Characteristics of authigenic carbonate minerals in carbonate concretions of the Chang 7 oil-bearing interval of Upper Triassic Yanchang Formation in Weibei area, Ordos Basin
Li Yun1,2, Hu Zuo-Wei1,2, Liu Can1,2, Dong Jie1,2, He Jing3, Yuan Xiao-Qi3, Wei Yang1,2
1 State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China; 2 Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China; 3 Exploration and Development Research Institute of Changqing Oil Field Branch,PetroChina, Xi’an 710018,China
Abstract：The early carbonate concretions would undergo the complex cementation of various carbonate mineral phases during the long-term burial process. The detailed petrology studies are the key to explore the genetic mechanism of the carbonate concretations. In this paper,the characteristics of authigenic carbonate minerals constituting the calcite and dolomite concretions that are rich in the shale of Chang 7 oil-bearing interval of Yanchang Formation in Weibei area of southern Ordos Basin,is studied through detailed observation in the field,together with the petrology studies and cathodoluminescence technology. The authigenic carbonate minerals constituting the concretions that may form in the early diagenesis,have marked features as follows: (1)the calcite spheres are composed of fibrous or flaky calcites. The crystalline calcites are filled between the calcite spheres,or the spheres are closely contacted because of compaction. Under the cathodoluminescence condition,the fibrous calcites show red orange light and dark red light,and the flaky calcites show dark light;(2)the calcites developed in fine-grained crystalline concretions show irregular shapes,containing many organism inclusions or residual fibrous textures. It shows that the natural bitumen and residual fiberous calcites appear between the calcite crystals,which presents dark red light under the cathodeluminescence;(3)the dolomite concretions are characterized as micrite and fine-grained crystalline dolomites. Authigenic fine-grained crystalline dolomite concretions usually contain large amounts of argillaceous bands. The fiber columnar dolomites are common in the argillaceous bands or organic matter enriched bands;(4)Fibrous and fiber columnar calcites and dolomites that present dark red color or colorless under the cathodeluminescence,usually grow along the cracks. The calcite and dolomite minerals developed in the carbonate concretions of Chang 7 oil-bearing interval,have different genetic types and complex cementation history. Spheroidal calcites and micritic dolomites produce at the beginning of the cementation,indicating the early genesis of concretions. Fine-grained crystalline calcites and dolomites indicate metasomatism. Crack-filled fibrous,radial and columnar shaped calcite and dolomite aggregates indicate strong compaction after the formation of concretions.
Li Yun,Hu Zuo-Wei,Liu Can et al. Characteristics of authigenic carbonate minerals in carbonate concretions of the Chang 7 oil-bearing interval of Upper Triassic Yanchang Formation in Weibei area, Ordos Basin[J]. JOPC, 2019, 21(4): 577-588.
