Electrical structure identification of deep shale gas reservoir in complex structural area using wide field electromagnetic method

To fully exploit the technical advantages of the large-depth and high-precision artificial source electromagnetic method in the complex structure area of southern Sichuan and compensate for the shortcomings of the conventional electromagnetic method in exploration depth,precision,and accuracy,the large-depth and high-precision wide field electromagnetic method is applied to the complex structure test area of the Luochang syncline and Yuhe nose anticline in the southern Sichuan.The advantages of the wide field electromagnetic method in detecting deep,low-resistivity thin layers are demonstrated.First,on the basis of the analysis of physical property data,a geological–geoelectric model is established in the test area,and the wide field electromagnetic method is numerically simulated to analyze and evaluate the response characteristics of deep thin shale gas layers on wide field electromagnetic curves.Second,a wide field electromagnetic test is conducted in the complex structure area of southern Sichuan.After data processing and inversion imaging,apparent resistivity logging data are used for calibration to develop an apparent resistivity interpretation model suitable for the test area.On the basis of the results,the characteristics of the electrical structure change in the shallow longitudinal formation of 6 km are implemented,and the transverse electrical distribution characteristics of the deep shale gas layer are delineated.In the prediction area near the well,the subsequent data verification shows that the apparent resistivity obtained using the inversion of the wide field electromagnetic method is consistent with the trend of apparent resistivity revealed by logging,which proves that this method can effectively identify the weak response characteristics of deep shale gas formations in complex structural areas.This experiment,it is shown shows that the wide field electromagnetic method with a large depth and high precision can effectively characterize the electrical characteristics of deep,low-resistivity thin layers in complex structural areas,and a new set of low-cost evaluation technologies for shale gas target layers based on the wide field electromagnetic method is explored.

The application of the high-frequency electromagnetic sounding method in the exploration of underground thermal water

High-frequency electromagnetic sounding is an electromagnetic exploration method using the natural high-frequency electromagnetic field as a field source. It has higher resolution and greater depth penetration than the direct current method and is especially fit for geothermal energy exploration and low- and mid-level groundwater detection. We introduce a successful application of high-frequency electromagnetic sounding for evaluating geothermal water resources. The high frequency electromagnetic system （MT-USA with a frequency range from 10 KHz to 1 Hz） is first applied to sample field data from China. A remote reference station is used to assure sampled data quality. We then perform 2D inversion image processing with the electrical method data. The results basically indicate the spatial distribution of underground geothermal water and provide favorable clues to finding the sources of the subsurface geothermal water in this area.

Application of Transient Electromagnetic Method with Multi-Radiation Field Sources in Deep Edge Mineral Resources Exploration

In recent years,in order to meet the practical needs of deep edge mine detection with large depth and high precision,transient electromagnetic method(TEM)near emission source detection mode has become an international advanced method(Xue et al.,2020).

Combined Application of Wide-Field Electromagnetic Method and Flow Field Fitting Method for High-Resolution Exploration： A Case Study of the Anjialing No. 1 Coal Mine

The Anjialing No. 1 Coal Mine in Shanxi Province, China, contains a complicated old goaf and an unknown water distribution that hold high potential for serious water hazards. Due to poor detection resolution, previous attempts have failed to determine the scope of the old goal and the water distribution in the mine by separate use of various exploration methods such as seismic method, direct current resistivity, audio magnetotellurics, controlled-source audio-frequency magnetotellurics, and transient electromag-netics. To solve this difficult problem, a combination of the wide-field electromagnetic method and the flow field fitting method with three-dimensional resistivity data inversion was applied to determine the precise scope of the goal and the locations where water is present, and to identify the hydraulic con- nection between the water layers so as to provide reliable technical support for safe coal production. Reasonable results were achieved, with all these goals being met. As a result, a mining area of nearly 4 km^2 has been released for operation.

