摘要:
三塘湖盆地火山岩中沸石分布广泛，石炭系—上二叠统火山岩储层发育层系主要为哈尔加乌组、卡拉岗组、条湖组。储层储集空间类型以次生溶蚀孔缝为主，构造裂缝型和不整合面溶蚀为辅。通过对研究区内所选井的岩石组分统计,发现火山岩岩性以中基性熔岩为主，杏仁体较发育，杏仁充填孔中以沸石类易溶矿物为主,为后期溶蚀作用的发生创造了条件。研究表明，浊沸石的形成主要有火山热液成因、交代蚀变成因和火山物质水化成因等。高pH 值对浊沸石的形成又特别有利。
通过薄片及电镜观察，结合X射线衍射分析、电子探针分析，确定了沸石的类型，探讨了沸石的成因。指出沸石类型以浊沸石为主，次为片沸石和方沸石，充填于气孔（杏仁体）和裂缝中，主要通过低温火山热液自生沉淀形成。
赋存于三塘湖盆地火山岩杏仁体和裂缝中的沸石类矿物，对储层性能的影响主要表现为两个方面：沸石的先期充填降低了孔渗条件，后期浊沸石的溶蚀才是改善储集性能的关键。通过分析沸石含量与面孔率及孔隙度的关系，指出火山岩储层中浊沸石充填为后期溶蚀造孔提供了物质基础，浊沸石的溶蚀是形成次生孔隙的关键。因此应加大对该区火山岩中浊沸石发育带的预测,为寻找潜在的有利储层提供方向。
Abstract:
The zeolite are widely distributed in volcanic rocks of Santanghu Basin, and the main groups developed in volcanic reservoirs of CarboniferousUpper Permian strata are Haerjiawu Group, Kalagang Group, Tiaohu Group. The types of reservoir space are mostly secondary dissolution aperture, with tectoclase and unconformity dissolution secondarily. Based on the study of the rock composition statistics of the wells in the selected area, We found that volcanic rocks were mainly intermediate and basic lava, amygdala developed relatively abundant, the filling holes in almond are typically zeolitebased soluble minerals and this characteristic create the helpful conditions for the postdissolution. Ourresults have shown that the main reason of laumontite formation are hydrothermal, metasomatic alteration and volcanic materials hydration, and so on. High pH has been particularly beneficial for the formation of laumontite.
By means of observations of thin section and microscopy, combining with Xray diffraction analysis, electron microprobe analysis, We determined the type of zeolite, discussed the causes of the zeolite, and pointed out that the main type of zeolite was adelforsit, with euzeolite and analcidite secondarily, they both filled in the holes (the amygdala) and the cracks, mainly through lowtemperature volcanic hydrothermal precipitation.
The zeolite minerals occurred in the volcanic amygdala and cracks of Santanghu Basin affected the reservoir properties mainly in two aspects: the early filling of zeolite reduced the porosity and permeability conditions, and the late laumontite dissolution is the key point to improve the reservoir properties. By analyzing the relationship of zeolite content with thin section porosity, indicating that the zeolite filling in the volcanic reservoir provides material basis for the postdissolution. Laumontite dissolution is the key to the formation of secondary porosity. So, laumontite growth zone of volcanic rocks in this area should be considered. to provide a direction for exploring potential reservoir.
点击查看大图
下载:
