Diagenesis and reservoir quality evolution of the Eocene sandstones in the northern Dongying Sag, Bohai Bay Basin, East China

Yuan, Guanghui; Gluyas, Jon; Cao, Yingchang; Oxtoby, N. H.; Jia, Zhenzhen; Wang, Yanzhong; Xi, Kelai; Li, Xiaoyan

doi:10.1016/j.marpetgeo.2015.01.006

Cited by 132 publications

(54 citation statements)

References 29 publications

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“…temperature [37,48]. During diagenetic process, material exchanges between particles and pore fluids (mainly feldspar dissolution) led the 18 O smow /‰ value of pore fluids to be heavier [35,39,43]. The 18 O smow /‰ value of pore water at eodiagenetic stage was about −4.8‰, which became heavier, reaching about −3‰ due to significant feldspar dissolution [35,49].…”

Section: Morphological and Distribution Characteristics Of Othermentioning

confidence: 99%

“…During diagenetic process, material exchanges between particles and pore fluids (mainly feldspar dissolution) led the 18 O smow /‰ value of pore fluids to be heavier [35,39,43]. The 18 O smow /‰ value of pore water at eodiagenetic stage was about −4.8‰, which became heavier, reaching about −3‰ due to significant feldspar dissolution [35,49]. In other words, Cc1 and Cc2, which were clearly anterior to feldspar dissolution, precipitated from pore fluids with 18 O smow /‰ value of −4.8‰ (Figures 6(a) (Figures 10(a), 10(b), and 12).…”

Section: Morphological and Distribution Characteristics Of Othermentioning

confidence: 99%

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Material Exchange and Migration between Pore Fluids and Sandstones during Diagenetic Processes in Rift Basins: A Case Study Based on Analysis of Diagenetic Products in Dongying Sag, Bohai Bay Basin, East China

et al. 2018

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The exchange and migration of basin materials that are carried by pore fluids are the essence of diagenesis, which can alter physical properties of clastic rocks as well as control formation and distribution of favorable reservoirs of petroliferous basins. Diagenetic products and pore fluids, resulting from migration and exchange of basin materials, can be used to deduce those processes. In this study, 300 core samples from 46 wells were collected for preparation of casting thin sections, SEM, BSE, EDS, inclusion analysis, and isotope analysis in Dongying Sag, Bohai Bay Basin, East China. Combined with geochemical characteristics of pore fluids and geological background of the study area, the source and exchange mechanisms of materials in the pore fluids of rift basins were discussed. It was revealed that the material exchange of pore fluids could be divided into five stages. The first stage was the evaporation concentration stage during which mainly Ca 2+ , Mg 2+ , and CO 3 2− precipitated as high-Mg calcites. Then came the shale compaction stage, when mainly Ca 2+ and CO 3 2− from shale compaction water precipitated as calcites. The third stage was the carboxylic acid dissolution stage featured by predominant dissolution of plagioclases, during which Ca 2+ and Na + entered pore fluids, and Si and Al also entered pore fluids and then migrated as clathrates, ultimately precipitating as kaolinites. The fourth stage was the organic CO 2 stage, mainly characterized by the kaolinization of K-feldspar as well as dissolution of metamorphic lithic fragments and carbon cements. During this stage, K + , Fe 2+ , Mg 2+ , Ca 2+ , HCO 3 − , and CO 3 2− entered pore fluids. The fifth stage was the alkaline fluid stage, during which the cementation of ferro-carbonates and ankerites as well as illitization or chloritization of kaolinites prevailed, leading to the precipitation of K + , Fe 2+ , Mg 2+ , Ca 2+ , and CO 3 2− from pore fluids.

