鄂尔多斯盆地奥陶系马五_5亚段白云岩储层形成机理与展布规律
|
摘要
以白云岩岩石结构分析为基础,结合白云岩碳氧同位素、锶同位素、有序度等地球化学测试资料,对鄂尔多斯盆地奥陶系马五5亚段白云岩形成机理进行了探讨。研究表明,马五5亚段具有储集意义的白云岩为粉晶白云岩和泥粉晶白云岩,其中泥粉晶白云岩有序度为0.71,阴极发光表现为不发光,δ~(13)C值为-0.10‰,δ~(18) O值为-6.30‰;粉晶白云岩阴极发光以暗红色为主,有序度为0.85,δ~(13) C值为-0.68‰,δ~(18) O值为-6.58‰。泥粉晶白云岩和粉晶白云岩的碳氧同位素值与全球中奥陶世海水值大体相当,反映了白云岩化作用流体与同期海水有关,具有渗透回流白云岩化作用特征。结合古地理背景,建立了渗透回流白云岩化作用模式,指出马五5亚段沉积期古气候干燥、炎热,同生期具备形成富镁卤水的能力,是马五5亚段白云岩形成的关键,同生期白云岩化作用奠定了白云岩的展布格局,为浅埋藏期富镁卤水提供有效的下渗通道,同时有利于埋藏期孔隙的保存。马五5亚段白云岩在空间上有序分布,靠近古隆起区以整段白云岩为主,榆林—神木地区受伊盟古陆南斜坡影响,以中上段白云岩为主,靖边—安塞地区以中段白云岩为主,这些白云岩段是有利的勘探目标。
Based on dolomite structure analysis,the formation mechanism of Ordovician Ma5_5 dolomite was discussed with geochemistry test data of carbon isotopes,oxygen isotopes,strontium isotopes,and order degree.The study showed that reservoir-effective lithology is mud-powder crystal dolomite and powder crystal dolomite.The mud-powder crystal dolomite is non-cathode luminescence with 0.71 order degree,0.1‰δ~(13)C,and-6.3‰ δ~(18) O,while the powder crystal dolomite is mainly dark-red cathode luminescence with0.85 order degree,-0.68‰ δ~(13) C,-6.58‰ δ~(18) O.The carbon and oxygen isotopes of mud-powder crystal dolomite and powder crystal dolomite are roughly equivalent to the value of seawater in the Middle Ordovician.It reflected that dolomitization fluid is related to the same period seawater,with characteristics of reflux-seepage dolomitization.Combined with palaeogeographic background,the reflux-seepage dolomitization model was established.The dry and hot paleoclimate,which had the ability to form Mg-rich brine in Ma5_5 deposition period,is the key to form Ma5_5 dolomite.Syngenetic dolomitization prepared the ground for the spread of dolomite,provided effective seepage channel for supergene dolomitization,and was conducive to the preservation of pores in burial period.Near the paleouplift area,the whole segment is dominanated by dolomite.Influenced by southern slope of the Yimeng paleocontinent,the middle and upper segment is dominanated by dolomite in Yulin-Shenmu area,and the middle segment is dominated by dolomite in Jingbian-Ansai area.The whole dolomite segment and the middle dolomite segment are favorable exploration targets.
Based on dolomite structure analysis,the formation mechanism of Ordovician Ma5_5 dolomite was discussed with geochemistry test data of carbon isotopes,oxygen isotopes,strontium isotopes,and order degree.The study showed that reservoir-effective lithology is mud-powder crystal dolomite and powder crystal dolomite.The mud-powder crystal dolomite is non-cathode luminescence with 0.71 order degree,0.1‰δ~(13)C,and-6.3‰ δ~(18) O,while the powder crystal dolomite is mainly dark-red cathode luminescence with0.85 order degree,-0.68‰ δ~(13) C,-6.58‰ δ~(18) O.The carbon and oxygen isotopes of mud-powder crystal dolomite and powder crystal dolomite are roughly equivalent to the value of seawater in the Middle Ordovician.It reflected that dolomitization fluid is related to the same period seawater,with characteristics of reflux-seepage dolomitization.Combined with palaeogeographic background,the reflux-seepage dolomitization model was established.The dry and hot paleoclimate,which had the ability to form Mg-rich brine in Ma5_5 deposition period,is the key to form Ma5_5 dolomite.Syngenetic dolomitization prepared the ground for the spread of dolomite,provided effective seepage channel for supergene dolomitization,and was conducive to the preservation of pores in burial period.Near the paleouplift area,the whole segment is dominanated by dolomite.Influenced by southern slope of the Yimeng paleocontinent,the middle and upper segment is dominanated by dolomite in Yulin-Shenmu area,and the middle segment is dominated by dolomite in Jingbian-Ansai area.The whole dolomite segment and the middle dolomite segment are favorable exploration targets.
