Abstract
Recently, numerous gas fields have been discovered in deep basins worldwide. However, the geochemistry of the produced water has been poorly studied. Here, we present the chemical and isotopic compositions of water produced from the deep (4–7 km) Bozhi–Dabei (BD) gas field, Tarim Basin, China. The data indicate that the produced water is a mixture of formation water and water condensed from gas. The latter of which has contents of lower total dissolved solids (TDS), different ionic compositions and more negative δD and δ18O values than that of formation water. The formation water in the Lower Cretaceous sandstone reservoirs consists mainly of meteoric water that was strongly affected by the dissolution of Paleogene halite, forming a regional seal. Meteoric water infiltrated the Kumugeliemu halite during the Kangcun–Kuqa stage (16.3–1.64 Ma, Middle Miocene–Late Pliocene interval). A smaller portion of the formation water consists of iodine-rich evaporated seawater that migrated together with gas from transgression-influenced layers in Triassic–Jurassic source rocks. Using the 129I dating model, different episodes of this migration in the Dabei (DB) East District were recognized, although the dating results were not precise. This study enhances our understanding of the migration and accumulation processes of formation water and natural gas in deep basins and suggests that the chemical and isotopic composition of formation water can be used together with that of gas to constrain the sources and accumulation processes of deeply buried gas.
Data availability
All data generated or analyzed during this study are included in this published article and its Supplementary Information files.
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Acknowledgements
We are grateful to Chen Naidong, Chen Chengshen, and Wang Jingchen for their assistance with sample collection and chemical analysis.
Funding
This study was financially supported by the National Natural Science Foundation of China (grant nos. 42125304 and 42573026). Theory of hydrocarbon enrichment under multisphere interactions of the Earth (THEMSIE04010104), and the State Key Laboratory of Organic Geochemistry (SKLOG2024-03). This is contribution No.is-3761 from GIGCAS.
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J.C. wrote the main manuscript text. Y.F., N.C. and J.X. conducted the experimental work. J.C. and Y.F. analyzed the results. H.Z. and T.M. provided the geological information of Bozi-Dabei gas field. W.J. and Y.W. improved the paper’s structure and language. H.Z., T.M., X.H. and P.P. revised the manuscript. All authors reviewed the manuscript.
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Chen, J., Fan, Y., Jia, W. et al. Water geochemistry in the Bozhi-Dabei area, Tarim Basin and its implications for natural gas accumulation in deep basin. Sci Rep (2026). https://doi.org/10.1038/s41598-026-38393-y
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DOI: https://doi.org/10.1038/s41598-026-38393-y
