Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China

Joint Authors

Lai, Jin
Wang, Guiwen
Chen, Jing
Wang, Shuchen
Zhou, Zhenglong
Fan, Xuqiang

Source

Geofluids

Issue

Vol. 2017, Issue 2017 (31 Dec. 2017), pp.1-13, 13 p.

Publisher

Hindawi Publishing Corporation

Publication Date

2017-07-30

Country of Publication

Egypt

No. of Pages

13

Main Subjects

Physics

Abstract EN

Two generations of carbonate cement as Type I (microcrystalline calcite and dolomite) and Type II (mainly Fe-calcite and Fe-dolomite) are recognized in Chang 8 sandstones, Ordos basin.

Carbonate cement in Chang 8 sandstones is closely related to the dissolved carbon from thermal maturation of organic matters.

Carbonate cement in the loosely packed framework grains precipitated shortly after deposition, and late-stage ferroan calcite and ferroan dolomite formed with progressive burial.

The early diagenetic carbonate cement is partially to completely replaced by late-stage ferroan calcite and ferroan dolomite.

Carbonate cement is much more commonly observed in sand bodies adjacent to Chang 7 source rocks.

With increasing distance from the Chang 7 oil layers, the carbonate cement content gradually decreases.

However, some tight carbonate cemented zones also occur at the sandstone-mudstone interfaces.

Dissolution of Ca-feldspars by organic acids-rich fluids, together with clay mineral transformations such as illitization of smectite, would provide Ca2+ and Mg2+ ions for carbonate cementation.

Organic acids and CO2 rich fluids would charge into the reservoirs with the hydrocarbons, and when the CO2 and acids were buffered by the framework grain dissolution, carbonate cement would precipitate with a decrease in CO2 concentration.

American Psychological Association (APA)

Lai, Jin& Wang, Guiwen& Chen, Jing& Wang, Shuchen& Zhou, Zhenglong& Fan, Xuqiang. 2017. Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China. Geofluids،Vol. 2017, no. 2017, pp.1-13.
https://search.emarefa.net/detail/BIM-1155901

Modern Language Association (MLA)

Lai, Jin…[et al.]. Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China. Geofluids No. 2017 (2017), pp.1-13.
https://search.emarefa.net/detail/BIM-1155901

American Medical Association (AMA)

Lai, Jin& Wang, Guiwen& Chen, Jing& Wang, Shuchen& Zhou, Zhenglong& Fan, Xuqiang. Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China. Geofluids. 2017. Vol. 2017, no. 2017, pp.1-13.
https://search.emarefa.net/detail/BIM-1155901

Data Type

Journal Articles

Language

English

Notes

Includes bibliographical references

Record ID

BIM-1155901