Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China
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 organi...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2017-01-01
|
| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2017/8681753 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832555833625411584 |
|---|---|
| author | Jin Lai Guiwen Wang Jing Chen Shuchen Wang Zhenglong Zhou Xuqiang Fan |
| author_facet | Jin Lai Guiwen Wang Jing Chen Shuchen Wang Zhenglong Zhou Xuqiang Fan |
| author_sort | Jin Lai |
| collection | DOAJ |
| description | 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. |
| format | Article |
| id | doaj-art-a48459a5e21847e7999bb39d17b613d3 |
| institution | Kabale University |
| issn | 1468-8115 1468-8123 |
| language | English |
| publishDate | 2017-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geofluids |
| spelling | doaj-art-a48459a5e21847e7999bb39d17b613d32025-02-03T05:47:06ZengWileyGeofluids1468-81151468-81232017-01-01201710.1155/2017/86817538681753Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, ChinaJin Lai0Guiwen Wang1Jing Chen2Shuchen Wang3Zhenglong Zhou4Xuqiang Fan5College of Geosciences, China University of Petroleum, Beijing 102249, ChinaCollege of Geosciences, China University of Petroleum, Beijing 102249, ChinaCollege of Geosciences, China University of Petroleum, Beijing 102249, ChinaCollege of Geosciences, China University of Petroleum, Beijing 102249, ChinaCollege of Geosciences, China University of Petroleum, Beijing 102249, ChinaCollege of Geosciences, China University of Petroleum, Beijing 102249, ChinaTwo 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.http://dx.doi.org/10.1155/2017/8681753 |
| spellingShingle | Jin Lai Guiwen Wang Jing Chen Shuchen Wang Zhenglong Zhou Xuqiang Fan Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China Geofluids |
| title | Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China |
| title_full | Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China |
| title_fullStr | Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China |
| title_full_unstemmed | Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China |
| title_short | Origin and Distribution of Carbonate Cement in Tight Sandstones: The Upper Triassic Yanchang Formation Chang 8 Oil Layer in West Ordos Basin, China |
| title_sort | origin and distribution of carbonate cement in tight sandstones the upper triassic yanchang formation chang 8 oil layer in west ordos basin china |
| url | http://dx.doi.org/10.1155/2017/8681753 |
| work_keys_str_mv | AT jinlai originanddistributionofcarbonatecementintightsandstonestheuppertriassicyanchangformationchang8oillayerinwestordosbasinchina AT guiwenwang originanddistributionofcarbonatecementintightsandstonestheuppertriassicyanchangformationchang8oillayerinwestordosbasinchina AT jingchen originanddistributionofcarbonatecementintightsandstonestheuppertriassicyanchangformationchang8oillayerinwestordosbasinchina AT shuchenwang originanddistributionofcarbonatecementintightsandstonestheuppertriassicyanchangformationchang8oillayerinwestordosbasinchina AT zhenglongzhou originanddistributionofcarbonatecementintightsandstonestheuppertriassicyanchangformationchang8oillayerinwestordosbasinchina AT xuqiangfan originanddistributionofcarbonatecementintightsandstonestheuppertriassicyanchangformationchang8oillayerinwestordosbasinchina |