U-Pb dating of oil charge in superimposed basins: A case study from the Tarim Basin, NW China

Chen, Jiaxu; Guo, Xiaowen; Tao, Ze; Cao, Z.; Wang, Bin; Zhang, Xuyou; Hao, Xinyue; Zhao, Jian‐xin

doi:10.1130/b36324.1

Cited by 11 publications

(2 citation statements)

References 44 publications

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“…Fluid inclusion analysis can also provide some constrains for thermal evolution history. Aqueous inclusions in calcite/dolomite tend to re‐equilibrate when heated to temperatures higher than those of initial entrapment, and therefore some homogenization temperatures may record a temperature close to the maximum reached by the rock (Barker & Goldstein, 1990; Chen et al, 2022; Guo et al, 2012). The maximum homogenization temperatures of aqueous inclusions in Sinian dolomite cement of the eastern and central Sichuan Basin were 250 and 224°C, respectively (Figure 7b).…”

Section: Discussionmentioning

confidence: 99%

Maturity assessment of solid bitumen in the Sinian carbonate reservoirs of the eastern and central Sichuan Basin, China: Application for hydrocarbon generation modelling

Chen

Guo

et al. 2022

Geological Journal

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Maturity assessment of solid bitumen is significant for the reconstruction of the thermal evolution history and obtaining the key periods of hydrocarbon generation for the Qiongzhusi source rocks in the eastern and central Sichuan Basin because of the absence of vitrinite in the marine mudstones. Based on the Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy analyses of solid bitumen, the thermal maturity of solid bitumen in the Sinian reservoir was evaluated, which was used to calibrate the thermal maturation history modelling results of the Qiongzhusi source rocks. The FTIR spectrums of solid bitumen are characterized by depleted aliphatic carbon and C O group, and enrichment of aromatic carbon, which indicates that the vitrinite reflectance equivalent (VR eq ) values of solid bitumen in the Sichuan Basin exceed at least 1.3%. The calculated VR eq values of solid bitumen inferred by Raman spectroscopy analysis are 3.8%-4.09% and 3.51%-3.77% in the eastern and central Sichuan Basin, respectively. The calculated VR eq values of bitumen in fluorite and calcite inclusions of the central Sichuan Basin vary from 3.54% to 3.64%. The thermal evolution history of the Qiongzhusi source rocks can be divided into two heating-cooling stages. At the end of the second heating stage, which is the Late Cretaceous, the Qiongzhusi source rocks reached the highest temperature of 250 and 225 C in the eastern and central Sichuan Basin, respectively. The different burial and thermal history of the Qiongzhusi source rocks controls their key periods of hydrocarbon generation in the eastern and central Sichuan Basin. Two episodes of intense oil generation of the Qiongzhusi source rocks were determined at 440-380 Ma and 290-260 Ma, and one phase of gas generation from oil cracking was from 260 to 85 Ma in the eastern Sichuan Basin. The intense oil generation of the Qiongzhusi source rocks occurred at 240-185 Ma and the oil cracking phase was from 185 to 90 Ma in the central Sichuan Basin.

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Section: Discussionmentioning

confidence: 99%

Maturity assessment of solid bitumen in the Sinian carbonate reservoirs of the eastern and central Sichuan Basin, China: Application for hydrocarbon generation modelling

Chen

Guo

et al. 2022

Geological Journal

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“…In recent years, Primary fluid inclusions trapped in cavity cement have been widely used to track the geological fluid charging history of the reservoir and can provide a direct record of the properties of the original geological fluids present at the time of trapping (Bodnar et al, 2014;Liu et al, 2020;Song et al, 2023), and in situ U-Pb dating on carbonates via laserablation inductively coupled-plasma mass spectrometry (LA-ICP-MS) can determine absolute ages of filled mineral in the reservoir, even if the mineral has a low uranium content (Roberts et al, 2020;Chen et al, 2022;Roberts and Robert, 2022), this provides an opportunity to apply fluid inclusion and U-Pb dating to decipher the timing of the diagenetic history of carbonate reservoir rocks. Herein, We apply LA-ICP-MS U-Pb dating and fluid geochemistry, combined with routine petrography, cathode luminescence.…”

Section: Introductionmentioning

confidence: 99%

Three-stage hydrocarbon accumulations in the Middle Permian in the Central Sichuan Basin

Zhang,

Liao,

et al. 2024

Front. Earth Sci.