Genetic model and exploration target area of geothermal resources in Hongtang Area, Xiamen, China

The geothermal resources in Fujian Province are mainly hydrothermal resources of medium-low temperature.To better understand the whole process and conditions of heat control in the middle and deep crust,this study focuses on the analysis of heat accumulation model in Hongtang Area of Xiamen,and the main conditions of the model such as faults and sags are explored and interpreted in detail by using gravity and wide-field electromagnetic methods.4 main faults(F33,F2,F12 and HT-F1)and 10 secondary faults(HT-F2,HT-F3,HT-F4,HT-F5,HT-F6,HT-F7,HT-F8,HT-F9,HT-F10 and HT-F11)were inferred,and the distribution range of sags was delineated.The convective geothermal system is composed of four components:Heat source,geothermal reservoir,heat-conductive fault and heat retaining cover,which form a quaternary heat accumulation model.According to the model,the intersection of the main faults F12,HTF1 and F33 can be delineated as the primary target area of geothermal exploration,while the intersection of the secondary faults(F12 and HT-F6;F12 and HT-F2;HT-F9,HT-F10 and F12;F12 and HT-F11;F33 and HT-F3;HT-F8 and HT-F3;HT-F2,HT-F10 and HT-F1)can be delineated as the secondary target area.Borehole DR01,which is located in the primary target area,shows that the water temperature increases from fast to slow in the depth range of 0–500 m,and stays at 36℃below 500 m.The reliability of the heat accumulation model and the target area was tested via geothermal boreholes,which is of great significance to the exploitation and utilization of geothermal resources in Hongtang Area of Xiamen.

湘南坪宝矿田岩浆热液成矿系统深部探测与地球化学约束

湘南是我国乃至世界最重要的钨锡多金属矿集区之一,发育了坪宝、柿竹园、骑田岭等多个大型矿床(田)。随着浅部资源逐渐枯竭,成矿系统深延与探测成为找矿突破的重点,尤其是覆盖层下隐伏成矿岩体、流体运移通道与矿体赋存空间的准确识别。本文以湘南坪宝矿田为例,采用广域电磁、构造解析与地球化学等方法揭示了成矿系统的空间结构与物质组成:(1)矿田深部(<5 km)存在4个隐伏的燕山期花岗岩体,包括宝山、黄沙坪、大坊、野鹅塘,岩体呈现不规则形态;(2)岩体侵位受NNE走向、NE走向与NW走向的区域断裂交汇联合控制,其岩体接触带与次级断裂为主要的控矿构造;(3)断层破碎带中方解石、石英、赤铁矿等热液矿物为成矿流体活动留下的痕迹,可用来识别成矿流体的源区与路径;(4)科学钻探证实了矿体与成矿运移通道深延稳定,且可能与深部隐伏岩体导通;(5)宝山矿区西部、黄沙坪矿区东部、大坊与野鹅塘矿区深部应为该区未来找矿勘查的重点。通过广域电磁、构造解析与矿物地球化学分析可以深入认识隐伏岩体的空间形态与形成时代,构建成矿物质与流体的“源-运-储”模型,开展成矿系统的深部探测与成矿潜力评价。

时频电磁法在金牛湖地区深部地热资源勘查中的应用

南京金牛湖地区地质构造复杂、低阻覆盖层厚、电磁干扰强,为了查明该地区深部地热资源,应用时频电磁法进行探测。本次布置了2条时频电磁法剖面,采用大功率发射信号能够有效地穿透低阻覆盖层,获得了信噪比较高的原始数据。通过对时频电磁数据的处理、分析、反演及综合解译,获得了勘查区4000 m以浅的二维电性结构模型。结合地热地质条件,优选了地热钻探井位,经钻探最终验证,推测地层与实际钻探基本吻合,在1600 m钻遇断裂,终孔深度2800 m,经后期抽水试验确定,日出水量大于500 m 3,钻井井口水温51℃,说明获得了优质的深部地热资源。综上所述,时频电磁法在金牛湖地区深部地热资源勘查中的应用效果较好,揭示了南京金牛湖地区较好的地热地质条件,为该地区地热旅游资源的开发利用奠定了坚实的基础。

