川西北地区与北美西部中上泥盆统白云岩沉积和储层对比  

Deposition and Reservoir Comparison of Middle-Upper Devonian Dolomite in Northwestern Sichuan,China,and Western America

作　　者：熊连桥[1,2] 姚根顺 熊绍云 郝毅 沈安江 Xiong Lianqiao Yao Genshun Xiong Shaoyun Hao yi Shen Anjiang(Research Institute of Petroleum Exploration ＆ Development, PetroChina, Beijing 100083,China PetroChina Hangzhou Research Institute of Geology, Hangzhou 310023, China Key Laboratory of Carbonate Reservoirs, CNPC, Hangzhou 310023, China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油杭州地质研究院,杭州310023 [3]中国石油集团碳酸盐岩储层重点实验室,杭州310023

出　　处：《地质科技情报》2017年第4期49-59,共11页Geological Science and Technology Information

基　　金：国家科技重大专项"大型油气田及煤层气开发"(2016ZX05004-002);中国石油集团科技重大专项"深层油气勘探开发关键技术研究"(2014E-32-09)

摘　　要：川西北龙门山地区与北美西部地区泥盆系均发育白云岩,但至今尚无两个地区白云岩特征的详细对比。北美西部地区泥盆系白云岩研究非常详尽,且有巨型重油油藏发现,将两个地区进行对比,可为川西北泥盆系白云岩油气勘探提供重要启示。在对两个地区泥盆系白云岩的沉积大地构造背景、地层分布特征、岩石学和沉积相特征、地球化学特征及储层特征对比的基础上,从油气成藏条件出发,分析了川西北泥盆系白云岩储层的勘探潜力。两个地区泥盆系白云岩的沉积大地构造背景、气候条件、海平面变化及纵向分布层位等具有较高的相似性,在泥盆纪均位于赤道与30°S之间,同属被动大陆边缘,川西北地区气候比较温暖湿润,而北美西部地区则相对干旱炎热。构造运动和海平面变化控制了碳酸盐岩的纵向分布,川西北地区在吉维特末期海侵达到最大,而北美西部在中弗拉期达到最大;纵向上,泥盆系白云岩在川西北地区和北美阿尔伯塔盆地主要分布于中上泥盆统,而在美国西部内华达州则遍及整个泥盆系。泥盆系白云岩在川西北地区继承中下泥盆统碎屑岩发育,在北美西部则发育于前寒武纪或早古生代基底之上;其沉积相在川西北地区以碳酸盐岩缓坡为背景,发育生物层、泻湖、潮坪和礁滩体,可见蒸发泵、混合水白云石化作用和埋藏白云石化作用,形成的白云岩粒度较细,以微晶、细晶、中晶为主;北美西部则以碳酸盐岩缓坡和蒸发台地为主,礁体和潮坪更为发育,埋藏白云石化作用更普遍,可见渗透回流白云石化和海水白云石化作用,多为中晶、粗晶白云岩。北美西部地区泥盆系白云岩物性较好,有利于原油聚集;川西北地区则较差,但次生孔隙发育,是良好的天然气储层,其成藏条件良好,具有广阔的天然气勘探前景。Devonian dolomite is well developed in western America and Longmen Mountain areas,but no detailed direct comparison has been made in the two regions.Hydrocarbon exploration in the northwestern Sichuan Basin reveals the huge exploration potential in Devonian dolomite.Detailed studies have been made in the Western America and huge heavy oil reservoirs have been discovered.Comparison between these two regions could provide significant insights for the hydrocarbon exploration in the Devonian dolomite in Longmen Mountain area.Tectonic setting,strata distribution,petrophysical and facies characteristics,geochemical features and reservoir features were compared.Based on the hydrocarbon accumulation factors,exploration potential in the Devonian dolomite of Longmen Mountain area was analyzed.These regions have several similarities,including tectonic setting,climate condition,sea level change and the vertical distribution of dolomite.The regions located between the paleo-equator and 30°S and were passive margins during Devonian.Climate in the northwestern Sichuan Basin was warm and wet,while the western America climate was much warmer and dryer.Tectonic and eustatic controlled the vertical distribution of carbonate.The maximum transgression appeared in Late Givetian in the northwestern Sichuan,while this appearance was in Middle Frasinian in the western America.Devonian dolomite in northwestern Sichuan and Alberta basin is mainly distributed in the Middle-Upper Devonian,but distributed through the whole Devonian in Nevada,America.Devonian dolomite in the western America developed directly on Precambrian crystalline basement or Early Paleozoic sedimentary rocks,but in the Longmen Mountain area,dolomite developed conformably on older Devonian siliciclastic strata.Bioherms,lagoon,tidal flat and reef buildings were appeared on the carbonate ramp in the northwestern Sichuan,on which the evaporate dolomitization,mixing water dolomitization and burial dolomitization could be found.However,reef buildings and tidal flat were commo

关 键 词：白云岩 中上泥盆统 北美西部 川西北地区 龙门山 油气勘探 

分 类 号：P588.24[天文地球—岩石学]