岩溶区页岩气勘探中的近地表地球物理探测技术应用研究  

Application of Near-Surface Geophysical Techniques in Shale Gas Exploration in Karst Area

作　　者：刘伟[1,2,3] 甘伏平 张庆玉[1,2] 潘晓东 何长响[1,2] 淡永 LIU Wei;GAN Fuping;ZHANG Qingyu;PAN Xiaodong;HE Changxiang;DAN Yong(Institute of Karst Geology,Guilin,Guangxi 541004;Key Laboratory of Karst Dynamics,Ministry of Natural Resources,Guilin,Guangxi 541004;School of Earth Science and Engineering,Nanjing University,Nanjing,Jiangsu 210046)

机构地区：[1]中国地质科学院岩溶地质研究所,广西桂林541004 [2]自然资源部岩溶动力学重点实验室,广西桂林541004 [3]南京大学地球科学与工程学院,江苏南京210046

出　　处：《地质与勘探》2023年第1期113-121,共9页Geology and Exploration

基　　金：中国地质调查局地质调查项目“南方碳酸盐岩地区油气页岩气调查评价”(编号:DD20221658);广西重点研发计划项目(编号:2020AB22013)联合资助。

摘　　要：岩溶区页岩气钻井在近地表常揭露溶洞、地下河、强裂隙带等不良地质体,严重制约了页岩气资源勘探开发的进程。在岩溶页岩气靶区利用地球物理技术探测对钻探不利的近地表地质结构构造,可有效规避钻井钻遇近地表强岩溶发育带、断层破碎带的风险。综合运用高密度电阻率成像法、音频大地电磁法和测氡法对贵州都匀和广西融安碳酸盐岩区的2个油气靶区进行了地下构造识别,结果表明:高密度电阻率成像法和音频大地电磁法能有效确定浅地表地下低阻构造的位置、宽度和产状,高密度电阻率成像法在50 m以浅深度拥有更高的分辨率,音频大地电磁法探测深度更深,但对地下介质的分辨率不高,氡气测量能很好地识别地下低阻构造的属性。高密度电阻率成像法、音频大地电磁法与测氡法三者可优势互补,组成有效识别岩溶区近地表地质结构构造的技术方法体系,可为南方岩溶区页岩气钻井避开近地表强岩溶发育带、断层破碎带以及最终位置的确定提供可靠的技术支撑。Shale gas drilling in karst areas often penetrates karst caves,underground rivers,strong fracture zones and other unfavorable geological bodies on near surface,which has seriously restricted the exploration and development of shale gas resources.Geophysical techniques can be utilized to detect near-surface geological structures unfavorable for drilling,which can effectively avoid the drilling risk of penetrating strong karst development zone and fault fracture zone.This work conducted ERT,AMT and radon measurements to identify underground structures in the Duyun hydrocarbon target area in Guizhou and Rong’an carbonate area in Guangxi.Results show that ERT and AMT can effectively determine the location,width and occurrence of subsurface low-resistivity structures,and ERT has higher resolution within 50 m underground.The AMT technique has a large detection depth but a lower resolution,and radon measurement can well distinguish the attribute of low-resistance structures.The joint measurement of the three methods complements each other,and forms a technical system for effectively identifying subsurface geological structures in karst areas.This study can provide reliable technical support for keeping shale gas drilling away from karst development zone,fault fracture zone,and also for the final location determination of shale gas drilling in karst area of South China.

关 键 词：页岩气 岩溶区 高密度电阻率成像法 音频大地电磁法 测氡法 地下构造 

分 类 号：P619.14[天文地球—矿床学]