EH4电磁成像系统在西南含盐含石膏隧洞勘察中的应用探析

本文介绍了EH4电磁成像系统的原理、工作方法和资料处理,通过EH4电磁成像系统在云南禄丰黑井隧洞勘察中的应用实例,提出该方法可以应用在含盐和石膏隧道勘察中,在勘查地质构造、岩石破碎带和含盐、含石膏地层方面有很好的效果,为这类隧道勘察提供了科学依据。

垂直电性源瞬变电磁监测在典型地质构造中的应用

矿井地层中存在的地质构造易引起地质灾害的发生,对矿井安全生产造成极大威胁。为提高瞬变电磁法探测精度与探测范围,以电磁场扩散理论为基础,运用正演模拟方法,分析了垂直电性源瞬变电磁场的响应曲线衰减规律,设计了矿井地质构造致灾区垂直电性源在线监测系统,并模拟了垂直电性源TEM对典型断层地质构造的识别能力。结果表明:当发射源长度为1 000 m时,可监测的偏移距离在500~4 500 m,监测深度可达2 000 m,可以满足地质构造的探测需求。感应电动势与电场的六分量在平面图中均可对断层地质构造进行有效识别,其中z方向分量的识别效果最好。在衰减曲线图中,dBx/t与dBy/t对于断层的识别能力较弱,而其余的四个分量均可对断层构造进行有效识别。

神府矿区采空区精细化综合勘探技术研究

为精细化查明神府矿区亿源煤矿井田内原不明小煤窑采空区,为采空区治理提供科学依据,需开展瞬变电磁法、钻探及测井等综合勘查技术工作,以明确采空区分布范围及富水情况。结果表明:从测井曲线中可以看出煤岩层物性稳定,曲线形态明显,煤层具有高电阻率、低密度、低伽玛特性,煤层属导电性较差的高阻层(最高大于1000Ω·m),其他泥岩、砂质泥岩、砂岩等呈现相对低阻特征,煤层与围岩物性差异明显;瞬变电磁法采用280 m矩形发射线框、发射频率25 Hz、增益2^(2)~2^(5)之间、发射电流8 A、积分时间15 s的参数组合进行探测,对已知采空区反映明显,推断3^(-1)煤层房柱式采空区总面积0.985 km^(2);通过钻探揭露了2^(-2)煤和3^(-1)煤房柱式采空区,验证了物探推断的3^(-1)煤采空区。测井、瞬变电磁法探测、钻探相互依托、相辅相成,达到了精细化综合勘探的目的。

多尺度电磁联合方法在贵州某磷矿深部岩溶探测中的应用

随着新能源行业的迅猛发展以及粮食需求的不断增多,深部磷矿资源开采迫在眉睫。贵州作为磷矿资源大省,品位高、矿层厚,具有很高的开采价值。但该地区呈现典型的喀斯特地貌特征,可溶岩总面积达12.88万km^(2),约占全省总面积的73%。开采过程中极易发生井喷、突泥等地质灾害,严重影响工程进度与开发成本,甚至造成人员伤亡。因此,探明地下岩溶发育情况对于磷矿开采工作十分重要。结合研究区地质条件以及磷矿埋藏深的特点,本文综合运用扩频激电法和可控源电磁法进行岩溶探测。两种方法优势互补,相互印证,通过对反演得到的电阻率剖面图进行定性分析,准确地圈定出岩溶发育区,为下一步磷矿开采工作提供参考,同时也为岩溶发育地区的物探工作提供有益的参考和借鉴。

三合一埋置装置的研制及在电磁勘探中的应用

在石油勘探行业,涉及到对勘探中所用的各种仪器进行埋置,各野外小队有各自的设备,种类繁多,通用性、互换性较差,而且现有埋置设备存在各自的优缺点。针对现状,现研制了一套电动分体式三合一埋置工具,可用于大部分勘探仪器的埋置,进行了三种勘探仪器的埋置试验,并应用于电磁勘探项目中,获得了勘探小队的认可,大大提高了生产效率,具有推广前景。