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Section: Morphological and Distribution Characteristics Of Othermentioning

confidence: 99%

Section: Morphological and Distribution Characteristics Of Othermentioning

confidence: 99%

Material Exchange and Migration between Pore Fluids and Sandstones during Diagenetic Processes in Rift Basins: A Case Study Based on Analysis of Diagenetic Products in Dongying Sag, Bohai Bay Basin, East China

et al. 2018

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“…6m, n, o). The large proportion of micropores results in much lower permeability of reservoirs than that of other reservoirs with the same porosity (Yuan et al 2013(Yuan et al , 2015Cao et al 2014). So middle and high porosity low permeability reservoirs are common.…”

Section: Reservoir Featuresmentioning

confidence: 99%

The coupling of dynamics and permeability in the hydrocarbon accumulation period controls the oil-bearing potential of low permeability reservoirs: a case study of the low permeability turbidite reservoirs in the middle part of the third member of Shahejie Formation in Dongying Sag

et al. 2016

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“…Mineral dissolution generally improves reservoir quality (Schmidt and McDonald 1979;Surdam et al 1984;Yuan et al 2015c;Cao et al 2012;Zhu et al 2007;Han et al 2007). Vitrinite reflectance (R 0 %) of organic matter in B14-X55-50,1608.83m B14-X55-50,1653.23m interbedded mudstones in the Xing'anling Group is up to 0.8 %-1.0 %, and thermal evolution of such organic matter has produced large amounts of CO 2 and organic acids, which have probably leached unstable minerals (Schmidt and McDonald 1979;Surdam et al 1984;Yuan et al 2015a).…”

Section: Selective Dissolution Of Mineralsmentioning

confidence: 99%

Selective dissolution of eodiagenesis cements and its impact on the quality evolution of reservoirs in the Xing’anling Group, Suderte Oil Field, Hailar Basin, China

et al. 2016

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Reservoirs in the Xing'anling Group in the Suderte Oil Field, Hailar Basin exhibit ultra-low to low permeability and high tuffaceous material content. This study comprehensively analyzed diagenesis and quality evolution of these low-permeability reservoirs using thin sections, SEM samples, rock physical properties, pore water data, as well as geochemical numerical simulations. Calcite and analcite are the two main types of cements precipitated in the eodiagenetic stage at shallow burial depths in the reservoirs. These two cements occupied significant primary intergranular pores and effectively retarded deep burial compaction. Petrography textures suggest selective dissolution of massive analcite and little dissolution of calcite in the mesodiagenetic stage. Chemical calculations utilizing the Geochemist's Workbench 9.0 indicated that the equilibrium constant of the calcite leaching reaction is significantly smaller than that of the analcite leaching reaction, resulting in extensive dissolution of analcite rather than calcite in the geochemical system with both minerals present. Numerical simulations with constraints of kinetics and pore water chemistry demonstrated that the pore water in the Xing'anling group is saturated with respect to calcite, but undersaturated with analcite, leading to dissolution of large amounts of analcite and no dissolution of calcite. Significant secondary intergranular pores have formed in analcite-cemented reservoirs from selective dissolution of analcite in the mesodiagenetic stage; the analcite dissolution formed preferential flow paths in the reservoirs, which promoted feldspar dissolution; and dissolution of such minerals led to the present reservoirs with medium porosity and low permeability. Calcite-cemented tight reservoirs have not experienced extensive dissolution of cements, so they exhibit ultra-low porosity and permeability.

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Diagenesis and reservoir quality evolution of the Eocene sandstones in the northern Dongying Sag, Bohai Bay Basin, East China

Cited by 132 publications

References 29 publications

Material Exchange and Migration between Pore Fluids and Sandstones during Diagenetic Processes in Rift Basins: A Case Study Based on Analysis of Diagenetic Products in Dongying Sag, Bohai Bay Basin, East China

Material Exchange and Migration between Pore Fluids and Sandstones during Diagenetic Processes in Rift Basins: A Case Study Based on Analysis of Diagenetic Products in Dongying Sag, Bohai Bay Basin, East China

The coupling of dynamics and permeability in the hydrocarbon accumulation period controls the oil-bearing potential of low permeability reservoirs: a case study of the low permeability turbidite reservoirs in the middle part of the third member of Shahejie Formation in Dongying Sag

Selective dissolution of eodiagenesis cements and its impact on the quality evolution of reservoirs in the Xing’anling Group, Suderte Oil Field, Hailar Basin, China

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