Rare earth elements (REEs) geochemistry of Sinian-Cambrian reservoir solid bitumens in Sichuan Basin, SW China: potential application to petroleum exploration

Shale contains a large number of nanopores. The nanopores control the reservoir structure. The formation of nanopores in shale is closely related to the sedimentary environment. The palaeosedimentary structural background determines the provenance and sedimentary diagenesis of mud shale during shale deposition, refines the palaeo-shale and palaeo-sedimentary-tectonic environments of the Longmaxi Formation in the southern Sichuan Basin by elemental geochemical means, and determines the palaeo-deposition of the Longmaxi Formation. The tectonic setting and a numerical simulation method are used to explore the sedimentary tectonic evolution characteristics of the Longmaxi Formation. The results show that the parent rock of the Longmaxi Formation is relatively enriched with light rare earth elements, and the distribution of heavy rare earth elements is relatively stable. The vertical direction shows a trend of increasing from the bottom of the formation to the top of the formation, showing a mixed genesis; the tectonic setting is a passive continental margin, and the active continental margin is the main margin.

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Molecular markers, carbon isotopes, and rare earth elements of highly mature reservoir pyrobitumens from Sichuan Basin, southwestern China: Implications for PreCambrian-Lower Cambrian petroleum systems

Precambrian Research ◽

10.1016/j.precamres.2018.08.005 ◽

2018 ◽

Vol 317 ◽

pp. 33-56 ◽

Cited By ~ 13

Author(s):

Zhonghong Chen ◽

Bernd R.T. Simoneit ◽

T.-G. Wang ◽

Zhiyong Ni ◽

Guanghui Yuan ◽

...

Keyword(s):

Rare Earth ◽

Molecular Markers ◽

Rare Earth Elements ◽

Carbon Isotopes ◽

Lower Cambrian ◽

Sichuan Basin ◽

Southwestern China ◽

Petroleum Systems

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Genesis of the Xifeng Low-Temperature Geothermal Field, Guizhou, SW China: Constrains From Geology, Element Geochemistry, and D-O Isotopes

Frontiers in Earth Science ◽

10.3389/feart.2021.782943 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yanyan Li ◽

Ji Dor ◽

Chengjiang Zhang ◽

Guiling Wang ◽

Baojian Zhang ◽

...

Keyword(s):

Rare Earth ◽

Low Temperature ◽

Rare Earth Elements ◽

Meteoric Water ◽

Hot Springs ◽

Geothermal Field ◽

Frictional Heat ◽

Geothermal System ◽

Sw China ◽

Deep Circulation

The Xifeng geothermal field is located in the Yangtze Craton, SW China, and is one of the most representative low-temperature geothermal fields in China. Widespread thermal anomalies, hot springs, and geothermal wells have been reported by previous studies. However, the nature and forming mechanisms of the field remain poorly understood. Element geochemical (ions, rare earth elements) and stable isotopic (D, O) composition of hot springs, geothermal fluids, rivers, and cold springs from different locations of the Xifeng geothermal field were analyzed in this study. The ions studies revealed that most samples featured the Ca-Mg-HCO3 type, except Xifeng hot springs, and which were characterized by the Ca-Mg-HCO3-SO4 type. Based on quartz geothermometers, the estimated reservoir temperature was 77°C. The results of stable isotopes (D, O) manifest that the Xifeng geothermal system was recharged by meteoric water at an elevation of 1,583 m from SW to NE. The research of rare earth elements (REE) revealed that their accumulation characteristics and obvious positive Eu anomaly were inherited from host feldspar-bearing reservoir dolomites through water-rock interactions. Combined with these observations, geological setting, and previous studies, it was concluded that the formation of the Xifeng geothermal field resulted from recharge, deep circulation, and secondary rising of the meteoric water along the faults. First, meteoric water infiltrated to depth through faults and crack zones. Second, the deep-infiltrated water was heated by radioactive heat, deep heat, and tectonic frictional heat. Finally, as the warmed-up waters underwent considerable deep circulation in the reservoir, it rose again along the main faults, and mixed with groundwater near the surface. Taken together, we suggest that the Xifeng geothermal system should be assigned as a faults-controlling, and deeply circulating meteoric water of low-temperature category.

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