scholarly journals Thermal and maturation history for Carboniferous source rocks in the Junggar Basin, Northwest China: implications for hydrocarbon exploration

2020 ◽  
Vol 17 (1) ◽  
pp. 36-50 ◽  
Author(s):  
Di Hu ◽  
Song Rao ◽  
Zhu-Ting Wang ◽  
Sheng-Biao Hu

AbstractThe reconstruction of thermal history is an important component of basin evolution and hydrocarbon exploration. Based on vitrinite reflectance data, we integrate the paleo-temperature gradient and paleo-heat flow methods to reconstruct the thermal history of Junggar Basin. Compared with present thermal state, the Junggar Basin experienced much a higher heat flow of ca. 80–120 mW/m2 during the Carboniferous. This feature can be attributed to large-scale volcanic events and related thermal effects. The hydrocarbon maturation history of Carboniferous source rocks indicates that the temperature rapidly reached the threshold of hydrocarbon generation during the Late Carboniferous and has never achieved such a high level since then. This characteristic resulted in the early maturation of hydrocarbons in Carboniferous source rocks. Meanwhile, the results reveal that hydrocarbon maturities are different among various tectonic units in Junggar Basin. The kerogen either rapidly broke through the dry gas period so that cracking of gas occurred or remained in the oil maturation window forming oil reservoirs, which depended on the tectonic background and depositional environment. In this study, we present the thermal and hydrocarbon maturation history since the Carboniferous, which has important implications for further hydrocarbon exploration in Junggar Basin.

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 733
Author(s):  
Dariusz Botor

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.


1987 ◽  
Vol 5 (4) ◽  
pp. 315-355 ◽  
Author(s):  
Song Cao ◽  
Ian Lerche

A one-dimensional, fluid flow/compaction model has been developed for petroleum explorationists to make quantitative studies of sedimentary basins. The following results can be obtained from the model: (1) basement subsidence (sediment load and tectonic effect); (2) structural evolution; (3) determination of erosion thickness of an unconformity; (4) changes of porosity, permeability, fluid flow rate and pore pressure with time and depth; (5) heat flow history; (6) temperature change with time and depth; (7) the value of thermal maturity indicators which change with time and depth; (8) hydrocarbon generation history including time and depth of peak hydrocarbon generation; and (9) prediction of possible directions of hydrocarbon migration and accumulation with time. The model is applicable to both frontier basins where only a few wells have been drilled and also to well-developed basins. The input data for the model are based mainly on commonly used geological and geochemical data from one well in a frontier basin or on similar data from many wells in a well-developed basin. Fifty-eight wells in the northern North Sea Basin have been used to reconstruct the geohistory, thermal history and hydrocarbon generation and migration history of the northern North Sea. The results accurately conformed to the well data, allowing determination of hydrocarbon generation amounts, migration times and accumulation sites, which are helpful for further hydrocarbon exploration in the northern North Sea Basin.


2021 ◽  
Vol 9 ◽  
Author(s):  
Yuchen Liu ◽  
Bo Liu ◽  
LiJuan Cheng ◽  
Jilin Xing ◽  
Shansi Tian ◽  
...  

A series of significant shale oil discoveries have been made recently in the Upper Cretaceous Qingshankou Formation in the Songliao Basin, providing a new resource target for shale oil exploration in Northeast China. In this context, an understanding of the tectonic-thermal evolution and maturation history of the Qingshankou Formation is of great significance for shale oil exploration and evaluation. In this study, the thermal history of the Qingshankou Formation since the Late Cretaceous was reconstructed using the paleothermal indicator method. The results indicate that two stages of thermal evolution exist in the southern part of the Songliao Basin: 1) the gradual heating stage during the Late Cretaceous; the heat flow gradually increases during this period and reaches a maximum heat flow value at the end of the Cretaceous. 2) The decline stage since the Neogene; the tectonic activity is relatively stable and the geothermal heat flow is gradually reduced, and the present-day heat flow ranges from 60.1 to 100.7 mW/m2, with an average of 78.2 mW/m2. In addition, the maturity history of the organic-rich shale was reconstructed based on the new thermal history. The Cretaceous Qingshankou shales underwent deep burial thermal metamorphism at the end of the Cretaceous, whereas thermal has faded since the Neogene. The hydrocarbon generation and migration since the Late Cretaceous period of K2qn1 were modeled based on the maturity model. Two main cooling events took place in the late Nenjiang period and the late Mingshui period in the Changling sag. These two tectonic events controlled the structural style and the formation of shale oil reservoirs in the southern Songliao Basin.


