This document discusses various methods for exploring and exploiting groundwater resources, including surface exploration techniques like remote sensing, geophysical methods, and geological mapping, as well as subsurface techniques like test drilling and geophysical well logging. It provides details on specific surface geophysical methods like electrical resistivity, seismic refraction and reflection, and gravitational surveys. Subsurface techniques covered include well construction, borehole geophysical logging tools for measuring resistivity, spontaneous potential, natural gamma radiation, neutron porosity, temperature, and borehole diameter. The document emphasizes integrating multiple exploration techniques to better understand subsurface geology and locate groundwater.

1. EXPLORATION AND EXPLOITATION GROUNDWATER FROM
JOURNAL AND MATERIALS
Lecturer : Dr.Mahendra Andiek Maulana S.T.,M.T
By Martheana Kencanawati/ID Students Number :
03111860010003
the 2nd Hydrology and
Groundwater Numeric Modelling
Assignment
POST GRADUATE PROGRAM CIVIL ENGINEERING DEPT.- ITS
FACULTY OF CIVIL ENVIRONMENTAL AND GEO ENGINEERING

2. 2. Remote Sensing
Exploration of Groundwater
3. Surface Geophysical Methods
(a) Electric Resistivity Method
(b) Seismic Refraction Method
(c) Seismic Reflection Method
(d) Gravimetric Method
(e) Magnetic Method
(f) Electromagnetic Method
(g) Ground Penetrating Radar
and others
Surface exploration
definition are non-invasive
ways to locate/mapping
the subsurface, why we
need surface exploration
because it has low budget
rather than sub
subsurface investigations
1. Geologic methods
Adapted from : Ir. Mohammad Sholichin MT., Ph.D
There
are
three
methods
include:

3. Subsurface exploration
1. Test drilling
• geologic log
• drilling time log
• Water level measurement
2. Geophysical logging/borehole geophysics
• Resistivity logging
• Spontaneous potential logging
• Radiation logging
• Temperature logging
• Caliper Logging
• Fluid Conductivity logging
• Fluid velocity logging
3. Tracer tests
Exploration of Groundwater

4. Usefulness of Resistivities
are:
valuable in determining
1. The depth and thickness
of groundwater aquifers
2. The depth to
groundwater, the depth
and thickness of clay
layers in some cases
3. The depth to bedrock,
and accordingly limit the
depth of well drilling.
Resistivity vary over a wide range, depending
on density, porosity, pore size and shape,
water content and quality, and temperature.

5. In relatively porous formations,
resistivity is controlled more by
water content and quality within the
formation than by the rock
resistivity.
For aquifers composed of
unconsolidated materials, the
resistivity decreases with the
degree of saturation and the salinity
of the groundwater.
Clay minerals conduct electric
current through their matrix,
therefore, clayey formations tend
to display lower resistivity than do
permeable alluvial aquifers.

6. Seismic Refraction Method (1)
based on the measurement of the
travel time of seismic waves refracted
at the interfaces between subsurface
layers of different velocity.
Seismic energy is provided by a source
(hammer, weight drop or small
explosive charge) located on the
surface.

7. 1. The seismic waves travel through the subsurface
at a velocity dependent on the density of the
soil/rock.
2. When the seismic wave front encounters an
interface where seismic velocity drastically
increases, a portion of the wave critically refracts
at the interface, traveling laterally along higher
velocity layers.
3. Due to compressional stresses along the interface
boundary, a portion of the wave front returns to
the surface
A series of seismic
receivers, geophones (right)
are laid out along the
survey line at regular
intervals and receive the
reflected wave energy.
Seismic Refraction Method (2)

8. Geophysical logging/ Borehole
geophysics
What is Borehole Geophysical
Logging?
1. Borehole geophysical logging is a
procedure to collect and
transmit specific information
about the geologic formations
penetrated by a well by raising
and lowering a set of probes or
sunders that contain water-tight
instruments in the well
2. The data collected can be used
to determine general formation
geology, fracture distribution,
vertical borehole flow, and
water-yielding capabilities.

