# Vadose zone water content characterization of a heterogeneous limestone by 3D-SNMR

Clémence Ryckebusch, Jean-Michel Baltassat, Anatoly Legchenko, Pauline

Kessouri, Nadia Amraoui, Mohamad Abbas, Mohamed Azaroual

► To cite this version:

Clémence Ryckebusch, Jean-Michel Baltassat, Anatoly Legchenko, Pauline Kessouri, Nadia Amraoui, et al.. Vadose zone water content characterization of a heterogeneous limestone by 3D-SNMR. EGU General Assembly 2023, Apr 2023, Vienne, Austria. 10.5194/egusphere-egu23-9156 . hal-03960205

HAL Id: hal-03960205

https://brgm.hal.science/hal-03960205

Submitted on 27 Jan 2023

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

Abstract

# Vadose zone water content characterization of a heterogeneous limestone by 3D-SNMR

Clémence Ryckebusch, J-M. Baltassat, A. Legchenko, P. Kessouri, N. Amraoui, J. Deparis, M. Abbas, M. Azaroual

Contact : c.ryckebusch@brgm.fr

<figure><img src="image_3.png" /></figure>

Géosciences pour une Terre durable
brgm

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

www.centre-valdeloire.fr

<figure><img src="image_6.png" /></figure>
# Context of the study

## Map of nitrate mean concentration in aquifers, 2011 (Database : ADES)

Mean in 2011 for an aquifer (mg/l)

<figure><img src="image_7.png" /></figure>

Beauce aquifer

More than 50

Between 40 and 50

Between 25 and 40

Between 10 and 25

Less than 10

No data

Aquifer with 1 point

<figure><img src="image_8.png" /></figure>

Guadeloupe

Martinique

Guyane

<figure><img src="image_9.png" /></figure>

<figure><img src="image_10.png" /></figure>

<figure><img src="image_11.png" /></figure>

Réunion

Mayotte

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>
# Context of the study

## Map of nitrate mean concentration in aquifers, 2011 (Database : ADES)

<figure><img src="image_14.png" /></figure>

Chorover et al, 2007. Catalina-Jemez CZO (artwork by R. Kindlimann)
# Context of the study

## Map of nitrate mean concentration in aquifers, 2011 (Database : ADES)

<figure><img src="image_15.png" /></figure>

Chorover et al, 2007. Catalina-Jemez CZO (artwork by R. Kindlimann)

### Problem

* Sampling and instrumentation to study the deep vadose zone

* Heterogeneity and complex behavior in vadose zone
# Context of the study

## Map of nitrate mean concentration in aquifers, 2011 (Database : ADES)

<figure><img src="image_16.png" /></figure>

Chorover et al, 2007. Catalina-Jemez
CZO (artwork by R. Kindlimann)

### Problem

* Sampling and instrumentation to study the deep vadose zone

* Heterogeneity and complex behavior in vadose zone

### Objective

* Thesis : Improve the vadose zone flow characterization and modeling by coupling Surface Nuclear Magnetic Resonance (SNMR) monitoring and hydrogeological modeling

* This study : Characterize the water content spatial heterogeneities in 3D VZ and 3D aquifer with a joint interpretation of 3D-SNMR and 3D electrical data
# Study site

<figure><img src="image_17.png" /><figcaption>Villamblain study sites and BSS soundings (ID X01--)</figcaption></figure>

<figure><img src="image_18.png" /></figure>
# Study site

## BSS and OZNS soundings

X0114

X0112

OZNS
sounding

X0117

X0119

X0107

<figure><img src="image_19.png" /></figure>

Simplified
geology

Highly weathered
limestone

## Villamblain study sites and BSS soundings (ID X01--)

<figure><img src="image_20.png" /></figure>
# Study site

## BSS and OZNS soundings

<figure><img src="image_21.png" /></figure>

Simplified
geology

Highly weathered
limestone

Upper fractured
limestone
(Pithiviers)

## Villamblain study sites and BSS soundings (ID X01--)

<figure><img src="image_22.png" /></figure>
# Study site

<figure><img src="image_23.png" /></figure>

Simplified
geology

Highly weathered
limestone

Upper fractured
limestone
(Pithiviers)

Marl

## Villamblain study sites and BSS soundings (ID X01--)

<figure><img src="image_24.png" /></figure>
# Study site

<figure><img src="image_25.png" /></figure>

Simplified
geology

Highly weathered
limestone

Upper fractured
limestone
(Pithiviers)

