Lithofacies division and comparison and characteristics of Longtan Formation shale in typical areas of Sichuan Basin and its surrounding
HE Yi,1, TANG Xuan,1, SHAN Yan-sheng,2, LIU Guang-xiang3, XIE Huang-chang1, MA Zi-jie1
1.China University of Geosciences （School of Energy）/Key Laboratory of Strategic Evaluation of Shale Gas Resources，Ministry of Natural Resources，Beijing 100083，China
There are many types of transitional facies shale， and the types of organic matter are complex. They are neither completely the same as continental nor completely the same as the characteristics of marine shale. Discussing transitional shale facies and their characteristics is a further understanding of shale gas storage space. This paper takes the Well M1 and Well DC1 shale of Permian Longtan Formation in the Sichuan Basin and its surrounding areas as the research objects ， combined with core observation， ordinary optical thin section observation， and argon ion polishing scanning electron microscope observation. The lithofacies are divided and compared and their characteristics are described. The results indicate that the shale lithofacies of the Longtan Formation in the typical areas of the Sichuan Basin and its periphery can be divided into five major categories according to the mineral content， which are clay shale facies， calcareous shale facies， siliceous shale facies， calcareous mixed shale facies， siliceous mixed shale facies. According to the abundance of organic matter， eight sub-categories are further divided into ultra-high organic matter siliceous shale facies， ultra-high organic matter siliceous mixed shale facies， ultra-high organic matter clay shale facies， high organic matter siliceous shale facies， high-organic clay shale facies， medium-organic calcareous shale facies， medium-organic clay shale facies and low-organic calcareous shale facies. Clay shale facies， siliceous shale facies and siliceous mixed shale lithofacies with high abundance of organic matter is favorable production zone， while calcareous and calcareous mixed shale facies with low abundance of organic matter is an unfavorable production zone. Clay shale facies is the most commonly developed lithofacies in shale facies. The abundance of organic matter in clay facies shale facies is higher than that of marine clay shale facies shale.
Keywords：Transitional facies
;
Marine facies
;
Typical areas in the Sichuan Basin and its periphery
;
Longtan Formation
;
Shale facies
;
Characteristics of organic matter
HE Yi, TANG Xuan, SHAN Yan-sheng, LIU Guang-xiang, XIE Huang-chang, MA Zi-jie. Lithofacies division and comparison and characteristics of Longtan Formation shale in typical areas of Sichuan Basin and its surrounding. Natural Gas Geoscience[J], 2021, 32(2): 174-190 doi:10.11764/j.issn.1672-1926.2020.09.009
(a)特高有机质硅质混合页岩相,M9样品,4 949.15 m, TOC=9.22%;(b)特高有机质硅质页岩相,M5样品,4 944.4 m, TOC=9.88%;(c)特高有机质黏土质页岩相,M20样品,4 960.42 m, TOC=4.696%;(d)高有机质硅质页岩相,M11样品,4 951.2 m, TOC=2.01%;(e)高有机质黏土质页岩相,M21样品,4 962.3 m, TOC=3.05%;(f)中有机质钙质混合页岩相,M2样品,4 941.5 m, TOC=1.41%;(g)中有机质黏土质页岩相,M16样品,4 956.8 m, TOC=1.62%;(h)灰色含泥灰岩,M15样品,4 955.7 m, TOC=0.369%
Fig.5
Lithofacies types and characteristics of shale in Longtan Formation in Well M1
(a)特高有机质黏土质页岩相,D4样品,723.2 m, TOC=7.15%;(b)高有机质黏土质页岩相,D7样品,862.6 m, TOC=2.91%;(c)高有机质砂质页岩相,D6样品,854.1 m, TOC=2.91%;(d)煤,D2样品,671 m, TOC=42.8%
Fig.6
Lithofacies and microscopic characteristics of Longtan Formation shale in Well DC1
5 不同页岩岩相的储层特征
目前，广泛应用于页岩气储层的孔隙定量分类方案是国际理论和应用化学学会（International Union of Pure and Applied Chemistry，IUPAC）关于孔隙的划分方法。IUPAC明确定义：小于2 nm的孔隙称为微孔（micropore），2~50 nm的孔隙称为中孔（mesopore），大于50 nm的孔隙称为宏孔（macropore）［34］。本文主要采用了高压压汞法和N2吸附法这2种方法分别对泥页岩2 nm以上的中孔和宏孔进行定量研究，结合电镜观察统计分析。根据电镜观察统计，微观尺度下各类孔隙的孔径大小情况是：有机质孔最小，一般在500 nm以下，其次为黏土与有机质的粒内孔和粒间孔，脆性矿物粒间孔稍大，最大的为碳酸盐矿物溶蚀孔，粒径可达10 μm。
SUN Y， JU Y W， LUO K Y， et al. Research on the formation process of marine-terrestrial shale gas based on basin evolution： Taking Shanxi Formation in the southeast of Ordos Basin as an example［C］//Proceedings of China Earth Sciences Joint Academic Annual Conference. Beijing： Geology Press， 2016：643-644.