9. • The application of geophysical logging to
groundwater hydrology lags far behind its
comparable using in petroleum exploration.
• The main reason is high cost. Most water
wells are shallow, small-diameter holes for
domestic water supply; logging costs would
be relatively large and unnecessary.
• But for deeper wells could cause more
expensive such as in municipal, irrigation or
injection purposes, logging can be
economically justified in terms of improved
well construction and performance.
Geophysical
logging/
Borehole
geophysics

10. Resistivity log
Groundwater
withdrawal
Groundwater
exploration
Subsurface
geophysical methods
Resistivity logging

11. Factors that influence formation resistivity:
1. Nature of water
2. Temperature of water
3. Rock structure
m
w
t
R
R


m
1
F


wt FRR 
Rt = formation resistivity
Rw = water resistivity
θ = porosity fraction
m = cementation factor
F = formation resistivity factor
Also,
m
i
R
R
F 

12. Multi-electrode method is most commonly
employed (minimizes the effects of drilling
fluid and well diameter)
Spacing between the electrodes, and their
arrangement, determine the radius of
investigation.
Short normal – records app. Resistivity of
the mud-invaded zone (useful for locating
boundaries of formations)
Long-normal – records app. Resistivity
beyond the invaded zone (useful for
obtaining information on fluids in thick
permeable formations)
Lateral – actual formation resistivity
beyond the mud-invaded zone
Typical electrode arrangement and standardized
distance for resistivity logs.

13. The use of resistivity logs are :
• interpretation and identification of rock types
• identification of the position of the water
table
• determination of bed contacts and bed
thickness
• determination of aquifer parameters
• evaluation of quality of formation water
• determination of depth of casing
Can be made only in the uncased portion of drill
holes.
Must contain drilled mud or water

14. measures differences in the
voltages of an electrode at
the land surface and an
electrode in the borehole
potentials are primarily
produced by electrochemical
cells formed by the electric
conductivity differences of
drilling mud and
groundwater where
boundaries of permeable
zones intersect a borehole.
Spontaneous potential (SP) logging

15. • Deflections of the SP curve occurs due to
the development of a liquid junction potential,
i.e. potential difference from across the
junction to mud filtrate into formation water.
• The potential read for shales normally varies
with depth differently. SP are measured
relative to this base line zero called the shale
line..
• If water in permeable bed is more saline than
drilling mud, SP is generally more –ve in the
permeable bed than in the adjacent clay &
vice versa.
• useful in determination of water quality
• The right hand boundary generally indicates
impermeable beds (e.g. clay, shale, and
bedrock)
• Left-hand boundary indicates sand and other
permeable layers
Spontaneous potential (SP) logging

16. Radiation
logging
Generally two types:
• (i) Measure the natural
radioactivity
• (ii) Detect the radiation
reflected to or induced into
formation from an artificial
source
• Natural-gamma logging
• Gamma-gamma logging
• Neutron logging

17. • all rocks emit natural gamma radiation
originating from unstable isotopes
(potassium, uranium, and thorium)
• Clay formations (shale, clay) emit more
rays than gravels and sands.
• Can be used to differentiate between
sand, clay and gravel (this is identifying
lithology, the primary application)
Natural-
Gamma
logging

18. •Gamma-Gamma logging
1. Gamma rays from a source in the probe (cobalt-60 or cesium-137) are
scattered and diffused through formation.
2. Part of the scattered rays re-enter the hole and are remeasured.
3. The higher the bulk density of formation, the smaller the number of
gamma-gamma rays that reach the detector.
4. Primary applications:
5. (i) identifying lithology
6. (ii) measurement of bulk density and porosity of rocks.

19. Neutron logging
1. Useful in determining the porosity of formations
2. A fast neutron source is used to bombard the rock
3. When any individual neutron collides with a hydrogen ion (of a
water molecule), some of the neutron’s energy is lost and it slows
down.
4. A large number of slow neutrons, as recorded by a slow neutron
counter, indicates a large number of fluid (i.e. high porosity)
5. Results are influenced by hole size. Therefore, in large uncased
holes, information on hole diameter is required for proper
interpretation.

20. Temperature logging Terms (1)
1. A vertical measurement of groundwater temperature in a well by a
resistance thermometer
2. Normally Temperature will increase according to geothermal gradients
(roughly 3oC for each 100 m depth)
3. Departures from this normal gradient may provide information on
circulation (hydrologic Cycle) or geologic conditions in the well.

21. 4. From temperature logging, we could apply:
(i) identify aquifers contributing water to a well.
(ii) Provide data on the source of water
(iii) identify rock types
(iv) calculate fluid viscosity and specific conductivity from fluid resistivity logs
(v) distinguish moving and stagnant water
5. From temperature logging, we could define weather we are normally cold water
which is whom may indicate recharge from ground surface ( in deep well)
6. Also from temperature logging we could define weather in normally warm water
may indicate water of deep-seated origin
7. Geothermal gradient is usually steeper in rocks with low permeability
TEMPERATURE LOGGING (2)

22. Caliper Logging
1. Provides a record of average hole diameter of a
borehole
2. Hole diameter will be equal to drilling bit when a
hard sandstone is traversed.
3. Diameter becomes larger for shales/clays as they
become wet with mud fluid, slough off and cave
into the hole.
4. Applications:
(i) identification of lithology and stratigraphic correlation
(ii) Locating fractures and other rock openings
(iii) Correcting other logs for hole-diameter effects

