祁连山木里地区电性结构及天然气水合物地质控制因素  

Electrical structure and geological controlling factors of natural gas hydrates in Muli,Qilian Mountains

作　　者：何梅兴[1] 裴发根[1,2] 方慧 张鹏辉[1] 何大双[1] 张小博 吕琴音[1] 仇根根 HE Meixing;PEI Fagen;FANG Hui;ZHANG Penghui;HE Dashuang;ZHANG Xiaobo;LÜQinyin;QIU Gengen(Institute of Geophysical and Geochemical Exploration,CAGS,Langfang 065000,China;College of Geophysics,Chengdu University of Technology,Chengdu 610059,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,河北廊坊065000 [2]成都理工大学地球物理学院,四川成都610059

出　　处：《中南大学学报（自然科学版）》2022年第3期879-889,共11页Journal of Central South University:Science and Technology

基　　金：中国地质科学院基本科研业务费项目(JYYWF20180902,JY201705)。

摘　　要：为了查明祁连山木里地区天然气水合物的分布规律和地质控制因素,研究陆域天然气水合物成藏机制,首先,以祁连山木里聚乎更矿区三露天为研究区,利用音频大地电磁测深(AMT)资料,开展AMT的二维和三维反演工作;其次,结合测井与钻孔资料,构建综合电性结构模型;最后,综合气源、断裂构造和冻土层等成藏要素,提出祁连山木里冻土区天然气水合物成藏模式。研究结果表明:研究区的三维电性结构模型以“东西分块、南北分带”为主要电性特征,较好地反映了泥岩、油页岩等主要地层、断裂构造的展布;从三维电性结构模型中新发现了2个“气烟囱”式的断裂通道,呈现“下宽上窄”的特征,指示了断裂破碎带的形态,其控制着区内天然气水合物的分布;天然气水合物主要位于逆冲推覆前锋带断层下盘,控矿构造样式以逆冲前锋型为主;断裂通道及冻土层是天然气水合物成藏的2个重要地质控制因素,天然气水合物分布具有“逆冲推覆前锋带、断裂破碎带和冻土层发育区”的规律。The purpose of the study is to identify the distribution pattern and geological controlling factors of natural gas hydrates in the Muli area of Qilian Mountains and study gas hydrate formation mechanism in land area.Firstly,Sanlutian of the Muli-Juhugeng mine was taken as the study area and 2-D and 3-D inversions of audio-frequency magnetotellurics(AMT)data was carried out.Secondly,a comprehensive electrical structure model was further constructed with the integrated application of logging and drilling data.Finally,a natural gas hydrate formation model in the Muli permafrost area of Qilian Mountains was proposed by combining the gas accumulation factors such as gas source fracture structure,and permafrost layer.The results show that 3-D electrical structure model of the study area is mainly characterized by"east-west blocking and north-south zoning",which better reflects the spread of major strata such as mudstone and oil shale and fracture structures.Two"gas chimney"type fracture channels are firstly identified from the 3-D electrical structure model,showing a"wide at the bottom and narrow at the top"feature.This indicates the morphology of the fracture zone,which controls the distribution of gas hydrates in the area.Natural gas hydrates are mainly distributed in the lower plate of the fault of thrust and nappe front belt,which is the main structure style controlling the distribution of gas hydrates.Fracture channel and permafrost layer are two important geological controlling factors for gas hydrate formation.The distribution of natural gas hydrates has the rule of"thrust and nappe front belt zone,fracture zone and permafrost layer zone".

关 键 词：祁连山 天然气水合物 音频大地电磁测深 气烟囱 成藏模式 

分 类 号：TH11[机械工程—机械设计及理论]