基于瞬变电磁法的张家峁煤矿地层富水性特征研究

煤矿地层的富水性探测对于煤矿的防水与治水工作至关重要。张家峁煤矿现阶段主采2-2煤层,面临上部基岩风化含水层和工作面前方火烧岩涌水的水害风险。鉴于瞬变电磁法对富水区、采空区、含水构造等高导异常体的高灵敏度等优势,本研究采用地面瞬变电磁法对该煤田西部特定区域2-2煤层上覆的基岩、风化带、第四系岩层以及烧变岩的富水性进行探测,在四个地层分别探查出低阻异常区6处、9处、9处和2处,并结合钻孔、地层、水文、地形和磁法探测成果等多元资料以及低阻异常区的可靠性,对低阻异常区的成因分别进行了综合分析,这可为该区域煤层开采防水与治水工作的规划与执行提供科学依据。同时,本研究也可为瞬变电磁法在其它地区地层富水性探测中的应用提供一套全面的数据采集、处理、反演以及分析与解释的参考与借鉴资料,以推动该技术在煤矿地层探测领域的进一步发展与应用。

综合物探技术在城市地铁勘察中的研究与案例浅析

在城市地铁勘察中,岩溶、断裂及软土等不良地质是主要工程隐患,严重威胁着工程后续的施工建设安全,在常规地质勘察之外,有必要采用有效且适宜于城市环境的物探手段予以查明,提高勘察资料的可靠度和覆盖面。城市环境复杂,场地条件限制多,不同物性干扰强,整体物探环境恶劣。笔者以徐州地铁4、5号线勘察为例,首先针对具体场地条件进行物探环境评估;其次对各种物探方法进行技术适应性分析,提出场地环境与技术方法的最佳耦合;最后,总结出一套适用性与操作性强的物探技术模式。综合对比分析结果表明:①微动、瞬变电磁等技术可作为城区主要的地面物探手段,能初步查明岩溶、断裂等地质体的位置与赋存特征;②在岩溶精细探测上,孔间CT(电磁波)技术能进一步圈定岩溶的发育规模和空间位置;③地面与孔间物探的合理选用或联合应用,能够提供不同勘察阶段、不同勘察精度所需的地质资料,满足城市地铁勘察需求。

航空地球物理勘查技术发展战略研究

航空地球物理勘探是重要的快速找矿勘查方法,21世纪以来我国航空地球物理勘查技术已取得长足进步,但现有技术与装备仍难以满足国家“新一轮找矿突破战略行动”和深地、深海探测等对重大关键核心技术与装备的新需求。本文聚焦我国航空地球物理勘查技术高质量发展布局,梳理和总结了国内外航空地球物理勘查技术发展现状,评估了当前国内外技术竞争和发展态势,分析研判了我国在该领域面临的主要挑战。结合科技发展新变化、新特征和新趋势,瞄准超导传感器、航空重力全张量梯度、航磁全张量梯度、多场源全深度航空电磁、航空地震等前沿关键技术,以及新一轮找矿突破战略行动等急需的实用化技术,制定了我国航空地球物理勘查技术发展路线图。针对前沿技术攻关能力不够强、技术适应性较差和创新基础较薄弱等问题,提出了组建国家级航空地球物理技术创新中心、开展第四代航空地球物理勘查技术研发和构建一体化的航空地球物理技术装备发展体系建议。

半航空瞬变电磁数据处理与解释在贺斯格乌拉露天煤矿水灾害勘探中的应用

为减少地下涌水对煤矿开采的影响,确保内蒙古自治区锡林郭勒盟贺斯格乌拉露天煤矿安全开采,笔者采用半航空瞬变电磁法对该煤矿进行地下水勘探。通过Occam反演获得地下低阻电性异常的分布情况,并与核磁和钻孔结果进行对比,得出以下主要结论:①第四纪松散岩类含水砂层相对高阻,白垩纪大磨拐河组碎屑岩类孔隙裂隙含水层及煤层表现为低电阻,完整的大磨拐河组地层表现为相对高阻;②测区地下水渗流通道主要分布在白垩纪地层碎屑岩类孔隙裂隙水含水层中;③地下富水区域主要集中在标高840~880 m这一范围内,随着深度变深,富水区域面积逐渐变小。

