东营凹陷沙河街组砂岩中自生高岭石特征及其成因探讨  

Characteristics and genetic mechanism of authigenic kaolinite in the sandstones of the Shahejie formation in the Dongying depression

作　　者：张雪芬[1] 陆现彩[1] 刘庆[2] 张林晔[2] 李娟[1] 马野牧[1] 张立虎[1] 

机构地区：[1]内生金属成矿机制国家重点实验室,南京大学地球科学与工程学院,南京210093 [2]中石化胜利油田分公司地质科学研究院,东营257015

出　　处：《南京大学学报（自然科学版）》2013年第3期331-342,共12页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金(40973029,41072096)

摘　　要：东营凹陷沙河街组砂岩是胜利油区主要的储集层,自生高岭石是该储层中最常见的自生粘土.通过显微镜和扫描电镜观察,并结合X射线衍射和电子探针成分分析,发现碎屑粘土含量极少,自生高岭石为主,其集合体呈书页状和蠕虫状,长石碎屑的溶蚀现象多见;高岭石多充填在次生孔隙内,原生孔隙中亦可见.通过分析碳酸盐胶结物的碳氧同位素组成研究了砂岩成岩流体与烃源岩间的可能继承关系,自生高岭石的形成主要受烃源岩成岩演化过程中排出的含烃流体影响,推测酸性的含烃流体与长石的相互作用是高岭石形成的主要机制.统计表明:高岭石的含量与岩石的孔隙度表现出较好的正相关性,亦支持其形成于长石溶蚀的观点.The sandstones of the Shahejie formation in the Dongying depression are the main reservoirs in Shengli Oil Field. Kaolinite is the most common authigenic mineral in these reservoirs. By employing multiple techniques including scanning electron microscopy（SEM）, X-ray diffraction（XRD）and electron probe micro-analyzer（EPMA）, it is confirmed that little clastic clays exist in sandstones while large amount of authigenie kaolinite have precipitated. The kaolinite occurs as agglomerates of booklets or vermicular crystals, which generally fill in secondary pores from dissolution of feldspars as well as in primary pores. Carbon and oxygen isotopes of carbonate cements were analyzed in order to better understand the inheritance relationship between diagenesis fluids of sandstones and source rocks. The results indicate that the fluid released from source rocks accompanying with hydrocarbon generation can result in the dissolution of clastic feldspar and the formation of authigenic kaolinite. So it is considered that the interactionof acidic hydrocarbon bearing fluid with feldspars is the primary genetic mechanism of anthigenic kaolinites. Statistics analysis shows that the content of kaolinites is well correlated to porosity in reservoirs, and anthigenic kaolinites are closely related to the dissolution of feldspars.

关 键 词：高岭石 含烃流体 同位素 氧成因机制 东营凹陷 

分 类 号：P618.130.2[天文地球—矿床学]