引文
[1] Yang Hua,Bao Hongping.Characteristics of hydrocarbon accumulation in the Middle Ordovician assemblages and their significance for gas exploration in the Ordos Basin[J].Natural Gas Industry,2011,31(12):11-20.杨华,包洪平.鄂尔多斯盆地奥陶系中组合成藏特征及勘探启示[J].天然气工业,2011,31(12):11-20.
[2] Yang Hua,Liu Xinshe,Zhang Daofeng.Main controlling factors of gas pooling in Ordovician marine carbonate reservoirs in the Ordos Basin and advances in gas exploration[J].Natural Gas Industry,2013,33(5):1-12.杨华,刘新社,张道锋.鄂尔多斯盆地奥陶系海相碳酸盐岩天然气成藏主控因素及勘探进展[J].天然气工业,2013,33(5):1-12.
[3] Zhao Junxing,Chen Hongde,Zhang Jinquan,et al.Genesis of dolomite in the fifth member of Majiagou Formation in the middle Ordos Basin[J].Acta Petrolei Sinica,2005,26(5):38-42.赵俊兴,陈洪德,张锦泉,等.鄂尔多斯盆地中部马五段白云岩成因机理研[J].石油学报,2005,26(5):38-42.
[4] Chen Zhiyuan,Ma Zhenfang,Zhang Jinquan.Genesis of the dolomite in M55subinterval Ordovician in central Ordos Basin[J].Petroleum Exploration and Development,1998,25(6):20-23.陈志远,马振芳,张锦泉.鄂尔多斯盆地中部奥陶系马五5亚段白云岩成因[J].石油勘探与开发,1998,25(6):20-23.
[5] Liu Deliang,Sun Xianru,Li Zhensheng.Analaysis of carbon and oxygen isotope on the Ordovician dolostones in the Ordos Basin[J].Petroleum Geology and Experiment,2006,28(2):155-162.刘德良,孙先如,李振生.鄂尔多斯盆地奥陶系白云岩碳氧同位素分析石油实验地质[J],2006,28(2):155-162.
[6] Huang Qingyu,Zhang Shaonan,Ding Xiaoqi,et al.Origin of dolomite of Ordovician Majiagou Formation,western and southern margin of the Ordos Basin[J].Petroleum Geology and Experiment,2010,32(2):147-154.黄擎宇,张哨楠,丁晓琪,等.鄂尔多斯盆地西南缘奥陶系马家沟组白云岩成因研究[J].石油实验地质,2010.32(2):147-154.
[7] Yang Hua,Fu Jinhua,Wei Xinshan,et al.Natural gas exploration domains in Ordovician marine carbonates,Ordos Basin[J].Acta Petrolei Sinica,2011,32(5):733-740.杨华,付金华,魏新善,等.鄂尔多斯盆地奥陶系海相碳酸盐岩天然气勘探领域[J].石油学报,2011,32(5):733-740.
[8] Wang Baoquan,Qaing Zitong,Zhang Fan,et al.Isotope characteristics of dolomite from the fifth member of the Ordovician Majiagou Formation,the Ordos Basin[J].Geochimica,2009,38(5):472-479.王保全,强子同,张帆,等.鄂尔多斯盆地奥陶系马家沟组马五段白云岩的同位素地球化学特征[J].地球化学,2009,38(5):472-479.
[9] Zhao Weiwei,Wang Baoqing.Geochemical characteristics of dolomite from 5th member of the Ordovician Majiagou Formation in Sulige area,Ordos Basin[J].Acta Geoscientica Sinica,2011,32(6):681-690.赵卫卫,王宝清.鄂尔多斯盆地苏里格地区奥陶系马家沟组马五段白云岩的地球化学特征[J].地球学报,2011,32(6):681-690.
[10] Zhao Junxing,Chen Hongde,Zhang Jinquan,et al.Genesis of dolomite in the fifth member of Majiagou Formation in the middle Ordos Basin[J].Acta Petrolei Sinica,2005,26(5):38-41,47.赵俊兴,陈洪德,张锦泉,等.鄂尔多斯盆地中部马五段白云岩成因机理研究[J].石油学报,2005,26(5):38-41,47.
