塘古坳陷YL6井寒武系盐下变质岩地层厘定及地质意义
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摘要
塔里木盆地台盆区广泛发育下寒武统白云岩,厚度大、生储盖条件优越使其具有广阔的勘探前景,而YL6井在中寒武统膏盐岩之下钻揭了一套巨厚大理岩,这对于早寒武世玛东构造带是否为正常沉积的台盆相碳酸盐岩提出了质疑。通过岩心、岩屑薄片、扫描电镜资料明确了塘古坳陷YL6井巨厚大理岩的岩石学特征,根据大理岩变质特征、特征变质矿物的分布以及海绵骨针的发现,结合地震、测井等资料进一步明确了YL6井大理岩的母岩时代及变质成因。研究表明:(1) YL6井大理岩表现为过渡变质特征,大理岩中的特征变质矿物和酸性热液相关矿物证明其为晚期酸性热液活动的变质产物,并非区域变质基底;(2)大理岩中古生物化石以及地震、沉积背景资料表明玛东地区广泛分布正常沉积的下寒武统白云岩,局部因断裂沟通热源导致变质;(3)玛东构造带寒武系盐下石油地质条件优越,具有寻找盐下原生构造油气藏以及岩性—构造复合油气藏的勘探潜力。
Thick layers of Cambrian dolomite with favorable petroleum geological conditions and great exploration potential are widely developed in the inter-platform basin of the Tarim Basin. However,the rocks under middle Cambrian in well YL6 are marble instead of dolomite,and their age determines whether the paleo-land extended to the Madong tectonic belt in the Early Cambrian. By analyzing the drill cores,slices,SEM data,fossils,logging and seismic data,we identified the petrological characteristics and formation of the marble in well YL6. We concluded that:( 1) Distribution of the marble in well YL6 is transitional,and the metamorphic minerals in the marble indicate that the marble in well YL6 was formed by local thermal metamorphism instead of regional metamorphism;( 2) Fossils and seismic data indicate that the Lower Cambrian dolomite is widely distributed in Madong area,and that the metamorphism occurred along deep faults which are locally distributed in this area;( 3) The Lower Cambrian sequences in the Madong area have favorable petroleum geological con-ditions and exploration potential for discovering primary reservoirs and structural-lithologic reservoirs.
Thick layers of Cambrian dolomite with favorable petroleum geological conditions and great exploration potential are widely developed in the inter-platform basin of the Tarim Basin. However,the rocks under middle Cambrian in well YL6 are marble instead of dolomite,and their age determines whether the paleo-land extended to the Madong tectonic belt in the Early Cambrian. By analyzing the drill cores,slices,SEM data,fossils,logging and seismic data,we identified the petrological characteristics and formation of the marble in well YL6. We concluded that:( 1) Distribution of the marble in well YL6 is transitional,and the metamorphic minerals in the marble indicate that the marble in well YL6 was formed by local thermal metamorphism instead of regional metamorphism;( 2) Fossils and seismic data indicate that the Lower Cambrian dolomite is widely distributed in Madong area,and that the metamorphism occurred along deep faults which are locally distributed in this area;( 3) The Lower Cambrian sequences in the Madong area have favorable petroleum geological con-ditions and exploration potential for discovering primary reservoirs and structural-lithologic reservoirs.
引文
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[19]李勇,陈才,冯晓军,等.塔里木盆地西南部南华纪裂谷体系的发现及意义[J].岩石学报,2016,32(3):825-832.
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[21]郭颖,汤良杰,余腾孝,等.塔里木盆地塘古巴斯坳陷玛东构造带断裂特征及成因探讨[J].大地构造与成矿学,2016,40(4):643-653.
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[23]斯尚华,陈红汉,谭先锋,等.塔里木盆地麦盖提斜坡玉北地区奥陶系油气输导体系与成藏期[J].地球科学,2013,38(6):1271-1280.
[24]倪斌,汤良杰,郭颖,等.塔里木盆地玉北地区埋藏史及热史分析[J].现代地质,2017,31(2):357-365.