[1] 邓秀芹,付金华,姚泾利,庞锦莲,孙勃. 2011. 鄂尔多斯盆地中及上三叠统延长组沉积相与油气勘探的突破. 古地理学报, 13(4): 443-455. [Deng X Q,Fu J H,Yao J L,Pang J L,Sun B.2011. Sedimentary facies of Yanchang Formation of Middle and Upper Triassic in Ordos Basin and the breakthrough of oil and gas exploration. Journal of Palaeogeography(Chinese Edition), 13(4): 443-455] [2] 董杰,胡作维,袁效奇,贺静,李云,王玉龙. 2017. 鄂尔多斯盆地南缘长7油层组碳酸盐结核的特征及石油地质意义. 成都理工大学学报(自然科学版), 44(5): 553-564. [Dong J,Hu Z W,Yuan X Q,He J,Li Y,Wang Y L.2017. Characteristics and petroleum geological significance of carbonate nodules of Chang7 formation in the southern margin of Ordos Basin. Journal of Chengdu University of Technology(Science &Technology Edition), 44(5): 553-564] [3] 李向军,罗静兰,罗晓容,王香增,姜呈馥,雷裕红,高潮,尹景涛. 2017. 鄂尔多斯盆地长7段泥页岩系孔隙特征及其演化规律. 地质科技情报, 36(4): 19-28. [Li X J,Luo J L,Luo X R,Wang X Z,Jiang C F,Lei Y H,Gao C,Yin J T.2017. Pore characteristics and evolution of shale system of Chang 7 member in Ordos Basin. Geological Science and Technology Information, 36(4): 19-28] [4] 秦艳,张文正,彭平安,周振菊. 2009. 鄂尔多斯盆地延长组长7段富铀烃源岩的铀赋存状态与富集机理. 岩石学报, 25(10): 2469-2476. [Qin Y,Zhang W Z,Peng P A,Zhou Z J.2009. Uranium occurrence and enrichment mechanism of uranium-rich source rocks in Yanchang Formation of Ordos Basin. Acta Petrologica Sinica, 25(10): 2469-2476] [5] 邱欣卫,刘池洋,李元昊,王光周,王建强. 2009. 鄂尔多斯盆地延长组凝灰岩夹层展布特征及其地质意义. 沉积学报, 27(6): 1138-1146. [Qiu X W,Liu C Y,Li Y H,Wang G Z,Wang J Q.2009. Distribution and geological significance of tuff intercalation in Yanchang Formation,Ordos Basin. Acta Sedimentologica Sinica, 27(6): 1138-1146] [6] 邱欣卫,刘池洋,毛光周,邓煜,王飞飞. 2010. 鄂尔多斯盆地上三叠统延长组凝灰岩夹层Th 元素的富集特征. 地质通报, 29(8): 1185-1191. [Qiu X W, Liu C Y,Mao G Z,Deng Y,Wang F F.2010. Enrichment characteristics of Th elements in tuff intercalation of Yanchang Formation of Upper Triassic in Ordos Basin. Geological Bulletin of China, 29(8): 1185-1191] [7] 邱欣卫,刘池洋,毛光周,吴柏林. 2011. 鄂尔多斯盆地延长组火山灰沉积物岩石地球化学特征. 地球科学, 36(1): 139-150. [Qiu X W,Liu C Y,Mao G Z,Wu B L.2011. Petrogeochemical characteristics of volcanic ash sediments in Yanchang Formation,Ordos Basin. Earth Science, 36(1): 139-150] [8] 孙宁亮,钟建华,刘绍光,田东恩,刘闯,曹梦春,杨冠群,郝兵. 2017. 鄂尔多斯盆地南部延长组重力流致密储集层成岩作用及物性演化. 地球科学, 42(10): 1802-1816. [Sun N L,Zhong J H,Liu S G,Tian D E,Liu C,Cao M C,Yang G Q,Hao B.2017. Diagenesis and physical evolution of gravity flow tight reservoir in Yanchang Formation,southern Ordos Basin. Earth Science, 42(10): 1802-1816] [9] 王多云,辛补社,杨华,付金华,姚泾利,张瑜. 2014. 鄂尔多斯盆地延长组长7底部凝灰岩锆石SHRIMP U-Pb 年龄及地质意义. 中国科学: 地球科学, 44(10): 2160-2171. [Wang D Y,Xin B S,Yang H,Fu J H,Yao J L,Zhang Y.2014. Shrimp U-Pb age of zircon from tuff at the bottom of Chang 7 of Yanchang Formation,Ordos Basin,and its geological significance. Scientia Sinica Terrae, 44(10): 2160-2171] [10] 王建强,刘池洋,李行,吴桐桐,吴经理. 2017. 鄂尔多斯盆地南部延长组长7段凝灰岩形成时代、物质来源及其意义. 