中扬子京山地区方解石脉成因及其对油气保存的指示意义

doi:10.11743/ogg20140105

摘要/Abstract

摘要： 野外观察中扬子京山地区逆冲推覆带和冲断褶皱带内奥陶系、二叠系和三叠系发育多期沿裂缝分布的方解石脉。通过稀土元素（REE），电子探针，氧同位素，流体包裹体分析及盆地模拟对方解石脉成因进行了研究。奥陶系和三叠系方解石脉REE呈现轻稀土元素（LREE）富集，重稀土元素（HREE）亏损，明显的正铕（Eu）异常，说明成脉流体受到了热液流体的影响；二叠系方解石脉REE总量低，LREE低度富集，HREE配分曲线平坦，中等程度负铈（Ce）异常，显示成脉流体为大气淡水成因。根据电子探针Fe，Mn元素分析，部分奥陶系方解石脉成因与其围岩碳酸盐溶解有关；二叠系方解石脉成因主要与大气淡水淋滤碳酸盐成分有关，三叠系方解石脉成因与其他层位海相碳酸盐成分有关。利用氧同位素温度和流体包裹体均一温度，结合研究区虚拟井的埋藏史和热史模拟结果，推测3套地层裂缝方解石脉体形成深度约在2 000~2 500 m，形成时间约为距今150~60 Ma。综合方解石脉地球化学特征分析认为，燕山期构造挤压抬升作用伴随的热液流体、成岩流体及地表水下渗作用使京山地区油气保存条件遭受了一定程度的破坏。

关键词: 稀土元素, 氧同位素, 方解石脉体, 油气保存, 中扬子地区

Abstract: Field observation shows that multiple phases of calcite veins occur along fractures in the Ordovician,Permian and Triassic of overthrust belts and fold-thrust belts in Jingshan region,Mid-Yangtze.Using rare earth elements(REE),electron microprobe,oxygen isotope,fluid inclusions and basin modeling,this paper analyzed the genesis of these calcite veins.The REE of calcite veins in the Ordovician and Triassic are characterized by enrichment of LREE,loss of HREE and obvious positive Eu anomaly,indicating that their vein-froming fluids were affected by hydrothermal fluids.Calcite veins in the Permian feature in low REE,only slight enrichment of LREE,flat HREE patterns,and the presence of a moderate negative Ce anomaly,implying that their vein-froming fluids originated from meteoric water infiltration.Analysis of Fe and Mn through electron microprobe indicates that some calcite veins in the Ordovician were derived from the dissolution of surrounding carbonate rocks,the calcite veins in the Permian were derived from leaching and dissolution of carbonates by meteoric water,and those in the Triassic were related to the dissolution of carbonate derived from other horizons.Combined with burial and thermal history modeling of pseudo-wells,analysis of oxygen isotope temperatures and homogenized temperature of fluid inclusions show that the calcite vines filling fractures in these 3 sequences were formed at 150~60 Ma ago at burial depth in the range from 2 000 m to 2 500 m.Based on a comprehensive analysis of geochemical behaviors of the calcite veins,it is believed that hydrothermal fluids,vein-froming fluids and meteoric water infiltration associated with tectonic compression and uplifting during Yanshan Orogeny may have damaged petroleum preservation conditions in Jingshan region to some extent.

Key words: rare earth element, oxygen isotope, calcite vein, petroleum preservation, Middle Yangtze region

中图分类号:

TE122.2

高键,何生,何治亮,等. 中扬子京山地区方解石脉成因及其对油气保存的指示意义[J]. 石油与天然气地质, 2014, 35(1): 33-41. doi: 10.11743/ogg20140105 Gao Jian,He Sheng,He Zhiliang,et al. Genesis of calcite vein and its implication to petroleum preservation in Jingshan region, Mid-Yangtze[J]. Oil & Gas Geology, 2014, 35(1): 33-41. doi: 10.11743/ogg20140105

