Hydrogeology Chart

8/12/2019 Hydrogeology Chart

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HydrogeologicCharacterization

Thomas Doe

Winter 2009


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What You Need to Know from

Previous Lecture Hydrologic Cycle Vadose Zone

Specific Yield Capillary pressure

Groundwater Flow Systems Confined versus Unconfined Flow Perched water Artesian Flow

Hydrologic Units Aquifer, Aquitard, Aquiclude

Properties

Hydraulic Conductivity (K) versus Permeability (k) General ranges for geologic materials Specific capacity (Q/h)

Porous versus Fracture Flow


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Hydrogeologic Characterization

Hydraulic Head and Pressure Hydraulic Gradient

Confined and Unconfined Flow to a Well Definition of Storage and Storativity Difference between De-pressuring and Dewatering

Steady flow and its applications

Theim equation Specific Capacity

Falling Head Test Packer test

Wire line packer

Lugeon Test Flow Log

Transient Flow and its Applications Pump Test Slug Test

Principles of Groundwater Monitoring Piezometer types Piezometer Design


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Pressure and Hydraulic Head

Energy that drives water

Gravity

Chemistry (mainly in clays)

Electricity (mainly in clays)

Pressure is a measure of total energy

Head is a measure of potential energyit iswhat drives flow

Elevation Head

Pressure Head

It is expressed


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Outline

Basic Properties and Parameters

Steady flow to a well

Transient flow to a well Groundwater monitoring


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Flow Velocity

Compare Fracture Velocity to Porous Medium Velocity1-m cubeT=1-e5Fracture Aperture = .0005 mSand porosity = 10%

Gradient = 1


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Steady Flow Methods

Packer Testing

Falling Head Test

Constant Pressure/Lugeon Test

Flow Logging

Heat pulse

Spinner

Hydrophysical


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Useful Definitions and Concepts

Transmissivity -- Properties of a conductor(aquifer, reservoir, single fracture, fracture zone)(L2/T)

Permeability, Hydraulic Conductivity -- Propertyof material inside conductor (L/T)


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Steady Radial Flow

Pressure and flowconstant

Only exists withconstant pressureboundary

Generally under-estimates due to skin

R

rw

h

Q

h

QrRT w

2

)ln(


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Steady Flow Applications

Specific Capacity

Drillers term Flow rate divided by a drawdown

Packer Test

Test usually run with inflatable well sealscommonengineering test

Lugeon Test

Packer test usually for grouting


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Flow Log

Both

Indicate locations of flow features and relativestrengths

Ambient Flow

Indicates up or downward flow due to naturalgradients

Pumped Flow Indicates transmissivity of flowing feature


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Spinner Hydrophysical Log

(1) Replace fluid with deionized water

(2) Log fluid resistivity while pumping


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FLOW RATE AND SINGLE POINT RESISTANCE LOGSDEPTHS OF LEAKY FRACTURESSP, KI0025F03

1E+1 1E+2 1E+3 1E+4 1E+5 1E+6

Flow rate (ml/h)

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

Depth(m)

1E+1 1E+2 1E+3

Single point resistance (ohm)

125.45

124.65

133.3

131.1

128.3

Heat Pulse LogPosiva (Finland) Heat Pulse FlowLog (sp)


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FIGURE E-12

FLOW LOGS FOR BOREHOLES P1-20 AND P1-21MAWS/Campo Landfill Stage 1 WMRP/CA

-250

-200

-150

-100

-50

0-1250 -750 -250 250 750

Depth,ft.

Flowrate, ml/min

Well P1-20

Ambient

Injection

CologAmbient

-250

-200

-150

-100

-50

0

-1250 -1000 -750 -500 -250 0 250 500 750 1000

Depth,

ft.

Flow, ml/min

Well P1-21

Ambient

Injection

Total Dep th: 142 ft


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Image Logging (Correlate Flow to Feature)

Borehole TV (BIPS) FMI (micro-resistivity)


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Wireline Packer

Aardvark/Tigre Tierra


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Packer Test (Fixed Interval Length)

Used in CivilEngineering

Testing at fixed intervallengths

Some zones have nofractures; some zoneshave multiple fractures

Efficient testing hassome no flows but not

too many


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Lugeon Test

Packer Test usually for grouting

1 Lugeon unit = 1 litre of water taken per metreof test length, per minute, at 10 bars pressure(150 psi approx)

Typically done in steps

Implications 1 Lugeon Unitno sweat

10 Lugeon Unitsfire up the grout mixer

>100 Lugeion Unitsfile for a change order


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Stepped Lugeon Test

LinearLaminar Flow

Hydrojacking,Washout

TurbulentFlow


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Hvorslev Falling Head

Fill hole and watchlevel decline

Steady Flow

High Perm (constantpressure) boundary

Variant on SteadyFlow Solution

http://www.aqtesolv.com/

2

1

2

ln 1ln

2

w wr R r hK

b t h


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Transient Testing

Pump Test

Maintain a constant flow and observe transientpressure

Maintain constant pressure and observe transientflow

Slug Test

Look at pressure decay after instant charge of water Interference Tests

Analyze connectivity, storage, diffusivity


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Radial Diffusion Equation(Radial Cylindrical Flow)

1 1r r

r hr

ht


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Exponential Integral (aka Theis equation):

p r t qT

ex

dx qT

rt

x

r t

( , )/( )

4 4 42 4

2

Ei -


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Exponential Integral and Derivative

0.01

0.1

1

10

0 5 10 15 20 25 30 35

logpD

log tD


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Semilog Approximation of the Exponential

Integral

Ei( u u u u u u

) . ln! ! !

........057722 2 3 3 4 4

2 3 4

p r t q

T

t

r( , ) . log

.2 3026

4

22462

(MKS units)

kh=T is inversely proportional to semilog slope


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Semi-log Line (Jacob-Cooper)

Method

Semi-Log Straight Line

0

5

10

15

20

-3 -2 -1 0 1 2 3 4 5 6 7 8 9

Log Time

Pressure

2.3

4

semi-log slope

QT

mm


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Derivative Methods

Plots P/log(t)

Intent to make semi-line unambiguous

Effect is a very powerful tool to interpretgeometry from tests

Derivative is a map of transmissivity versusdistance from the well

Shape of derivative constrains network geometry


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Well Test Function (Exponential Integral) and

(Semilog) Derivative

0.01

0.1

1

10

0 5 10 15 20 25 30 35

logpD

log tD


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Slug Test

http://www.aqtesolv.com/

Transient Flow Infinite Aquifer

Variations forBoundaries

Variations forclosed (water-filled) or open

(open hole with

air waterinterface)systems


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Comments on Interference Tests

Radius of Investigation (very handy !!!)

Estimate diffusivity from response time

Independent of dimension

tr 2


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Interference Demo

Well 2

Well 3


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Groundwater Piezometer Systems

Key Point: Isolate different parts of flow systemWater SamplingPressure monitoring (eg determine flow, seasonal changes, pore pressure)Avoid cross contamination

http://www.claire.co.uk/


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Bure : Westbay System


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Westbay Systems


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Anomalous Osmotic Pressure

(chemically induced)

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