【作者】 李琼；

【导师】 刘池阳；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2007， 硕士

【摘要】 本研究将铀矿和油气勘探理论相结合，通过对鄂尔多斯盆地西南地区钻井资料的归纳、统计以及岩芯的测试，应用测井解释、岩性、岩相分析、铀源以及数学分析等手段，对研究区深部放射性异常的分布、特征、成因及其对生烃的影响等方面进行了探讨。研究得出，长7段存在三层放射性异常：长7~1、长7~3的顶部和底部，各层异常分布上具一定的规律以及相互联系，且以铀元素显著富集为特征。关于放射性异常的成因，研究认为，一方面，延长组尘凝灰岩可能为铀的富集提供重要铀源；另外一方面，除了同沉积成因之外，不排除铀为同生沉积后生富集的可能，铀可能在后期发生了迁移，铀的迁移与后期构造变动引起的沉积、古地下水的注入以及古水文地质旋回有关；此外，古气候变化、晚三叠世西南缘较强烈的构造变动、延长组上部残留地层的厚层砂体、浊积扇相的浊积岩等因素，为放射性异常铀元素的富集提供了有利的沉积环境。通过计算和归纳认为，深部放射性异常对烃源岩具放射性生热加温作用和放射性催化作用，一定程度上，可以促进长7段烃源岩的生烃演化。探讨深部放射性异常及其对烃源岩演化的影响，有助于对浅部铀矿的铀源、深部古铀矿、油-铀相伴生机理等科学问题的理解，也为多种能源矿产共存富集的深入研究提供一条新的思路，具有比较重要的科学研究意义。更多还原

【Abstract】 Combining the prospecting theory of oil and gas with that of uranium, through the induction and statistics of well data and the test of rock cores in southwestern Ordos basin, the distribution, the characteristics, the genesis, and the impacts on hydrocarbon-generation of the deep radioactive anomaly are mainly studied in this paper, by means of well logging interpretation, lithology, petrographical, uranium traceback and mathematical analysis and so on.The study shows, with the feature of enrichment of uranium, three parts of significant deep radioactive anomaly exists in chang 7: chang 7~1, the top and the bottom parts of chang 7~3 member. They are regulated in distribution and probably also relates with each. Several factors for the genesis of the radioactive anomaly are analysed in the research. Firstly, the volcanoc ash tuff in Yanchang formation is probably an extremely important uranium source for the enrichment of uranium in studied area. Further more, besides the syndepositional origin model, the uranium enriched in this area, might also form in the synsedimentary stage and mineralize in the epigenetic phase. The uranium has once migrated later, the orientation of which was perhaps related with the hydrogeologic cycle, the deposition and the injected paleofluid caused by tectonic disturbance. More important, there are some indispensable advantages for the enrichment of uranium, such as, the intensive tectonic disturbance of the southwest part in Late Triassic, the massive sand body of the relic upper Yanchang formation, the turbidite of hackberry facies, and the paleoclimate and so on. Finally, the impacts that the deep radioactive anomaly on generating rock, are mainly thermocatalysis and radioactive catalysis, which have improved the evolution of the hydrocarbon generation of the oil source rock of chang 7 member.Probing into the deep radioactive anomaly and its effects on the embracing rocks, is conductive to the comprehension on some scientific issues, such as a source of shallow uranium deposits, the deep paleo-uranium deposits, and the mechanism of the oil-uranium association. Besides, it provides a new idea for the research of accumulation and distribution patterns for multi-energy mineral deposits, which is rather important in scientific study.更多还原