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The Middle Permain Maokou Formation (P2m) is a new region of natural gas exploration in the Sichuan Basin, is characterized by bioclastic limestone with localized dolomitization, and karst fractured-vuggy reservoirs. Currently, on the gas source, hydrocarbon accumulation process and control factors in the Sichuan Basin during the Permian are lacking. To bridge this gap, herein, we identified the filling sequence minerals inside the pores/vugs, along with the oil charge of the Maokou Formation using drill cores, thin sections, oil inclusion analysis, and U-Pb dating of calcite cements. The results showed that the reservoir space of the Maokou Formation was predominated by the residual dissolved pores/vugs, fractures, and dissolved fractures. The pores/vugs underwent four stages of mineral filling by very fine-fine (-crystalline, CC1) calcite → fine-medium calcite (CC2: from 256.4 ± 1.7 to 244.1 ± 6.3 Ma) → fibrous calcite (FC; ∼183.9 ± 8.2 Ma) → coarse-macro calcite (CC3; ∼171.5 ± 5.3 Ma). Combined with the homogenization temperature and salty of fluid inclusion, we considered that three stages of oil charge were present in the Maokou Formation reservoirs. The first stage involved the formation of paleo-oil reservoirs during the Late Permian to Early Triassic, corresponding to the high-maturity aqueous inclusions in CC2, with a homogenization temperature of 106.7°C–137.8°C. At that time, the oil generation from the Lower Cambrian Qiongzhusi Formation rocks peaked, and the generated hydrocarbons migrated upward into the Maokou Formation through the strike-slip faults in the basin center. The second stage involved the formation of paleo-oil reservoirs during the Early Jurassic. The Permian source rocks reached the oil generation window with hydrocarbon expulsion, which was consistent with the oil inclusions in FC. The third stage involved the formation of paleo-gas reservoirs during the Middle Jurassic to Early Cretaceous, corresponding to the high-density methane inclusions and bitumen inclusions occurring in CC3, with the homogenization temperature peaking at 151.9°C–178°C. The natural gas in the Middle Permian of the Central Sichuan Basin is predominantly sourced from the Lower Cambrian Qiongzhusi Formation mudstone and partially from the source rocks of the Middle Permian, indicating a significant source-reservoir conduit of the strike-slip faults in the basin center. The findings provide considerable baseline data to advance further research in the Sichuan Basin.

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Differential evolution of pore fluid pressure in the Sinian carbonate reservoirs of the central and eastern Sichuan Basin, China: Implication for gas preservation and destruction

Chen,

et al. 2024

Geological Journal

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Trillions of cubic meters of gas reserve have been found in the Sinian Dengying carbonate reservoirs with normal pressure in the central Sichuan Basin, while no industrial gas reservoir have been detected in the Sinian Dengying reservoir with normal pressure in the eastern Sichuan Basin. The pore fluid pressure of gas reservoir is usually closely related to total gas content. To investigate the pore fluid pressure evolution and its implication for gas reserve preservation in the Sinian Dengying reservoir of the central and eastern Sichuan Basin, we conducted a comprehensive analysis including fluid inclusion petrography, microthermometry and Raman spectroscopy. The timings of gas inclusions captured in the central and eastern Sichuan Basin occurred from 175 to 92 Ma and 191 to 183 Ma, respectively. The presence of two‐phase vapour‐solid bitumen inclusions with similar phase proportions in a single fluid inclusion assemblage of fluorite provides direct evidence of in situ oil cracking to gas. The widespread solid bitumen from the Sinian Dengying reservoir in the central Sichuan Basin indicates the existence of massive oil cracking, which results in the formation of overpressure in the reservoir. Pore fluid pressure evolution of the Sinian Dengying reservoir of the central Sichuan Basin experiences normal pressure stage (200–155 Ma), overpressure development stage (155–90 Ma) and overpressure release stage (90–0 Ma). The maximum pore fluid pressure and its corresponding pressure coefficient of the Sinian Dengying reservoir of the central Sichuan Basin are approximately 141.4 MPa and 1.95, respectively. The overpressure development stage reflects the processes of oil cracking and gas accumulation, and the overpressure release stage reflects the dissipation of some natural gas in the Sinian Dengying reservoir of the central Sichuan Basin. The pore fluid pressure of the Sinian Dengying reservoir in the eastern Sichuan Basin has maintained at normal pressure since 200 Ma, indicating that the gas reservoir was small during the oil cracking stage and natural gas completely leaked due to tectonic uplift.

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U-Pb dating of oil charge in superimposed basins: A case study from the Tarim Basin, NW China

Cited by 11 publications

References 44 publications

Maturity assessment of solid bitumen in the Sinian carbonate reservoirs of the eastern and central Sichuan Basin, China: Application for hydrocarbon generation modelling

Maturity assessment of solid bitumen in the Sinian carbonate reservoirs of the eastern and central Sichuan Basin, China: Application for hydrocarbon generation modelling

Three-stage hydrocarbon accumulations in the Middle Permian in the Central Sichuan Basin

Differential evolution of pore fluid pressure in the Sinian carbonate reservoirs of the central and eastern Sichuan Basin, China: Implication for gas preservation and destruction

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