【作者】 白清华；

【导师】 柳益群；

【作者基本信息】 西北大学 ， 矿物学、岩石学、矿床学， 2009， 硕士

【摘要】 鄂尔多斯盆地上三叠统延长组储层砂岩中的浊沸石胶结物虽然占据了大部分原生粒间孔隙,但是后期溶蚀作用形成的次生孔隙又成为油气的主要储集空间。因此,对延长组砂岩中浊沸石及其次生孔隙的分布及成因的研究对于该区的油气勘探具有重要意义。通过岩芯观察,偏光显微镜下普通薄片、铸体薄片观察,流体包裹体测温,扫描电镜及能谱分析,粘土矿物X衍射和电子探针等分析方法,研究了延长组含浊沸石砂岩的岩石学特征。结合延长组的地质背景和前人对浊沸石的研究资料,研究了延长组含浊沸石砂岩的成岩作用,建立了成岩序列。对浊沸石胶结物的形成机理有了更深刻的理解。主要取得以下认识:1.浊沸石在平面上分布具有由盆地东北向西南方向随物源距离的增加而减少的趋势,完全来自盆地西或西南方向物源时浊沸石缺失。纵向上呈现从长7顶部—长6—长4+5—长3—长2含量逐渐下降的趋势。对长6而言,也有由底部至顶部浊沸石含量降低的趋势。但是也偶有例外。2.研究区长6大量出现的浊沸石溶蚀孔隙应该与长7烃源岩大量生烃脱羧作用形成的有机酸进入上覆地层有关,根据浊沸石溶蚀孔隙的分布情况判断,进入上覆地层的通道应该主要是裂缝。3.鄂尔多斯盆地延长组浊沸石的形成是来自盆地东北部的火山物质在成岩过程中水化和斜长石钠长石化共同作用的结果。浊沸石的形成主要分为两期:首先在早成岩期,凝灰质泥岩及火山碎屑组分中的蒙脱石随着温度的升高逐渐脱水最终形成含水很少且较稳定的浊沸石和钠长石。其次,进入中成岩期,物源来自盆地东北部的储层砂岩中大量的斜长石,通过斜长石钠长石化形成浊沸石。更多还原

【Abstract】 Although laumontite cements in Yanchang formation of Upper Triassic of Ordos Basin occupied the lots of porosity, its dissolution provides more secondary porosity, it is major stored space of oil-gas. Therefore, the formation process and distribution of laumontite cements are very important for exploring reservoirs.Using core observation, the microscope, fluid inclusions analysis, SEM and energy spectrum, clay mineral X-diffraction and electron microprobe et., studied the petrologic characters of Yanchang Formation sandstone. Based on the geological setting and research findings about laumontite in the early, studied the diagenesis of sandstone in the Yanchang formations and established the mode of the diagenesis. More knowledge of the precipitation mechanism of the laumonite cements was gotten.The main conclusions are as follows:1. Laumontite plane distribution in the basin, northeast to southwest direction from the source with increasing distance in the trend of declining, when source completely from the West or south-west of the basin were missing laumontite. Vertically on top of chang7 - chang6 - chang4 +5 - chang3 - chang2 content of has the gradual downward trend. For the purposes of chang6, from the bottom to the top content of laumontite has trend of decreased. However, occasional exceptions.2. A large number of laumontite porosity solution in chang6 should be more source rocks in the role of hydrocarbon come from chang7 formed by decarboxylation of organic acids into the overlying strata. In accordance with laumontite dissolution to determine the distribution of the porosity into the overlying strata channel should be mainly fracture.3. The research show that formation of laumontite of the yanchang formation is relation of sediments formed by volcanic activity and volcanic tuff rock come from the Yinshan fold belt. Laumontite were in the course of diagenetic hydration and albite plagioclase the results of the combined effect of petrochemicals. The formation of laumontite divided into two: First of all, in the early diagenesis period, montmorillonite of tuffaceous mudstone and volcanic clastic components gradually with increasing temperature dehydration and eventually the formation of water-bearing little and more stable laumontite and albite. Second, enter the period of diagenesis, source come from the north-eastern basin of the reservoir sandstone in a large number of plagioclase by albite plagioclase petrochemical form laumontite.更多还原