相对高放射性砂岩成因及储集性能定性评价——以鄂尔多斯盆地志丹油田长6油层组为例  

Genesis of the sandstone with higher radioactivity and the qualitative evaluation of its reservoir property:taking Chang 6 oil-bearing strata in Zhidan Oilfield,Ordos Basin as an example

作　　者：孙佩[1,2] 张小莉[1,2] 郭兰[1,2] 申怡博[1,2] 

机构地区：[1]西北大学大陆动力学国家重点实验室,陕西西安710069 [2]西北大学地质学系,陕西西安710069

出　　处：《西安石油大学学报（自然科学版）》2010年第2期18-21,共4页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：西北大学研究生创新基金项目(编号:2009YZZ42)

摘　　要：鄂尔多斯盆地志丹油田长6部分砂岩放射性较高,且整体具有低阻特点.相对高放射性和低阻特征给测井识别砂泥岩带来一定的困难,易把相对高放射性砂岩当成泥岩处理,从而造成有效储层的漏失.以生产动态资料为根据,利用测井和岩心资料,结合岩石物理分析,对相对高放射性砂岩的成因及其储集性能进行了综合分析.研究认为,研究区长6储层砂岩的相对高放射性是钙碱性火山物质溶解、蚀变造成Th、U的富集而形成的;火山物质沉积方式不同,相对高放射性砂岩储层自然伽马曲线形态特征不同,储集性能也有差别;水携式含凝灰质砂岩自然伽马曲线呈箱状、中—高值放射性,储集性能较好,空降型凝灰岩自然伽马曲线呈尖刀状、高放射性,储集性能较差.A part of Chang 6 oil-bearing sandstone is of higher radioactivity and lower electric resistance,which makes the lithologic identification in logging become difficult,and it is easy that the sandstone of higher radioactivity and lower electric resistance is mistook for mudstone.Thus some effective reservoir will be omitted.The genesis and the reservoir property of the sandstone of Chang 6 oil-bearing strata in Zhidan Oilfield in Ordos Basin are analyzed according logging and core data,and combined with rock physics analysis.It is held that the higher radioactivity of the sandstone in the studied area is due to the enrichment of thorium and uranium caused by the dissolution and the alteration of alkaline volcanic materials.The shape features of the natural gamma curves and the reservoir property of the sandstone of higher ratioactivity are different according to the different depositional styles of the volcanic materials.The carried-by-water tuffaceous sandstone is of box-shaped natural gamma curve,moderate to high radioactivity and better reservoir property;the landing-from-air volcanic tuff is of sharp knife-shaped natural gamma curve,high radioactivity and worse reservoir property.

关 键 词：相对高放射性砂岩 测井响应特征 成因 鄂尔多斯盆地 

分 类 号：TE121.3[石油与天然气工程—油气勘探] TE122.3