沉积学报, 35(4): 691-704. [Wang J Q,Liu C Y,Li X,Wu T T,Wu J L.2017. Formation age,material source and its significance of tuff in member 7 of Yanchang Formation in southern Ordos Basin. Acta Sedimentologica Sinica, 35(4): 691-704] [11] 杨华,付金华,袁效奇. 2016. 鄂尔多斯盆地南缘地质剖面图集. 北京: 石油工业出版社. [Yang H,Fu J H,Yuan X Q.2016. Geological Profile Atlas of the Southern Margin of Ordos Basin. Beijing: Petroleum Industry Press] [12] 杨华,张文正. 2005,论鄂尔多斯盆地长7段优质油源岩在低渗透油气成藏富集中的主导作用: 地质地球化学特征. 地球化学, 34(2): 147-154. [Yang H,Zhang W Z.2005. Discussion on the leading role of high quality source rock of Chang7 member in Ordos Basin in accumulation of low permeability oil and gas reservoir: Geological and geochemical characteristics. Geochimica, 34(2): 147-154] [13] 杨华,窦伟坦,刘显阳,张才利. 2010. 鄂尔多斯盆地三叠系延长组长7沉积相分析. 沉积学报, 28(2): 254-263. [Yang H,Dou W T,Liu X Y,Zhang C L.2010. Sedimentary facies analysis of Chang 7 of Triassic Yanchang Formation in Ordos Basin. Acta Sedimentologica Sinica, 28(2): 254-263] [14] 杨智,付金华,郭秋麟,林森虎,陈宁生,潘松圻,李士祥. 2017. 鄂尔多斯盆地三叠系延长组陆相致密油发现、特征及潜力. 中国石油勘探, 22(6): 9-15. [Yang Z,Fu J H,Guo Q L,Lin S H,Chen N S,Pan S Q,Li S X.2017. Discovery,characteristics and potential of continental dense oil in the Yanchang Formation of Triassic,Ordos Basin. China Petroleum Exploration, 22(6): 9-15] [15] 张本浩,吴柏林,刘池洋,邱欣卫. 2011. 鄂尔多斯盆地延长组长7富铀烃源岩铀的赋存状态. 西北地质, 44(2): 124-132. [Zhang B H,Wu B L,Liu C Y,Qiu X W.2011. The occurrence of uranium in the uranium rich source rocks of Chang 7 of Yanchang Formation in the Ordos Basin. Northwestern Geology, 44(2): 124-132] [16] 张辉,彭平安,张文正. 2014. 鄂尔多斯盆地延长组长7段凝灰岩锆石U-Pb年龄、Hf同位素组成特征及其地质意义. 岩石学报, 30(2): 565-575. [Zhang H,Peng P A,Zhang W Z.2014. Isotopic characteristics of zircon U-Pb age and its geological significance of tuff from Member 7 of Yanchang Formation in Ordos Basin. Acta Petrologica Sinica, 30(2): 565-575] [17] 张文正,杨华,李剑峰,马军. 2006. 论鄂尔多斯盆地长7优质油源岩在低渗透油气成藏富集中的主导作用: 强生排烃特征及机理分析. 石油勘探与开发, 33(3): 289-293. [Zhang W Z,Yang H,Li J F,Ma J.2006. On the leading role of Chang7 high quality source rocks in the accumulation of low permeability oil and gas reservoirs in Ordos Basin: Johnson hydrocarbon expulsion characteristics and mechanism analysis. Petroleum Exploration and Development, 33(3): 289-293] [18] 张文正,杨华,杨奕华,孔庆芬,吴凯. 2008. 鄂尔多斯盆地长7优质烃源岩的岩石学、元素地球化学特征及发育环境. 地球化学, 37(1): 59-64. [Zhang W Z,Yang H,Yang Y H,Kong Q F,Wu K.2008. Petrology,elemental geochemistry and developmental environment of Chang7 high quality source rocks in Ordos Basin. Geochimica, 37(1): 59-64] [19] 张文正,杨华,侯林慧,刘飞. 2009. 鄂尔多斯盆地延长组不同烃源岩17α(H)-重排藿烷的分布及其地质意义. 中国科学: 地球科学, 39(10): 1438-1445. [Zhang W Z,Yang H,Hou L H,Liu F.2009. The distribution and geological significance of 17α-HI-rearrangement of different hydrocarbon source rocks in Yanchang Formation,Ordos Basin,China. Science China: Earth Sciences, 39(10): 1438-1445] [20] 张文正,杨华,解丽琴,杨奕华. 2010. 湖底热水活动及其对优质烃源岩发育的影响: 以鄂尔多斯盆地长7烃源岩为例. 石油勘探与开发, 37(4): 424-429. [Zhang W Z,Yang H,Xie L Q,Yang Y H.2010. Hydrothermal activity under the lake and its influence on the development of high quality source rocks: A case study of Chang7 source rock in Ordos Basin. Petroleum Exploration and Development, 37(4): 424-429] [21] 张文正,杨华,解丽琴,解古巍. 2011. 