WANG J X. Middle-Late Ordovician Sedimentary Facies and Lithofacies Paleogeographic Features in Dejiang Area， Guizhou［D］.Chengdu： Chengdu University of Technology， 2018：1-68.
YUAN T， WEI X F， ZHANG H R， et al. The division of shale facies in the Upper Ordovician Wufeng Formation and Lower Silurian Longmaxi Formation in the Sichuan Basin and its periphery［J］. Petroleum Geology and Experiment，2020，42（3）：371-377.
WANG Y M， DONG D Z， LI X J， et al. New breakthroughs in China's shale gas exploration and development and development prospects［J］. Natural Gas Industry，2016，36（1）：19-32.
JIANG Z X， TANG X L， LI Z， et al. Pore Structure and Gas-bearing Properties of Typical Marine and Continental Shale Reservoirs in China［M］. Beijing： Science Press，2018：1-388.
LIANG D X，HU S Y， GU Z D， et al. The formation and evolution of the Kaijiang paleo-uplift in the Sichuan Basin and its control on natural gas accumulation［J］. Natural Gas Industry，2015，35（9）：35-41.
LIU G X， JIN Z J， DENG M， et al. The shale gas exploration potential of the Upper Permian Longtan Formation in the eastern Sichuan Basin［J］.Oil and Gas Geology，2015，36（3）：481-487.
WANG H， GUO L J， HONG Y J， et al. Upper Permian sequence stratigraphy and coal accumulation in China coal field， west Guizhou［J］. Journal of Palaeogeography，2011，13（5）： 493-500.
LUO J X， HE Y B， WANG D， et al. Rock characteristics and sedimentary environment analysis of the Permian in Tongzi Songkan， Guizhou［J］. Science and Technology Review，2013，31（2）：37-44.
XIE H C. Characteristics of Lithofacies and Pore Structure of Marine-continent Transitional Facies Shale： Taking Longtan Formation in Southern Sichuan-Northern Guizhou as an Example［D］.Beijing： China University of Geosciences（Beijing），2019：1-89.
WANG C， ZHANG B Q， SHU Z G， et al. Lithofacies and reservoir characteristics of marine shale from Wufeng Formation to Longmaxi Formation in Fuling area， Sichuan Basin［J］.Oil and Gas Geology， 2018，39（3）：485-497.
LIU Z B， LIU G X， HU Z Q， et al. Lithofacies types， assemblage characteristics of continental shale strata and their significance for oil and gas exploration： Taking the Middle and Lower Jurassic in the Sichuan Basin as an example［J］.Natural Gas Industry，2019.39（12）：10-21.
WANG C， ZHANG B Q， LU Y C， et al. Lithofacies distribution and main controlling factors of shale in the first member of Wufeng Formation-Longmaxi Formation in Jiaoshiba area［J］.Acta Petrolei Sinica，2018，39（6）：631-644.
JIANG Y Q， SONG Y T， QI L， et al. Fine division and logging prediction of Chinese marine shale facies： Taking the Longmaxi Formation in the Weiyuan area of the southern Sichuan Basin as an example［J］. Earth Science Frontiers，2016，23（1）：107-118.
ZHAO J H， JIN Z J， JIN Z K， et al. Lithofacies and sedimentary environment of shale of Wufeng Formation and Longmaxi Formation in Sichuan Basin［J］.Acta Petrolei Sinica，2016，37（5）：572-586.
RAN B， LIU S G， SUN W， et al. Lithofacies classification of shale of Lower Paleozoic Wufeng-Longmaxi Formation in Sichuan Basin and its periphery［J］. Earth Science Frontiers，2016，23（2）：96-107.
ZUO R S， YANG W， WANG G Y， et al. Micro-reservoir characteristics under the control of continental shale facies in the Xujiahe Formation in the western Sichuan Depression［J］. Special Oil and Gas Reservoirs，2016，26（6）：22-26.
SHAO S X， ZENG J H， ZHANG S W， et al. Types， characteristics and genesis of kaolinite in sandstone reservoirs of Shahejie Formation in Dongying Sag［J］. Acta Sedimentologica Sinica，2015，33（6）：1204-1216.
ROWE H D，LOUCKS R G，RUPPEL S C， et al. Mississippian Barnett Formation， Fort Worth Basin， Texas： Bulk geochemical inferences and Mo-TOC constraints on the severity of hydrographic restriction［J］.Chemical Geology，2009，257（1-2）：16-25.
LI Z， JIANG Z X， TANG X L， et al. Lithofacies of the Lower Silurian Longmaxi Formation shale in southeast Chongqing and its control on pore structure［J］.Earth Science，2017，42（7）： 1116-1123.
