Formation and preservation of ultra-deep high-quality dolomite reservoirs under the coupling of sedimentation and diagenesis in the central Tarim Basin, NW China

Wang, Ping; Wang, Guangwei; Chen, Yong Q.; Hao, Fang; Yang, Xianzhang; Hu, Fangjie; Zhou, Ling; Yao, Yan; Guo, Yang; Wang, Xiaoxue; Cong, Fuyun

doi:10.1016/j.marpetgeo.2022.106084

Cited by 11 publications

(1 citation statement)

References 44 publications

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“…The development of carbonate reservoirs is intricately controlled by three primary geological factors: sedimentation, diagenesis, and tectonic stress [19][20][21][22][23]. Microphases of deposition serve as the foundational material for reservoir formation and development.…”

Section: Introductionmentioning

confidence: 99%

Karstification and Its Role in the Formation of Carbonate Reservoirs: A Case Study from the Ordovician Majiagou Formation in Jingbian, Ordos Basin, North China

Peng,

Li,

Cheng

et al. 2023

Minerals

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The discovery of natural gas reserves in Lower Paleozoic carbonate formations has generated significant enthusiasm regarding the potential for oil and gas exploration in the deeper carbonate reservoirs of the Ordos Basin. Significant progress has been made in the field of natural gas exploration, especially within the carbonate reservoirs of the Ordovician Majiagou Formation. In this study, we conducted a comprehensive analysis, including microscopic examination of thin sections and the inspection of 60-m cores from five wells, to classify pore types and investigate various forms of karstification in the fifth member of the Majiagou Formation. Our findings have identified distinct pore types, including interparticle pores, separate-vuggy pores, and touching-vuggy pores, in this formation. The dominant forms of karstification in this area were identified as syngenetic karstification, weathering crust karstification, and burial karstification. Importantly, our investigation emphasizes the significant influence of factors such as sea level fluctuations, exposure duration, and the presence of acidic formation water in shaping the observed patterns of karstification. Syngenetic karstification and shallow-buried karstification have emerged as key stages in the formation of natural gas reservoirs. Moreover, our research emphasizes the importance of structural and composite fractures observed in the fifth member of the Majiagou Formation. These unfilled fractures serve as crucial microfracture networks, facilitating oil and gas migration and contributing to the overall development of reservoirs. The research results are of great significance for understanding the formation process of carbonate reservoirs in the Majiagou Formation, Ordos Basin.

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Section: Introductionmentioning

confidence: 99%

Karstification and Its Role in the Formation of Carbonate Reservoirs: A Case Study from the Ordovician Majiagou Formation in Jingbian, Ordos Basin, North China

Peng,

Li,

Cheng

et al. 2023

Minerals

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Genesis and reservoir preservation mechanism of 10 000‐m ultradeep dolomite in Chinese craton basin

Zhu,

Li,

Zhao

et al. 2024

Deep Underground Science and Engineering

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The 10 000‐m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin. However, major challenges such as the genesis of dolomite, the formation time of high‐quality reservoirs, and the preservation mechanism of reservoirs have always limited exploration decision‐making. This research systematically elaborates on the genesis and reservoir‐forming mechanisms of Sinian–Cambrian dolomite, discussing the ancient marine environment where microorganisms and dolomite develop, which controls the formation of large‐scale Precambrian–Cambrian dolomite. The periodic changes in Mg isotopes and sedimentary cycles show that the thick‐layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale. Lattice defects and dolomite embryos can promote dolomitization. By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights, the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed, and the mechanism of dolomitization was also demonstrated. The properties of calcite and dolomite (104)/(110) grain boundaries and their dissolution mechanism in carbonate solution were revealed, showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs. The in situ laser U‐Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks. This research also proposed that dolomitization occurred during the quasi‐contemporaneous or shallow‐burial periods within 50 Ma after deposition and pores formed during the quasi‐contemporaneous to the early diagenetic periods. And it was clear that the quasi‐contemporaneous dolomitization was the key period for reservoir formation. The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large‐scale dolomite reservoirs. It clarifies the targets for oil and gas exploration at depths over 10 000 m. The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10 000‐m deep oil exploration.

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Genesis of ultra-deep dolostone and controlling factors of large-scale reservoir: A case study of the Sinian Dengying Formation and the Cambrian Longwangmiao Formation in the Sichuan Basin

Li,

Zhu,

Zhang

2024

Sci. China Earth Sci.

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Formation and preservation of ultra-deep high-quality dolomite reservoirs under the coupling of sedimentation and diagenesis in the central Tarim Basin, NW China

Cited by 11 publications

References 44 publications

Karstification and Its Role in the Formation of Carbonate Reservoirs: A Case Study from the Ordovician Majiagou Formation in Jingbian, Ordos Basin, North China

Karstification and Its Role in the Formation of Carbonate Reservoirs: A Case Study from the Ordovician Majiagou Formation in Jingbian, Ordos Basin, North China

Genesis and reservoir preservation mechanism of 10 000‐m ultradeep dolomite in Chinese craton basin

Genesis of ultra-deep dolostone and controlling factors of large-scale reservoir: A case study of the Sinian Dengying Formation and the Cambrian Longwangmiao Formation in the Sichuan Basin

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