methylphenanthrene indices values specify immature levels of the shales. The normal alkane data reflect that marine macrophyte, algae, and land plants were contributed to the organic matter of Ranikot shales. Dibenzothiophene/phenanthrene ratio (0.11), phytane/n-C18 ratio (0.53), pyrite, and glauconite elucidate that the depositional environment of the Ranikot shale is marine. The XRD analysis of the shale from the Ranikot Formation revealed that it is brittle shale and dominated by 39.5 to 50.9 wt. % quartz. The present study, integration with the US EIA report demarcated the Ranikot Formation influential horizon as a shale gas resource.

scholarly journals THE ZONATION OF COAL RANK IN MUARA ENIM FORMATION BASED ON THE REFLECTION STUDY

2021 ◽  
Vol 56 (4) ◽  
pp. 484-490
Author(s):  
Irfan Marwanza ◽  
Chairul Nas ◽  
Masagus Ahmad Azizi ◽  
Riskaviana Kurniawati ◽  
Ardiansyah
Keyword(s):  
Vitrinite Reflectance ◽  
Volatile Matter ◽  
Plant Residue ◽  
Petrographic Analysis ◽  
Coal Rank ◽  
Anthracite Coal ◽  
Reflectance Analysis ◽  
Southwest Region ◽  
Physical Changes ◽  
Descriptive Method

Coal is a sedimentary rock containing approximately 50% to 70% carbon derived from the accumulation of plant residue that had undergone chemical and physical changes. In this research, the petrographic analysis method of coal was conducted based on the following parameters, measuring vitrinite reflectance (Ro%), estimation of moisture, volatile matter, and carbon-hydrogen content. This study aims to determine the zonation of coal rank through the vitrinite reflectance analysis in Maura Enim Formation. The samples observed were obtained from the Muara Enim Formation, which had undergone certain geological events to form lignite and anthracite coal ranks, then analyzed using the descriptive method. The results showed that the reflectance value of vitrinite was between 0.20% - 0.44%, which was utilized in the sorting of coal from lignite - sub-bituminous, according to ASTM D2798-06 (2006). Furthermore, in the Southwest region, coal is formed through greater pressure than those in the Northeast. Generally, the level of difference is caused by pressure, temperature, and time factor. Therefore, this study is recommended as a guideline in determining coal rank through vitrinite reflectance analysis in different formations.

scholarly journals Hydrocarbon Generation Potential of Chia Gara Formation in Three Selected Wells, Northern Iraq

2019 ◽  
Vol 11 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Wrya J. Mamaseni ◽  
Srood F Naqshabandi ◽  
Falah Kh. Al-Jaboury
Keyword(s):  
Organic Matter ◽  
Hydrocarbon Generation ◽  
Peak Oil ◽  
Low Oxygen ◽  
High Hydrogen ◽  
Northern Iraq ◽  
Average Value ◽  
Kerogen Type ◽  
Oil Generation ◽  
Rock Eval

Abstract In this study collected samples of Chia Gara Formation in Atrush, Shaikhan and Sarsang oilfields are used to geochemical characteristics of organic matter in this formation. This determination was based on Rock-Eval pyrolysis and Biomarker analyses. The Chia Gara Formation can be considered as good to excellent source rock; it’s TOC content ranges from 1.14-8.5wt% with an average of 1.85%, 3.91%, and 6.94% in Atush-1, Mangesh-1 and Shaikhan-8 wells respectively. The samples of Chia Gara Formation contain kerogen type II. These properties are considered optimal for oil generation. The low oxygen index (OI) and pristane/phytane (Pr/Ph) ratios (Average 20.73, 0.61 respectively) and high hydrogen index (HI) (average 637.6) indicate that the formation was deposited under anoxic condition. According to regular sterane (C27%, C28%, C29%) and terpanes ratios (C29/C30, C31/C30 hopane), the formation was deposited in marine environment. The average value of the Carbon Preference Index (CPI) is one with Tmax values of more than 430 ºC; these indicate peak oil window for the selected samples. Overall, the 20S/(20S+20R), ββ/(ββ+αα)C29 steranes and 22R/(22R+22S)C32homohopane, with Ts/ (Ts+Tm), and moretane/ hopane ratios point to a mature organic matter and to the ability of the formation to generate oil.

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