Marl

Lower fractured
limestone
(Etampes)

<figure><img src="image_26.png" /></figure>

➤ Weathered and highly heterogeneous limestone in VZ

Villamblain study sites and BSS soundings (ID X01--)

<figure><img src="image_27.png" /></figure>
# Study site

<figure><img src="image_28.png" /></figure>

## Simplified geology

Highly weathered
limestone

Upper fractured
limestone
(Pithiviers)

Marl

Lower fractured
limestone
(Etampes)

## Villamblain study sites and BSS soundings (ID X01--)

<figure><img src="image_29.png" /></figure>

https://plateformes-pivots.eu/o-zns/

* Weathered and highly heterogeneous limestone in VZ

* O-ZNS study site
# Geophysical investigation and data processing

<figure><img src="image_30.png" /></figure>

Map of geophysical investigations done simultaneously
(09/2020) on OZNS study site before the well drilling
# Geophysical investigation and data processing

<figure><img src="image_31.png" /></figure>

Map of geophysical investigations done simultaneously (09/2020) on OZNS study site before the well drilling

<table><thead><tr><th></th><th>SNMR</th><th>ERT/IP</th></tr></thead><tbody><tr><td>Acquisition</td><td>10 soundings</td><td>8 profiles</td></tr><tr><td>Configuration</td><td>SQ 50m 2 tours<br>Tx-Rx 16 pulses</td><td>48 electrodes 2.5m<br>dipole-dipole</td></tr><tr><td>Device</td><td>Numis POLY (IRIS<br>Instrument)</td><td>Syscal Pro switch<br>(IRIS Instrument)</td></tr><tr><td>3D-inversion</td><td>Samovar</td><td>BERT</td></tr></tbody></table>
# Geophysical investigation and data processing

<figure><img src="image_32.png" /></figure>

Map of geophysical investigations done simultaneously (09/2020) on OZNS study site before the well drilling

<table><thead><tr><th></th><th>SNMR</th><th>ERT/IP</th></tr></thead><tbody><tr><td>Acquisition</td><td>10 soundings</td><td>8 profiles</td></tr><tr><td>Configuration</td><td>SQ 50m 2 tours<br>Tx-Rx 16 pulses</td><td>48 electrodes 2.5m<br>dipole-dipole</td></tr><tr><td>Device</td><td>Numis POLY (IRIS<br>Instrument)</td><td>Syscal Pro switch<br>(IRIS Instrument)</td></tr><tr><td>3D-inversion</td><td>Samovar</td><td>BERT</td></tr></tbody></table>

## SNMR data

* S/N between 1.5 and 6.6 ; RMSE = 16.2 nV ;
  Noise level = 50 nV

## Electrical data

* ERT : RMSE = 7 %

* IP : preliminary result
# Data interpretation in the Beauce limestone context

<figure><img src="image_33.png" /></figure>
# Data interpretation in the Beauce limestone context

<figure><img src="image_34.png" /></figure>
# Data interpretation in the Beauce limestone context

Water in porous media

<figure><img src="image_35.png" /></figure>

SNMR detection threshold
in Beauce limestone

<table><thead><tr><th>Geophysical method</th><th>Parameter measured</th><th>Interpretation</th></tr></thead><tbody><tr><td rowspan="2">SNMR</td><td>Water content</td><td>Decrease with clay content or with decreasing porosity</td></tr><tr><td>Time relaxation</td><td>(Not used to date)</td></tr></tbody></table>
# Data interpretation in the Beauce limestone context

Water in porous media

<figure><img src="image_36.png" /></figure>

SNMR detection threshold
in Beauce limestone

<table><thead><tr><th>Geophysical method</th><th>Parameter measured</th><th>Interpretation</th></tr></thead><tbody><tr><td rowspan="2">SNMR</td><td>Water content</td><td>Decrease with clay content or with decreasing porosity</td></tr><tr><td>Time relaxation</td><td>(Not used to date)</td></tr><tr><td>ERT</td><td>Electrical resistivity</td><td>Decrease with clay content and/or limestone alteration</td></tr><tr><td>IP</td><td>Chargeability</td><td>Increase with clay content</td></tr></tbody></table>
# 3D SNMR and ERT/IP inverse models

<figure><img src="image_37.png" /></figure>

<figure><img src="image_38.png" /></figure>

<figure><img src="image_39.png" /></figure>
# 3D SNMR and ERT/IP inverse models

<figure><img src="image_40.png" /></figure>

<figure><img src="image_41.png" /></figure>

<figure><img src="image_42.png" /></figure>
Water content heterogeneities resulting from SNMR 3D inversion