2018 ◽  
Vol 36 (5) ◽  
pp. 1229-1244
Author(s):  
Xiao-Rong Qu ◽  
Yan-Ming Zhu ◽  
Wu Li ◽  
Xin Tang ◽  
Han Zhang

The Huanghua Depression is located in the north-centre of Bohai Bay Basin, which is a rift basin developed in the Mesozoic over the basement of the Huabei Platform, China. Permo-Carboniferous source rocks were formed in the Huanghua Depression, which has experienced multiple complicated tectonic alterations with inhomogeneous uplift, deformation, buried depth and magma effect. As a result, the hydrocarbon generation evolution of Permo-Carboniferous source rocks was characterized by discontinuity and grading. On the basis of a detailed study on tectonic-burial history, the paper worked on the burial history, heating history and hydrocarbon generation history of Permo-Carboniferous source rocks in the Huanghua Depression combined with apatite fission track testing and fluid inclusion analyses using the EASY% Ro numerical simulation. The results revealed that their maturity evolved in stages with multiple hydrocarbon generations. In this paper, we clarified the tectonic episode, the strength of hydrocarbon generation and the time–spatial distribution of hydrocarbon regeneration. Finally, an important conclusion was made that the hydrocarbon regeneration of Permo-Carboniferous source rocks occurred in the Late Cenozoic and the subordinate depressions were brought forward as advantage zones for the depth exploration of Permo-Carboniferous oil and gas in the middle-northern part of the Huanghua Depression, Bohai Bay Basin, China.


2021 ◽  
Vol 2 (1) ◽  
pp. 38-43
Author(s):  
Elena A. Glukhova ◽  
Pavel I. Safronov ◽  
Lev M. Burshtein

The article presents the one-dimensional basin modeling performed in four wells to reconstruct the thermal history of deposits and reconstruct the effective values of the heat flow density.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Haiping Huang ◽  
Hong Zhang ◽  
Zheng Li ◽  
Mei Liu

To the accurate reconstruction of the hydrocarbon generation history in the Dongying Depression, Bohai Bay Basin, East China, core samples of the Eocene Shahejie Formation from 3 shale oil boreholes were analyzed using organic petrology and organic geochemistry methods. The shales are enriched in organic matter with good to excellent hydrocarbon generation potential. The maturity indicated by measured vitrinite reflectance (%Ro) falls in the range of 0.5–0.9% and increases with burial depth in each well. Changes in biomarker and aromatic hydrocarbon isomer distributions and biomarker concentrations are also unequivocally correlated with the thermal maturity of the source rocks. Maturity/depth relationships for hopanes, steranes, and aromatic hydrocarbons, constructed from core data indicate different well locations, have different thermal regimes. A systematic variability of maturity with geographical position along the depression has been illustrated, which is a dependence on the distance to the Tanlu Fault. Higher thermal gradient at the southern side of the Dongying Depression results in the same maturity level at shallower depth compared to the northern side. The significant regional thermal regime change from south to north in the Dongying Depression may exert an important impact on the timing of hydrocarbon maturation and expulsion at different locations. Different exploration strategies should be employed accordingly.


