In situ U-Pb dating and geochemical characterization of multi-stage dolomite cementation in the Ediacaran Dengying Formation, Central Sichuan Basin, China: Constraints on diagenetic, hydrothermal and paleo-oil filling events

Su, Ao; Chen, Honghan; Feng, Yuexing; Zhao, Jianxin; Wang, Zecheng; Hu, Mingzeng; Jiang, Hua; Nguyen, Ai Duc

doi:10.1016/j.precamres.2021.106481

Cited by 30 publications

(29 citation statements)

References 74 publications

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Section: Geochemistry and Fluid Inclusionmentioning

confidence: 59%

“…4.3.1 Oxygen, carbon, and strontium isotopes According to data from previous studies and this study (Zhou et al, 2016;Feng et al, 2017;Peng B. et al, 2018;Gu et al, 2019;Zhou et al, 2020;Su et al, 2022) The MD has 87 Sr/ 86 Sr ratios ranging from 0.707789 to 0.709800 (average 0.708804, n=10) (Zhou et al, 2016;Feng et al, 2017;Gu et al, 2019;Su et al, 2022). The 87 Sr/ 86 Sr FIGURE 4 (A) Crossplot of δ 13 C and δ 18 O for different rock fabrics in the Dengying Formation of Central Sichuan Basin (FD, MCD, and SD data are from Feng et al, 2017;Su et al, 2022). (B) Crossplot of δ 13 C and 87 Sr/ 86 Sr for different rock fabrics in the Dengying Formation of Central Sichuan Basin ( 87 Sr/ 86 Sr data for FD, MCD, and SD are from Feng et al, 2017;Su et al, 2022;87 Sr/ 86 Sr data for late Precambrian seawater are from Burns et al, 1994).…”

Section: Geochemistry and Fluid Inclusionmentioning

confidence: 59%

“…The 87 Sr/ 86 Sr FIGURE 4 (A) Crossplot of δ 13 C and δ 18 O for different rock fabrics in the Dengying Formation of Central Sichuan Basin (FD, MCD, and SD data are from Feng et al, 2017;Su et al, 2022). (B) Crossplot of δ 13 C and 87 Sr/ 86 Sr for different rock fabrics in the Dengying Formation of Central Sichuan Basin ( 87 Sr/ 86 Sr data for FD, MCD, and SD are from Feng et al, 2017;Su et al, 2022;87 Sr/ 86 Sr data for late Precambrian seawater are from Burns et al, 1994).…”

Section: Geochemistry and Fluid Inclusionmentioning

confidence: 99%

“…The abundant drilling cores of the Dengying Formation provide an excellent study target for the effect of diagenesis evolution on the quality of deep dolomite reservoirs. In terms of the reservoir-forming mechanism of deep dolomite reservoirs in the Dengying Formation, most of the viewpoints believe that the supergene karstification during Tongwan Movement plays a key role (Wang et al, 2014;Zhou et al, 2016;Zhou et al, 2020;Su et al, 2022). Zhu et al (2015) agreed with this view, but also emphasized the constructive role of recrystallization during supergene karstification.…”

Section: Introductionmentioning

confidence: 99%

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Effects of diagenesis on quality of dengying formation deep dolomite reservoir, Central Sichuan Basin, China: Insights from petrology, geochemistry and in situ U-Pb dating

Wang

Yang³

et al. 2023

Front. Earth Sci.

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The Ediacaran Dengying Formation in Central Sichuan Basin is the deep dolomite gas reservoir with the largest natural gas reserves in China, providing an excellent example for understanding the effect of diagenesis evolution on deep dolomite reservoir quality. By integrating petrology, geochemistry and in situ U-Pb dating, this study aims to reveal the genesis of different rock fabrics and their corresponding diagenetic events, and to discuss the temporal relationship of diagenetic events and their effects on the reservoir quality of Dengying Formation. Two phases of dolomite and three phases of dolomite cement are identified in Ediacaran Dengying Formation deep dolomite reservoirs of Central Sichuan Basin as follows: 1) matrix dolomites (MD), 2) fine-medium crystalline dolomites (FMD), 3) fibrous dolomites (FD), 4) medium-coarse crystalline dolomites (MCD), and 5) saddle dolomite (SD). By analyzing petrographic and temporal relationships between these fabrics, it is suggested that the deep dolomite reservoir of Dengying Formation in Central Sichuan Basin has experienced six diagenetic stages, including 1) syndiagenetic stage, 2) the first-time early diagenetic stage, 3) epidiagenetic stage, 4) the second-time early diagenetic stage, 5) middle diagenetic stage and 6) late diagenetic stage. Microbial dolomitization during syndiagenetic stage produced limited increase in reservoir porosity, but it is of great significance for preservation of reservoir spaces. Silicification is most unfavorable for reservoir formation, but its duration and influence range are very limited. At epidiagenetic stage, the physical properties of Dengying Formation dolomite reservoir have been greatly improved. Two-time early diagenetic stages are both destructive for preservation of reservoir spaces. During middle diagenetic stage, two-stage of hydrothermal alterations occurred, corresponding to Late Silurian to Devonian and Late Permian, respectively. Hydrothermal alteration of the MD is both constructive and destructive, but overall it is constructive, and the improvement of physical properties is limited. For the karstified MD, both two-stage hydrothermal alterations were destructive, resulting in damage of reservoir physical properties caused by cementation by two-stage SD and one-stage MVT minerals.

