海拉尔盆地碳钠铝石—柯绿泥石—钠板石三元共生特征及其油气地质意义

Combined characteristics of dawsonite-corrensite-allevardite and its geological significance of hydrocarbon exploration in Hailaer Basin

运用岩石薄片分析、扫描电镜和X射线衍射精细结构分析,在海拉尔盆地白垩系南屯组凝灰质砂岩和沉凝灰岩中发现三元共生的碳钠铝石—柯绿泥石—钠板石组合。这三种矿物共生构成火山凝灰质蚀变的特征矿物组合,是同生期古火山事件的可靠沉积和成岩后生蚀变记录,也是火山凝灰物质成岩后生条件由酸性过渡到碱性的古环境转变的标型记录。而且伴生的凝灰质溶蚀所形成的次生孔隙可大大改善储层物性,从而扩大了勘探下限深度。上述矿物组合与油气藏关系密切,因此也是寻找有效储层发育带和油气藏的重要标志。

The ternary combination of dawsonite-corrensite-allevardite was found in the sand tuff and sedimentary tuff in the Cretaceous Nantun Formation of Hailaer Basin using the rock section and SEM and X-ray diffraction fine texture analyses.The three kinds of associated minerals have implied the characteristic mineral combination of volcanic tuffaceous alteration,which illustrated the reliable deposition of the contemporaneous palaeovolcano events and signified the diagenetic epigenetic alteration records in the volcanic tuffaceous matters transiting from the acidic environment to the alkaline environment.The secondary pores associated with the tuffaceous alteration could greatly improve the reservoir properties and extend the lower limit of exploration depth.The above-mentioned mineral combination is closely related to hydrocarbon reservoirs and is the important mark for searching the development zone of effective reservoir and hydrocarbon reservoir.