Identifying Deep Saturated Coal Bed Zones in China through the Use of Large Loop TEM

2018 ◽  
Vol 23 (1) ◽  
pp. 135-142
Author(s):  
Guo-qiang Xue ◽  
Wei-ying Chen ◽  
Zhen-jun Ma ◽  
Dong-yang Hou
Keyword(s):  
Geophysical Methods ◽  
Cost Effective ◽  
Shanxi Province ◽  
Coal Bed ◽  
Detection Accuracy ◽  
Coal Beds ◽  
Large Loop ◽  
Transient Electromagnetic ◽  
Coal Deposits ◽  
The Time Domain

Most of the shallow mineral deposits of China have already been mined because of the country's fast-growing social and economic development. Consequently, the exploration and mining of deep-seated coal deposits have become alternative ways to satisfy the energy needs for both domestic and industrial use. To ensure safe mining practices and avoid the intrusion of water from the bases of coal deposits, it has become essential to investigate the distribution of deep-seated coal deposits using appropriate and cost-effective geophysical methods. For example, a coal mine located in the southern part of China's Shanxi Province is characterized by a roof of dry rocks, whereas the coal beds in this area are saturated. A new technique which uses a large loop transient electromagnetic method (hereafter referred to as a modified central loop TEM) to detect geological targets located at deeper levels in the subsurface was successfully developed and applied in this study. The detection abilities of this technique, such as the time-domain responses and depth of investigation, as well as its sensitivity to deep targets, were analyzed. This new method was successfully employed to detect the floor of a 900 m deep coal seam at the location of the saturated coal beds in Shanxi Province. Wells were drilled to confirm the results, showing that the proposed method is both applicable and convenient for future exploration purposes. TEM could potentially be used to detect geological materials located at greater depths with higher detection accuracy. [Figure: see text]

Using HEM surveys to evaluate disposal of by-product water from CBNG development in the Powder River Basin, Wyoming

Geophysics ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. B77-B84 ◽  
Author(s):  
Brian A. Lipinski ◽  
James I. Sams ◽  
Bruce D. Smith ◽  
William Harbert
Keyword(s):  
River Basin ◽  
Produced Water ◽  
Water Discharge ◽  
Geophysical Methods ◽  
Powder River Basin ◽  
Coal Bed ◽  
Coal Beds ◽  
Occam’S Inversion ◽  
Product Water ◽  
Location Strategies

Production of methane from thick, extensive coal beds in the Powder River Basin of Wyoming has created water management issues. Since development began in 1997, more than 650 billion liters of water have been produced from approximately 22,000 wells. Infiltration impoundments are used widely to dispose of by-product water from coal bed natural gas (CBNG) production, but their hydrogeologic effects are poorly understood. Helicopter electromagnetic surveys (HEM) were completed in July 2003 and July 2004 to characterize the hydrogeology of an alluvial aquifer along the Powder River. The aquifer is receiving CBNG produced water discharge from infiltration impoundments. HEM data were subjected to Occam’s inversion algorithms to determine the aquifer bulk conductivity, which was then correlated towater salinity using site-specific sampling results. The HEM data provided high-resolution images of salinity levels in the aquifer, a result not attainable using traditional sampling methods. Interpretation of these images reveals clearly the produced water influence on aquifer water quality. Potential shortfalls to this method occur where there is no significant contrast in aquifer salinity and infiltrating produced water salinity and where there might be significant changes in aquifer lithology. Despite these limitations, airborne geophysical methods can provide a broadscale (watershed-scale) tool to evaluate CBNG water disposal, especially in areas where field-based investigations are logistically prohibitive. This research has implications for design and location strategies of future CBNG water surface disposal facilities within the Powder River Basin.

Full Waveform Inversions of Borehole Transient Electromagnetic Virtual Wave Fields and Potential Applications

2020 ◽  
Vol 25 (2) ◽  
pp. 211-222
Author(s):  
Fan Tao ◽  
Qi Zhipeng ◽  
Yan Bin ◽  
Zhao Zhao ◽  
Wang Bingchun ◽  
...  
Keyword(s):  
Wave Field ◽  
Shanxi Province ◽  
Small Scale ◽  
Detection Accuracy ◽  
Dynamic Correction ◽  
Wave Fields ◽  
Full Waveform ◽  
Transient Electromagnetic ◽  
Good Imaging ◽  
Imaging Results

The transient electromagnetic method (TEM) for boreholes uses fixed source loops to launch at excavation faces, and is able to realize the mobile reception of secondary fields in the boreholes and detections of low-resistance hazards. This method is known as high detection accuracy, due to the fact that the receiving points are close to the anomalies. However, the interpretation method for this device has not yet been perfected. The present study's goal was to realize the interpretations of boreholes TEM based on inverse transform algorithms of the TEM wave-fields and full waveform inversions. It was found that under the conditions of transient electromagnetic virtual wave-fields, the characteristics of the virtual wave-field time-distance curves of the two-dimensional device could be examined, and a corresponding dynamic correction algorithm was successfully obtained. The wave-field velocities were analyzed using an equivalent conductive plane method. Additionally, the pseudo-seismic inversions of the tunnel-borehole TEM data were realized using full waveform inversion technology. Then, the inversion results of the three-dimensional numerical simulations, flume physical simulations, and downhole field simulations were calculated. It was observed that good imaging results had been obtained for small-scale borehole radial anomalies. Finally, the proposed method was applied to the engineering practices in an underground coal mine in Shanxi Province. The practicability and effectiveness of the proposed method in the fine detection of the properties, forms, and scale of water-logged goaf roadways were successfully tested in the field. The research results indicated that the roadway-borehole transient electromagnetic detection method was complementary to the underground geophysical exploration and drilling, and could be effectively applied in the detection of water-logged goaf roadways.

Inversions of surface and borehole data from large‐loop transient electromagnetic system over a 1‐D earth

Geophysics ◽  
2001 ◽  
Vol 66 (4) ◽  
pp. 1090-1096 ◽  
Author(s):  
Z. Zhang ◽  
J. Xiao
Keyword(s):  
Early Time ◽  
Late Time ◽  
Inversion Algorithm ◽  
Borehole Data ◽  
Electromagnetic System ◽  
Large Loop ◽  
Transient Electromagnetic ◽  
Surface Data ◽  
The Time Domain ◽  
The Magnetic Field

Large‐loop electromagnetic (EM) systems that measure transient EM (TEM) data on the surface or in boreholes have shown increased application in exploration geophysics. Accurate interpretation of borehole TEM data is necessary to discover deep hidden targets that cannot be detected with surface systems. However, the inversion of borehole TEM data has not been fully addressed. In this paper, we study the propagation of the TEM field from a large‐loop EM borehole system inside a layered earth and develop a new inversion algorithm to reconstruct layered conductivity structures from large‐loop TEM data measured with both surface and borehole configurations. The magnetic field and sensitivities are first computed in the frequency domain and are then transformed into the time domain where the inversion is performed. The surface data have a higher S/N ratio at early time channels, while the borehole data have a higher S/N ratio at late time channels. Consequently, the surface data can be inverted to better resolve shallow structures, and the borehole data can be used to better detect deep structures. The merits of joint inversions of borehole and surface data are explored. We test our inversion algorithm using numeric examples.

scholarly journals Geothermal resource exploration by using Numerical simulation and comprehensive geophysical method

2021 ◽  
Author(s):  
Yang Yang ◽  
Bin Xiong ◽  
Sanxi Peng ◽  
Ibrar Iqbal ◽  
Tianyu Zhang
Keyword(s):  
Detection Efficiency ◽  
Energy Resource ◽  
Clean Energy ◽  
Shanxi Province ◽  
Geothermal System ◽  
Exploratory Research ◽  
Geothermal Resource ◽  
Geothermal Resources ◽  
Transient Electromagnetic ◽  
Resistivity Model

Abstract Geothermal energy is an important renewable clean energy resource with high development and usage potential. Geothermal resources, on the other hand, are buried deep below, and mining hazards are significant. Geophysical investigation is frequently required to determine the depth and location of geothermal resources. The Transient Electromagnetic Method (TEM) and the Controlled Source Audio Frequency Magnetotellurics (CSAMT) have the highest detection efficiency and accuracy of all electromagnetic exploration methods. This article initially explains the algorithm theory of the finite difference technique before establishing a simplified geothermal system resistivity model. Established on the simplified resistivity model, a simulation analysis of the ability of CSAMT and TEM to distinguish target body faults at different resistivities and dip angles was performed, and the effectiveness and difference of the two methods in detecting typical geothermal resource targets was verified. A complete exploratory research of CSAMT and TEM was conducted in Huairen County, Shuozhou City, Shanxi Province, China, based on theoretical analysis. Both approaches can reflect the geoelectric structure of the survey region, demonstrating the efficacy of the two methods in detecting genuine geothermal resources.

scholarly journals Sensing as a Service for the Internet of Things

2016 ◽  
Vol 4 (3) ◽  
pp. 28
Author(s):  
Omar Subhi Aldabbas
Keyword(s):  
Internet Of Things ◽  
Cost Effective ◽  
Sensor Data ◽  
Detection Accuracy ◽  
Heterogeneous Services ◽  
Coordination Languages ◽  
Spatio Temporal ◽  
Temporal Events ◽  
New Applications ◽  
Common Application

Internet of Things (IoT) is a ubiquitous embedded ecosystem known for its capability to perform common application functions through coordinating resources, which are distributed on-object or on-network domains. As new applications evolve, the challenge is in the analysis and usage of multimodal data streamed by diverse kinds of sensors. This paper presents a new service-centric approach for data collection and retrieval. This approach considers objects as highly decentralized, composite and cost effective services. Such services can be constructed from objects located within close geographical proximity to retrieve spatio-temporal events from the gathered sensor data. To achieve this, we advocate Coordination languages and models to fuse multimodal, heterogeneous services through interfacing with every service to achieve the network objective according to the data they gather and analyze. In this paper we give an application scenario that illustrates the implementation of the coordination models to provision successful collaboration among IoT objects to retrieve information. The proposed solution reduced the communication delay before service composition by up to 43% and improved the target detection accuracy by up to 70%, while maintaining energy consumption 20% lower than its best rivals in the literature.

The Development of Near-source Electromagnetic Methods in China

2018 ◽  
Vol 23 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Guo-qiang Xue
Keyword(s):  
High Efficiency ◽  
Academic Research ◽  
Electromagnetic Method ◽  
Detection Accuracy ◽  
Wide Field ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic ◽  
Detection Technology ◽  
Deep Depth ◽  
Central Loop

Near-source electromagnetic technology has been developed and applied in the exploration of petroleum, metallic ore, coal, and engineering geology due to its high efficiency, high detection accuracy, and deep depth of investigation. In this paper, research and applications of the frequency-domain electromagnetic sounding method (FDEM), wide-field electromagnetic method (WFEM), modified central-loop transient electromagnetic method (TEM), and short-offset grounded-wire TEM (SOTEM) with obvious near-source characteristics, were reviewed and analyzed. From the 1960s to 1990s, the FDEM method and equipment were extensively developed in China. These methods have played important roles in the exploration of coal resources. Based on controlled source audio-frequency magnetotelluric (CSAMT) and FDEM methods, a new method has been developed by deriving a new expression to calculate apparent resistivity. This method, which is referred to as WFEM, has been studied, applied, and received great attention in China. To increase work efficiency and reduce the influence of local transverse anisotropy on the detection processes, a modified central-loop TEM detection technology based on the central loop transient electromagnetic method was developed in China. The advantages of SOTEM in near-source surveys with high resolution and increased depth detection stimulated academic research interest to further develop grounded-wire TEM techniques. [Figure: see text]