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Section: Geochemistry and Fluid Inclusionmentioning

confidence: 59%

Section: Geochemistry and Fluid Inclusionmentioning

confidence: 59%

Section: Geochemistry and Fluid Inclusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of diagenesis on quality of dengying formation deep dolomite reservoir, Central Sichuan Basin, China: Insights from petrology, geochemistry and in situ U-Pb dating

Wang

Yang³

et al. 2023

Front. Earth Sci.

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“…Annulus compression zone and gas channeling are challenging (Bu et al, 2016;Zhao et al, 2018;Zeng et al, 2019;Bu et al, 2020a;Bayanak et al, 2020) problems in the development and production of oil and gas wells because cement rings are subjected to casing internal pressure (Bu et al, 2020b;Guo et al, 2020;Kuanhai et al, 2020;Kuanhai et al, 2021) and formation stress (Su et al, 2022). The failure of its mechanical integrity (Wang and Taleghani, 2014;Omosebi et al, 2017) leads to damage, cracks, and the appearance of microannular gaps on the cemented surface, yielding annulus packing failure (Yousuf et al, 2021), introducing enormous safety hazards to the later exploitation of oil and gas wells.…”

Section: Introductionmentioning

confidence: 99%

Research on the Mechanical Integrity of Low-Density Cement Mortar

Xie¹,

Cheng

et al. 2022

Front. Mater.

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Poor mechanical integrity of cement sheaths during the production of oil and gas wells may cause air channeling and water channeling issues in the wells, leading to severe safety problems, and adversely affecting the safety and efficiency of the oil and gas resources production. This article focuses on a low-density cement slurry system with added floating beads. The compressive strength and flexural strength of cement stones, the mechanical integrity of cement rings, and triaxial mechanical properties were assessed. The optimal dosage of floating beads and the evolution of the cement stone’s mechanical properties and deformation ability were discussed. Bonding strengths of the first and the second interfaces were evaluated using the shrinkage test results of the cement mortar. Finally, the microscopic mechanism of the change in mechanical properties was analyzed by scanning electron microscopy. The results showed that the cement mortar exhibited the best compressive strength, mechanical integrity, and deformability after blending with 15% floating beads. At the same time, the volume shrinkage of the cement mortar mixed with 15% floating beads was the smallest, only 0.00667%, plausibly indicating good bonding with a casing and the formation to reduce the occurrence of gas channeling. Finally, the microscopic test of the cement mortar showed that the bonding between floating beads and cement was not tight, so internal cracks in the cement easily developed along the bonding part of cement and floating beads. The more floating beads were mixed, the more likely was cement mortar destroyed.

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Hydrothermal silicification in Ediacaran Dengying Formation fourth member deep dolomite reservoir, Central Sichuan Basin, China: Implications for reservoir quality

Wang

Jiang

Yang³

et al. 2023

Geological Journal

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The Ediacaran Dengying Formation fourth member in Central Sichuan Basin is the deep dolomite gas reservoir with the largest natural gas reserves in China, providing an excellent example for understanding the effect of hydrothermal silicification on deep dolomite reservoir quality. By integrating petrology, geochemistry and physical property measurement, this study aims to reveal the genesis of different quartz phase and their corresponding diagenetic events, and to discuss the temporal relationship of diagenetic events and their effects on the quality of deep dolomite reservoir in Dengying fourth member. Three phases of quartz cement are identified in Ediacaran Dengying Formation deep dolomite reservoirs of Central Sichuan Basin as follows: (1) first‐stage quartz filled in primary reservoir spaces, (2) second‐stage quartz mainly filled in secondary reservoir spaces, and (3) third‐stage quartz filled in secondary reservoir spaces with Mississippi Valley‐Type minerals. By analysing petrographic and temporal relationships between these fabrics, it is suggested that the first‐stage quartz precipitated during the syndiagenetic stage, the second‐stage quartz precipitated during middle diagenetic stage, and the third‐stage quartz precipitated during middle diagenetic stage as well. Silicification during syndiagenetic stage is characterized by replacement of cryptocrystalline quartz and cementation of first‐stage quartz within matrix dolomite (MD). After syndiagenetic silicification, the mineral composition of the MD changed from magnesium calcium carbonate to silica, and the later constructive diagenetic alterations were almost ineffective. The distribution of syndiagenetic silicification during syndiagenetic stage gradually decreases from the platform‐interior to the platform‐margin. The second‐stage and third‐stage quartz cements, derived from two‐stage hydrothermal silicification in the middle stage, are both destructive for reservoir preservation. This study, combined with coeval vapour–liquid inclusions Th data and thermal‐burial models, constrains the time of the second‐stage quartz to ca. 403–408 Ma, suggesting an hydrothermal silicification related to the Caledonian movement. The time of the third‐stage quartz cement is constrained to ca. 259.4 Ma, associated with Late Permian eruption of Emeishan flood basalts.

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In situ U-Pb dating and geochemical characterization of multi-stage dolomite cementation in the Ediacaran Dengying Formation, Central Sichuan Basin, China: Constraints on diagenetic, hydrothermal and paleo-oil filling events

Cited by 30 publications

References 74 publications

Effects of diagenesis on quality of dengying formation deep dolomite reservoir, Central Sichuan Basin, China: Insights from petrology, geochemistry and in situ U-Pb dating

Effects of diagenesis on quality of dengying formation deep dolomite reservoir, Central Sichuan Basin, China: Insights from petrology, geochemistry and in situ U-Pb dating

Research on the Mechanical Integrity of Low-Density Cement Mortar

Hydrothermal silicification in Ediacaran Dengying Formation fourth member deep dolomite reservoir, Central Sichuan Basin, China: Implications for reservoir quality

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