川东北地区飞仙关组优质白云岩储层的成因  

Genesis of dolostone reservoir of Feixianguan Formation in Lower Triassic of northeast Sichuan Basin

作　　者：郑荣才[1] 耿威[1] 郑超[2] 李爽[2] 李瑰丽[2] 罗平[3] 文华国[1] 

机构地区：[1]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [2]中国石油西南油气田分公司重庆气矿,重庆400021 [3]中国石油勘探开发研究院油气储层重点实验室,北京100083

出　　处：《石油学报》2008年第6期815-821,共7页Acta Petrolei Sinica

基　　金：中国石油天然气股份有限公司科技项目“川东北三叠系飞仙关组鲕滩白云岩储层形成机理与分布特征研究”部分成果

摘　　要：以岩石结构分析为基础,根据锶微量元素和锶同位素地球化学特征,对川东北普光气田下三叠统飞仙关组白云岩储层成因进行了研究。结果表明:埋藏白云岩的结构明显有别于准同生白云岩;飞仙关组各类碳酸盐岩的87Sr/86Sr值变化范围覆盖了全球早三叠世海水锶同位素范围,其平均值与全球早三叠世平均值基本一致,具有早三叠世海水锶同位素组成特征;埋藏白云岩87Sr/86Sr值变化范围和平均值与川东北地区飞仙关期海水锶同位素组成特征非常接近,说明白云岩化流体具有强烈的飞仙关期海水锶同位素组成特征;飞仙关组白云岩为成岩期多期次埋藏交代作用的产物,白云岩化流体来自于地层中高镁、高锶和高盐度的同期经萨勃哈环境浓缩的海源地层水。Based on the rock structure, strontium trace element and strontium isotope geochemistry characteristics, the genesis of high quality dolostone reservoir of Feixianguan Formation were analyzed in the Lower Triassic of northeast Sichuan Basin. The result indicates that the rock structure of the deep burial dolostone is quite different from that of penecontemporaneous dolostone. The ^87 Sr to ^86 Sr ratios of carbonate rocks in Feixianguan Formation cover the range of that of global seawater in the early Triassic. The average value is consistent with that of the global in the early Triassic. The ^87 Sr to ^86 Sr ratio of the burial dolostone in Feixianguan Formation contains the changing range of that of global seawater in the early Triassic and can well approximate to that of seawater in the early Triassic of northeast Sichuan Basin. The average value of ^87 Sr to ^86 Sr ratio is closer to that of seawater in the global early Triassic, which shows that dolostone diagenesis fluids have much strontium isotope composition characteristics in Triassic seawater. The dolostone of Feixianguan Formation is the product of diagenesis in multi-period replacement-burial, and the dolostone diagenesis flu ids come from condensed sea source water in sabkha, which is rich in Mg, Sr and high salinity.

关 键 词：川东北地区 下三叠统 飞仙关组 白云岩储层 锶微量元素 锶同位素 成岩流体 海源地层水 

分 类 号：TE112.21[石油与天然气工程—油气勘探]