2021 ◽  
Author(s):  
Jennifer Spalding ◽  
Jeremy Powell ◽  
David Schneider ◽  
Karen Fallas

<p>Resolving the thermal history of sedimentary basins through geological time is essential when evaluating the maturity of source rocks within petroleum systems. Traditional methods used to estimate maximum burial temperatures in prospective sedimentary basin such as and vitrinite reflectance (%Ro) are unable to constrain the timing and duration of thermal events. In comparison, low-temperature thermochronology methods, such as apatite fission track thermochronology (AFT), can resolve detailed thermal histories within a temperature range corresponding to oil and gas generation. In the Peel Plateau of the Northwest Territories, Canada, Phanerozoic sedimentary strata exhibit oil-stained outcrops, gas seeps, and bitumen occurrences. Presently, the timing of hydrocarbon maturation events are poorly constrained, as a regional unconformity at the base of Cretaceous foreland basin strata indicates that underlying Devonian source rocks may have undergone a burial and unroofing event prior to the Cretaceous. Published organic thermal maturity values from wells within the study area range from 1.59 and 2.46 %Ro for Devonian strata and 0.54 and 1.83 %Ro within Lower Cretaceous strata. Herein, we have resolved the thermal history of the Peel Plateau through multi-kinetic AFT thermochronology. Three samples from Upper Devonian, Lower Cretaceous and Upper Cretaceous strata have pooled AFT ages of 61.0 ± 5.1 Ma, 59.5 ± 5.2 and 101.6 ± 6.7 Ma, respectively, and corresponding U-Pb ages of 497.4 ± 17.5 Ma (MSWD: 7.4), 353.5 ± 13.5 Ma (MSWD: 3.1) and 261.2 ± 8.5 Ma (MSWD: 5.9). All AFT data fail the χ<sup>2</sup> test, suggesting AFT ages do not comprise a single statistically significant population, whereas U-Pb ages reflect the pre-depositional history of the samples and are likely from various provenances. Apatite chemistry is known to control the temperature and rates at which fission tracks undergo thermal annealing. The r<sub>mro</sub> parameter uses grain specific chemistry to predict apatite’s kinetic behaviour and is used to identify kinetic populations within samples. Grain chemistry was measured via electron microprobe analysis to derive r<sub>mro</sub> values and each sample was separated into two kinetic populations that pass the χ<sup>2</sup> test: a less retentive population with ages ranging from 49.3 ± 9.3 Ma to 36.4 ± 4.7 Ma, and a more retentive population with ages ranging from 157.7 ± 19 Ma to 103.3 ± 11.8 Ma, with r<sub>mr0</sub> benchmarks ranging from 0.79 and 0.82. Thermal history models reveal Devonian strata reached maximum burial temperatures (~165°C-185°C) prior to late Paleozoic to Mesozoic unroofing, and reheated to lower temperatures (~75°C-110°C) in the Late Cretaceous to Paleogene. Both Cretaceous samples record maximum burial temperatures (75°C-95°C) also during the Late Cretaceous to Paleogene. These new data indicate that Devonian source rocks matured prior to deposition of Cretaceous strata and that subsequent burial and heating during the Cretaceous to Paleogene was limited to the low-temperature threshold of the oil window. Integrating multi-kinetic AFT data with traditional methods in petroleum geosciences can help unravel complex thermal histories of sedimentary basins. Applying these methods elsewhere can improve the characterisation of petroleum systems.</p>


Geology ◽  
2020 ◽  
Vol 48 (4) ◽  
pp. 374-378
Author(s):  
Miao Wang ◽  
Yong Chen ◽  
Wyatt M. Bain ◽  
Guoqi Song ◽  
Keyu Liu ◽  
...  

Abstract Fluid overpressures are widely expected during hydrocarbon generation and expulsion from source rocks, yet direct evidence for this phenomenon is lacking in the case of organic-rich shales. Here we show that formation of bed-parallel fibrous calcite veins in mature laminated organic-rich shales in the Eocene Dongying depression, Bohai Bay Basin, east China, occurred in direct response to fluid overpressure due to hydrocarbon generation. The evidence for overpressure is recorded by coexisting primary aqueous and petroleum inclusions in the calcite fibers. Our results show that all analyzed fluid-inclusion assemblages record variable degrees of overpressure during vein dilation, ranging from only modestly in excess of hydrostatic, to approaching and perhaps exceeding lithostatic. Thus, our results indicate that fluid pressures during dilation of horizontal veins are not necessarily equal to the opposing force of overburden throughout the history of opening. This suggests that at least some of the vein dilation is accommodated by concomitant narrowing of the adjacent wall-rock laminae, likely by scavenging (dissolution and reprecipitation) of CaCO3 from the adjacent wall rock.


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