邛西地区须家河组二段钙质夹层特征与成因  

Features and genesis of calcite-cement intercalations in the second member of Xujiahe formation in Qiongxi area

作　　者：黄东[1] 戴鸿鸣[1] 杨跃明[2] 杜诚[2] 王应容[2] 李玖勇[3] 

机构地区：[1]西南石油大学 [2]中国石油西南油气田公司川西北气矿 [3]中国石油西南油气田公司能源勘探开发公司

出　　处：《天然气工业》2009年第6期31-32,45,共3页Natural Gas Industry

基　　金：四川省重点学科建设基金项目(编号:SZD0414)的资助

摘　　要：在四川盆地邛西地区上三叠统须家河组二段储层中,以胶结物形式存在的方解石相当普遍,其含量、分布及溶解程度直接影响储集层的储集性能。为此,根据实测岩心分析资料、薄片鉴定资料、测井资料等对该区须二段储层钙质夹层的特征和成因进行了分析,研究表明:钙质夹层在测井曲线上具有低伽马、低声波时差和刺刀状高电阻率值特征,钙质夹层主要集中在泥质层附近,在局部地区对天然气具有一定的渗流屏障作用;根据实测方解石胶结物碳、氧同位素分析表明,泥质岩或煤系地层排烃时生成的有机酸是酸性水的主要来源。Calcites in the form of cement are quite common in the second member of the Upper Triassic Xujiahe formation of Qiongxi area,Sichuan basin,and their content,distribution and degree of dissolution directly influence the performance of the reservoirs. Core test data,thin section data and log data are used to analyze the features and genesis of the calcite-cement intercalations in the second member of the Xujiahe formation in the study area. The calcite-cement intercalations are characterized by low Gama value,low interval transit time and bayonet-like high resistivity on borehole logs. They mainly occur near argillaceous beds and act as barriers in local areas. Analysis of the measured carbon and oxygen isotope of calcite cements shows that the organic acid generated during hydrocarbon expelling of argillaceous rocks or coal measures is the main source of acidulous water.

关 键 词：四川盆地 邛西地区 晚三叠世 方解石 夹层 同位素法 有机酸 

分 类 号：P618.13[天文地球—矿床学]