Controls of Late Jurassic-Early Cretaceous tectonic event on source rocks and seals in marine sequences, South China

Jin, Zhijun; Yuan, Yusong; Liu, Quanyou; Yujin, Wo

doi:10.1007/s11430-012-4494-0

Cited by 26 publications

(11 citation statements)

References 6 publications

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“…Giving these details, a simple model was set to state the uplifting and denudation process since Late Cretaceous from the eastern to the western Sichuan Basin (Figure ). It has been suggested that the uplifting and denudation of the eastern Sichuan Basin were a result of progressive north‐westward propagation of the Yanshanian intracontinental deformation in southern China due to the compression between the Kula–Pacific Plate and the Eurasian Plate (Jin, et al, ; Wang et al, ; Yan et al, ; Yuan et al, ) and of the south‐westward thrust‐nappe tectonics from Dabashan intracontinental deformation (Shi et al, ). As shown in Figure , when the eastern Sichuan Basin started to uplift and undergo deformation at ~100 Ma, there was still a depression in the western Sichuan depression (also called Longmen mountain foreland basin) and accepted deposits (Figure a), till the Cenozoic uplifting started (Figure b) due to the Late Cretaceous to Cenozoic compressional event in the Longmen mountain fold‐thrust belt caused by the collision between India Plate and Eurasia Plate (Yan et al, ; Yuan et al, ).…”

Section: Discussionmentioning

confidence: 99%

Constraining the denudation process in the eastern Sichuan Basin, China using low‐temperature thermochronology and vitrinite reflectance data

et al. 2018

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The temperature history of samples and maximum palaeogeothermal profiles of boreholes were reconstructed based on low-temperature thermochronology and vitrinite reflectance data, and the results provide limits for the timescale and amount of uplift-denudation of the eastern Sichuan Basin. The thermal history showed that the uplifting and cooling of eastern Sichuan Basin began around the Late Cretaceous (approximately 100-80 Ma). The region had experienced a continuous cooling process from the Late Cretaceous until the present, with the geothermal gradient decreasing from 32-36°C/km to 20-23°C/km. The amount of denudation at the Puguang region in north-eastern Sichuan was approximately 2.3 km, whereas that at south-eastern Sichuan was 1.9 km, and the erosion thickness in the eastern Sichuan fold belt that was revealed via the field samples is 2.3 ± 0.3-2.6 ± 0.3 km. The north-eastern Sichuan experienced sustained cooling with inconspicuous fluctuations, whereas the thrust belt and the south-eastern Sichuan Basin presented 2-4 stages with different cooling rates. It may indicate that the eastern Sichuan fold belt experienced a complex structural evolution, characterized by episodic upliftings and deformations since Late Cretaceous, while a different and gentle deformation took place in the northeastern Sichuan Basin.

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Section: Discussionmentioning

confidence: 99%

Constraining the denudation process in the eastern Sichuan Basin, China using low‐temperature thermochronology and vitrinite reflectance data

et al. 2018

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“…These dolomites became crucial for petroleum accumulation in the Proterozoic Dengying Formation (Figure 1), as demonstrated by widespread bitumen and proven gas reserves of 408:61 × 108 m 3 (1.5 tcf) and 4,403:8 × 108 m 3 (15.6 tcf) in the Weiyuan and Anyue gas fields, respectively [25]. During the Mesozoic to Cenozoic periods, this area experienced several phases of tectonic movement, including the Caledonian, Indosinian, and Yashanian movements [33,34]. The Caledonian tectonic phase in this region resulted in erosion of most of the upper Silurian, Devonian, and Carboniferous strata across the South China Block.…”

Section: Geological Settingmentioning

confidence: 99%

Pore Preservation and Failure Mechanism of Sinian Dengying Formation Carbonate Reservoirs: A Case Study of Two Ultradeep Wells in the Sichuan Basin, Western China