[2]崔海峰,田雷,刘军,等.麦盖提斜坡东段断裂活动特征及油气意义[J].石油地球物理勘探,2016,51(6):1241-1250.
[3]冯增昭,鲍志东,吴茂炳,等.塔里木地区寒武纪岩相古地理[J].古地理学报,2006,8(4):427-439.
[4]林畅松,李思田,刘景彦,等.塔里木盆地古生代重要演化阶段的古构造格局与古地理演化[J].岩石学报,2011,27(1):210-218.
[5]刘伟,张光亚,潘文庆,等.塔里木地区寒武纪岩相古地理及沉积演化[J].古地理学报,2011,13(5):529-538.
[6]陈永权,严威,韩长伟,等.塔里木盆地寒武纪-早奥陶世构造古地理与岩相古地理格局再厘定[J].天然气地球科学,2015,26(10):1831-1843.
[7]高华华,何登发,童晓光,等.塔里木盆地寒武纪构造-沉积环境与原型盆地演化[J].现代地质,2017,31(1):102-118.
[8]王永亚,干福熹.广西陆川蛇纹石玉的岩相结构及成矿机理[J].岩矿测试,2012,31(5):788-793.
[9]李洁,黄小龙.江西雅山花岗岩浆演化及其Ta-Nb富集机制[J].岩石学报,2013,29(12):4311-4322.
[10]黄瑞芳,孙卫东,丁兴,等.橄榄石蛇纹石化过程中氢气和烷烃的形成[J].岩石学报,2015,31(7):1901-1907.
[11]张明峰,王先彬,妥进才,等.蛇纹石化作用的气体形成研究进展[J].地球科学与环境学报,2016,38(1):11-20.
[12]丁伟明,钱逸.湖南石门杨家坪晚震旦世至早寒武世小壳化石[J].微体古生物学报,1988,5(1):39-55.
[13]胡杰,陈哲,薛耀松,等.皖南早寒武世荷塘组海绵骨针化石[J].微体古生物学报,2002,19(1):53-62.
[14]陈永权,蒋少涌,周新源,等.塔里木盆地寒武系层状硅质岩与硅化岩的元素、δ30Si、δ18O地球化学研究[J].地球化学,2010,39(2):159-170.
[15]陈曼云,金巍,郑常青.变质岩鉴定手册:地质调查工作方法指导手册[M].北京:地质出版社,2009:74-75.
[16]杨鑫,李慧莉,岳勇,等.塔里木盆地震旦纪末地层-地貌格架与寒武纪初期烃源岩发育模式[J].天然气地球科学,2017,28(2):189-198.
[17]李浩武,王建君,邬光辉,等.塔里木盆地塘古孜巴斯坳陷西部中加里东期断裂特征及形成机制[J].中南大学学报(自然科学版),2014,45(12):4331-4341.
[18]张光亚,刘伟,张磊,等.塔里木克拉托寒武纪-奥陶纪原型盆地、岩相古地理与油气[J].地学前缘,2015,22(3):269-276.
[19]李勇,陈才,冯晓军,等.塔里木盆地西南部南华纪裂谷体系的发现及意义[J].岩石学报,2016,32(3):825-832.
[20]杜金虎,潘文庆.塔里木盆地寒武系盐下白云岩油气成藏条件与勘探方向[J].石油勘探与开发,2016,43(3):327-339.
[21]郭颖,汤良杰,余腾孝,等.塔里木盆地塘古巴斯坳陷玛东构造带断裂特征及成因探讨[J].大地构造与成矿学,2016,40(4):643-653.
[22]黄太柱,蒋华山,马庆佑.塔里木盆地下古生界碳酸盐岩油气成藏特征[J].石油与天然气地质,2014,35(6):780-787.
[23]斯尚华,陈红汉,谭先锋,等.塔里木盆地麦盖提斜坡玉北地区奥陶系油气输导体系与成藏期[J].地球科学,2013,38(6):1271-1280.
[24]倪斌,汤良杰,郭颖,等.塔里木盆地玉北地区埋藏史及热史分析[J].现代地质,2017,31(2):357-365.