[11] Huang Sijing.Carbonate Diagenesis[M].Beijing:Geological Publishing House,2010:54-58,254-256.黄思静.碳酸盐岩的成岩作用[M].北京:地质出版社,2010:54-58,254-256.
[12] Veizer J,Ala D,Azmy K,et al.87Sr/86Sr,δ13 C andδ18 O evolution of Phanerozoic seawater[J].Chemical Geology,1999,161(1):59-88.
[13] Keith M L,Weber J N.Isotopic composition and environmental classification of selected limestone and fossils[J].Geochimi Cochimi Acta,1964,28:1787-1816.
[14] Bathursl R G C.Carbonate Sediments and Their Diagenetic[M].New York:Elaecier Publishing Company,1971:145-156.
[15] Guard I P.Carbonate cemenlalion in themiddle Jurassic Oseherg reservoir sandstone,Oseherg field,Norway:A case of deep burial high temperature poikilotopic calcite[J].Sedimentary,1998,26(4):285-307.
[16] Siegel D F,Gregg J M.Classification of dolomite rock textures[J].Journal of Geology,1987,98:739-748.
[17] Amthor J E,Mountjoy E W Machel H G..Regional-scale porosity and permeability variations in Upper Devonian Leduc buildups:Implication for reservoir development and prediction in carbonates[J].AAPG Bulletin,1994,78:1541-1559.
[18] Fang Shaoxian,He Jiang,Hou Fanghao,et al.Reservoirs pore space types and evolution in M55to M51submembers of Majiagou Formation of Middle Ordovician in central gasfield area of Ordos Basin[J].Acta Petrologica Sinica,2009,25(10):2425-2441.方少仙,何江,侯方浩,等.鄂尔多斯盆地中部气田区中奥陶统马家沟组马五5—马五1亚段储层孔隙类型和演化[J].岩石学报,2009,25(10):2425-2441.
[19] Bao Hongping,Zhang Yunfeng,Wang Qianping,et al.Distribution and evolution of sedimentary microfacies of submember 5Majiagou Formation in the Ordos Basin[J].Coalgeology&Exploration,2016(5):16-21.包洪平,张云峰,王前平,等.鄂尔多斯盆地马五5亚段沉积微相分布及演化[J].煤田地质与勘探,2016(5):16-21.
[20] Longman M W.Carbonate diagenetic textures from nearsurface diagenetic environments[J].AAPG Bulletin,1980,64:461-487.
[2] Yang Hua,Liu Xinshe,Zhang Daofeng.Main controlling factors of gas pooling in Ordovician marine carbonate reservoirs in the Ordos Basin and advances in gas exploration[J].Natural Gas Industry,2013,33(5):1-12.杨华,刘新社,张道锋.鄂尔多斯盆地奥陶系海相碳酸盐岩天然气成藏主控因素及勘探进展[J].天然气工业,2013,33(5):1-12.
[3] Zhao Junxing,Chen Hongde,Zhang Jinquan,et al.Genesis of dolomite in the fifth member of Majiagou Formation in the middle Ordos Basin[J].Acta Petrolei Sinica,2005,26(5):38-42.赵俊兴,陈洪德,张锦泉,等.鄂尔多斯盆地中部马五段白云岩成因机理研[J].石油学报,2005,26(5):38-42.
[4] Chen Zhiyuan,Ma Zhenfang,Zhang Jinquan.Genesis of the dolomite in M55subinterval Ordovician in central Ordos Basin[J].Petroleum Exploration and Development,1998,25(6):20-23.陈志远,马振芳,张锦泉.鄂尔多斯盆地中部奥陶系马五5亚段白云岩成因[J].石油勘探与开发,1998,25(6):20-23.
[5] Liu Deliang,Sun Xianru,Li Zhensheng.Analaysis of carbon and oxygen isotope on the Ordovician dolostones in the Ordos Basin[J].Petroleum Geology and Experiment,2006,28(2):155-162.刘德良,孙先如,李振生.鄂尔多斯盆地奥陶系白云岩碳氧同位素分析石油实验地质[J],2006,28(2):155-162.
