摘要
以探讨柴达木盆地北缘侏罗系大煤沟组7段(J_2d^7)油页岩低放射性的控制因素为目的,选取鱼卡地区典型井目的层段的油页岩和暗色页岩为研究对象,结合测井资料及含油率、有机地球化学、X射线衍射、元素地球化学等岩心测试分析资料,对二者的组构、水体介质条件、放射性物质供给特征及其与岩石放射性的关系进行详细对比分析。结果表明:与暗色页岩段相比,油页岩整体具有低的自然GR值,具有高的含油率、有机质丰度及沉积期还原性较强水体介质条件,具有较低的黏土矿物含量及沉积期母岩区较弱的风化程度。初步分析得出,有机质富集及贫氧水体介质条件对于区内油页岩的低放射性无明显影响,而古气候条件由温湿到逐步干热,导致陆源黏土矿物及放射性物质输入有限是油页岩低放射性形成的关键。
The factors controlling the low radioactivity of oil shales in the 7th Section of Dameigou Formation of Jurassic in Northern Qaidam Basin were primarily discussed. Taking oil shales and dark shales in typical wells in Yuqia area as the research objects,the constituent,water-medium condition,radioactivity-source supply and their relation with radioactivity were analyzed in detail combined with logging data,oil-yield test and the analysis of organic geochemistry,X-ray diffraction and element geochemistry. The results show that,compared with dark shales,oil shales are generally characterized by the following attributes,lower GR,higher oil yield and organic matter content, stronger reducing-sedimentary water, lower clay-mineral content and weaker source weathering. Therefore,it can be inferred that the enrichment of organic matters and the condition of anoxic water medium hardly influence the radioactivity of oil shales,however,the limited input of terrestrial clay minerals and radioactive substances,caused by the semiarid climate,may dominate the low radioactivity of oil shales in the study area.
出处
《现代地质》
CAS
CSCD
北大核心
2016年第4期905-913,共9页
Geoscience
基金
中国地质调查局"青海柴达木盆地重要页岩气远景区调查评价"项目(1212011221045)
青海省地质勘查基金项目"青海省侏罗系油页岩资源调查评价"
科技部重大科技专项"西北地区中生界陆相典型页岩气赋存方式与富集规律研究"(2016ZX05025-001-006)
国家自然科学基金青年基金项目"柴北缘鱼卡-红山地区中生代构造热演化恢复:来自磷灰石裂变径迹和镜质体反射率的联合约束"(41502200)
关键词
大煤沟组7段
油页岩
低放射性
有机质丰度
风化作用
古气候
柴达木盆地北缘
the 7th section of Dameigou Formation
oil shale
low radioactivity
organic matter content
paleoclimate
northern Qaidam Basin
