内蒙古西部额济纳旗及邻区二叠系烃源岩热演化与油气的关系  

The relationship between the thermal evolution of Permian source rocks and oil and gas in Ejin Banner and its vicinities,western Inner Mongolia

作　　者：韩伟[1] 姜亭[1] 李玉宏[1] 魏建设[1] 

机构地区：[1]中国地质调查局西安地质调查中心．陕西西安710054

出　　处：《地质通报》2011年第6期911-915,共5页Geological Bulletin of China

基　　金：中国地质调查局国土资源大调查项目《西北地区中小盆地群油气资源远景调查》(编号:1212010733506)资助

摘　　要：分析了额济纳旗及其邻区二叠系烃源岩热演化史与油气生成的关系。根据镜质组反射率、包裹体均一温度、磷灰石裂变径迹等资料得出研究区达到最大埋深时的古地温梯度,分析额济纳旗地区热演化史的信息,进一步研究了热演化与油气生成的关系。研究结果表明,额济纳旗地区在白垩纪达到最大埋深,古地温梯度为4.1～5.5℃/100m。通过与邻区查干凹陷比较分析,认为额济纳旗地区古地温梯度高于现今的地温梯度,二叠系烃源岩热演化程度主要受古地温场的控制。热演化史与油气关系的研究结果表明,额济纳旗部分地区二叠系烃源岩在晚二叠世已进入油气生成期,生烃阶段以干气为主,在早白垩世热演化程度达到最高。This research aims at analyzing the relationship between the geothermal evolution of Permian source rocks and hydrocarbon generation in Ejin Banner and its vicinities.Based on the information of vitrinite reflectance,temperature data of liquid-phase inclusions and apatite fission tracks,the authors measured the paleogeothermal gradient of Ejin Banner area when it reached maximum gradient.Based on an analysis of the geothermal evolution history of Ejin Banner area,the authors investigated the relationship between the geothermal evolution and hydrocarbon generation.The results indicate that Ejin Banner area reached maximum gradient in Cretaceous period,with the paleogeothermal gradient being 4.1～5.5℃/100m.A comparison with the neighboring Chagan sag has revealed that the paleogeothermal gradient of Ejin Banner area was higher than its modern geothermal gradient.The Permian source rock geothermal evolution was mainly controlled by the paleogeothermal field.The research on the relationship between the geothermal evolution history and hydrocarbon generation indicates that some parts of Ejin Banner area entered into the hydrocarbon generation period in Late Permian.During the hydrocarbon-forming phase,the dry gas was dominant.In the Early Cretaceous period,the geothermal evolution of this area reached its maximum level.

关 键 词：额济纳旗地区 二叠纪 热演化史 古地温梯度 磷灰石裂变径迹 

分 类 号：P534.46[天文地球—古生物学与地层学] P618.13[天文地球—地质学]