Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, China

The Majiagou Formation in the Fuxian area of the southeastern Ordos Basin has undergone a complex diagenetic evolution history under the influence of eustacy and the Caledonian karstification, resulting in several complex reservoir types. Through analyses of mineralogy, petrology, and reservoir geol...

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Main Authors: Ning Gu, Juntao Zhang, Xiaohui Jin, Jiaqi Yang, Fei Yang, Lu Liu
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2025-03-01
Series:Energy Geoscience
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666759224000738
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author Ning Gu
Juntao Zhang
Xiaohui Jin
Jiaqi Yang
Fei Yang
Lu Liu
author_facet Ning Gu
Juntao Zhang
Xiaohui Jin
Jiaqi Yang
Fei Yang
Lu Liu
author_sort Ning Gu
collection DOAJ
description The Majiagou Formation in the Fuxian area of the southeastern Ordos Basin has undergone a complex diagenetic evolution history under the influence of eustacy and the Caledonian karstification, resulting in several complex reservoir types. Through analyses of mineralogy, petrology, and reservoir geology, three major types of dolomite reservoirs with different genetic mechanisms, including anhydritic moldic-dissolved pore type, dolomitic intercrystalline-pore type, and fractured type were identified, and their formation mechanisms and distribution patterns were examined. The aphanocrystalline to very fine-crystalline anhydritic dolomite was resulted from Sabhak dolomitization, and is characterized by small size of crystals and high content of anhydrite. Dolomite reservoirs of anhydritic moldic-dissolved pore type were developed in multi-stage dissolution processes and mainly distributed at higher positions of the paleogeomorphology where the filling was weak. The very fine to fine-crystalline dolomite of shoal facies was formed under seepage-reflux dolomitization, and characterized by larger sizes of crystals and well-developed intercrystalline pores. Dolomite reservoirs of intercrystalline-pore type were mainly developed at the lower positions of the paleogeomorphology where bedding-parallel karst dissolution was strong. The fractured dolomite reservoirs, generated by the anhydrite swelling and karst cave collapse, occur in multiple horizons but within limited areas due to multi-stage fillings.
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institution Kabale University
issn 2666-7592
language English
publishDate 2025-03-01
publisher KeAi Communications Co., Ltd.
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series Energy Geoscience
spelling doaj-art-f33e287d7efa46989ed6f530c50bb36d2025-01-30T05:15:04ZengKeAi Communications Co., Ltd.Energy Geoscience2666-75922025-03-0161100358Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, ChinaNing Gu0Juntao Zhang1Xiaohui Jin2Jiaqi Yang3Fei Yang4Lu Liu5Petroleum Exploration and Production Research Institute, SINOPEC, Beijing, 102206, China; Corresponding author.Petroleum Exploration and Production Research Institute, SINOPEC, Beijing, 102206, ChinaPetroleum Exploration and Production Research Institute, SINOPEC, Beijing, 102206, ChinaPetroleum Exploration and Production Research Institute, SINOPEC, Beijing, 102206, ChinaHuabei Oil & Gas Branch, SINOPEC, Zhengzhou, Henan, 450000, ChinaHuabei Oil & Gas Branch, SINOPEC, Zhengzhou, Henan, 450000, ChinaThe Majiagou Formation in the Fuxian area of the southeastern Ordos Basin has undergone a complex diagenetic evolution history under the influence of eustacy and the Caledonian karstification, resulting in several complex reservoir types. Through analyses of mineralogy, petrology, and reservoir geology, three major types of dolomite reservoirs with different genetic mechanisms, including anhydritic moldic-dissolved pore type, dolomitic intercrystalline-pore type, and fractured type were identified, and their formation mechanisms and distribution patterns were examined. The aphanocrystalline to very fine-crystalline anhydritic dolomite was resulted from Sabhak dolomitization, and is characterized by small size of crystals and high content of anhydrite. Dolomite reservoirs of anhydritic moldic-dissolved pore type were developed in multi-stage dissolution processes and mainly distributed at higher positions of the paleogeomorphology where the filling was weak. The very fine to fine-crystalline dolomite of shoal facies was formed under seepage-reflux dolomitization, and characterized by larger sizes of crystals and well-developed intercrystalline pores. Dolomite reservoirs of intercrystalline-pore type were mainly developed at the lower positions of the paleogeomorphology where bedding-parallel karst dissolution was strong. The fractured dolomite reservoirs, generated by the anhydrite swelling and karst cave collapse, occur in multiple horizons but within limited areas due to multi-stage fillings.http://www.sciencedirect.com/science/article/pii/S2666759224000738Anhydritic moldic poreDolomiteMajiagou FormationFuxian areaOrdos Basin
spellingShingle Ning Gu
Juntao Zhang
Xiaohui Jin
Jiaqi Yang
Fei Yang
Lu Liu
Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, China
Energy Geoscience
Anhydritic moldic pore
Dolomite
Majiagou Formation
Fuxian area
Ordos Basin
title Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, China
title_full Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, China
title_fullStr Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, China
title_full_unstemmed Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, China
title_short Reservoir characteristics and distribution of the Majiagou Formation in the Fuxian area of Ordos Basin, China
title_sort reservoir characteristics and distribution of the majiagou formation in the fuxian area of ordos basin china
topic Anhydritic moldic pore
Dolomite
Majiagou Formation
Fuxian area
Ordos Basin
url http://www.sciencedirect.com/science/article/pii/S2666759224000738
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