Profiling Transmissivity and 

Contamination in Fractures 

Intersecting Boreholes

USEPA-USGS Fractured Rock Workshop

EPA Region 2

14 January 2014

Claire Tiedeman and Tom Imbrigiotta, USGS
Profiling Transmissivity and Contamination in Boreholes 2

Motivation: Hydraulic Conductivity Varies by

Orders of Magnitude in Fractured Rock

This variability results in complex groundwater 

flow and contaminant transport paths
 Characterizes permeability variability with depth. 

 Provides quantitative order-of-magnitude T estimates at a 

scale of a few meters around borehole.

 Methods:

Profiling Transmissivity in Boreholes

Profiling Transmissivity and Contamination in Boreholes 3

Straddle 

Packer 

Testing

Flute

Liner 

Installation

Borehole 

Flow 

Logging
Profiling Transmissivity and Contamination in Boreholes 4

Packer Testing Equipment
 To determine depths of test intervals, use results from 

geophysical logging: 

 Acoustic & optical televiewer: Identify fracture locations

 Caliper: Avoid placing packers on fractured or rough borehole wall sections

 Flow logs: First cut at revealing permeable fractures

 Overview of steps:

 Lower packers to first interval to be tested.

 Measure stabilized water levels before and after packer inflation, so that 

ambient hydraulic head can be calculated. 

 If interval is permeable enough, conduct a hydraulic test by pumping. 

During the test, conduct geochemical sampling. 

 If interval is not permeable enough to pump, conduct hydraulic test by 

fluid injection. No geochemical sampling.

 Move packers to the next interval to be tested.

Transmissivity Profiling using Straddle Packers 

Profiling Transmissivity and Contamination in Boreholes 5
 After packer inflation, allow pressure to stabilize in test interval.

 Turn on pump.

 Datalogger records pumping rate, pressure in test interval, and 

pressure in borehole above and below interval. Software shows 

real-time data.

 Pressure in test interval:

 If becoming extremely low: Stop, perform injection test

 If not changing much: Interval may be too transmissive to conduct a 

hydraulic test with the available pump

 Continue pumping until pressure roughly stabilizes – 10-20 min. 

(Geochemical sampling will require longer pumping). 

 Turn off pump. 

Hydraulic Tests by Fluid Pumping –

Permeable Intervals

Profiling Transmissivity and Contamination in Boreholes 6
 After packer inflation, allow pressure to stabilize.

 Start injecting water from up-hole tank. Tank can be at 

atmospheric pressure or higher. 

 Record injection rate and pressures. Software shows real-time 

data.

 Continue injection until pressure roughly stabilizes. Tests are 

usually run for 10 to 20 minutes. 

 If using a pressurized water tank, increase tank pressure and 

conduct a second injection test. Conducting tests at two 

pressures allows evaluating if results are repeatable, and if so, 

increases confidence in T estimate.

Hydraulic Tests by Fluid Injection –

Less Permeable Intervals

Profiling Transmissivity and Contamination in Boreholes 7
Profiling Transmissivity and Contamination in Boreholes 8

Theim equation for 

steady-state radial flow 

to a pumping well
 T values calculated by Theim equation are order-of-magnitude 

estimates because:

 Test conditions typically do not perfectly conform to the conditions 

assumed by the Theim equation (steady-state purely radial flow with 

constant Q) 

 Uncertainty and variability in measurements of Q

 Uncertainty in radius of influence of test (this uncertainty has a much 

smaller effect because the logarithm of R appears in the equation).

 Because of the large range of T at fractured rock sites, these 

order-of-magnitude estimates are still valuable! 

 These limitations apply to T estimates from both straddle 

packer and FLUTe liner methods

Limitations of Transmissivity Estimates

Profiling Transmissivity and Contamination in Boreholes 9
Profiling Transmissivity and Contamination in Boreholes 10

Crystalline Rock
Sedimentary Rock

Profiling Transmissivity and Contamination in Boreholes 11
 Evert liner into borehole.

 Borehole water below bottom 

of liner is pushed into the rock.

 Flow rate into rock over a 

borehole interval is calculated 

from liner descent velocities 

and ‘excess head’ that drives 

liner installation.

 Transmissivity calculated from 

this flow rate. 

