音频大地电磁勘探在羌塘盆地可燃冰成藏条件探测中的应用研究  

Application of audio magnetotelluric exploration in the exploration of combustible ice reservoir forming conditions in Qiangtang basin,northern Tibet

作　　者：姚大为[1,2] 王大勇 YAO Dawei;WANG Dayong(Institute of Geophysical and Geochemical Exploration,CAGS,Langfang 065000,China;Laboratory of Geophysical EM Probing Technologies,MLR,Langfang 065000,China)

机构地区：[1]中国地质科学院地球物理地球化学勘查研究所,廊坊065000 [2]自然资源部地球物理电磁法探测技术重点实验室,廊坊065000

出　　处：《物探化探计算技术》2022年第5期634-639,共6页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：中国地质调查局天然气水合物试采专项(GZH201400301)。

摘　　要：青藏高原最大的含油含气盆地是羌塘盆地,盆地内广泛分布多年冻土是天然气水合物(可燃冰)形成的良好盖层条件,具备很好的找矿前景。为了在羌塘盆地探明可燃冰的基本成藏地质地球物理条件,在双湖地区鸭湖区块开展了音频大地电磁(AMT)探测研究。探测结果表明:AMT探测对冻土层反应灵敏,可以有效探测可燃冰冻土盖层的底界展布;对断裂构造反应明显,可以清晰圈定天然气运移通道、储集层的分布状态;二维反演地电断面显示鸭湖冻土区冻土层厚度在50 m~100 m之间,冻土厚度主要由海拔高程、地表水丰度、地质构造破碎带和沉积层松散度等因素控制。研究结果进一步佐证了鸭湖冻土区所具备的良好冻土盖层、发达的天然气运移通道和储集层构造,是可燃冰的成藏与藏储有利区块。Qiangtang basin is the largest oil and gas basins of the Tibetan plateau,the permafrost is widely distributed,which leads to a good formed condition and prospecting of gas hydrate.There is carried out audio magnetotelluric(AMT)exploration research in Yahu area to find out the basic accumulation conditions of geology and geophysics of the natural gas hydrate in Qiangtang basin.The detection results show that AMT detection had high sensitivity to the permafrost.This could distinguish effectively bottom boundary of permafrost caprock distribution and delineate clearly natural gas migration pathway reservoir distribution.The result of 2-D inversion of geoelectric section showed the thickness of Yahu frozen permafrost is between 50 to 100 meters.The development degree of frozen soil is affected mainly by tectonic fracture zone,sedimentary loose bed,surface water and the factors such as elevation height control.The results further supported that Yahu regions have good conditions of frozen soil cover layer,good rich gas migration channel and reservoir structure.It is a good block which is suitable for accumulation and reserves for gas hydrates.

关 键 词：羌塘盆地 冻土层 天然气水合物(可燃冰) AMT 

分 类 号：P631.2[天文地球—地质矿产勘探]