23. Groundwater withdrawal
1. Groundwater exploration
2. Well construction methods
3. Well design (to get optimum quantity of
water economically from a given geological
condition to meet the requirement for a
particular scheme)
4. Well completion (placement and cementing of
casing, screens)
5. Well development (increase specific capacity,
obtain maximum economic well life)
Courtesy: google images.com

24. TYPES OF WELLS AND METHODS OF
CONSTRUCTION
Factors important in choosing the type of wells
1. Quantity of water required
2. Economic consideration
3. Hydro-geologic consideration
4. Depth of water table
Courtesy: google images.com

25. Well Construction Methods
1. Dug wells
2. Bored wells
3. Driven wells
4. Jetted wells
1. Percussion (Cable tool) method
2. Hydraulic Rotary method
3. Air Rotary method
Shallow depths;
Domestic wells;
Unconsolidated
formations
Municipal, industrial
Domestic wells;
Unconsolidated and
consolidated formations

26. MUNICIPAL, INDUSTRIAL
DOMESTIC WELLS
Courtesy: google images.com

27. EXPLORING GROUND WATER (1)
Groundwater exploration is a typical assignment of a hydrogeologist or an engineer.
Identifying the location of its availability is a challenging assignment
Exploration of groundwater requires a basic understanding of its position in the subsurface geological setup.
Groundwater Exploration is conducted through either by direct or indirect methods.
Test drilling is the direct approach to find out the resource.
This cost a lot.

28. EXPLORING GROUND WATER (2)
Every individual couldn’t perform a test drilling.
During the past two centuries, more and more
techniques had been improved to explore the
groundwater.
They are classified into surface and sub-surface
methods.
Courtesy: google images.com

29. SURFACE METHODS
The surface methods are capable
to operate and implement. These
requirement minimum facilities
such as topo-sheets, maps,
reports, some field measurements
and interpretations of data in the
laboratories.
The surface methods of groundwater
exploration include the following:
– Esoteric Methods
– Geomorphologic methods
– Geological & structural Methods
– Soil and Micro-Biological Methods
– Remote Sensing Techniques
– Surface Geophysical Methods
(Balsubramanian 2007)

30. SUBSURFACE METHODS
The subsurface methods of groundwater exploration includes both Test Drilling &
Borehole Geophysical Logging techniques.
When compared to the surface methods, the subsurface methods are very
expensive.
These are done by government from level projects where it has large scale
investigations were carried out to ascertain the results of surface surveys.
The subsurface methods are very accurate methods as the help in direct
observations of features in the form of bore-hole lithologs as core samples and also
geophysical measurements of formation properties.(Balsubramanian,2007)

31. Sultan Awad Sultan et.al (2009) proof in their research
include followings:
Different geophysical tools such as geoelectric, gravity, and magnetic have been applied to detect
groundwater potentiality and structural elements, which controlled a geometry of the groundwater
aquifers in the study area. Nineteen vertical electrical soundings measured using ABEM SAS 4000
equipment through Schlumberger configuration of AB/2 ranged from 1.5 to 1,000 m;
the quantitative interpretation was carried out using manual and analytical techniques.
The results of quantitative interpretation used to construct six geoelectrical crosssections indicate
that the subsurface sequence of the study area consists of seven geoelectrical units. These units are
Quaternary sand sheet and sand dunes, Quaternary aquifer, marly limestone, clay, sandy clay, clay
with sandstone intercalation, and deep Nubian sandstone aquifer

32. CONCLUSION
1. Previous geological, hydrogeological and geophysical methods are employed to target
the groundwater potential zones. The interpretation of satellite images and aerial
photographs also help more in this process.
2.Groundwater exploration is a very unique. As it is a hidden resource, various indirect
methods are conducted to identify the points.
3. The success in the groundwater targeting depends on experience of understanding
the geological conditions, structural conditions and hydrogeological conditions which
favors the occurrence of groundwater.
4.The modern tools like remote sensing and aerial photography also provide a lot of
spatial data for a sudden meaningful of the domain for a better decision-making
(Balsubramanian ,2007)

33. REFERENCES
A. Balsubramanian 2007. Methods of Groundwater Exploration, Technical
Reports Centre For Advanced Studies In Earth Science ,University Of Mysore,
Ir. Mohammad Sholichin MT., Ph.D, Investigasi dan Interpretasi data Pendugaan
Airtanah, www.water.lecture.ub.ac.id
Sultan Awad Sultan & Hatem M. Mekhemer & Fernando M. Santos, 2009
Groundwater exploration and evaluation by using geophysical interpretation
(case study: Al Qantara East, North Western Sinai, Egypt) Arabian Journal of
Geosciences · August 2009 DOI: 10.1007/s12517-008-0028-7