scholarly journals DETERMINATION OF GAS ACCUMULATIVE AREAS WITHIN THE COAL BASINS BY TRANSIENT ELECTROMAGNETIC SOUNDING METHOD

2015 ◽  
Vol 0 (42) ◽  
pp. 106-108
Author(s):  
I. Skopychenko ◽  
V. Finchuk
Keyword(s):  
Electromagnetic Sounding ◽  
Transient Electromagnetic

scholarly journals Transient electromagnetic sounding for groundwater

Geophysics ◽  
1986 ◽  
Vol 51 (4) ◽  
pp. 995-1005 ◽  
Author(s):  
David V. Fitterman ◽  
Mark T. Stewart
Keyword(s):  
Numerical Models ◽  
Groundwater Exploration ◽  
High Porosity ◽  
Electromagnetic Sounding ◽  
Numerical Studies ◽  
Transient Electromagnetic ◽  
Formation Resistivity ◽  
Sand And Gravel ◽  
Freshwater Aquifers

The feasibility of using the transient electromagnetic sounding (TS or TDEM) method for groundwater exploration can be studied by means of numerical models. As examples of its applicability to groundwater exploration, we study four groundwater exploration problems: (1) mapping of alluvial fill and gravel zones over bedrock; (2) mapping of sand and gravel lenses in till; (3) detection of salt or brackish water interfaces in freshwater aquifers; and (4) determination of hydrostratigraphy. These groundwater problems require determination of the depth to bedrock; location of resistive, high‐porosity zones associated with fresh water; determination of formation resistivity to assess water quality; and determination of lithology and geometry, respectively. The TS method is best suited for locating conductive targets, and has very good vertical resolution. Unlike other sounding techniques where the receiver‐transmitter array must be expanded to sound more deeply, the depth of investigation for the TS method is a function of the length of time the transient is recorded. Present equipment limitations require that exploration targets with resistivities of 50 Ω ⋅ m or more be at least 50 m deep to determine their resistivity. The maximum depth of exploration is controlled by the geoelectrical section and background electromagnetic (EM) noise. For a particular exploration problem, numerical studies are recommended to determine if the target is detectable.

The harmonic and transient electromagnetic response of a thin dipping dike

Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 934-952 ◽  
Author(s):  
P. Weidelt
Keyword(s):  
Formal Solution ◽  
Harmonic Excitation ◽  
Electromagnetic Response ◽  
Approximate Determination ◽  
Finite Conductivity ◽  
Circular Loop ◽  
Decay Modes ◽  
Transient Electromagnetic ◽  
Free Decay

An exact solution is given for the electromagnetic induction in a dipping dike of finite conductivity, represented as a thin half‐sheet in a nonconducting surrounding. The problem is formulated for arbitrary dipole or circular loop [Formula: see text] configurations. The formal solution obtained by the Wiener‐Hopf technique is cast into a rapidly convergent triple integral suitable for an effective numerical treatment. A good agreement is found between numerical results and analog measurements available for harmonic excitation. The transient response is obtained as a superposition of the half‐sheet free‐decay modes and is illustrated by some numerical examples for coincident loops, including a diagram for the approximate determination of conductance and depth of a vertical dike.

NEW METHOD OF IMPULSIVE ELECTROMAGNETIC LOGGING SOUNDING: MAPPING OF THE BAZHENOVSKAYA FORMATION FROM JURASSIC RESERVOIRS PENETRATED BY INCLINED-HORIZONTAL WELLS

2021 ◽  
pp. 31-39
Author(s):  
M. I. Epov ◽  
◽  
V. N. Glinskikh ◽  
M. N. Nikitenko ◽  
K. V. Sukhorukova ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Modeling ◽  
Middle Jurassic ◽  
High Sensitivity ◽  
Horizontal Wells ◽  
New Method ◽  
Electromagnetic Sounding ◽  
Bazhenov Formation ◽  
Spatial Locations

The work is devoted to the substantiation of new geophysical technology for mapping the Bazhenovskaya Formation based on an impulsive electromagnetic sounding from wells. Theoretically shown the possibility of its application to study the formation from highly inclined and subhorizontal wells drilled in the Upper and Middle Jurassic formations. Numerical modeling of the signals in realistic geoelectric models of the Bazhenov Formation with real well trajectories is carried out on the example of the East Surgut field. The calculations have established that the determination of spatial locations of the top and bottom of the beds is possible when using different-length sondes. Zones of high sensitivity of the full magnetic field matrix to the boundaries with a sufficient signal level at considerable distance, even with a small sonde length, are determined. It is theoretically established that pulsed sounding of the Bazhenov Formation from the Upper and Middle Jurassic reservoirs is feasible for both mapping the boundaries of the formation and tracing its lateral variability.

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