C、O同位素在川东北碳酸盐岩储层研究中的应用  

Application of Carbon and Oxygen Isotope to Carbonate Reservoirs in Northeast Sichuan Basin

作　　者：陈梅[1] 王龙樟[1,2] 张雄[1] 陈志斌[1] 

机构地区：[1]中国地质大学,武汉430074 [2]中国地质大学构造与油气资源教育部重点实验室,武汉430074

出　　处：《沉积学报》2011年第2期217-225,共9页Acta Sedimentologica Sinica

基　　金：中国石油化工股份有限公司项目(批准号:P06081)资助

摘　　要：通过对川东北鸡唱地区碳酸盐岩的C、O同位素分析,结合岩石薄片镜下研究和阴极发光分析及前人的研究成果,探讨飞仙关组三级海平面变化趋势和白云岩化作用机理。为了便于分析,将样品分为泥晶灰岩和白云岩两组。泥晶灰岩的C、O同位素分析结果表明:δ13C全为正值,明显分为两段,先快速上升、然后低辐振荡下降,指示海平面在飞一段初期快速上升、达到最大海泛面后,呈振荡、缓慢下降的趋势;δ13C演化曲线整体呈上升趋势,与三叠纪全球海平面上升的背景相吻合;δ18O对海平面升降的指示意义不明显,可能是由于后期成岩作用对原始δ18O的改造所致。白云岩C、O同位素分析结果表明:δ13C(0.91‰～2.09‰)、δ18O(-3.45‰～-9.29‰)的正交投点落在第二象限,结合薄片镜下研究和阴极发光分析,认为研究区白云岩成因为埋藏白云岩化。The trend of third-order sea-level changes and mechanism of dolomitization are studied,based on C,O isotope analysis of carbonate rocks,as well as microscopic research,CL analysis,and previous studies of Feixianguan Formation in Jichang of northeast Sichuan Basin.In convenience to analysis,the samples were grouped into two sets of micrite limestone and dolomite.The C,O isotope analysis of micrite limestone shows that the value of δ13C are all positive,and two stages are clear,that is,the first stage is a fast rising stage and followed a falling-stage with a wave shape.The result suggests that the sea level increases quickly in the early First Section of Feixianguan Formation,then,shows a slowly falling trend with sublevel fluctuation after maximum flooding surface.The δ13C evolution curve is rising totally,which is in accord with the rising trend of the Triassic global sea level.The implications of δ18O on the sea-level changes is obscure,due to the processes of late diagenesis.The C,O isotope analysis of dolomite shows that the orthogonal points of δ13C（0.91‰~2.09‰） and δ18O（-3.45‰^-9.29‰） fall in the second quadrant.The result,combining with microscope studies and cathodeluminescent analysis,suggests that dolomitization was formed in the buried condition.

关 键 词：川东北 碳酸盐岩 碳、氧同位素 海平面变化 埋藏白云岩化 

分 类 号：P588.245[天文地球—岩石学]