鄂尔多斯盆地延长组长7优质烃源岩中超微化石的发现及意义. 古生物学报, 50(1): 109-117. [Zhang W Z,Yang H,Xie L Q,Xie G W.2011. Discovery and significance of ultrafossils from high quality source rocks of Yanchang 7 in Ordos Basin. Acta Palaeontologica Sinica, 50(1): 109-117] [22] 张文正,杨华,杨伟伟,吴凯,刘飞. 2015. 鄂尔多斯盆地延长组长7湖相页岩油地质特征评价. 地球化学, 44(5): 505-515. [Zhang W Z,Yang H,Yang W W,Wu K,Liu F.2015. Evaluation of geological characteristics of lacustrine shale oil in Chang 7 of Yanchang Formation,Ordos Basin. Geochimica, 44(5): 505-515] [23] 张烨毓,周文,唐瑜,邓虎成,彭先锋,陈文玲,王勃力,肖睿. 2013. 鄂尔多斯盆地三叠系长7油层组页岩储集层特征. 成都理工大学学报(自然科学版), 40(6): 671-676. [Zhang Y Y,Zhou W,Tang Y,Deng H C,Peng X F,Chen W L,Wang B L,Xiao R.2013. Shale reservoir characteristics of Chang 7 Formation of Triassic in Ordos Basin.Journal of Chengdu University of Technology(Science &Technology Edition), 40(6): 671-676] [24] 张忠义,陈世加,杨华,付金华,姚泾利,喻建,杨智,张文正,邓秀芹. 2016. 鄂尔多斯盆地三叠系长7段致密油成藏机理. 石油勘探与开发, 43(4): 590-599. [Zhang Z Y,Chen S J,Yang H,Fu J H,Yao J L,Yu J,Yang Z,Zhang W Z,Deng X Q.2016. Formation mechanism of dense oil in Chang 7 section of Triassic system in Ordos Basin. Petroleum Exploration and Development, 43(4): 590-599] [25] Allison P A,Pye K.1994. Early diagenetic mineralization and fossil preservation in modern carbonate concretions. Palaios, 9: 561-575. [26] Bojanowski M J,Barczuk A,Wetzel A.2014. Deep-burial alteration of early-diagenetic carbonate concretions formed in Paleozoic deep-marine greywackes and mudstones(Bardo Unit,Sudetes Mountains,Poland). Sedimentology, 61: 1211-1239. [27] Coleman M L.1993. Microbial processes: Controls on the shape and composition of carbonate concretions. Marine Geology, 11: 127-140. [28] Coniglio M,Cameron J S.1990. Early diagenesis in a potential oil shale:Evidence from calcite concretions in the Upper Devonian Kettle Point Formation,southwestern Ontario. Bulletin of Canadian Petroleum Geology, 38: 64-77. [29] Dale A,John C M,Mozley P S,Smalley P C,Muggeridge A H.2014. Time-capsule concretions: Unlocking burial diagenetic processes in the Mancos shale using carbonate clumped isotopes. Earth and Planetary Science Letters, 394: 30-37. [30] Feistner K.1989. Petrographic examination and re-interpretation of concretionary carbonate horizons from the Kimmeridge clay,Dorset. Journal of the Geological Society, 146: 345-350. [31] Fisher Q,Raiswell R,Marshall J.1998. Siderite concretions from nonmarine shales(Westphalian A)of the Pennines,England: Controls on their growth and composition. Journal of Sedimentary Research, 68: 1034-1045. [32] Hendry J P,Pearson M J,Trewin N H,Fallick A E.2006. Jurassic septarian concretions from NW Scotland record interdependent bacterial,physical and chemical processes of marine mudrock diagenesis. Sedimentology, 53: 537-565. [33] Huggett J M.1994. Diagenesis of mudrocks and concretions from the London Clay Formation in the London Basin. Clay Minerals, 29: 693-707. [34] Klein J,Mozley P,Campell A,Cole R.1999. Spatial