参考文献

[1] 刘光鼎.论中国油气二次创业[J].海洋地质动态,2002,18(11):1-3. Liu Guangding.The second round of oil and gas exploration of China[J].Marine Geology Letter,2002,18(11),1-3.
[2] 何治亮,魏修成,钱一雄,等.海相碳酸盐岩优质储层形成机理与分布预测[J].石油与天然气地质,2011,32(4):489-498. He Zhiliang,Wei Xiucheng,Qian Yixiong,et al.Forming mechanism and distribution prediction of quality marine carbonate reservoirs[J].Oil & Gas Geology,2011,32(4):489-498.
[3] 李晋超,马永生,张大江,等.中国海相油气勘探若干重大科学问题[J].石油勘探与开发,1998,25(5):1-2. Li Jinchao,Ma Yongsheng,Zhang Dajiang,et al.Some important scientific problems on petroleum exploration in marine formations of China[J].Petroleum Exploration and Development,1998,25(5):1-2.
[4] 马永生,楼章华,郭彤楼,等.中国南方海相地层油气保存条件综合评价技术体系探讨[J].地质学报,2006,80(3):406-417. Ma Yongsheng,Lou Zhanghua,Guo Tonglou,et al.An Exploration on a technological system of petroleum preservation evaluation for marine strata in South China[J].Acta Geologica Sinica,2006,80(3):406-417.
[5] 王根海.中国南方海相地层油气勘探现状及建议[J].石油学报,2000,21(5):1-6. Wang Genhai.Petroleum exploration in the marine strata in southern china—exploration situation and proposal[J].Acta Petrolei Sinica,2000,21(5):1-6.
[6] 董福湘,刘立,曲希玉.大港滩海地区沙一段下部储层中方解石脉的成因[J].西安石油大学学报(自然科学版),2011,26(6):9-13. Dong Fuxiang,Liu Li,Qu Xiyu.Genesis of calcite vein in lower submember of No 1 member of Shahejie Formation,Dagang beach area[J].Journal of Xi'an Shiyou University(Edition of Natural Sciences),2011,26(6):9-13.
[7] 王东,王国芝,刘树根,等.塔东地区英东2井寒武系-奥陶系储层流体地球化学示踪[J].石油与天然气地质,2012,33(6):867-876. Wang Dong,Wang Guozhi,Liu Shugen,et al.Geochemical tracing of the Cambrian-Ordovician reservoir fluid in Well Yingdong-2,eastern Tarim Basin[J].Oil & Gas Geology,2012,33(6):867-876.
[8] 舒晓辉,张军涛,李国蓉,等.四川盆地北部栖霞组-茅口组热液白云岩特征与成因[J].石油与天然气地质,2012,33(3):442-448,458. Shu Xiaohui,Zhang Juntao,Li Guorong,et al.Characteristics and genesis of hydrothermal dolomites of Qixia and Maokou Formations in northern Sichuan Basin[J].Oil & Gas Geology,2012,33(3):442-448,458.
[9] 高福红,刘立,邹海峰,等.大港探区早古生代碳酸盐岩中方解石脉特征[J].世界地质,2001,20(3):257-263. Gao Fuhong,Liu Li,Zou Haifeng,et al.Calcite veins characteristics in Early Palaeozoic carbonate rock in Dagang region[J].Global Geology,2001,20(3):257-263.
[10] Zhong S J,Alfonso M.Partitioning of rare earth elements(REEs) between calcite and seawater Solutions at 25 ℃ and 1 atm,and high dissolved REE concentrations[J].Geochimica et Cosmochimica Acta,1995,59:443-453.
[11] 王芙蓉,何生,杨兴业.方解石脉对中扬子地区沉湖土地堂复向斜油气保存单元的指示意义[J].矿物岩石,2012,32(1):94-100. Wang Furong,He Sheng,Yang Xingye.Indication of calcite vein cha-racteristics on petroleum preservation in the chenhutuditang syclino-rium,Middle Yangtze region,Southern China[J].Journal of Mineralogy and Petrology,2012,32(1):94-100.
[12] 李梅,金爱民,楼章华,等.准噶尔盆地地层流体特征与油气运聚成藏[J].石油与天然气地质,2012,33(4):607-615 Li Mei,Jin Aimin,Lou Zhanghua,et al.Formation fluid characteristics and hydrocarbon migration and accumulation in Junggar Basin[J].Oil & Gas Geology,2012,33(4):607-615.
[13] 杨兴业,何生,何治亮,等.京山地区方解石脉包裹体、同位素特征及古流体指示意义[J].中国石油大学学报(自然科学版),2013,37(1):19-26. Yang Xingye,He Sheng,He Zhiliang,et al.Characteristics and pale-fluid activity implications of fluid-inclusion and isotope of calcite veins in Jingshan,Northern Mid-Yangtze[J].Journal of China University of Petroleum(Edition of Natural Sciences),2013,37(1):19-26.
