TY - JOUR

T1 - Improving the accuracy of 1D surface nuclear magnetic resonance surveys using the multi-central-loop configuration

AU - Kremer, Thomas

AU - Müller-Petke, Mike

AU - Michel, Hadrien

AU - Dlugosch, Raphael

AU - Irons, Trevor

AU - Hermans, Thomas

AU - Nguyen, Frédéric

N1 - Funding information: We gratefully acknowledge the help of Ann Elen and Annie Royen from the University of Liege and the University of Leuven who both helped with the acquisition of the noise field data at the Belgian sites. We also thank three anonymous reviewers for their insightful comments. This work was made possible thanks to the funding of the BEWARE program from the Walloon region (Belgium) , convention n° 1610044 . We gratefully acknowledge the help of Ann Elen and Annie Royen from the University of Liege and the University of Leuven who both helped with the acquisition of the noise field data at the Belgian sites. We also thank three anonymous reviewers for their insightful comments. This work was made possible thanks to the funding of the BEWARE program from the Walloon region (Belgium), convention n? 1610044.

PY - 2020/6

Y1 - 2020/6

N2 - Surface nuclear magnetic resonance is a near-surface geophysical method for characterizing the spatial distribution of liquid water in the top 100 m of the subsurface. The recovered water content models are obtained through the solution of an ill-posed inverse problem that is a function of acquisition parameters, including location and shape of the transmitter and receiver coils. In this paper, we introduce the multi-central-loop acquisition and inversion strategy where one or several smaller receivers coils are placed in the center of the larger transmitter loop and where all the data sets synchronously recorded through each loop are inverted simultaneously. We investigate the attributes of this acquisition and inversion strategy including the ability to provide improved resolution, accuracy and reduced uncertainty on the estimated subsurface models compared to single channel acquisition methods. Using widely-adopted inversion methods and introducing a new data interpretation technique called Bayesian Evidential Learning 1D imaging, we show that the multi-central-loop configuration provides improved recovery of synthetic models and reduced levels of inverted parameter uncertainty. A field case is also presented where the multi-central-loop results appear to better match the lithologic knowledge of the area compared with single channel configurations, again providing smaller uncertainties.

AB - Surface nuclear magnetic resonance is a near-surface geophysical method for characterizing the spatial distribution of liquid water in the top 100 m of the subsurface. The recovered water content models are obtained through the solution of an ill-posed inverse problem that is a function of acquisition parameters, including location and shape of the transmitter and receiver coils. In this paper, we introduce the multi-central-loop acquisition and inversion strategy where one or several smaller receivers coils are placed in the center of the larger transmitter loop and where all the data sets synchronously recorded through each loop are inverted simultaneously. We investigate the attributes of this acquisition and inversion strategy including the ability to provide improved resolution, accuracy and reduced uncertainty on the estimated subsurface models compared to single channel acquisition methods. Using widely-adopted inversion methods and introducing a new data interpretation technique called Bayesian Evidential Learning 1D imaging, we show that the multi-central-loop configuration provides improved recovery of synthetic models and reduced levels of inverted parameter uncertainty. A field case is also presented where the multi-central-loop results appear to better match the lithologic knowledge of the area compared with single channel configurations, again providing smaller uncertainties.

KW - Hydrogeophysics

KW - Model uncertainty

KW - Multi-central-loop configuration

KW - Resolution studies

KW - Surface nuclear magnetic resonance

UR - http://www.scopus.com/inward/record.url?scp=85084190052&partnerID=8YFLogxK

U2 - 10.1016/j.jappgeo.2020.104042

DO - 10.1016/j.jappgeo.2020.104042

M3 - Article

AN - SCOPUS:85084190052

VL - 177

JO - Journal of applied geophysics

JF - Journal of applied geophysics

SN - 0926-9851

M1 - 104042

ER -