scholarly journals Characterization of geothermally relevant structures at the top of crystalline basement in Switzerland by filters and gravity forward modelling

2014 ◽  
Vol 199 (1) ◽  
pp. 226-241 ◽  
Author(s):  
Yassine Abdelfettah ◽  
Eva Schill ◽  
Pascal Kuhn
Keyword(s):  
Crystalline Basement ◽  
Forward Modelling ◽  
Gravity Forward Modelling

Elliptical harmonic method for gravity forward modelling of 2D bodies

2021 ◽  
Vol 95 (5) ◽  
Author(s):  
Cheng Chen ◽  
Shaofeng Bian ◽  
Motao Huang
Keyword(s):  
Forward Modelling ◽  
Harmonic Method ◽  
Gravity Forward Modelling

Experiences with the use of mass-density maps in residual gravity forward modelling

2018 ◽  
Vol 62 (4) ◽  
pp. 596-623 ◽  
Author(s):  
Meng Yang ◽  
Christian Hirt ◽  
Robert Tenzer ◽  
Roland Pail
Keyword(s):  
Mass Density ◽  
Forward Modelling ◽  
Residual Gravity ◽  
Gravity Forward Modelling ◽  
Density Maps

Characterization of crystalline basement aquifers with MRS: comparison with boreholes and pumping tests data in Burkina Faso

2005 ◽  
Vol 3 (3) ◽  
pp. 205-213 ◽  
Author(s):  
J.M. Vouillamoz ◽  
M. Descloitres ◽  
G. Toe ◽  
A. Legchenko
Keyword(s):  
Burkina Faso ◽  
Crystalline Basement ◽  
Pumping Tests ◽  
Basement Aquifers

scholarly journals Utilizing pre-polarization to enhance SNMR signals—effect of imperfect switch-off

2020 ◽  
Vol 222 (2) ◽  
pp. 815-826 ◽  
Author(s):  
Thomas Hiller ◽  
Raphael Dlugosch ◽  
Mike Müller-Petke
Keyword(s):  
Spin Dynamics ◽  
Subsurface Water ◽  
Spin Excitation ◽  
Forward Modelling ◽  
Response Signal ◽  
Small Surface ◽  
Dynamics Simulations ◽  
Measured Response ◽  
Established Technique

SUMMARY Surface nuclear magnetic resonance (SNMR) is a well-established technique for the hydrogeological characterization of the subsurface up to depths of about 150 m. Recently, SNMR has been adapted to investigate also the shallow unsaturated zone with small surface loop setups. Due to the decreased volume, a pre-polarization (PP) field prior to the classical spin excitation is applied to enhance the measured response signal. Depending on the strength and orientation of the applied PP-field, the enhancement can often reach several orders of magnitude in the vicinity of the PP-loop. The theoretically achievable enhancement depends on the assumption of an adiabatic, that is perfect, switch-off of the corresponding PP-field. To study the effect of imperfect switch-off, we incorporate full spin dynamics simulations into the SNMR forward modelling. The affected subsurface volume strongly depends on the chosen PP switch-off ramp and the geometry of the loop setup. Due to the imperfect switch-off, the resulting SNMR sounding curves can have significantly decreased signal amplitudes. For comparison, the signal amplitudes of either a 1 ms exponential or linear switch-off ramp are reduced by 17 and 65 per cent, respectively. Disregarding this effect would therefore yield an underestimation of the corresponding subsurface water content of similar magnitude.

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