基于地球物理方法的金属矿床勘探技术研究

随着经济的快速发展,金属矿床的勘探与开发成为许多国家的重要战略目标。然而,金属矿床的勘探具有复杂性和高风险性。因此,寻求高效和准确的勘探技术成为解决这一问题的关键。地球物理方法作为一种有效的勘探手段,具有较高的可靠性和准确性,被广泛应用于金属矿床的勘探。地球物理方法通过测量金属矿床区域的重力、磁力、电磁和地震等物理属性,实现对地下矿床的准确定位和性质分析。本文基于山东省济南市莱芜区角峪地区庄地区富铁矿普查项目野外地质调查形成的矿床地质数据、地球物理勘探资料,详细研究基于地球物理方法的金属矿床勘探技术,分析各种方法的原理和适用范围。通过本研究,期望为金属矿床勘探提供科学可靠的技术支持,促进资源开发与利用的可持续发展。

瞬变电磁法在吉林省辽源市煤矿采空区勘探中的应用

瞬变电磁法采用电磁感应原理,可以有效的进行地层划分,并推断单一剖面的煤矿采空影响区的分布位置、埋藏深度及纵向厚度,可以达到传统意义上的纵向二维(2 Dimensional,2D)勘探效果。本文是在大量收集勘探区基础地质资料的基础上,结合勘探区内采空区的特点及其围岩的地球物理特征,通过对传统意义上的实测剖面数据进行处理、反演,不仅绘制出各剖面视电阻率反演拟断面图,达到传统意义上的纵向二维(2D)勘探效果;还通过GeoIPAS软件将反演数据重新整合处理,绘制不同标高的视电阻率反演平面等值线图,可以达到软件构建的横向二维(2D)勘探效果;并根据横向、纵向二维(2D)勘探成果绘制三维立体图,通过立体三维(3 Dimensional,3D)勘探效果进行更直观的解译分析。最后综合剖面断面图、平面等值线图及三维立体图,绘制综合解译成果图,划分煤矿采空影响区的平面异常,圈定异常位置及分布范围。所圈定的两处平面异常进行了钻探验证,验证结果与瞬变电磁法推断解译结果吻合度较高。这说明本文研究成果对提高瞬变电磁法在煤矿采空区探测精度上具有实际应用价值。

综合物探和钻探技术在第四纪隐伏断层探测中的应用

采用以高分辨率地震勘探为主,配合瞬变电磁和高密度电阻率探测的方法,快速、准确圈定了北坞断裂的上断点位置、埋深等信息;通过跨断层联合剖面钻探和地球物理测井工作,查明了晚第四纪地层特征和层序,精确定位了目标断层的空间位置和断层位移量,进而揭示了目标断层的活动性。结果表明:综合物探技术的解释结果和钻探结果基本吻合,证明了方法的有效性。

Application of geophysical methods in fine detection of urban concealed karst:A case study of Wuhan City,China

The construction of modern livable cities faces challenges in karst areas,including ground collapse and engineering problems.Wuhan,with a population of 13.74×10^(6) and approximately 1161 km^(2)of soluble rocks in the urban area of 8569.15 km^(2),predominantly consists of concealed karst areas where occasional ground collapse events occur,posing significant threats to underground engineering projects.To address these challenges,a comprehensive geological survey was conducted in Wuhan,focusing on major karstrelated issues.Geophysical methods offer advantages over drilling in detecting concealed karst areas due to their efficiency,non-destructiveness,and flexibility.This paper reviewed the karst geological characteristics in Wuhan and the geophysical exploration methods for karst,selected eight effective geophysical methods for field experimentation,evaluated their suitability,and proposed method combinations for different karst scenarios.The results show that different geophysical methods have varying applicability for karst detection in Wuhan,and combining multiple methods enhances detection effectiveness.The specific recommendations for method combinations provided in this study serve as a valuable reference for karst detection in Wuhan.