[14] 何治亮,汪新伟,李双建,等.中上扬子地区燕山运动及其对油气保存的影响[J].石油实验地质,2011,33(1):1-11. He Zhiliang,Wang Xinwei,Li Shuangjian,et al.Yanshan movement and its influence on petroleum preservation in middle-upper Yangtze region[J].Petroleum Geology & Experiment,2011,33(1):1-11.
[15] 肖开华,陈红,沃玉进,等.江汉平原区构造演化对中、古生界油气系统的影响[J].石油与天然气地质,2005,26(5):688-693. Xiao Kaihua,Chen Hong,Wo Yujin,et al.Impact of tectonic evolution on Paleozoic and Mesozoic petroleum systems in Jianghan plain[J].Oil & Gas Geology,2005,26(5):688-693.
[16] 赵志根,高良敏.δEu、δCe计算方法的标准化问题[J].标准化学报,1998,19(5):23-25. Zhao Zhigen,Gao Liangmin.The standardized question of δEu and δCe calculation method[J].Journal of Standardized,1998,19(5):23-25.
[17] 李闫华,鄢云飞,谭俊,等.稀土元素在矿床学研究中的应用[J].地质找矿论丛,2007,22(4):294-298. Li Yanhua,Yan Yunfei,Tanjun,et al.The application of rare earth elements in research of ore deposits[J].Contributions to geology and mineral resources research,2007,22(4):294-298.
[18] O'Neil J R,Clayton R N,Mayeda T K.Oxygen isotope fractionation in divalent metal carbonates[J].The Journal of Chemical Physics,1969,51(12):5547-5558.
[19] 王衍琦.阴极发光显微镜在储层研究中的应用[M].北京:石油工业出版社,1996. Wang Yanqi.The application of Cathodoluminescence microscopy in the study of reservoir[M].Beijing:Petroleum Industry Press,1996.
[20] 李荣清.湖南多金属成矿区方解石的稀土元素分布特征及其成因意义[J].矿物岩石,1995,15(4):72-77. Li Rongqing.Rare earth element distribution and its genetic signification of calcite in Hunan polymetallic metallogenic province[J].Journal of Mineralogy and Petrology,1995,15(4):72-77.
[21] 彭建堂,胡瑞忠,漆亮,等.锡矿山热液方解石的REE分配模式及其制约因素[J].地质论评,2004,50(1):25-32. Peng Jiantang,Hu Ruizhong,Qi Liang,et al.REE Distribution pattern for the hydrothermal calcites from the Xikuangshan antimony deposit and its constraining factors[J].Geological Review,2004,50(1):25-32.
[22] Bau M.Rare-earth element mobility during hydrothermal and metamorphic fluid-rock interaction and the significance of the oxidation state of europium[J].Chemical Geology,1991,93:219-230.
[23] Haskin M A,Haskin L A.Rare earth in European shales:a redetermination[J].Science,1966,154:507-509.
[24] Bau M,Dulsk P.Comparative study of yttrium and rare-earth element behaviors in fluorine-rich hydrothermal fluids[J].Contrib Mineral Petrology,1995,119:213-223.
[25] Lottermoser B G.Rare earth elements and hydrothermal ore form action processes[J].Ore Geology Reviews,1992,7(1):25-41.
[26] Klinkhammer G P,Elderfield H,Mitra A.Geochemical implications of rare earth element patterns in hydrothermal fluids from mid-ocean ridges[J].Geochimica et Cosmochimica Acta,1994,58(23):5105-5113.
[27] 胡文瑄,陈琪,王小林,等.白云岩储层形成演化过程中不同流体作用的稀土元素判别模式[J].石油与天然气地质,2010,31(6):810-818. Hu Wenxuan,Chen Qi,Wang Xiaolin,et al.REE models for the discrimination of fluids in the formation and evolution of dolomite reservoirs[J],Oil & Gas Geology,2010,31(6):810-818.
[28] 亨德森.稀土元素地球化学[M].北京:地质出版社,1989:195-213. Henderson.REE Geochemistry[M].Beijing:Geological Publishing House,1989:195-213.
[29] Sverlensky D A.Europium redox equilibria in aqueous solution[J].Earth and Planetary Science Letters,1984,67:70-78.