distribution of carbon and oxygen isotopes in laterally extensive carbonate-cemented layers: Implications for mode of growth and subsurface identification. Journal of Sedimentary Research, 69: 184-191. [35] Lash G G,Blood D.2004. Geochemical and textural evidence for early(shallow)diagenetic growth of stratigraphically confined carbonate concretions,Upper Devonian Rhinestreet black shale,western New York. Chemical Geology, 206: 407-424. [36] Loyd S J,Berelson W M,Lyons T W,Hammond D E, Corsetti F A.2012. Constraining pathways of microbial mediation for carbonate concretions of the Miocene Monterey Formation using carbonate-associated sulfate. Geochimica et Cosmochimica Acta, 78: 77-98. [37] Loyd S J,Dickson J,Boles J R,Tripati A K.2014. Clumped-isotope constraints on cement paragenesis in septarian concretions. Journal of Sedimentary Research, 84: 1170-1184. [38] Mavotchy N O,El Albani A,Trentesaux A,Fontaine C,Pierson-Wickmann A C,Boulvais P,Riboulleau A,Pemba L N,Pambo F,Gauthier-Lafaye F.2016. The role of the early diagenetic dolomitic concretions in the preservation of the 2.1-Ga paleoenvironmental signal: The Paleoproterozoic of the Franceville Basin,Gabon. Comptes Rendus Geoscience, 348: 609-618. [39] McBride E F,Picard M D,Milliken K L.2003. Calcite-cemented concretions in Cretaceous sandstone,Wyoming and Utah,U.S.A. Journal of Sedimentary Research, 73: 462-483. [40] Mercedes-Martína R,Rogersona M R,Brasier A T,Vonhof H B,Prior T J,Fellows S M,Reijmer J J G,Billing I,Pedley H M.2016. Growing spherulitic calcite grains in saline,hyperalkaline lakes: Experimental evaluation of the effects of Mg-clays and organic acids. Sedimentary Geology, 335: 93-102. [41] Mozley P S.1996. The internal structure of carbonate concretions in mudrocks: A critical evaluation of the conventional concentric model of concretion growth. Sedimentary Geology, 103: 85-91. [42] Raiswell R.1971. The growth of Cambrian and Liassic concretions. Sedimentology, 17: 147-171. [43] Raiswell R.1988. Evidence for surface reaction-controlled growth of carbonate concretions in shales. Sedimentology, 35: 571-575. [44] Raiswell R,White N J M.1978. Spatial aspects of concretionary growth in the upper Lias of Northeast England. Sedimentary Geology, 20: 291-300. [45] Raiswell R,Fisher Q.2000. Mudrock-hosted carbonate concretions: A review of growth mechanisms and their influence on chemical and isotopic composition. Journal of the Geological Society, 157: 239-251. [46] Selles-Martinez J.1996. Concretion morphology,classification and genesis. Earth-Science Reviews, 41: 177-210. [47] Wanas H A.2008. Calcite-cemented concretions in shallow marine and fluvial sandstones of the Birket Qarun Formation(Late Eocene),El-Faiyum depression,Egypt: Field,petrographic and geochemical studies: Implications for formation conditions. Sedimentary Geology, 212: 40-48. [48] Weeks L G.1957. Origin of carbonate concretions in shales,Magdalena Valley,Columbia. Geological Society of American Bulletin, 68: 95-102.