SHAN Y S， BI C Q， CHI H P， et al. Geological characteristics of coalbed methane in Yangmeishu syncline and optimization of favorable development intervals in Liupanshui area［J］.Natural Gas Geoscience，2018，29（1）： 122-129.
TANG X， ZHANG J C， DING W L， et al. Reservoir and gas-bearing properties of Upper Paleozoic marine-continent transition facies shale in the southeastern Ordos Basin［J］. Ear-th Science Frontiers，2016，23（2）： 147-157.
SHAN Y S， BI C Q， CHI H P， et al. Geological characteristics of coalbed methane in Yangmeishu syncline and optimization of favorable development intervals in Liupanshui area［J］.Natural Gas Geoscience，2018，29（1）： 122-129.
WU J Y， LV Z X， QING Y H， et al. Genesis of authigenic chlorite in tight oil reservoirs and its influence on physical properties： Taking the Shaximiao Formation in the north of the middle east of Sichuan as an example［J］. Lithologic Reservoirs，2020，32（1）：76-85.
JIN P P， OU C H， MA Z G， et al. Evolution of montmorillonite and related clay minerals and their influence on shale gas development［J］.Geophysical Prospecting for Petroleum，2018，57（3）：344-355.
WANG Y M，DONG D Z，YANG H，et al. Quantitative characterization of reservoir space in the Lower Silurian Longmaxi Shale， southern Sichuan， China［J］. Earth Sciences，2014，57（2）： 313-322.
THOMMES M. Physisorption of gases， with special reference to the evaluation of surface area and pore size distribution （IUPAC Technical Report）［J］.Chemistry International， 2016，38（1）：25-43.
LIU H， CAO T T， QI M H， et al. Characteristics of Longtan Formation shale gas reservoir in Huayingshan Area， eastern Sichuan Basin［J］. Natural Gas Geoscience， 2019， 30（1）：11-26.
GUO X S， HU D F， LIU R B， et al. Geological conditions and exploration potential of Permian marine-continent transitional facies shale gas in the Sichuan Basin［J］. Natural Gas Industry，2018，30（10）：11-18.
WANG C， ZHANG B Q， SHU Z G， et al. Lithofacies and reservoir characteristics of marine shale from Wufeng Formation to Longmaxi Formation in Fuling area， Sichuan Basin［J］.Oil and Gas Geology，2018，39（3）：485-497.
WU L Y， HU D F， LU Y C， et al. The dominant lithofacies of shale from Wufeng Formation to Longmaxi Formation in Fuling Gas Field， Sichuan Basin［J］.Petroleum Exploration and Development，2016，43（2）：189-197.
YUAN T， WEI X F， ZHANG H R， et al. Lithofacies division of shale from Upper Ordovician Wufeng Formation to Lower Silurian Longmaxi Formation in the Sichuan Basin and its periphery［J］.Petroleum Geology & Experiment，2020，42（3）：371-377.
ZHAO P R， GAO B， GUO Z F， et al. The exploration potential of Upper Permian marine-continent transition facies and deep-water shelf facies shale gas in Sichuan Basin［J］.Petroleum Geology & Experiment，2020，42（3）：335-344.
... [9-11]Sedimentary facies, contours and sampling locations of the Longtan Formation in the study area<sup>[<xref ref-type="bibr" rid="R9">9</xref>-<xref ref-type="bibr" rid="R11">11</xref>]</sup>Fig.1
... [9-11]Sedimentary facies, contours and sampling locations of the Longtan Formation in the study area<sup>[<xref ref-type="bibr" rid="R9">9</xref>-<xref ref-type="bibr" rid="R11">11</xref>]</sup>Fig.1
Sedimentary facies, contours and sampling locations of the Longtan Formation in the study area<sup>[<xref ref-type="bibr" rid="R9">9</xref>-<xref ref-type="bibr" rid="R11">11</xref>]</sup>Fig.1
Sedimentary facies, contours and sampling locations of the Longtan Formation in the study area<sup>[<xref ref-type="bibr" rid="R9">9</xref>-<xref ref-type="bibr" rid="R11">11</xref>]</sup>Fig.1
... 目前，广泛应用于页岩气储层的孔隙定量分类方案是国际理论和应用化学学会（International Union of Pure and Applied Chemistry，IUPAC）关于孔隙的划分方法.IUPAC明确定义：小于2 nm的孔隙称为微孔（micropore），2~50 nm的孔隙称为中孔（mesopore），大于50 nm的孔隙称为宏孔（macropore）［34］.本文主要采用了高压压汞法和N2吸附法这2种方法分别对泥页岩2 nm以上的中孔和宏孔进行定量研究，结合电镜观察统计分析.根据电镜观察统计，微观尺度下各类孔隙的孔径大小情况是：有机质孔最小，一般在500 nm以下，其次为黏土与有机质的粒内孔和粒间孔，脆性矿物粒间孔稍大，最大的为碳酸盐矿物溶蚀孔，粒径可达10 μm. ...
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