Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos Basin

In recent years, significant progress has been made in exploring the Lower Paleozoic deep natural gas of the Qingyang paleo-uplift in the southwestern Ordos Basin. However, the reservoirs in this region are generally tight, and the formation mechanisms of high-quality reservoirs are complex, making...

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Main Authors: Zhaobing CHEN, Tianyi PANG, Zekun HAO, Wei SONG, Kerong YANG, Fengming MENG, Jianrong GAO, Chenyang DUAN
Format: Article
Language:zho
Published: Editorial Office of Petroleum Geology and Experiment 2025-05-01
Series:Shiyou shiyan dizhi
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Online Access:https://www.sysydz.net/cn/article/doi/10.11781/sysydz2025030490
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author Zhaobing CHEN
Tianyi PANG
Zekun HAO
Wei SONG
Kerong YANG
Fengming MENG
Jianrong GAO
Chenyang DUAN
author_facet Zhaobing CHEN
Tianyi PANG
Zekun HAO
Wei SONG
Kerong YANG
Fengming MENG
Jianrong GAO
Chenyang DUAN
author_sort Zhaobing CHEN
collection DOAJ
description In recent years, significant progress has been made in exploring the Lower Paleozoic deep natural gas of the Qingyang paleo-uplift in the southwestern Ordos Basin. However, the reservoirs in this region are generally tight, and the formation mechanisms of high-quality reservoirs are complex, making sweet spot prediction difficult. Based on drilling, logging, and seismic data, as well as experimental test data, this study analyzed the reservoir development types and main controlling factors of the gas-bearing layers, including the Cambrian Zhangxia Formation and Sanshanzi Formation, and the second and fourth members of the Ordovician Majiagou Formation (Ma 2 and Ma 4). A genesis model of the Lower Paleozoic reservoirs in the Qingyang paleo-uplift was established. Four types of reservoirs were developed in the region: dolomite reservoirs, shoal reservoirs, karst reservoirs (supergene karst and fault-karst reservoirs), and structural micro-fracture reservoirs. Among them, the Sanshanzi Formation as well as the Ma 2 and Ma 4 members mainly featured dolomite reservoirs, while shoal reservoirs dominated the Zhangxia Formation. Karst reservoirs and structural micro-fracture reservoirs were developed across all layers. The controlling effect of sedimentary facies belts, weathered crusts, and faults on the development of Lower Paleozoic reservoirs in the Qingyang paleo-uplift was significant. Sedimentary facies belts controlled the development of intergranular (dissolution) pores in shoals and intercrystalline (dissolution) pores in dolomite. Two phases of weathered crusts controlled the development of supergene karst reservoirs, with the weathered crusts at the top of the Ordovician being the most influential. Karst residual hills controlled the planar distribution of strong dissolution areas. The vertical dissolution intensity and gas content of reservoirs were closely related to their distance from the top of the weathered crust. Faults controlled the distribution of fault-karst reservoirs, and their associated micro-fractures effectively improved the reservoir properties. Based on these findings, four reservoir genesis models, including shoal-fault type, residual hill-fault type, dolomite-karst type, and dolomite-fault type, were established, providing insights into the exploration of the Lower Paleozoic natural gas in the Qingyang paleo-uplift.
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publisher Editorial Office of Petroleum Geology and Experiment
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spelling doaj-art-e0c46d5fb05a493cab7c149338d2855f2025-08-20T03:14:39ZzhoEditorial Office of Petroleum Geology and ExperimentShiyou shiyan dizhi1001-61122025-05-0147349050310.11781/sysydz2025030490sysydz-47-3-490Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos BasinZhaobing CHEN0Tianyi PANG1Zekun HAO2Wei SONG3Kerong YANG4Fengming MENG5Jianrong GAO6Chenyang DUAN7School of Earth Sciences and Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, ChinaSchool of Earth Sciences and Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, ChinaSchool of Petroleum Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaExploration Division of Yumen Oilfield Company, PetroChina, Jiuquan, Gansu 735019, ChinaNo.2 Gas Production Plant of Changqing Oilfield Company, PetroChina, Xi'an, Shaanxi 710200, ChinaResearch Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, ChinaSchool of Earth Sciences and Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, ChinaIn recent years, significant progress has been made in exploring the Lower Paleozoic deep natural gas of the Qingyang paleo-uplift in the southwestern Ordos Basin. However, the reservoirs in this region are generally tight, and the formation mechanisms of high-quality reservoirs are complex, making sweet spot prediction difficult. Based on drilling, logging, and seismic data, as well as experimental test data, this study analyzed the reservoir development types and main controlling factors of the gas-bearing layers, including the Cambrian Zhangxia Formation and Sanshanzi Formation, and the second and fourth members of the Ordovician Majiagou Formation (Ma 2 and Ma 4). A genesis model of the Lower Paleozoic reservoirs in the Qingyang paleo-uplift was established. Four types of reservoirs were developed in the region: dolomite reservoirs, shoal reservoirs, karst reservoirs (supergene karst and fault-karst reservoirs), and structural micro-fracture reservoirs. Among them, the Sanshanzi Formation as well as the Ma 2 and Ma 4 members mainly featured dolomite reservoirs, while shoal reservoirs dominated the Zhangxia Formation. Karst reservoirs and structural micro-fracture reservoirs were developed across all layers. The controlling effect of sedimentary facies belts, weathered crusts, and faults on the development of Lower Paleozoic reservoirs in the Qingyang paleo-uplift was significant. Sedimentary facies belts controlled the development of intergranular (dissolution) pores in shoals and intercrystalline (dissolution) pores in dolomite. Two phases of weathered crusts controlled the development of supergene karst reservoirs, with the weathered crusts at the top of the Ordovician being the most influential. Karst residual hills controlled the planar distribution of strong dissolution areas. The vertical dissolution intensity and gas content of reservoirs were closely related to their distance from the top of the weathered crust. Faults controlled the distribution of fault-karst reservoirs, and their associated micro-fractures effectively improved the reservoir properties. Based on these findings, four reservoir genesis models, including shoal-fault type, residual hill-fault type, dolomite-karst type, and dolomite-fault type, were established, providing insights into the exploration of the Lower Paleozoic natural gas in the Qingyang paleo-uplift.https://www.sysydz.net/cn/article/doi/10.11781/sysydz2025030490reservoir typesreservoir genesis modelslower paleozoicqingyang paleo-upliftordos basin
spellingShingle Zhaobing CHEN
Tianyi PANG
Zekun HAO
Wei SONG
Kerong YANG
Fengming MENG
Jianrong GAO
Chenyang DUAN
Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos Basin
Shiyou shiyan dizhi
reservoir types
reservoir genesis models
lower paleozoic
qingyang paleo-uplift
ordos basin
title Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos Basin
title_full Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos Basin
title_fullStr Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos Basin
title_full_unstemmed Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos Basin
title_short Main controlling factors and genesis models of reservoir development in Lower Paleozoic of Qingyang paleo-uplift, Ordos Basin
title_sort main controlling factors and genesis models of reservoir development in lower paleozoic of qingyang paleo uplift ordos basin
topic reservoir types
reservoir genesis models
lower paleozoic
qingyang paleo-uplift
ordos basin
url https://www.sysydz.net/cn/article/doi/10.11781/sysydz2025030490
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