Transmissivity Profiling using the FLUTe

Profiling Transmissivity and Contamination in Boreholes 12

Installation of Liner

From Carl Keller
 The 3 methods compare 

well for the high-T 

intervals.

 Greater differences 

between packer and 

FLUTe results for lower-T 

intervals. 

Comparison of T Estimates in Schist

Profiling Transmissivity and Contamination in Boreholes 13

Packers FLUTe Flow Logging
 FLUTe:

 Cost-effective means of obtaining T estimates if liner is 

installed to prevent cross-contamination.

 Simpler equipment and easier to conduct

 Potentially has higher spatial resolution (but small-scale 

variability may be caused by borehole effects).

 Packers:

 Conditions conform much better to assumptions of 

Theim equation, so T estimates are likely more accurate.

 Lower detection limit for T.

 In addition to T estimates, tests yield ambient heads of 

packed off intervals, and opportunity for sampling 

geochemistry.

Comparison of Packers and FLUTe

for T Profiling

Profiling Transmissivity and Contamination in Boreholes 14
 Identification of high T fractures that may be 

advective contaminant transport pathways.

 Identification of low T fractures and rock intervals 

where diffusion is likely a dominant transport 

process. 

 Use T results together with contaminant and 

geochemical profiling results, ambient hydraulic head 

estimates, and other borehole information to guide 

design of multilevel monitoring systems. 

Summary: Value of Information 

from Transmissivity Profiling

Profiling Transmissivity and Contamination in Boreholes 15
 Water-quality profiling conducted in same intervals 

being pumped for transmissivity testing

 Samples collected using a submersible pump installed 

between two packers

 Sampling method

 Water pumped to surface through splitter and flowthrough cell

 Field WQ parameters measured to stability

 Samples collected for VOCs and inorganics

Water-Quality Profiling

Profiling Transmissivity and Contamination in Boreholes 16
Water-Quality Sampling

Profiling Transmissivity and Contamination in Boreholes 17
0

10

20

30

40

50

60

70

80

90

100

110

120

1 10 100 1,000 10,000 100,000

D

e

p

t

h (ft

B

L

S

E)

Concentration (ug/L)

VOCs vs Depth 

NAWC 71BR Packer Test Samples 06/07 

TCE

transDCE

11DCE

VC

cisDCE

Packer Test Water-Quality Profiling

Profiling Transmissivity and Contamination in Boreholes 18
0

20

40

60

80

100

120

0 20 40 60 80 100 120 140 160 180

D

e

p

t

h (ft

B

L

S

E)

Concentration (mg/L)

Major Anions vs Depth 

NAWC 71BR Packer Test Samples 6/07

Alkalinity

Chloride

Sulfate

Packer Test Water-Quality Profiling

Profiling Transmissivity and Contamination in Boreholes 19
0

20

40

60

80

100

120

0 5 10 15 20 25 30 35 40 45 50

D

e

p

t

h (ft

B

L

S

E)

Concentration (mg/L)

Major Cations vs Depth 

NAWC 71BR Packer Test Samples 6/07

Ca

Mg

Na

K

Packer Test Water-Quality Profiling

Profiling Transmissivity and Contamination in Boreholes 20
Packer Test Water-Quality Profiling

Profiling Transmissivity and Contamination in Boreholes 21

Sample 

ID

Sample 

Interval 

Depths

Sample 

Interval 

Length

Transmis

-sivity

Pumping

Rate

CFC-12 (CCl2F2) 

Concentrations

Replicates Mean Std Dev

(ft amsl) (ft) (ft2/day) (gpm) (n) (pg/L) (pg/L)

H1 

Open

684-459 225 2.6 0.53 3 168 5

H1-1 657-642 15 1.3 0.32 3 92 1

H1-2 586-571 15 0.7 0.98 3 77 5

Mirror Lake Well H1 – Depth Dependent CFC-12 Concs
 Identification of depths with differing contaminant 

concentrations may help define which fractured rock 

intervals may be along transport pathways. 

 Identification of depths with differing water 

chemistries may help define which intervals have 

different terminal electron accepting processes 

ongoing.

 Water-quality results together with transmissivity

profiling results and other borehole information can 

be used to guide design of multilevel monitoring 

systems. 

Value of Information from

Water-Quality Profiling

Profiling Transmissivity and Contamination in Boreholes 22