<figure><img src="image_43.png" /></figure>
Water content heterogeneities resulting from SNMR 3D inversion

<figure><img src="image_44.png" /></figure>

<figure><img src="image_45.png" /></figure>

Legend :

<figure><img src="image_46.png" /></figure>

Water level

<figure><img src="image_47.png" /></figure>

<figure><img src="image_48.png" /></figure>
# Identification of lithological heterogeneities from electrical 3D inversion results

<figure><img src="image_49.png" /></figure>

Legend :

<figure><img src="image_50.png" /></figure>

Water level

<figure><img src="image_51.png" /></figure>

Inverted water content

<figure><img src="image_52.png" /></figure>

Schematic water content
Identification of lithological heterogeneities from electrical 3D inversion
results

<figure><img src="image_53.png" /></figure>

Legend :

<figure><img src="image_54.png" /></figure>

Water level

<figure><img src="image_55.png" /></figure>

Inverted water
content

<figure><img src="image_56.png" /></figure>

Schematic
water content

<figure><img src="image_57.png" /></figure>

Inverted
resistivity
Identification of lithological heterogeneities from electrical 3D inversion
results

<figure><img src="image_58.png" /></figure>

Legend :

<figure><img src="image_59.png" /></figure>

Water level

<figure><img src="image_60.png" /></figure>

Inverted water
content

<figure><img src="image_61.png" /></figure>

Schematic
water content

<figure><img src="image_62.png" /></figure>

Inverted
resistivity

<figure><img src="image_63.png" /></figure>

Inverted
chargeability
# SNMR water content and geoelectrical model of an anomalous area in weathered Beauce Limestone aquifer and ZNS

<figure><img src="image_64.png" /></figure>
# Conclusion and perspectives

## Conclusion :

Joint interpretation of SNMR and ERT/IP data in a 3D aquifer and VZ :

* Identify spatial heterogeneities

* Variable hydrogeological properties : Lithology + water content
# Conclusion and perspectives

## Conclusion :

Joint interpretation of SNMR and ERT/IP data in a 3D aquifer and VZ :

* Identify spatial heterogeneities

* Variable hydrogeological properties : Lithology + water content

Variable hydrogeological properties => variable hydrodynamic and VZ flow properties ?
# Conclusion and perspectives

## Conclusion :

Joint interpretation of SNMR and ERT/IP data in a 3D aquifer and VZ :

* Identify spatial heterogeneities

* Variable hydrogeological properties : Lithology + water content

Variable hydrogeological properties => variable hydrodynamic and VZ flow properties ?

## Future work :

Use these results to characterize the VZ hydrodynamic and flow properties with :

* Time-lapse SNMR monitoring

* Hydrogeological modeling
<figure><img src="image_65.png" /></figure>

Abstract

Thank you

Clémence Ryckebusch, J-M. Baltassat, A. Legchenko, P. Kessouri, N. Amraoui, J. Deparis, M. Abbas, M. Azaroual

Contact : c.ryckebusch@brgm.fr

<figure><img src="image_66.png" /></figure>

<figure><img src="image_67.png" /></figure>

<figure><img src="image_68.png" /></figure>

<figure><img src="image_69.png" /></figure>
# SNMR principles

<figure><img src="image_70.png" /><figcaption>**Figure 1.1.** Typical phases of a magnetic resonance experiment (top) and corresponding magnetic resonance measurements (bottom)</figcaption></figure>

Source: LEGTCHENKO, Anatoly, 2013. *Magnetic Resonance Imaging for Groundwater*. John Wiley & Sons. ISBN 978-1-118-64947-3

Relaxation time
~ Mean Pore
size

Signal amplitude
~ Water content

**Measurement scale :**

Multidecametric (field)

**Data measured :**

Signal amplitude, relaxation time

**Parameters :**

Water content, mean porosity distribution

**Particularity of field NMR :**

No detection of water content for smaller pore sizes
3D water content and lithological spatial heterogeneities

<figure><img src="image_71.png" /><figcaption>Maps of electrical resistivity (left) and chargeability (right) at an elevation of 120 m (vadose zone)</figcaption></figure>

<figure><img src="image_72.png" /></figure>

<figure><img src="image_73.png" /><figcaption>SNMR Water content maps at an elevation of 114 m (vadose zone) and 111 m (aquifer)</figcaption></figure>

<figure><img src="image_74.png" /></figure>