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利用临兴地区下石盒子组沉积砂体的重矿物、阴极发光、微量元素等资料,运用统计、计算等方法,确定出研究区下石盒子组的储层碎屑颗粒来源,并结合盆地周缘喷发出的火山物质探讨物源对储层的影响。研究结果表明,研究区下石盒子组砂岩中碎屑颗粒物源主要来自盆地北部阴山山脉,其母岩岩性为片麻岩相、变粒岩相、麻粒岩相及混合花岗岩、花岗闪长岩、火山岩等,主体由前寒武纪变质岩构成,填隙物物源主要为盆地周缘火山喷发形成的凝灰质。在物源控制下,下石盒子组砂岩骨架颗粒组分具有高含量岩屑特点,但由于水流的分异作用,千枚岩、泥板岩等塑性岩屑常存在于中砂级以下的砂岩中,在压实作用下破坏储层储集性能,粒度较粗的砂岩则因具有高含量刚性颗粒特点仍然可以形成优质储层;而同沉积的火山物质因不受水流分异作用的影响而广泛存在于各粒级砂岩中,因其具有塑性特征,在压实作用下加剧了储层致密化。火山物质为绿泥石环边的形成提供了物质基础,抑制石英加大边,在接受溶蚀后形成良好储层。由于物源区母岩长石矿物含量较低,粒内以及粒间孔隙多数由火山物质的溶蚀所提供。因此,火山物质相对于母岩区碎屑颗粒对储层的影响更大,是导致储层致密化以及非均质性的重要因素。
Based on the data of heavy minerals, cathodoluminescence and trace elements of the sedimentary sand body in Xiashihezi Formation in Linxing area, the source of reservoir detritus and the source of reservoir detritus in the Xiashihezi Formation in the study area are determined by means of statistics and calculation, Eruption volcanic material to explore the impact of provenance on the reservoir. The results show that the source rocks of the Xiashihezi sandstones in the study area are mainly from the Yinshan Mountains in the northern part of the basin. The lithology of the parent rocks is gneissic, granulitic, granulitic and mixed granite, Feldspathic rocks and volcanic rocks. The main body is composed of Precambrian metamorphic rocks. The source of interstitial materials is mainly tuffaceous formed by volcanic eruptions on the periphery of the basin. Under the control of provenance, the grain composition of sandstones in Xiashihezi Formation is characterized by high content of cuttings, but plastic cuttings such as phyllite and shale often exist in the sandstone below the mid-sand level due to the differentiation of water flow , The reservoir performance is destroyed under the action of compaction, and the sandstone with coarse grain size can still form a good reservoir due to the high content of rigid particles. However, the volcanic material in the same sediment is not affected by the current differentiation Widely existed in various sandstones, its compaction has aggravated the densification of reservoirs due to its plastic characteristics. Volcanic material provides the material basis for the formation of chlorite rings, suppresses quartz from increasing edges, and forms well reservoirs upon dissolution. Due to the low feldspar mineral content in the source area, intragranular and intergranular pores are mostly provided by volcanic erosion. Therefore, the impact of the volcanic material on the reservoir is greater than that on the parent rock, which is an important factor leading to the densification and heterogeneity of the reservoir.