[6] Huang Qingyu,Zhang Shaonan,Ding Xiaoqi,et al.Origin of dolomite of Ordovician Majiagou Formation,western and southern margin of the Ordos Basin[J].Petroleum Geology and Experiment,2010,32(2):147-154.黄擎宇,张哨楠,丁晓琪,等.鄂尔多斯盆地西南缘奥陶系马家沟组白云岩成因研究[J].石油实验地质,2010.32(2):147-154.
[7] Yang Hua,Fu Jinhua,Wei Xinshan,et al.Natural gas exploration domains in Ordovician marine carbonates,Ordos Basin[J].Acta Petrolei Sinica,2011,32(5):733-740.杨华,付金华,魏新善,等.鄂尔多斯盆地奥陶系海相碳酸盐岩天然气勘探领域[J].石油学报,2011,32(5):733-740.
[8] Wang Baoquan,Qaing Zitong,Zhang Fan,et al.Isotope characteristics of dolomite from the fifth member of the Ordovician Majiagou Formation,the Ordos Basin[J].Geochimica,2009,38(5):472-479.王保全,强子同,张帆,等.鄂尔多斯盆地奥陶系马家沟组马五段白云岩的同位素地球化学特征[J].地球化学,2009,38(5):472-479.
[9] Zhao Weiwei,Wang Baoqing.Geochemical characteristics of dolomite from 5th member of the Ordovician Majiagou Formation in Sulige area,Ordos Basin[J].Acta Geoscientica Sinica,2011,32(6):681-690.赵卫卫,王宝清.鄂尔多斯盆地苏里格地区奥陶系马家沟组马五段白云岩的地球化学特征[J].地球学报,2011,32(6):681-690.
[10] Zhao Junxing,Chen Hongde,Zhang Jinquan,et al.Genesis of dolomite in the fifth member of Majiagou Formation in the middle Ordos Basin[J].Acta Petrolei Sinica,2005,26(5):38-41,47.赵俊兴,陈洪德,张锦泉,等.鄂尔多斯盆地中部马五段白云岩成因机理研究[J].石油学报,2005,26(5):38-41,47.
[11] Huang Sijing.Carbonate Diagenesis[M].Beijing:Geological Publishing House,2010:54-58,254-256.黄思静.碳酸盐岩的成岩作用[M].北京:地质出版社,2010:54-58,254-256.
[12] Veizer J,Ala D,Azmy K,et al.87Sr/86Sr,δ13 C andδ18 O evolution of Phanerozoic seawater[J].Chemical Geology,1999,161(1):59-88.
[13] Keith M L,Weber J N.Isotopic composition and environmental classification of selected limestone and fossils[J].Geochimi Cochimi Acta,1964,28:1787-1816.
[14] Bathursl R G C.Carbonate Sediments and Their Diagenetic[M].New York:Elaecier Publishing Company,1971:145-156.
[15] Guard I P.Carbonate cemenlalion in themiddle Jurassic Oseherg reservoir sandstone,Oseherg field,Norway:A case of deep burial high temperature poikilotopic calcite[J].Sedimentary,1998,26(4):285-307.
[16] Siegel D F,Gregg J M.Classification of dolomite rock textures[J].Journal of Geology,1987,98:739-748.
[17] Amthor J E,Mountjoy E W Machel H G..Regional-scale porosity and permeability variations in Upper Devonian Leduc buildups:Implication for reservoir development and prediction in carbonates[J].AAPG Bulletin,1994,78:1541-1559.
[18] Fang Shaoxian,He Jiang,Hou Fanghao,et al.Reservoirs pore space types and evolution in M55to M51submembers of Majiagou Formation of Middle Ordovician in central gasfield area of Ordos Basin[J].Acta Petrologica Sinica,2009,25(10):2425-2441.方少仙,何江,侯方浩,等.鄂尔多斯盆地中部气田区中奥陶统马家沟组马五5—马五1亚段储层孔隙类型和演化[J].岩石学报,2009,25(10):2425-2441.
[19] Bao Hongping,Zhang Yunfeng,Wang Qianping,et al.Distribution and evolution of sedimentary microfacies of submember 5Majiagou Formation in the Ordos Basin[J].Coalgeology&Exploration,2016(5):16-21.包洪平,张云峰,王前平,等.鄂尔多斯盆地马五5亚段沉积微相分布及演化[J].煤田地质与勘探,2016(5):16-21.
[20] Longman M W.Carbonate diagenetic textures from nearsurface diagenetic environments[J].AAPG Bulletin,1980,64:461-487.