Insights of Cleat Attribute of Barakar Coal Deposits of Son Valley Basin, India: Implication for Coal Bed Methane Exploration

2021 ◽  
Vol 9 (1) ◽  
pp. 56-65
Author(s):  
Susheel Kumar ◽  
◽  
Atul Kumar Varma ◽  
Vinod Atmaram Mendhe ◽  
◽  
...  
Keyword(s):  
Central India ◽  
Atomic Ratio ◽  
Volatile Matter ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Sem Images ◽  
Coal Deposits ◽  
Terrestrial Source ◽  
Type Composition ◽  
The Face

Cleat attributes and coal quality have been evaluated through field observation, SEM images analysis and proximate-ultimate analyses on representative coal samples collected from four different underground coal mines of Son-Valley coal Basin of central India for the characterization of coal bed methane prospective. The coal samples were characterized as durainic-clarodurainic-vitrainic type to durocalrainic-clarainic type based on litho-type composition. Cleats were identified as face cleat and butt cleat range 5-10 cm-1 to 2–3 cm-1 depending on the litho-types whereas, cleat density ranges 7-16 cm-2 revealed that cleat development is influenced by litho-types. The cleat orientation shows two main strikes almost NW-SE to NNW-SSE and NE-SW to ENE-WSW elucidates the face cleat and butt cleats are perpendicular to each other. SEM images for coal samples were analysed to validate the cleat geometry at micro-scale, illustrates that face cleat and butt cleats are orthogonal to each other. The technological properties viz. moisture (Wa), volatile matter yield (VMdaf) ash yield (Ad) of coal samples are placed in the range of 0.66–11.80, 32.0–50.05 and 13.23–43.73 wt.% respectively. The fuel ratios of all the samples varied from 1.05–2.35 indicating that coal samples were of sub-bituminous to bituminous rank. The carbon and hydrogen (Cdaf, Hdaf) content of samples ranges from 68.89–86.08 and 5.22–6.60 wt.% respectively. The atomic ratio H/C and O/C through van-Krevelen diagram demonstrate the predominance of type-III/IV kerogens usually derived from terrestrial source in studied coal belongs to the gas genesis window.

scholarly journals Detection of Breaking Waves in Single Wave Gauge Records of Surface Elevation Fluctuations

2019 ◽  
Vol 36 (9) ◽  
pp. 1863-1879 ◽  
Author(s):  
Dan Liberzon ◽  
Alexandru Vreme ◽  
Sagi Knobler ◽  
Itamar Bentwich
Keyword(s):  
Water Waves ◽  
Cost Effective ◽  
Breaking Waves ◽  
Recognition Algorithm ◽  
New Method ◽  
Surface Elevation ◽  
Detection Accuracy ◽  
Single Wave ◽  
Accurate Detection ◽  
Forced Waves

We report the development of a new method for accurate detection of breaking water waves that addresses the need for an accurate and cost-effective method that is independent of human decisions. The new detection method, which enables the detection of breakers using only surface elevation fluctuation measurements from a single wave gauge, supports the development of a new method for research relating to water waves and wind–wave interactions. According to the proposed method, detection is based on the use of the phase-time method to identify breaking-associated patterns in the instantaneous frequency variations of surface elevation fluctuations. A wavelet-based pattern recognition algorithm is devised to detect such patterns and provide accurate detection of breakers in the examined records. Validation and performance tests, conducted using both laboratory and open-sea data, including mechanically generated and wind-forced waves, are reported as well. These tests allow us to derive a set of parameters that assure high detection accuracy rates. The method is shown to be capable to achieve a positive detection rate exceeding 90%.

Sign in / Sign up

Export Citation Format

Share Document