Sun

Liu

et al. 2021

Geofluids

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Despite being one of the most important factors in deep oil and gas exploration, the preservation mechanisms of ultradeep carbonate reservoirs remain poorly understood. This study performed thin-section, geochemistry, field emission scanning electron microscopy, fluid inclusion, and basin model analysis of samples from two boreholes over 8,000 m deep in the Sichuan Basin to determine the pore features and preservation mechanism of the Sinian (Ediacaran) Dengying Formation carbonate reservoirs. The reservoir of CS well #1 is characterised by pore diameters larger than a centimetre (average porosity 7.48%; permeability 0.8562 mD), and the pores are mainly filled with dolomite or bitumen. In contrast, the reservoir of MS well #1 is predominantly composed of micron-scale residual pores (average porosity 1.74%; permeability 0.0072 mD), and the pores are typically filled with dolomite, bitumen, and multistage quartz. The burial thermal histories suggest that both reservoirs were subjected to high pressure (i.e., pressure coefficient > 1.5 ) before the Late Cretaceous. However, the pressure coefficient of the reservoir of MS well #1 has decreased to less than 1.0 owing to strong structural adjustment this well since the Late Cretaceous, which allowed other ore-forming fluids to enter and fill the pores, resulting in further compaction of the pores. In contrast, the pressure coefficient of CS well #1 is 1.1–1.2, which effectively prevented other ore-forming fluids from entering and filling the pores. The findings show that the dynamic adjustment of the Dengying Formation palaeo-gas reservoir indirectly affects the preservation or failure of the reservoir. The occurrence and geometry of bitumen in the Dengying reservoir exhibit good consistency with the pressure changes in both boreholes. In particular, bitumen with an annular shape and contraction joints in reservoir pores is widespread in CS well #1, which is attributed to the continuous preservation of palaeo-gas fields. Conversely, bitumen with a broken particle shape is located among the epigenetic minerals widespread in MS well #1, which is attributed to failure and depletion of the palaeo-gas fields.

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“…During the periods of largest gas generation, OM pore formation, seal formation of direct cap rocks overlapped and formed a strong matching for shale gas accumulation and preservation in the Wufeng and Longmaxi Formations (Figures 7 and 11). Meanwhile, the regional seal of the Lower Triassic gypsum layer was formed during the Late Jurassic-Early Cretaceous [74], before the periods of greatest gas generation and OM pore formation.…”

Section: Source and Seal Evolutionmentioning

confidence: 99%

Coevolutionary Dynamics of Organic-Inorganic Interactions, Hydrocarbon Generation, and Shale Gas Reservoir Preservation: A Case Study from the Upper Ordovician Wufeng and Lower Silurian Longmaxi Formations, Fuling Shale Gas Field, Eastern Sichuan Basin

et al. 2020

Self Cite

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Shale gas deposits are self-sourced, self-accumulating, and self-preserving in the Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation of the Fuling Shale Gas Field in the eastern Sichuan Basin. They were both seemingly mixed by secondary oil cracking and kerogen cracking gases during the high maturation window. The reservoir space primarily consists of mineral pores and organic matter (OM) pores, and the shale gas was mainly trapped by a high-pressure system. In this study, the Fuling O3w-S1l Shale Gas Field in the eastern Sichuan Basin was used as a case study to discuss the coevolutionary process and organic-inorganic interactions of hydrocarbon generation, accumulation, and preservation. The results indicate that the processes and mechanisms of organic-inorganic interactions and coevolution of hydrocarbon generation and reservoir preservation are quite different among the shale graptolite zones (GZ) with respect to hydrocarbon generation, types and characteristics of shale gas reservoirs, seal characteristics, and their spatiotemporal relations. In the WF2-LM4 GZ, the favorable OM, biogenic authigenic quartz and organic-inorganic interactions are highly coupled, leading to the high level of coevolution demonstrated within the field, as well as to the favorable conditions for shale gas accumulation. Conversely, the overlying LM5-LM8 GZ seemingly exhibits early densification and late charge and has a reverse mode of reservoir development (i.e., low degree of coevolution). These two coevolutionary processes were conducive to the development of a high degree of spatiotemporal matching between the reservoir (i.e., WF2-LM4 GZ) and the seal (i.e., LM5-LM8 GZ). This is due to underlying differences in their coevolutionary histories. The synthetic work presented here on the coevolutionary processes and mechanisms of formation for organic-inorganic interactions and hydrocarbon generation and reservoir preservation reveals insights into the driving mechanisms of shale gas enrichment, providing a basis for effectively predicting favorable enrichment intervals for shale gas worldwide.

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Controls of Late Jurassic-Early Cretaceous tectonic event on source rocks and seals in marine sequences, South China

Cited by 26 publications

References 6 publications

Constraining the denudation process in the eastern Sichuan Basin, China using low‐temperature thermochronology and vitrinite reflectance data

Constraining the denudation process in the eastern Sichuan Basin, China using low‐temperature thermochronology and vitrinite reflectance data

Pore Preservation and Failure Mechanism of Sinian Dengying Formation Carbonate Reservoirs: A Case Study of Two Ultradeep Wells in the Sichuan Basin, Western China

Coevolutionary Dynamics of Organic-Inorganic Interactions, Hydrocarbon Generation, and Shale Gas Reservoir Preservation: A Case Study from the Upper Ordovician Wufeng and Lower Silurian Longmaxi Formations, Fuling Shale Gas Field, Eastern Sichuan Basin

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