【作者】 罗文琴；

【导师】 张金功；

【作者基本信息】 西北大学 ， 固体地球物理学， 2011， 硕士

【副题名】以鄂尔多斯盆地上古生界为例

【摘要】 鄂尔多斯盆地上古生界砂岩致密,除压实作用外,流体向固体转化的作用是一个重要的影响因素。本文在区域地质、埋藏史、热演化史以及盆地流体动力场和化学场资料的基础上,利用岩心资料、薄片资料、常规岩心物性测试资料,对鄂尔多斯盆地上古生界由流体转化成的主要固体(石英、铁方解石、固体沥青等)在砂岩孔隙中的分布特征进行了研究,并对其成因进行了初步分析。同时,对由流体转化成的主要固体(石英、铁方解石、固体沥青等)的含量与砂岩孔隙结构、孔隙度、渗透率的关系进行了初步研究。取得的主要认识如下：(1)鄂尔多斯盆地上古生界由流体转化成的固体主要有石英、铁方解石和固体沥青,其中石英主要分布于粒间孔隙的边缘和较小的粒间喉道中,而铁方解石和固体沥青可充满整个粒间孔隙和喉道。(2)由流体转化成的石英主要在砂岩粒间孔隙边缘和较小的粒间喉道分布,说明鄂尔多斯盆地上古生界存在SiO2过饱和流体形成的条件,但缺少向流体中持续补充SiO2的条件。铁方解石可充满整个粒间孔隙和喉道,说明鄂尔多斯盆地上古生界存在含Fe2+、Ca2+、CO32-流体混合的条件,也存在向流体中持续补充Fe2+、Ca2+、CO32-的条件。固体沥青可充满整个粒间孔隙和喉道,说明鄂尔多斯盆地上古生界存在可溶沥青质的大量产生和大规模运移分异的条件。(3)由流体转化成的石英含量与砂岩孔隙度、渗透率无明显对应关系,当由流体转化成的石英含量较高时,砂岩的孔隙度和渗透率也可能较高。而铁方解石含量和固体沥青含量与砂岩孔隙度、渗透率呈负相关关系,当铁方解石含量和固体沥青含量增高时,砂岩的孔隙度和渗透率均明显降低。更多还原

【Abstract】 In this dissertation, the author analyzes the products——quartz, ferrocalcite and solid bitumen, from transformation of fluids to solids, and their impact on pore structure, porosity and permeability of sandstone, by core material, thin section and core properties, based on regional geology, burial history and basin fluid history. The conclusions are as follows:(1) In Upper Paleozoic of Ordos Basin, quartz, ferrocalcite and solid bitumen are general solid products of transformation from fluids. Quartz, from the transformation of fluids to solids, often fills throats and the edges of intergranular pores of sandstone. Ferrocalcite, as well as solid bitumen could completely fill large intergranular pores and throats of sandstone.(2) From the distribution, in sandstone pores, of quartz, ferrocalcite and solid bitumen, we can infer that in Upper Paleozoic of Ordos Basin, there are conditions for the forming of fluid with high SiO2 concentration, the mixing of fluids containing Fe2+, Ca2+and CO32-, the supplement of Fe2+, Ca2+ and CO32- to fluid, and the producing and migrating of dissoluble bitumen, but no conditions for the supplement of SiO2 to fluid.(3) The content of quartz, from the transformation of fluids to solids, has no corresponding relationship with porosity and permeability of sandstone. When the content of quartz is high, the porosity and permeability of sandstone may still high. Ferrocalcite, as well as solid bitumen, has negative correlation with porosity and permeability of svandstone. The porosity and permeability of sandstone both fall down abruptly when one of the contents of ferrocalcite and solid bitumen is high.更多还原